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1
Lu, Taofeng, Gregory Reimonn, Gregory Morose, Evan Yu e Wan-Ting Chen. "Removing Acrylic Conformal Coating with Safer Solvents for Re-Manufacturing Electronics". Polymers 13, n. 6 (18 marzo 2021): 937. http://dx.doi.org/10.3390/polym13060937.
Abstract (sommario):
Conformal coating is typically composed of polymeric film and is used to protect delicate electronic components such as printed-circuit boards. Without removing conformal coating, it would be difficult to repair these complicated electronics. Methylene chloride, also called dichloromethane (DCM), has a widespread usage in conformal coating stripper products. The high toxicity of DCM increases human health risk when workers are exposed to DCM during the conformal coating removal processes. Therefore, the replacement of DCM would be beneficial to greatly improve the overall safety profile for workers in the electronics and coating industries. This research identified and evaluated alternative chemicals for replacing DCM used in acrylic conformal coating stripping operations. The solubility of an acrylic conformal coating was measured and characterized using Hansen solubility parameters (HSP) theory. Coating dwell time tests using various solvent blends verified the accuracy of the created HSP solubility sphere. A data processing method was also developed to identify and screen potential alternative solvent blends in terms of safety, toxicity, and cost-effectiveness. The identified safer solvent blends were demonstrated to provide equivalent stripping performance as compared to DCM based coating strippers within an acceptable cost range. The results of this research will be of value to other types of conformal coatings, such as silicone and polyurethane, where DCM is commonly used in similar coating stripping operations. By safely removing conformal coating, delicate electronics would be available for re-manufacturing, enabling a circular economy.
2
Rajendran, Mohana, e Marto Giftlin. "Novel Development of Corrosion Resistant Paint Using Printed Circuit Board from Modern Electronic Wastes". Trends in Sciences 19, n. 6 (25 febbraio 2022): 2901. http://dx.doi.org/10.48048/tis.2022.2901.
Abstract (sommario):
The growth in the industrial technology and communication sectors has enhanced the usage of electronic gadgets exponentially. Thus, it becomes highly essential to find new solution to utilize or dispose these e-wastes, in order to reduce the e-waste generation. Various reports mentioned that the major component of these e-wastes is their Printed Circuit Boards. Therefore, a new ideology is proposed to use these boards to produce a new coating with good corrosion resistance. At first the boards were separated from the discarded electronic appliances and various electrical elements were separated from these boards. Then the plain circuit boards are pulverized into fine particles and mixed with paint in 3 different proportions ranging from 1:4 to 1:2. The resulting mix was applied over the steel specimen and tested for corrosion resistance. The assessment was done in the aspects of contact angle, weight loss percentage, potentio dynamic polarization technique and electro chemical impedance spectroscopy. From the results it was clear that increase in the addition of printed circuit powder content in the corrosion proof paint coating enhanced the efficiency of the corrosion resistant behaviour 3.5 times than the specimen with uncoated steel specimens. This development of corrosion resistant behaviour of printed circuit powder was attributed from the inertness offered by the presence of silicon dioxides towards the corrosive fluids. Although, the coating of 1:2 proved to be optimum to protect the steel elements from the aggressive corrosion environment, by considering the workability aspects the 1:3 combination was suggested for the innovative development of anti-corrosion paint coating from the e-waste resources.
HIGHLIGHTS
Life cycles of every electronic wastes end with the hazardous challenging disposals
Innovative utilizations of these electronic wastes for the corrosion resistant structural applications were detailed
An anti corrosive coating for steel reinforcement was developed from the waste printed circuit boards
Coating by printed circuit board powder enhanced 3.5 times more protection from the corrosion
GRAPHICAL ABSTRACT
3
Szocinski, Michal. "AFM-assisted investigation of conformal coatings in electronics". Anti-Corrosion Methods and Materials 63, n. 4 (6 giugno 2016): 289–94. http://dx.doi.org/10.1108/acmm-09-2014-1426.
Abstract (sommario):
Purpose This paper aims to presents a new method of investigation of local properties of conformal coatings utilized in microelectronics. Design/methodology/approach It is based on atomic force microscopy (AFM) technique supplemented with the ability of local electrical measurements, which apart from topography acquisition allows recording of local impedance spectra, impedance imaging and dc current mapping. Potentialities of the proposed AFM-assisted approach have been demonstrated on commercially available epoxy-coated electronic printed boards in as-received state and after six-year service. Findings The technique proved to be capable of identification, spatial localization and characterization of conformal coating defects. Practical implications The proposed approach can be utilized for assessment of protective film state in such demanding fields as electronics or electrotechnics where the classical techniques of anticorrosion coatings investigation cannot be employed due to small element dimensions and relatively low coating thickness. Originality/value The approach adopted by the author is novel in the field of organic coatings investigation.
4
Lee, Sang, e Sangyoon Lee. "Fabrication and Characterization of Roll-to-Roll Printed Air-Gap Touch Sensors". Polymers 11, n. 2 (2 febbraio 2019): 245. http://dx.doi.org/10.3390/polym11020245.
Abstract (sommario):
Although printed electronics technology has been recently employed in the production of various devices, its use for the fabrication of electronic devices with air-gap structures remains challenging. This paper presents a productive roll-to-roll printed electronics method for the fabrication of capacitive touch sensors with air-gap structures. Each layer of the sensor was fabricated by printing or coating. The bottom electrode, and the dielectric and sacrificial layers were roll-to-roll slot-die coated on a flexible substrate. The top electrode was formed by roll-to-roll gravure printing, while the structural layer was formed by spin-coating. In particular, the sacrificial layer was coated with polyvinyl alcohol (PVA) and removed in water to form an air-gap. The successful formation of the air-gap was verified by field emission scanning electron microscopy (FE-SEM). Electrical characteristics of the air-gap touch sensor samples were analyzed in terms of sensitivity, hysteresis, and repeatability. Experimental results showed that the proposed method can be suitable for the fabrication of air-gap sensors by using the roll-to-roll printed electronics technology.
5
Pfeiffenberger, Neal T., e Saeid Biria. "Enhanced UVA LED-Cured Conformal Coatings for Printed Circuit Boards". International Symposium on Microelectronics 2021, n. 1 (1 ottobre 2021): 000281–85. http://dx.doi.org/10.4071/1085-8024-2021.1.000281.
Abstract (sommario):
Abstract Conformal coatings are thin polymeric layers applied on (RF)/microwave printed circuit boards, chips, dies and other electronic components to protect them from moisture and corrosion. Despite this protection, exposure to excessive humidity can cause delamination, increase dissipation factors and dielectric constants of the coating, and changing circuit switching-speed. In this paper, we will discuss dielectric performance of UVA LED-curable resin formulations with enhanced flexibility and adhesion as a new approach compared to traditional mercury UV curable conformal coatings. These advances reduce the potential for delamination, delivering greater protection of different applications, especially those for extreme environments.
6
Tantrairatn, Suradet, Paphakorn Pitayachaval, Sirisak Rangklang e Jiraphon Srisertpol. "A Comparison of Cover Coat Methods for Electronic Flexible Printed Circuit (E-FPC) Based on Peeling Strength". Advanced Materials Research 421 (dicembre 2011): 489–92. http://dx.doi.org/10.4028/www.scientific.net/amr.421.489.
Abstract (sommario):
In electronic flexible printed circuit (E-FPC) manufacturing procedure, the cover laminating process in which the line circuit (copper wire) is covered with hot cover layer on the printed circuits is importance process. This process will help to increase elasticity, strength and corrosion protection to the product therefore this process can affect directly to quality of the printed circuit. The process for laminating printed circuits can be classified into two methods by coating with industry iron and hot bar machine. This article compares the quality of the electrical circuit between industry iron and hot bar machine methods in the cover coating process by using Peeling Strength to indicate the quality in the same temperature and time condition. The experimental result illustrates the electrical circuits using the hot bar machine method give Peeling Strength value in the acceptable range and the laminating surface of circuits is smooth and uniform. On the other hand, Peel Strength value of electrical circuits using the industry iron method is unsteady and lower than the acceptable range. Moreover the result circuit product has wrinkled coating surface and become the waste product.
7
Kellomäki, Tiiti, Johanna Virkki, Sari Merilampi e Leena Ukkonen. "Towards Washable Wearable Antennas: A Comparison of Coating Materials for Screen-Printed Textile-Based UHF RFID Tags". International Journal of Antennas and Propagation 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/476570.
Abstract (sommario):
(Radio frequency identification) RFID tags integrated into clothing enable monitoring of people without their conscious effort. This requires tags to be an unnoticeable part of clothing and comfortable to wear. In this study, RFID antennas were screen printed on two different fabrics, six different coating materials for the (integrated circuits) ICs were applied, and the reliability of these RFID tags was tested with moisture and laundry tests. Generally, glue-type coating materials were easier to handle and could be spread precisely. All the tags were operational immediately after the coatings were applied, and five of the coating materials were seen to protect the IC from detaching in the laundry. It was found that the uneven fabric surface caused discontinuities and breaks in narrow conductors, and thus hard coatings may also be needed to keep the tag from breaking in laundry.
8
Park, Won-Tae, e Yong-Young Noh. "A self-aligned high resolution patterning process for large area printed electronics". Journal of Materials Chemistry C 5, n. 26 (2017): 6467–70. http://dx.doi.org/10.1039/c7tc01590a.
9
Senophiyah-Mary, J., R. Loganath e T. Meenambal. "A novel method for the removal of epoxy coating from waste printed circuit board". Waste Management & Research: The Journal for a Sustainable Circular Economy 36, n. 7 (20 giugno 2018): 645–52. http://dx.doi.org/10.1177/0734242x18782392.
Abstract (sommario):
The printed circuit board, which is the heart of all electronic devices, is a rich source of metal, which could act as a future resource. Bioleaching, a biological treatment, would be an appropriate method for the environmentally sound management of e-waste. Various strippers are used to remove the epoxy coating and it is harmful to remove the epoxy coating with those solvents and salts in the open because of the presence of brominated flame retardants on the surface of the printed circuit board, which leads to serious health issues. An alternate process is required to remove the epoxy coating thereby enhancing the bioleaching process. Sonication is the process of applying sound energy to agitate particles in a solvent bath. The combined process of sonication and solvent stripping in a closed environment could decrease the time for stripping the epoxy coating. An attempt has been made to optimise the stripping agent for the removal of epoxy coating and from the experiment it was found that bath sonication could easily remove the epoxy coating from the waste printed circuit board with no emission of toxic gases. An optimum time of 5 min was enough for the stripping process prior to the soak time of 8 h at 5 N NaOH solution, while a longer time and high concentration of chemicals would be required to remove the epoxy coating with usual methods.
10
Nmadu, D., N. C. Eli-Chukwu, U. U. Uma, O. E. Ogah, A. A. Parshuto, M. I. Eheduru, S. I. Ezichi e C. N. Ogbonna-Mba. "Using High Voltage Electrochemical Oxidation (HVEO) to obtain protective coatings, surface finishing on electronic materials". Digest Journal of Nanomaterials and Biostructures 17, n. 2 (aprile 2022): 569–77. http://dx.doi.org/10.15251/djnb.2022.172.569.
Abstract (sommario):
Electronics and microelectronic components such as printed circuit board, capacitors, CPU heat sinks, hard drive, etc. commonly encounter harsh environmental conditions during their operational lifetime. To protect the electronics materials from conditions like corrosion, wear, humidity and contaminants, aluminium protective coating materials can be used. However, the behavior of materials in harsh environments and their effect on the reliability of electronics in industrial products has been studied only very little. Moreover, the changes in the parameters (current density, temperature and time) of commonly used aluminium under various conditions remain largely unknown. In this paper, High Voltage Electrochemical Oxidation (HVEO) was used to produce a high microhardness of 440HV and high surface thickness of up to 44µm oxide coatings on aluminum alloy AMg2 (analogues of 5052-H32 alloy) for electronic components protection. The process was carried out in electrolyte of tartaric acid and sulfuric acid as an electrolyte under constant duration for each sample and various anodizing temperatures and current densities. The samples used in the study were aluminum used for commercial electronics devices designed for use in harsh conditions.
11
Kolesnyk, Kostiantyn, Andrzej Łukaszewicz, Volodymyr Dutka, Dmytro Zahoruiko e Bohdan Vasylyshyn. "Automated design of printed circuit boards made by electronic computer –aided design (CAD) with the next using in CNC- machine". Computer Design Systems. Theory and Practice 4, n. 1 (2022): 9–16. http://dx.doi.org/10.23939/cds2022.01.009.
Abstract (sommario):
The article presents methods and means of 3D design of printed circuit boards in CAx. Automated placement of elements on the board is implemented by means of API SolidWorks using Visual Studio C#. The API application works by an algorithm that allows you to create a 3D layout of printed circuit boards. Each component of the library contains a conditional graphic notation of the element. With the help of the implemented algorithm, a comprehensive approach is provided, which consists in the fact that already at this stage the preparation of the strategy for tracing the conductors of the future printed circuit board is carried out, the classes of circuits are determined and the necessary technological parameters are set, as well as the data necessary for the preparation of design documentation is generated. After the completion of the work on the input of the scheme, a check is made for the presence of errors and compliance with the specified parameters, and if the test is successful, a list of circuits is generated for transfer to the tracing program. From this moment, any possibility of errors in the subsequent stages of design is excluded. CAD DipTrace was used to trace printed circuit boards and generate g-code. Printed circuit board processing is carried out on a CNC machine - CNC3018 using the Candle program. The printed circuit board tracks are created by forming a groove between the track and the metallized coating of the textolite. With the help of the formed height map, the uniform removal of the metallization layer over the entire area of the textolite is ensured. In addition, holes are drilled for the output elements of the circuit, the printed circuit board is cut along the contour and covered with a layer of tin to prevent oxidation of its metallized coating. The considered CAD methods and tools made it possible to automate the design of the printed circuit board of the FM radio receiver control module. As a result of the performed work, means of automating the design of printed circuit boards were applied and a fully functional printed circuit board with a track width of 0.8 mm was obtained.
12
Wang, Wan Gang, Yong Peng e Xiao Ping Wang. "Key Parameter Optimization in Wave Soldering". Advanced Materials Research 323 (agosto 2011): 84–88. http://dx.doi.org/10.4028/www.scientific.net/amr.323.84.
Abstract (sommario):
Wave soldering is mainly used in electronic assembling process of traditional through-hole cartridge printed-circuit board and hybrid packaged process combining surface mounting with through-hole cartridge components. Compared with manual welding, wave soldering has advantages of high productive efficiency, good welding quality and high reliability. Wave soldering process is a complex and systematic project. During the practical productive process, flux coating quantity, preheat temperature of printed board, soldering temperature and time, uphill height of printed board and peak height should be strictly controlled and its process parameter should be comprehensively regulated in order to achieve better soldering quality.
13
Dabert, Marine, Dorina T. Papanastasiou, Loïc Vidal, Samar Hajjar-Garreau, Daniel Bellet, Daniel Lougnot e Lavinia Balan. "Enhancing the Properties of Photo-Generated Metallized Nanocomposite Coatings through Thermal Annealing". Nanomaterials 14, n. 2 (15 gennaio 2024): 193. http://dx.doi.org/10.3390/nano14020193.
Abstract (sommario):
In this work, the effect of thermal annealing on silver nanoparticles@polymer (AgNPs@polymer) nanocomposite coatings was investigated. These photo-generated metallized coatings have a spatial distribution of metal nanoparticles, with a depth-wise decrease in their concentration. During annealing, both structural and morphological variations, as well as a spatial reorganization of AgNPs, were observed, both at the surface and in the core of the AgNPs@polymer coating. Owing to their increased mobility, the polymer chains reorganize spontaneously, and, at the same time, a hopping diffusion process, caused by the minimization of the surface energy, promotes the migration and coalescence of the silver nanoparticles towards the surface. The layer of discrete nanoparticles gradually transforms from a weakly percolative assembly to a denser and more networked structure. Consequently, the surface of the coatings becomes significantly more electrically conductive, hydrophobic, and reflective. The general trend is that the thinner the nanohybrid coating, the more pronounced the effect of thermal annealing on its spatial reorganization and properties. These results open up interesting prospects in the field of metallized coating technology and pave the way for integration into a wide variety of devices, e.g., efficient and inexpensive reflectors for energy-saving applications, electrically conductive microdevices, and printed electronic microcircuits.
14
Pappas, Daphne, Sebastian Guist e Dhia Ben Salem. "Plasma Surface Engineering: An Enabling Technology Designed to Clean and Protect Printed Circuit Boards". International Symposium on Microelectronics 2020, n. 1 (1 settembre 2020): 000197–200. http://dx.doi.org/10.4071/2380-4505-2020.1.000197.
Abstract (sommario):
Abstract Long term reliability and performance of printed circuit boards (PCBs) are strongly affected by the presence of surface contaminants from the manufacturing and assembly processes. Flux and solder residue, dust particles, oils and greases are often found on the assembled boards and can inhibit the successful application of conformal coatings that are used to protect the electronic components. Surface contaminants can cause coating delamination, dendritic growth, electromigration, corrosion and result in compromised coatings. In the first part of this paper, the fundamental mechanism of plasma-induced removal of organic contaminants from PCBs will be presented. While vacuum based plasmas are considered the traditional solvent-free technology for surface cleaning, a new approach involving air plasma operating under atmospheric pressure conditions is gaining interest due to its adaptability for industrial inline processing. The low concentration of oxygen that is available in the plasma gas is effective in vaporizing organic contaminants leaving behind a clean surface. Additionally, atmospheric plasma processes focusing on the development of functional nanocoatings on PCBs have been investigated. These plasma-enhanced chemical vapor deposition (PECVD) processes involve the delivery and vaporization of small volumes of solvent-free precursors that react with the plasma to form thin coatings on polymer substrates. Depending on the chemical structure of the precursor used, adhesion promoting, water repellant or electrical barrier coatings of 30–100nm thickness can be deposited. These protective functional coatings do not require any curing or special handling and no chemical waste is generated. The latest developments in atmospheric pressure PECVD for electronics protection will be presented in the second part of the paper. Besides the improvement of device performance and reliability, the application of PECVD has the potential to replace chemical substances such as primers known to have harmful impact on human health and the environment.
15
Son, Ha Huu, Nguyen Phi Long, Nguyen Van Thanh, Nguyen Thi Hong Ngoc, Dang Minh Thuy, Le Quoc Pham e Luu Van Tuynh. "Polyalphaolefin Oil/MgO-20 Nanofluids Coating Shows Corrosion Resistance, High Moisture Resistance, and Water Resistance for Electrical and Electronic Equipment". Coatings 13, n. 9 (10 settembre 2023): 1576. http://dx.doi.org/10.3390/coatings13091576.
Abstract (sommario):
The PAO/MgO nanofluids-based dielectric fluid DF(MgO-20) has significantly increased corrosion resistance as a coating. Electrochemical studies show that the DF(MgO-20) coating has protection efficiency of up to 99% for steel, copper, and aluminum. This coating is capable of providing corrosion protection for steel samples for up to 120 h in salt spray tests, and printed circuit boards (PCBs) for more than 20 days in salt spray tests in accordance with the ASTM B117 standard. The DF(MgO-20) coating fully meets the moisture resistance and fungal resistance standards required by the MIL-1-46058 C standard. The coating also demonstrates water displacement, meeting the requirements of the MIL-PRF-81309G standard. The DF(MgO-20) coating is able to protect electronic equipment working in underwater environment for up to 20 days. The aforementioned outstanding protection properties are achieved thanks to the nanofluid effect of the DF(MgO-20) dielectric fluid with the presence of MgO nano-additives that increase its overflow ability. The coating penetrates deeply and adheres tightly to the metal substrates, helping to separate them from moisturizing agents and corrosive agents. The research results aim to apply this coating to protect electronic equipment working in the tropical marine climate of Vietnam.
16
Xu, Jin Qiu, Jian Feng Bai, Jing Wei Wang, Bo Liang, He Cheng, Jie Guan e Li Jun Wang. "Microbial Leaching of Copper from Waste Electronic Scraps". Advanced Materials Research 508 (aprile 2012): 228–32. http://dx.doi.org/10.4028/www.scientific.net/amr.508.228.
Abstract (sommario):
Microbial leaching was used to mobilize copper from two kinds of waste electronic scraps used as raw materials for printed wire boards. Both of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans used to solubilize copper from the samples. The experimental results demonstrated that the percentages of copper basically increased with decrease of sieve fraction of the samples. The green non-conductive coating of the waste electronic scraps was proved to have little effect on the leaching efficiency of both of the pure culture of Acidithiobacillus ferrooxidans and Acidithiobacil thiooxidans or their mixed culture. Acidithiobacillus ferrooxidans has larger solubilizing capability for copper than Acidithiobacillus thiooxidans.
17
Li, Wei Wei, Li Xin Mo, Ji Lan Fu, Wen Bo Li, Jun Ran, Xin Ming Fan, Ya Ling Li e Lu Hai Li. "Preparation of Water-Based Nano-Silver Gravure Conductive Ink Used for Printed Electronics". Applied Mechanics and Materials 262 (dicembre 2012): 523–26. http://dx.doi.org/10.4028/www.scientific.net/amm.262.523.
Abstract (sommario):
Printed electronic industry develops fast and has great potential. In order to prepare water-based nano-silver gravure conductive ink used for printed electronics, liquid chemical reduction method is used. Ag+(5.89M) at high concentration acting as the precursor is reduced by hydrazine hydrate with PVP as the protecting agent. For one time of reaction, silver content of 9.25% is obtained. After washing and centrifuging the silver colloids for three times to purity, some amount of deionized water, resin and additives are added to the silver paste to fabricated water-based nano-silver conductive ink for gravure. Then, samples obtained by coating or proofing are dried and surface resistance and adhesion are measured. The results indicated that the silver particles prepared have size of about 50~100nm and most of the particles are spherical with small amount nanoplates. The nano-silver gravure conductive ink has 52.63% silver content and 3.58% PVP. Surface resistance of samples coated after sintering at 120°C for 30s can reach 129.5mΩ/sq and the resistivity is 1.49×10-4Ω.cm. The ink layer surface has no drop after 3M method which indicating good adhesion. The ink is suitable for gravure and can be used in printed electronics.
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Xu, Pingye, e Michael C. Hamilton. "Reduced-Loss Ink-Jet Printed Flexible CPW With Copper Coating". IEEE Microwave and Wireless Components Letters 23, n. 4 (aprile 2013): 178–80. http://dx.doi.org/10.1109/lmwc.2013.2248704.
19
Carlos, Emanuel, Rita Branquinho, Elina Jansson, Jaakko Leppäniemi, José Menezes, Rita Pereira, Jonas Deuermeier et al. "Printed zinc tin oxide diodes: from combustion synthesis to large-scale manufacturing". Flexible and Printed Electronics 7, n. 1 (31 gennaio 2022): 014005. http://dx.doi.org/10.1088/2058-8585/ac4bb1.
Abstract (sommario):
Abstract Printed metal oxide devices have been widely desired in flexible electronic applications to allow direct integration on foils and to reduce electronic waste and associated costs. Especially, semiconductor devices made from non-critical raw materials, such as Zn, Sn (and not, for example, In), have gained significant interest. Despite considerable progress in the field, the upscale requirements from lab to fab scale to produce these materials and devices remain a challenge. In this work, we report the importance of solution combustion synthesis (SCS) when compared with sol–gel in the production of zinc tin oxide (ZTO) thin films using a solvent (1-methoxypropanol) that has lower environmental impact than the widely used and toxic 2-methoxyethanol. To assure the compatibility with low-cost flexible substrates in high-throughput printing techniques, a low annealing temperature of 140 °C was achieved for these thin films by combining SCS and infrared annealing in a short processing time. These conditions allowed the transition from spin-coating (lab scale) to flexographic printing (fab scale) at a printing speed of 10 m min−1 in a roll-to-roll pilot line. The ZTO (1:1 Zn:Sn-ratio) diodes show a rectification ratio of 103, a low operation voltage (⩽3 V), promising reproducibility and low variability. The results provide the basis for further optimisation (device size, encapsulation) to meet the requirements of diodes in flexible electronics applications such as passive-matrix addressing, energy harvesting and rectification.
20
Ibrahim Zamkoye, Issoufou, Houda El Gbouri, Remi Antony, Bernard Ratier, Johann Bouclé, Laurent Galmiche, Thierry Trigaud e Pierre Audebert. "Characterization and Electronic Properties of Heptazine Layers: Towards Promising Interfacial Materials for Organic Optoelectronics". Materials 13, n. 17 (29 agosto 2020): 3826. http://dx.doi.org/10.3390/ma13173826.
Abstract (sommario):
For the first time, an original compound belonging to the heptazine family has been deposited in the form of thin layers, both by thermal evaporation under vacuum and spin-coating techniques. In both cases, smooth and homogeneous layers have been obtained, and their properties evaluated for eventual applications in the field of organic electronics. The layers have been fully characterized by several concordant techniques, namely UV-visible spectroscopy, steady-state and transient fluorescence in the solid-state, as well as topographic and conductive atomic force microscopy (AFM) used in Kelvin probe force mode (KPFM). Consequently, the afferent energy levels, including Fermi level, have been determined, and show that these new heptazines are promising materials for tailoring the electronic properties of interfaces associated with printed electronic devices. A test experiment showing an improved electron transfer rate from a tris-(8-hydroxyquinoline) aluminum (Alq3) photo-active layer in presence of a heptazine interlayer is finally presented.
21
Yang, Tong, Xinyu Li, Bo Yu e Cheng Gong. "Design and Print Terahertz Metamaterials Based on Electrohydrodynamic Jet". Micromachines 14, n. 3 (15 marzo 2023): 659. http://dx.doi.org/10.3390/mi14030659.
Abstract (sommario):
Terahertz metamaterials are some of the core components of the new generation of high-frequency optoelectronic devices, which have excellent properties that natural materials do not have. The unit structures are generally much smaller than the wavelength, so preparation is mainly based on semiconductor processes, such as coating, photolithography and etching. Although the processing resolution is high, it is also limited by complex processing, long cycles, and high cost. In this paper, a design method for dual-band terahertz metamaterials and a simple, rapid, low-cost metamaterial preparation scheme based on step-motor-driven electrohydrodynamic jet technology are proposed. By transforming an open-source 3D printer, the metamaterial structures can be directly printed without complex semiconductor processes. To verify effectiveness, the sample was directly printed using nano conductive silver paste as consumable material. Then, a fiber-based multi-mode terahertz time-domain spectroscopy system was built for testing. The experimental results were in good agreement with the theoretical simulation.
22
Aziz, Shahid, Junaid Ali, Krishna Singh Bhandari, Wenning Chen, Sijia Li e Dong Won Jung. "Reverse Offset Printed, Biocompatible Temperature Sensor Based on Dark Muscovado". Sensors 22, n. 22 (11 novembre 2022): 8726. http://dx.doi.org/10.3390/s22228726.
Abstract (sommario):
A reverse-offset printed temperature sensor based on interdigitated electrodes (IDTs) has been investigated in this study. Silver nanoparticles (AgNPs) were printed on a glass slide in an IDT pattern by reverse-offset printer. The sensing layer consisted of a sucrose film obtained by spin coating the sucrose solution on the IDTs. The temperature sensor demonstrated a negative temperature coefficient (NTC) with an exponential decrease in resistance as the temperature increased. This trend is the characteristic of a NTC thermistor. There is an overall change of ~2800 kΩ for the temperature change of 0 °C to 100 °C. The thermistor is based on a unique temperature sensor using a naturally occurring biocompatible material, i.e., sucrose. The active sensing material of the thermistor, i.e., sucrose used in the experiments was obtained from extract of Muscovado. Our temperature sensor has potential in the biomedical and food industries where environmentally friendly and biocompatible materials are more suitable for sensing accurately and reliably.
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Yoo, Young-Ran, Seokyeon Won e Young-Sik Kim. "Effect of Conformal Coating on Electrochemical Migration Behavior of Multi-Layer Ceramic Capacitor for Automotives Based on Water Drop Test". Coatings 14, n. 3 (18 marzo 2024): 359. http://dx.doi.org/10.3390/coatings14030359.
Abstract (sommario):
A large amount of multi-layer ceramic capacitor (MLCC) is mounted inside a printed circuit board (PCB) constituting electronic components. The use of MLCC in electric vehicles and the latest mobile phones is rapidly increasing with the latest technology. Environments in which electronic components are used are becoming more diverse and conformal coatings are being applied to protect mounted components from these environments. In particular, MLCCs in electronic components mainly have voltage applied. They might be used in environments where humidity exists for various reasons. In a humid environment, electrochemical migration (ECM) will occur, with the cathode and anode on the surface of the MLCC encountering each other. This can result in product damage due to a short circuit. In this study, the effects of voltage, NaCl concentration, and distance between electrodes on a non-mount MLCC, surface mount MLCC, and solder pad pattern were evaluated using a water drop test (WDT). Based on the analysis of the effects of the presence of conformal coating, applied voltage, concentration of NaCl, and the distance between electrodes, a mechanism model for ECM behavior in MLCCs was proposed.
24
Diatezo, Léopold, Minh-Quyen Le, Christine Tonellato, Lluis Puig, Jean-Fabien Capsal e Pierre-Jean Cottinet. "Development and Optimization of 3D-Printed Flexible Electronic Coatings: A New Generation of Smart Heating Fabrics for Automobile Applications". Micromachines 14, n. 4 (29 marzo 2023): 762. http://dx.doi.org/10.3390/mi14040762.
Abstract (sommario):
Textile-based Joule heaters in combination with multifunctional materials, fabrication tactics, and optimized designs have changed the paradigm of futuristic intelligent clothing systems, particularly in the automobile field. In the design of heating systems integrated into a car seat, conductive coatings via 3D printing are expected to have further benefits over conventional rigid electrical elements such as a tailored shape and increased comfort, feasibility, stretchability, and compactness. In this regard, we report on a novel heating technique for car seat fabrics based on the use of smart conductive coatings. For easier processes and integration, an extrusion 3D printer is employed to achieve multilayered thin films coated on the surface of the fabric substrate. The developed heater device consists of two principal copper electrodes (so-called power buses) and three identical heating resistors made of carbon composites. Connections between the copper power bus and the carbon resistors are made by means of sub-divide the electrodes, which is critical for electrical–thermal coupling. Finite element models (FEM) are developed to predict the heating behavior of the tested substrates under different designs. It is pointed out that the most optimized design solves important drawbacks of the initial design in terms of temperature regularity and overheating. Full characterizations of the electrical and thermal properties, together with morphological analyses via SEM images, are conducted on different coated samples, making it possible to identify the relevant physical parameters of the materials as well as confirm the printing quality. It is discovered through a combination of FEM and experimental evaluations that the printed coating patterns have a crucial impact on the energy conversion and heating performance. Our first prototype, thanks to many design optimizations, entirely meets the specifications required by the automobile industry. Accordingly, multifunctional materials together with printing technology could offer an efficient heating method for the smart textile industry with significantly improved comfort for both the designer and user.
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Baek, Inwoo, Chul-Min Lim, Kyoung Youl Park e Bong Ki Ryu. "Enhanced Metal Coating Adhesion by Surface Modification of 3D Printed PEKKs". Coatings 12, n. 6 (17 giugno 2022): 854. http://dx.doi.org/10.3390/coatings12060854.
Abstract (sommario):
PEKK (polyether-ketone-ketone) polymer has been actively studied in applying electronic devices in satellites owing to its excellent light weight and thermal resistance. However, the limitation of metal coating to form on the PEKK surface is due to the high-volume resistivity and surface resistance. Here, we have investigated the correlations between the chemical treatment of the surface and adhesion strength between polymer–metal coating. Three-dimensional printed PEKK objects were manufactured and nickel was deposited on the surface by electroless plating. As the concentration of H2SO4 increased from 12.5 to 14.3 mol/L, the pore diameter showed a tendency to increase. However, as growing pore induced connecting each other, the pore size re-decreased from 15.1 to 18.0 mol/L. To control pore size and uniformity, we investigated the pore diameter of 3D printed PEKK as a function of treatment time and temperature. Uniform pores were observed at a temperature of 50 °C which were formed after 10 min and the average pore size was 0.28. After H2SO4 swelling, samples were re-treated in the KMnO4-H3PO4 etching system for the hydrophilic group. KMnO4 broken C=C bonding and generated hydrophilic groups such as -COOH and -OH, the contact angle decreased from 64.7 to 51.1° compared with H2SO4 swelling. XPS survey spectra confirmed that not only breaking C=C bonding but also increasing hydrophilicity due to -OH, -C-, -SO3 and the catalyst absorption of Pd was improved. As a result of adhesive strength by ASTM D3359, compared with the H2SO4 swelling, the KMnO4-H3PO4 etching system showed 5B which is the best result in standard test methods by adhesive tape test and peeling amount on the tape was less than 0.01%.
26
Jo, Minho, Seongyong Kim, Gyoujin Cho, Taik-Min Lee, Jongsu Lee e Changwoo Lee. "Achieving specified geometric quality in a fully printed flexible functional layer using process parameters in roll-to-roll printed electronics". Flexible and Printed Electronics 7, n. 1 (14 febbraio 2022): 014007. http://dx.doi.org/10.1088/2058-8585/ac509a.
Abstract (sommario):
Abstract Roll-to-roll (R2R) gravure printing is mainly used in the manufacture of conductive lines or electronic devices because complex patterns can be printed quickly and accurately on flexible substrates using an engraved pattern roll. Gravure printing has several advantages including multi-layer printing of large-area functional layers and continuous production of electronic devices such as thin-film transistors (TFTs) or complex electronic circuits. Existing studies have demonstrated that printing quality can be improved by determining the desired conditions of coating and printing machine without changing the ink and web properties. However, few studies have focused on controlling the geometry of printed patterns and coated layers according to the web tension and web speed, considering spreading effect and ink transfer. In this study, the effects of the controllable parameters in R2R gravure printing, namely web tension and web speed, on the geometry of the gate electrode, dielectric layer, and source–drain electrode of a TFT are examined. We obtained metamodels to estimate the thicknesses and widths of the conductive and dielectric patterns of a printed TFT according to the web tension and speed of a pilot-scale R2R gravure printing machine using design of experiment. The developed metamodels exhibited superior performance, with an average estimation error of 4.18 ± 3.05%. We further analyzed variations in the thickness of the gate electrode and dielectric layer according to fluctuations in the tension in the R2R printing process. Our results show that fluctuations in the tension should be maintained constant to achieve a uniform geometry of the printed pattern. This study demonstrates that the geometry of the printed pattern can be controlled using web tension and web speed, without changing the ink properties.
27
Yang, Xiaofan, Huang Li, Haiyang Lin, Yicong Chen e Rongjie Ji. "Effect of Substrate Pretreatment Process on the Cutting Performance of Diamond-Coated PCB Micro-Milling Tools". Micromachines 14, n. 1 (27 dicembre 2022): 73. http://dx.doi.org/10.3390/mi14010073.
Abstract (sommario):
Diamond coatings were deposited on PCB (printed circuit board) carbide milling tool substrates under various schemes of acid and alkali pretreatment by hot filament chemical vapor deposition (HFCVD). Scanning electron microscopy and X-ray coating analysis were used to examine the surface morphology of the milling tools and the impact of de-cobalt from the substrate surface after pretreatment. Milling experiments were carried out to study the cutting performance of diamond-coated PCB micro-milling tools under various pretreatment processes. The results show that abrasive wear, coating flaking, and cutting-edge chipping are the main failure forms of coated PCB milling tools. The substrate pretreatment process with 20 min of alkali etching followed by 20 s of acid etching allows the diamond-coated micro-milling tools to produce the best film–substrate adhesion and substrate strength. These milling tools also have the longest service lives and are suitable for the high-speed cutting processing of PCB.
28
Dill, Simone, e Volker Rößiger. "Coating thickness measurement of thin gold and palladium coatings on printed circuit boards using X‐ray fluorescence". Circuit World 37, n. 2 (17 maggio 2011): 20–26. http://dx.doi.org/10.1108/03056121111128288.
29
Nguyen, Van-Cuong, Minh-Quyen Le, Jean-François Mogniotte, Jean-Fabien Capsal e Pierre-Jean Cottinet. "Extrusion-Based 3D Printing of Stretchable Electronic Coating for Condition Monitoring of Suction Cups". Micromachines 13, n. 10 (27 settembre 2022): 1606. http://dx.doi.org/10.3390/mi13101606.
Abstract (sommario):
Suction cups (SCs) are used extensively by the industrial sector, particularly for a wide variety of automated material-handling applications. To enhance productivity and reduce maintenance costs, an online supervision system is essential to check the status of SCs. This paper thus proposes an innovative method for condition monitoring of SCs coated with printed electronics whose electrical resistance is supposed to be correlated with the mechanical strain. A simulation model is first examined to observe the deformation of SCs under vacuum compression, which is needed for the development of sensor coating thanks to the 3D printing process. The proposed design involves three circle-shaped sensors, two for the top and bottom bellows (whose mechanical strains are revealed to be the most significant), and one for the lip (small strain, but important stress that might provoke wear and tear in the long term). For the sake of simplicity, practical measurement is performed on 2D samples coated with two different conductive inks subjected to unidirectional tensile loading. Graphical representations together with analytical models of both linear and nonlinear piezoresistive responses allows for the characterization of the inks’ behavior under several conditions of displacement and speed inputs. After a comparison of the two inks, the most appropriate is selected as a consequence of its excellent adhesion and stretchability, which are essential criteria to meet the target field. Room temperature extrusion-based 3D printing is then investigated using a motorized 3D Hyrel printer with a syringe-extrusion modular system. Design optimization is finally carried out to enhance the surface detection of sensitive elements while minimizing the effect of electrodes. Although several issues still need to be further considered to match specifications imposed by our industrial partner, the achievement of this work is meaningful and could pave the way for a new generation of SCs integrated with smart sensing devices. The 3D printing of conductive ink directly on the cup’s curving surface is a true challenge, which has been demonstrated, for the first time, to be technically feasible throughout the additive manufacturing (AM) process.
30
Gholampour, Nadia, Dominikus Brian e Morteza Eslamian. "Tailoring Characteristics of PEDOT:PSS Coated on Glass and Plastics by Ultrasonic Substrate Vibration Post Treatment". Coatings 8, n. 10 (24 settembre 2018): 337. http://dx.doi.org/10.3390/coatings8100337.
Abstract (sommario):
In this work, we excited as-spun wet films of PEDOT:PSS by ultrasonic vibration with varying frequency and power. This is a low-cost and facile technique for tailoring the structural and surface characteristics of solution-processed thin films and coatings. We deposited the coatings on both rigid and flexible substrates and performed various characterization techniques, such as atomic force microscopy (AFM), scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), transmittance, electrical conductivity, and contact angle measurements, to understand how the ultrasonic vibration affects the coating properties. We found that as a result of ultrasonic vibration, PEDOT:PSS sheet conductivity increases up to five-fold, contact angle of water on PEDOT:PSS increases up to three-fold, and PEDOT:PSS roughness on glass substrates substantially decreases. Our results affirm that ultrasonic vibration can favor phase separation of PEDOT and PSS and rearrangement of PEDOT-rich charge transferring grains. In addition to providing a systematic study on the effect of ultrasonic frequency and power on the film properties, this work also proves that the ultrasonic vibration is a novel method to manipulate and tailor a wide range of properties of solution-processed thin films, such as compactness, chain length and arrangement of polymer molecules, conductivity, and surface wettability. This ultrasonication method can serve organic, printed and flexible electronics.
31
NAGASHIMA, Yoshiyuki, Junpei BABA, Katsuhiko SYUTOH e Eisuke MASADA. "Surge Dielectric Strength between Printed Circuit Board Conductive Foils with Solder Resist Coating." Journal of Japan Institute of Electronics Packaging 5, n. 6 (2002): 609–12. http://dx.doi.org/10.5104/jiep.5.609.
32
Sloma, Marcin, Daniel Janczak, Grzegorz Wroblewski, Anna Mlozniak e Malgorzata Jakubowska. "Electroluminescent structures printed on paper and textile elastic substrates". Circuit World 40, n. 1 (28 gennaio 2014): 13–16. http://dx.doi.org/10.1108/cw-10-2013-0037.
Abstract (sommario):
Purpose – New types of substrates were used for fabrication of printed electroluminescent structures. Polymer foils mainly used as substrates for such optoelectronic elements were replaced with paper and textiles. Printing on non-transparent substrate requires elaboration of printed transparent electrode, while usually polyester foils with sputtered ITO transparent electrodes are used. The paper aims to discuss these issues. Design/methodology/approach – Electroluminescent structures were fabricated with elaborated polymer compositions filled with nanomaterials, such as carbon nanotubes and graphene platelets, dielectric and luminophore nanopowders. Structures were printed as “reverse stack”, where transparent electrode is printed on top of the last luminophore layer. For that carbon nanotubes and graphene platelets filled composition was used, deposited with spray-coating technique. Findings – Main issue with new substrates is proper wetting with the use of screen-printing pastes, and much higher roughness especially for textiles. Originality/value – Fully functional structures were obtained, but several disadvantages were observed that needs to be eliminated in further studies.
33
Nguyen, Van-Cuong, Minh-Quyen Le, Sophie Bernadet, Yoann Hebrard, Jean-François Mogniotte, Jean-Fabien Capsal e Pierre-Jean Cottinet. "Design Rules of Bidirectional Smart Sensor Coating for Condition Monitoring of Bearings". Polymers 15, n. 4 (7 febbraio 2023): 826. http://dx.doi.org/10.3390/polym15040826.
Abstract (sommario):
This paper reports a novel monitoring technique of bearings’ bidirectional load (axial and radial) based on a smart sensor coating, which is screen printed onto the surface of a cross-shaped steel substrate. To ensure the accuracy and stability of measurement as well as the durability of the printed coating, the developed prototype is built according to design rules commonly used in electronic circuits. The finite element model (FEM) is used to predict the mechanical property of the tested substrate under either unidirectional or bidirectional loads. Regarding the output voltage of the piezoelectric sensor, experimental results are revealed to be well-corelated to the numerical simulation. It is pointed out that the output signal generated from the sensor (electrode) could be particularly affected due to the capacitive parasite coming from the conductive tracks (CTs). Such a phenomenon might be reduced by printing them on the dielectric layer rather than on the piezocomposite layer. The study also investigates a highly anisotropic shape of electrodes (rectangular instead of circle), indicating that the orientation of such electrodes (axial or radial) does affect the output measurement. To sum up, the high performance of a sensor network coating depends not only on the ultimate characteristics of its own materials, but also on its structural design. Such an issue has been rarely reported on in the literature, but is nonetheless crucial to achieving reliable condition monitoring of bearings, especially for multidirectional loads—a key signature of early failure detection.
34
Scholz, Bernd, Ismir Pekmic, Syed Sajid Ahmad e Aaron Reinholz. "High via density thin metal-core PCB using electro-coated dielectric". International Symposium on Microelectronics 2010, n. 1 (1 gennaio 2010): 000615–21. http://dx.doi.org/10.4071/isom-2010-wp3-paper2.
Abstract (sommario):
Conventional printed circuit boards (PCBs) may be replaced by thinner metalcore boards for some applications, as well as for package substrates. Using thin, metalcore technology may provide advantages for radio frequency (RF) circuits and packages, and increase heat dissipation for high power applications. The metalcore technology has several layers including the metal core, electrocoated dielectric, sputtered metal layers, and electroplated copper. Especially for RF application and automotive electronics printed circuit boards with a metal core is gaining interest. The advantage of metal core PCB is the low thermal coefficient as well as the possibility to achieve a high density of vias and electronic component assembly. This paper describes the realization of metal core PCB with a dense array of vias and with a low thermal coefficient. The dielectric layer is applied after vias have been formed providing a high density electronics assembly on a double sided PCB which exhibits the heat dissipation of a metal core with minimal thermal expansion. After photochemically etching an array of vias, the metal core can be optionally plated with copper. The insulating dielectric is applied using a highly reliable electrodeposited coating. Metal core substrate provides the opportunity to form a via to the metal core to provide electrical grounding. The final traces are fabricated on top and bottom and can be interconnected through via openings.
35
Gogoi, Banashree, Carson Gockley, Sushmitha Venu, Yizhen Zhu, Pranith Alluri, Ayinawu Abdul Malik, Mitesh Suhas Despande et al. "Ultrafast and Large-Scale Fabrication of PEDOT:PSS Nanofilms Using Electrical-Field-Assisted Direct Ink Deposition". Molecules 28, n. 16 (10 agosto 2023): 5989. http://dx.doi.org/10.3390/molecules28165989.
Abstract (sommario):
The importance of conductive polymers has significantly increased over the decade due to their various applications, such as in electronic devices, sensors, and photovoltaics. Poly(3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS) is one of the most successfully and widely used polymers in practical applications. Spin coating is extensively used to fabricate these conductive films; however, it has disadvantages. It is inherently a batch process with relatively low output and high solution wastage. To address these issues, we developed a novel printing process called electrical-field-assisted direct ink deposition (EF-DID), which yields a continuous, homogenous film with high electrical conductivity. In this process, we studied the formation of nanodroplets under an electrical field and their effects on film characteristics. Furthermore, dimethyl sulfoxide (DMSO) was considered as an additive solvent to increase the conductivity and wettability of the films. We then compared EF-DID-printed PEDOT:PSS films with spin-coated films to better understand the film properties. Finally, inverted perovskite solar cell devices were fabricated and compared, where the PEDOT:PSS layers were prepared by EF-DID printing and spin coating. Based on the experimental results, a solution of 20% PEDOT:PSS in DMSO (vol/vol) printed by EF-DID for 15 s provided optimal morphology.
36
Couble, E. C., O. B. Dutkewych, S. M. Florio, M. V. Marsh e R. F. Staniunas. "Immersion, Non‐electrolytic Tin/lead Plating Process". Circuit World 19, n. 1 (1 aprile 1992): 63–70. http://dx.doi.org/10.1108/eb046192.
Abstract (sommario):
The technological development and characteristics of an innovative process and composition for immersion plating and fusing of a solderable tin/lead deposit over copper are discussed. The process offers a viable alternative to hot air solder levelling, electrodeposition/selective stripping, or inhibitor coatings for maintaining solderability of printed wiring boards. A flat, uniform solderable tin/lead coating on all feature surfaces and edges is achieved. A number of important benefits are derived. The ability to coat any copper surface uniformly, including fine pitch features, is substantially enhanced. Solderability is improved because of a thick, flat, co‐planar and uniform tin/lead deposit on all copper surfaces. Typical thickness and composition of the fused alloy are 150 to 300 microinches (4 to 8 microns) and 65 to 75% tin.
37
Wassmer, Marcel, Waldemar Diel e Klaus Krueger. "Inkjet Printing of Fine-Line Thick-Film Inductors". Journal of Microelectronics and Electronic Packaging 7, n. 4 (1 ottobre 2010): 205–13. http://dx.doi.org/10.4071/imaps.258.
Abstract (sommario):
Inkjet printing is the emerging technology for the deposition of a variety of particles. The reliable printing of nano-silver inks shows the possibilities of digital fabrication of microelectronic circuits and raises the question for further use with other particles. To compete with common thick-film screen printing as a production method it is consequential and necessary to investigate the inkjet printing of all passive electronic thick-film components. Inductors are frequently required in electronic circuits, yet they represent a main challenge for thick-film printing. With the development of new materials, which are suitable for low-temperature cofired ceramic processes, the integration of passive components promises new applications. In a first step, different ferrite particle compositions are dispersed to stabilized inks that can be used with a commercial inkjet print head. The stability of the ink is fundamental for reliable drop formation. In addition, the viscosity must fit to the print heads' operational ranges and the magnetic properties must be taken into account. In a second step, the effect of substrate coating and drop volume variation toward the shape of the printed structures are defined and shown. The fundamental construction methods of inkjet-printed inductors on fired ceramic are investigated. First, silver coils are printed without ferrite to optimize the printing pattern. Subsequently, coils are embedded in inkjet printed ferrite layers. Depending on the geometrical layout, several drying and firing steps are necessary, leading to a more complex production process and influencing the electrical properties. Finally, it is shown that inkjet printing is very effective for built-up of multilayer thick-film inductors, and the high accuracy of the printing process promises accurate electrical values.
38
Huang, Yunzhong, Chao Yang, Xiang Tan, Zhenhai Zhang, Shouxu Wang, Jiacong Hu, Wei He et al. "Benzaldehyde derivatives on tin electroplating as corrosion resistance for fabricating copper circuit". Nanotechnology Reviews 11, n. 1 (1 gennaio 2022): 3125–37. http://dx.doi.org/10.1515/ntrev-2022-0497.
Abstract (sommario):
Abstract Electrodeposited tin is a crucial corrosion-resistant metal to protect electronic interconnection and copper circuits in the manufacturing process of electronic products. The corrosion-resistant properties of electrodeposited tin can be improved with the addition of additives in electrodeposition. Three benzaldehyde derivatives including vanillin, ethyl vanillin, and veratraldehyde as brighteners were investigated for tin electrodeposition. Computational and experimental analyses were conducted to investigate the relationship between coating properties and the chemical factors including the molecular structure, adsorption process, and electrochemical behavior of the brighteners. The computational work demonstrated that all three brighteners could hold high reactivity and spontaneously absorb on the tin surface. The results of linear sweep voltammetry tests (LSV) illustrated that all three brighteners effectively increased the cathode polarization but ethyl vanillin exhibited the best inhibiting performance in the tin deposition. Besides, the adsorption behavior of brighteners on the tin layer also affected the grain morphology and preferred growth orientation of the crystal surface. The corrosion rate and side erosion results both indicated that ethyl vanillin could benefit to form a tin coating with good corrosion performance to meet the requirement of copper circuit fabrication of printed circuit board.
39
Nguyen, Van-Cuong, Victor Oliva-Torres, Sophie Bernadet, Guilhem Rival, Claude Richard, Jean-Fabien Capsal, Pierre-Jean Cottinet e Minh-Quyen Le. "Haptic Feedback Device Using 3D-Printed Flexible, Multilayered Piezoelectric Coating for In-Car Touchscreen Interface". Micromachines 14, n. 8 (2 agosto 2023): 1553. http://dx.doi.org/10.3390/mi14081553.
Abstract (sommario):
This study focuses on the development of a piezoelectric device capable of generating feedback vibrations to the user who manipulates it. The objective here is to explore the possibility of developing a haptic system that can replace physical buttons on the tactile screen of in-car systems. The interaction between the user and the developed device allows completing the feedback loop, where the user’s action generates an input signal that is translated and outputted by the device, and then detected and interpreted by the user’s haptic sensors and brain. An FEM (finite element model) via ANSYS multiphysics software was implemented to optimize the haptic performance of the wafer structure consisting of a BaTiO3 multilayered piezocomposite coated on a PET transparent flexible substrate. Several parameters relating to the geometric and mechanical properties of the wafer, together with those of the electrodes, are demonstrated to have significant impact on the actuation ability of the haptic device. To achieve the desired vibration effect on the human skin, the haptic system must be able to drive displacement beyond the detection threshold (~2 µm) at a frequency range of 100–700 Hz. The most optimized actuation ability is obtained when the ratio of the dimension (radius and thickness) between the piezoelectric coating and the substrate layer is equal to ~0.6. Regarding the simulation results, it is revealed that the presence of the conductive electrodes provokes a decrease in the displacement by approximately 25–30%, as the wafer structure becomes stiffer. To ensure the minimum displacement generated by the haptic device above 2 µm, the piezoelectric coating is screen-printed by two stacked layers, electrically connected in parallel. This architecture is expected to boost the displacement amplitude under the same electric field (denoted E) subjected to the single-layered coating. Accordingly, multilayered design seems to be a good alternative to enhance the haptic performance while keeping moderate values of E so as to prevent any undesired electrical breakdown of the coating. Practical characterizations confirmed that E=20 V/μm is sufficient to generate feedback vibrations (under a maximum input load of 5 N) perceived by the fingertip. This result confirms the reliability of the proposed haptic device, despite discrepancies between the predicted theory and the real measurements. Lastly, a demonstrator comprising piezoelectric buttons together with electronic command and conditioning circuits are successfully developed, offering an efficient way to create multiple sensations for the user. On the basis of empirical data acquired from several trials conducted on 20 subjects, statistical analyses together with relevant numerical indicators were implemented to better assess the performance of the developed haptic device.
40
Mo, Lixin, Jun Ran, Li Yang, Yi Fang, Qingbin Zhai e Luhai Li. "Flexible transparent conductive films combining flexographic printed silver grids with CNT coating". Nanotechnology 27, n. 6 (13 gennaio 2016): 065202. http://dx.doi.org/10.1088/0957-4484/27/6/065202.
41
Son, Yeonho, Dongho Shin, Minkyu Kang e Caroline Sunyong Lee. "Coating 1-Octanethiol-Coated Copper Nano-Ink on a Paper Substrate via Multi-Pulse Flash Light Sintering for Application in Disposable Devices". Electronic Materials 1, n. 1 (23 settembre 2020): 28–39. http://dx.doi.org/10.3390/electronicmat1010004.
Abstract (sommario):
Inkjet-printed patterns were formed on a paper substrate using anti-oxidant copper nano-ink for application to disposable electronic devices. To prevent substrate damage, the pattern was flash light sintered under ambient conditions using the multi-pulse technique. Pure copper nanoparticles were coated with 1-octanethiol for oxidation resistance using the dry-coating method. Mixing these with 1-octanol solvent at a concentration of 30 wt% produced the copper nano-ink. Photo paper was used as the substrate. The contact angle between the photo paper and copper nano-ink was 37.2° and the optimal energy density for the multi-pulse flash light sintering technique was 15.6 J/cm2. Using this energy density, the optimal conditions were an on-time of 2 ms (duty cycle of 80%) for three pulses. The resistivity of the resulting pattern was 2.8 × 10−7 Ω∙m. After bending 500 times to a radius of curvature of 30 mm, the relative resistance (ΔR/R0) of the multi-pulse flash light-sintered pattern hardly changed compared to that of the unbent pattern, while the single-pulse-sintered pattern showed dramatic increase by 8-fold compared to the unbent pattern. Therefore, the multi-pulse light sintering technique is a promising approach to produce an inkjet-printed pattern that can be applied to disposable electronic devices.
42
Alam, Maksudul M., Bidyut Biswas, Alexi K. Nedeltchev, Haesook Han, Asanga D. Ranasinghe, Pradip K. Bhowmik e Kisholoy Goswami. "Phosphine Oxide Containing Poly(pyridinium salt)s as Fire Retardant Materials". Polymers 11, n. 7 (3 luglio 2019): 1141. http://dx.doi.org/10.3390/polym11071141.
Abstract (sommario):
Six new rugged, high-temperature tolerant phosphine oxide-containing poly(4,4′-(p-phenylene)-bis(2,6-diphenylpyridinium)) polymers P-1, P-2, P-3, P-4, P-5, and P-6 are synthesized, characterized, and evaluated. Synthesis results in high yield and purity, as confirmed by elemental, proton (1H), and carbon 13 (13C) nuclear magnetic resonance (NMR) spectra analyses. High glass transition temperatures (Tg > 230 °C) and high char yields (>50% at 700 °C) are determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. These new ionic polymers exhibit excellent processability, thin-film forming, high-temperature resistance, fire-resistance and retardation, coating, adhesion, mechanical and tensile strength, and n-type (electron transport) properties. The incorporation of phosphine oxide and bis(phenylpyridinium) moieties in the polymer backbones leads to high glass transition temperatures and excellent fire retardant properties, as determined by microcalorimetry measurements. The use of organic counterions allows these ionic polymers to be easily processable from several common organic solvents. A large variety of these polymers can be synthesized by utilizing structural variants of the bispyrylium salt, phosphine oxide containing diamine, and the counterion in a combinatorial fashion. These results make them very attractive for a number of applications, including as coating and structural component materials for automobiles, aircrafts, power and propulsion systems, firefighter garments, printed circuit boards, cabinets and housings for electronic and electrical components, construction materials, mattresses, carpets, upholstery and furniture, and paper-thin coatings for protecting important paper documents.
43
Dean, Robert N., Michael C. Hamilton e Michael E. Baginski. "Capacitive Fringing Field Moisture Sensors Implemented in Flexible Printed Circuit Board Technology". Journal of Microelectronics and Electronic Packaging 11, n. 3 (1 luglio 2014): 122–27. http://dx.doi.org/10.4071/imaps.415.
Abstract (sommario):
Capacitive fringing field sensors are often used in applications where moisture is detected, since the dielectric constant of liquid water is approximately 80 times greater than the dielectric constant of air. Most of these sensors, however, are realized using rigid substrates. Some applications would benefit from using a flexible capacitive fringing field sensor that could be conformally mounted on a nonplanar surface. Flexible printed circuit board technology is a mature commercially available process for manufacturing flexible electronics. This same technology can also be used to realize flexible fringing field moisture sensors where the patterned Cu foil is used for the electrodes and the soldermask coating electrically insulates the electrodes from being electrically shorted by moisture in the detection environment. Sensors were designed and characterized through flat and bending tests in air and in water. The tests demonstrated that bending a sensor over a radius of curvature as small as 13.7 mm had no measurable impact on sensor performance in air or in water. The sensors achieved a 3:1 increase in capacitance when immersed in water compared with in air.
44
Janek, Florian, Nadine Eichhorn, Sascha Weser, Kerstin Gläser, Wolfgang Eberhardt e André Zimmermann. "Embedding of Ultrathin Chips in Highly Flexible, Photosensitive Solder Mask Resist". Micromachines 12, n. 8 (21 luglio 2021): 856. http://dx.doi.org/10.3390/mi12080856.
Abstract (sommario):
This work presents an embedding process for ultrathin silicon chips in mechanically flexible solder mask resist and their electrical contacting by inkjet printing. Photosensitive solder mask resist is applied by conformal spray coating onto epoxy bonded ultrathin chips with a daisy chain layout. The contact pads are opened by photolithography using UV direct light exposure. Circular and rectangular openings of 90 µm and 130 µm diameter, respectively, edge length are realized. Commercial inks containing nanoparticular silver and gold are inkjet printed to form conductive tracks between daisy chain structures. Different numbers of ink layers are applied. The track resistances are characterized by needle probing. Silver ink shows low resistances only for multiple layers and 90 µm openings, while gold ink exhibits low resistances in the single-digit Ω-range for minimum two printed layers.
45
Petko, Joshua S., Philip A. Lovell, Jeremy D. Clifton, Alexander J. Bersani e Karl F. Schoch. "RF Test Article Experiment on the Impact of Non-Hexavalent Chromium-Based Conversion Coatings on Electrical Assemblies". International Symposium on Microelectronics 2018, n. 1 (1 ottobre 2018): 000712–17. http://dx.doi.org/10.4071/2380-4505-2018.1.000712.
Abstract (sommario):
Abstract Conversion coatings are treatments applied to aluminum structures to inhibit corrosion while maintaining electrical conductivity. In aerospace applications, the most common type of conversion coatings (MIL-DTL-5541 Type I) contain hexavalent chromium compounds as the corrosion-inhibiting agent. These Type I conversion coatings have a long pedigree and are highly effective in preventing corrosion; however, the hexavalent chromium compounds in these coatings are carcinogenic and water-soluble. Therefore, the use of these compounds is highly regulated in order to protect both workers and the public, leading to high cost in both use and disposal. Regulations are also beginning to restrict outright use, where new designs for the DOD are prohibited from using Type I coatings by DFARS 48 CFR Parts 223 and 252 and all use has been prohibited by Europe by REACH regulations since September 2017. In response, more environmentally friendly non-hexavalent chromium-based processes, referred to as MIL-DTL-5541 Type II conversion coatings, have become available. However, the long term reliability and performance impacts resulting from the use of these coatings are not fully understood and there is an ongoing effort in the aerospace industry organized by NASA to fully define these impacts while hardware is still in the design stage. While significant work has been performed to define the corrosion performance of various type-II conversion coatings, there has been minimal work performed to quantify the impact a type-II conversion coating would have on RF electrical assemblies. The standard methodologies defined by MIL-DTL-81706B have significant limitations and cannot fully capture the impact at microwave frequencies. For this reason, an investigation is underway at Northrop Grumman to quantify the impact these coatings may have on the quality, reliability, and performance of our electronic systems. At IMAPS 2017, Northrop Grumman introduced a RF test article designed to assess the longitudinal impact a Type II conversion coating would have on RF electrical assemblies where plated printed wiring boards (PWBs) and aluminum structures come in intimate contact. The test article features a specialized suspended stripline/microstrip stepped impedance filter designed to de-tune in the presence of galvanic corrosion. This talk follows the work presented in IMAPS 2017 by discussing an experiment where three different populations of test articles, each coated with a different type of conversion coating, are subjected to environmental testing. This talk also discusses how an initial measurement of these test articles before environmental exposure showed little difference between these populations. Finally, this talk reviews the initial results of this experiment, discussing environmental testing and the RF measurements captured during these tests.
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Walter, Piotr, Andrzej Pepłowski, Łukasz Górski, Daniel Janczak e Małgorzata Jakubowska. "Disposable, acetylcholinesterase-coated, screen-printed carbon electrodes for the determination of organophosphorus pesticides". Microelectronics International 36, n. 3 (1 luglio 2019): 120–26. http://dx.doi.org/10.1108/mi-12-2018-0084.
Abstract (sommario):
Purpose Because of the bioaccumulation effect, organophosphorus pesticides cause long-term damage to mammals, even at small concentrations. The ability to perturb the phospholipid bilayer structure as well as the overstimulation of cholinergic receptors makes them hazardous to humans. Therefore, there is a need for a quick and inexpensive detection of organophosphorus pesticides for agricultural and household use. As organophosphorus pesticides are acetylcholinesterase (AChE) inhibitors, biosensors using this mechanism hold a great promise to meet these requirements with a fraction of reagents and time used for measurement comparing to laboratory methods. This study aims to manufacture AChE-coated, screen-printed carbon electrodes applicable in such amperometric biosensors. Design/methodology/approach AChE enzyme, known for catalytic activity for the hydrolysis of acetylthiocholine (ATCh), could be used to obtain electrochemically active thiocholine from acetylthiocholine chloride in aqueous solutions. Using Malathion’s inhibitory effect towards AChE, pesticides’ presence can be detected by reduction of anodic oxidation peaks of thiocholine in cyclic voltammetry. Findings The conducted research proved that it is possible to detect pesticides using low-cost, simple-to-manufacture screen-printed graphite (GR) electrodes with an enzymatic (AChE) coating. Investigated electrodes displayed significant catalytic activity to the hydrolysis of ATCh. Owing to inhibition effect of the enzyme, amperometric response of the samples decreased in pesticide-spiked solution, allowing determination of organophosphorus pesticides. Originality/value Printed electronics has grown significantly in recent years as well as research focused on carbon-based nanocomposites. Yet, the utilization of carbon nanocomposites in screen-printed electronics is still considered a novelty in the market. Biosensors have proved useful not only in laboratory conditions but also in home applications, as glucometers are a superior solution for glucose determination for personal use. Although pesticides could be detected accurately using chromatography, spectroscopy, spectrometry or spectrophotometry, the market lacks low-cost, disposable solutions for pesticide detection applicable for household use. With biosensing techniques and electric paths screen-printed with GR or graphene nanocomposites, this preliminary research focuses on meeting these needs.
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Mei, Zequn, e Helen Holder. "A Thermal Fatigue Failure Mechanism of 58Bi-42Sn Solder Joints". Journal of Electronic Packaging 118, n. 2 (1 giugno 1996): 62–66. http://dx.doi.org/10.1115/1.2792133.
Abstract (sommario):
Surface mount components soldered with 58Bi–42Sn on printed circuit boards fell off after about 500 cycles of−45°C ↔ 100°C in a thermal chamber. Failure analysis revealed that the failure was caused by dissolving of Pb from either HAL (hot air leveled) board surfaces or component lead coatings into the Bi-Sn solder joints, forming 52Bi–32Pb–16Sn eutectic phase that melts at 95°C. The dissolving of Pb occurred primarily at reflow, when the Bi-Sn was molten. During the thermal cycling, the small amount (<7 volume % of a Bi-Sn solder joint) of the low melting eutectic phase provided liquid channels for fast atom transportation, causing exceptionally significant grain growth and phase agglomeration in the whole volume of the solder joint, which in turn caused dramatic reduction in mechanical strength of the solder joints. Solutions to the failure may be either using Pb-free coating on both board surfaces and component leads, or limiting the product service temperature to below 95°C.
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Bing Hong, Gui, Yi Hua Luo, Kai Jen Chuang e Chih Ming Ma. "Preparing and Applying Silver Nanoparticles in Conductive Ink and Inkjet Painting". Journal of Nanoscience and Nanotechnology 21, n. 12 (1 dicembre 2021): 5979–86. http://dx.doi.org/10.1166/jnn.2021.19518.
Abstract (sommario):
Noble metal nanoparticles have special properties in optical, electronic, and physical chemistry due to their high surface area and volume. With the development of electronic printing technology, inkjet printing has gradually replaced traditional spin coating and blade coating, since it leads to more material savings and a faster batch production, and the pattern can be easily designed by a computer. In this study, Ag nanoparticles were prepared by a chemical reduction method. Non-toxic, environment-friendly agents were selected to fabricate a single-shape, uniform-size, crystal-form, and monodisperse product. The effects of the reducing agent ratio and the stabilizer ratio on the size, shape, and stability of the nanoparticles are discussed. The silver nanoparticles were characterized by an ultraviolet-visible spectrophotometer (UV-vis) and a transmission electron microscope (TEM). In addition, in order to prepare conductive ink that can stably disperse for a long time and that can be applied to inkjet printing on a PET flexible substrate at a lower sintering temperature, a sintering agent and a commercial surfactant were added. The experimental results show that the best addition ratio of the precursor to the reducing agent and the stabilizer is 1:6:1. The conductive silver ink was printed and treated by a70 mM NaCl solution, and the electric resistivity was 5.17×10−4 Ω· cm.
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Yang, Lilin, Dongzhi Wang, Guoxiang Zhou, Zhidan Lan e Zhihua Yang. "Glass-Ceramic Coating on Silver Electrode Surface via 3D Printing". Materials 16, n. 8 (21 aprile 2023): 3276. http://dx.doi.org/10.3390/ma16083276.
Abstract (sommario):
Silver electrodes are commonly used as a conductive layer for electromagnetic devices. It has the advantages of good conductivity, easy processing, and good bonding with a ceramic matrix. However, the low melting point (961 °C) results in a decrease in electrical conductivity and migration of silver ions under an electric field when it works at high temperatures. Using a dense coating layer on the silver surface is a feasible way to effectively prevent the performance fluctuation or failure of the electrodes without sacrificing its wave-transmitting performance. Calcium-magnesium-silicon glass-ceramic (CaMgSi2O6) is a diopside material that has been widely used in electronic packaging materials. However, CaMgSi2O6 glass-ceramics (CMS) are facing tough challenges, such as high sintering temperature and insufficient density after sintering, which significantly confine its applications. In this study, CaO, MgO, B2O3, and SiO2 were used as raw materials to manufacture a uniform glass coating on the silver and Al2O3 ceramics surface via 3D printing technology followed by high-temperature sintering. The dielectric and thermal properties of the glass/ceramic layer prepared with various CaO-MgO-B2O3-SiO2 components were studied, and the protective effect of the glass-ceramic coating on the silver substrate at high temperatures were evaluated. It was found that the viscosity of the paste and the surface density of the coating increase with the increase of solid contents. The 3D-printed coating shows well-bonded interfaces between the Ag layer, the CMS coating, and the Al2O3 substrate. The diffusion depth was 2.5 μm, and no obvious pores and cracks can be detected. According to the high density and well-bonded glass coating, the silver was well protected from the corrosion environment. Increasing the sintering temperature and extending the sintering time is beneficial to form the crystallinity and the densification effect. This study provides an effective method to manufacture a corrosive-resistant coating on an electrically conductive substrate with outstanding dielectric performances.
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Lyons, Karen Swider, e Benjamin D. Gould. "Lightweight Titanium Metal Bipolar Plates for PEM Fuel Cells". Materials Science Forum 879 (novembre 2016): 613–18. http://dx.doi.org/10.4028/www.scientific.net/msf.879.613.
Abstract (sommario):
Bipolar plates (BPPs) serve multiple roles in polymer electrolyte membrane fuel cells (PEMFCs). When assembled in a stack, they provide the structural backbone of the stack, plus serial electronic connections. They also provide gas (air and fuel) and coolant distribution pathways. Traditionally, bipolar plates have been made of carbon, but these are being replaced in favor of metal bipolar plates made of stamped foils. The Naval Research Laboratory has explored making titanium metal BPPs using 3D printing methods (direct metal laser sintering – DMLS) and superplastic forming, and then using a gold/TiO2 surface layer for corrosion resistance. The 3D printed plates are made as one piece with the coolant flow internal to the resulting 2-mm thick structure. Their surface roughness requires smoothing prior to coating to increase their cell-to-cell conductivity. We found that 3D printed cells with 22 and 66 cm2 active areas are slightly warped, preventing the robust sealing of the stacks. The formed plates are made in separate pieces and then joined. Despite the high temperatures required for superplastic forming, the resulting plates are thin and lightweight, making them highly attractive for lightweight compact PEMFC stacks.