Дисертації з теми "Sintering of silver powder"
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Zhang, Zhiye. "Sintering of Micro-scale and Nanscale Silver Paste for Power Semiconductor Devices Attachment." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/28902.
Повний текст джерелаPh. D.
Riva, Raphaël. "Solution d'interconnexions pour la haute température." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0064/document.
Повний текст джерелаSilicon has reached its usage limit in many areas such as aeronautics. One of the challenges is the design of power components operable in high temperature and/or high voltage. The use of wide bandgap materials such as silicon carbide (SiC) provides in part a solution to meet these requirements. The packaging must be adapted to these new types of components and new operating environnement. However, it appears that the planar integration (2D), consisting of wire-bonding and soldered components-attach, can not meet these expectations. This thesis aims to develop a three dimensional power module for the high temperature aeronautics applications. A new original 3D structure made of two silicon carbide dies, silver-sintered die-attaches and an encapsulation by parylene HT has been developed. Its various constituting elements, the reason for their choice, and the pratical realization of the structure are presented in this manuscript. Then, we focus on a failure mode specific to silver-sintered attaches : The silver migration. An experimental study allows to define the triggering conditions of this failure. It is extended and analyzed by numerical simulations
Blackmore, Katherine Ann 1969. "Sintering of heterogeneous glass powder compacts." Thesis, The University of Arizona, 1995. http://hdl.handle.net/10150/291349.
Повний текст джерелаHascoët, Stanislas. "Mise en oeuvre de nouveaux matériaux d’assemblage dans les modules multipuces de puissance (MCM)." Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0123/document.
Повний текст джерелаUse of wide band gap chip in the power electronic industry requires an optimization of the close environment (packaging). Indeed, the can often sustain lower temperature than the die, especially the solder that are used to bond the parts of the module. Consequently, new bonding methods are investigated to enhance the performance of the packages. Silver sintering bonding technique is one the most promising. This method allow to bond parts at moderate temperature and the formed joint to operate at very high temperature (until the melting point of silver). This work is focused on the development of this bonding technique in the case of bonding a dies on a substrate. A study of the influence of the different parameters on the strength of the formed bond has been done. It revealed a major influence of the finishes of the bonded parts. Bonding on silver finished substrate results in good mechanical strength of the bond even after ageing. Furthermore, no interface issues are observed. However, the most used finish for power electronic is not silver but nickel-gold. Regarding this type of finish, the bond quality depends on the gold thickness, sintering profile and also sintering atmosphere. A solid solution of silver and gold seems to develop on the surface of the substrate, decreasing the section of the silver grains in contact with the substrate. Thus the mechanical strength of the assembly is decreased. This effect should be limited by the gold available for the Au-Ag solid solution growth. When sintering under nitrogen, the diffusion of silver on the gold surface is much lower than under air. Good results have been obtained with these configurations and even after ageing. Adding pressure during the thermal treatment seems also to minimize the phenomenon, probably by increasing the number of silver grains in contact with the substrate surface and so reducing the free surface for Au-Ag layer formation. Those results have been used to build prototypes, one of whom has been electrically tested with success at temperatures up to 300°C
Marsh, P. "Sintering of mixed powders." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282832.
Повний текст джерелаDhavale, Tushar. "Low power laser sintering of iron powder." Thesis, University of the West of England, Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522529.
Повний текст джерелаBooysen, Gerrie Jacobus. "Bridge tooling through layered sintering of powder." Thesis, Bloemfontein : Central University of Technology, Free State, 2007. http://hdl.handle.net/11462/72.
Повний текст джерелаFaster mould production methods will undeniably impact positively on the product development community. Rapid Tooling (RT) concepts, in context with the product development process and related product development theories, were analysed. Conventional tooling techniques used such as epoxy plastic tooling and machined injection moulding techniques were used as point of departure for the research work, which focused on Laser Sintering of powder materials. The new generation RT materials that are available at the Central University of Technology, Free State, are a vast improvement on the old materials. RT materials are constantly being developed and the project aims were to stay abreast with the latest developments. The thesis gives a complete overview of all related technologies, and also an in-depth discussion of both the Selective Laser Sintering (SLS) and Laser Sintering (LS) processes. Mould size limitations, as well as general tooling design issues, polishing and finishing techniques were all taken into account. Data has been collected to compare mould inserts grown with RP machines with that of conventionally machined tools. Aspects such as tool life, part quality, lead times and cost were used as parameters to determine the differences and make recommendations. Through analysis of several experiments and industrial case studies, RT through sintered materials was proven as a capable technology, giving the option of an intermediate (bridge tooling) or even a final step of tooling. Recommendations for future use were made in terms of insert size and geometry, accuracy, durability and shrinkages, to ensure the feasibility of the RT process in SA.
Eane, Radu Bogdan. "Metal powder effects on selective laser sintering." Thesis, University of Leeds, 2002. http://etheses.whiterose.ac.uk/4016/.
Повний текст джерелаKempen, Daniel. "Thermomechanical modelling of powder compaction and sintering." Doctoral thesis, Università degli studi di Trento, 2019. https://hdl.handle.net/11572/369024.
Повний текст джерелаSilver, Kathleen G. "Processing of nano-sized boron carbide powder." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/26476.
Повний текст джерелаCommittee Chair: Speyer, Robert; Committee Member: Judson, Elizabeth; Committee Member: Sanders, Thomas. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Subrahmanyam, Gowri. "Sintering and its enhancement in ferrous powder compacts." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/32009.
Повний текст джерелаApplied Science, Faculty of
Materials Engineering, Department of
Graduate
Chen, Xiaolin. "Particle packing, compaction and sintering in powder metallurgy." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0014/NQ34746.pdf.
Повний текст джерелаHauser, Carl. "Selective laser sintering of a stainless steel powder." Thesis, University of Leeds, 2003. http://etheses.whiterose.ac.uk/2631/.
Повний текст джерелаZhang, Li 1973. "Shockwave consolidation of nano silver powder into bulk nano structured silver." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100238.
Повний текст джерелаTahir, Abdul Malik. "Alloy element redistribution during sintering of powder metallurgy steels." Doctoral thesis, KTH, Fysiokemisk strömningsmekanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145251.
Повний текст джерелаQC 20140515
Nabeel, Muhammad. "Diffusion of Elemental Additives during Sintering." Thesis, KTH, Materialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-100702.
Повний текст джерелаAlbiston, John Nigel. "The activated sintering of silver-tungsten compacts, produced via the reduction of silver tungstate." Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329591.
Повний текст джерелаMcWilliams, Brandon A. Zavaliangos Antonios. "Numerical simulation of electric field assisted sintering /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2763.
Повний текст джерелаPines, Michael Louis. "Pressureless sintering of powder processed functionally graded metal-ceramic plates." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1999.
Повний текст джерелаThesis research directed by: Dept. of Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Best, Serena M. "Characterisation, sintering and mechanical behaviour of hydroxyapatite ceramics." Thesis, Queen Mary, University of London, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321276.
Повний текст джерелаGateaud, Arnaud. "Physical and chemical mechanisms of lubricant removal during stage I of the sintering process." Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-040606-161143/.
Повний текст джерелаHall, Bradley Devin. "Powder processing, powder characterization, and mechanical properties of LAST (lead-antimony-silver-tellurium) and LASTT (lead-antimony-silver-tellurium-tin) thermoelectric materials." Diss., Connect to online resource - MSU authorized users, 2008.
Знайти повний текст джерелаTitle from PDF t.p. (viewed on Aug. 7, 2009) Includes bibliographical references (p. 151-159). Also issued in print.
Kim, Hyungchan. "Low temperature sintering of nanosized ceramic powder YSZ-bismuth oxide system /." Connect to this title online, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1092765117.
Повний текст джерелаTitle from first page of PDF file. Document formatted into pages; contains xxvi, 249 p.; also includes graphics (some col.). Includes bibliographical references (p. 241-249).
Alhambra, Edgar M. "A preliminary attempt at sintering an ultrafine alumina powder using microwaves." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA284978.
Повний текст джерелаIp, Samuel Chun Hung. "Study of radiative heat transfer in porous media for sintering applications /." View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?MECH%202002%20IP.
Повний текст джерелаIncludes bibliographical references (leaves 82-85). Also available in electronic version. Access restricted to campus users.
Wildan, Muhammad W. "Zirconia-matrix composites reinforced with metal." Thesis, University of Strathclyde, 2000. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21428.
Повний текст джерелаBai, Guofeng. "Low-Temperature Sintering of Nanoscale Silver Paste for Semiconductor Device Interconnection." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29409.
Повний текст джерелаPh. D.
Erdem, Derya. "Microwave Sintering And Characterization Of Soft Magnetic Powder Metallurgical Ni-fe Alloys." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613550/index.pdf.
Повний текст джерелаSteward, Nigel Ian. "Influence of particle size distribution on the sintering of ceramic powder compacts." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47674.
Повний текст джерелаHalilovic, Selma. "Evaluation of new powder grade for furnace control pieces in sintering process." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-448371.
Повний текст джерелаLiu, Xin. "Numerical modeling and simulation of selective laser sintering in polymer powder bed." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI012/document.
Повний текст джерелаMany industrial and academic interests concerning the additive manufacturing processes are developed in the last decades. As one of the most promising technique of additive manufacturing, the Selective Laser Sintering (SLS) has been valued by both industry and academic. However, it remains that several phenomena are still not well understood in order to properly model the process and propose quality improvement of parts made. The goal of this Ph.D. project is to develop a framework of numerical simulation in order to model the SLS process in polymer powder bed, meanwhile understanding multiple physical phenomena occurring during the process and studying the influence of process parameters on the quality of final product. In contrast to traditional approach, based on the equivalent homogeneous material in numerical modeling of partial differential equations derived from conservation laws, we propose a global model to simulate powder-based additive manufacturing by using the Discrete Element method (DEM). It consists in a coupling between four different physical models: radiative heat transfer, discrete heat conduction, sintering and granular dynamics models. Firstly, the submodel of radiative heat transfer concerns the interaction between the laser beam and powder bed. Several phenomena are considered, including the reflection, transmission, absorption and scattering. Besides, a modified Monte Carlo ray-tracing method is developed in order to study the influence of scattering on the distribution of the deposited laser energy inside the powder bed Furthermore, the submodel of discrete heat conduction describes the inter-particles heat diffusion. Moreover, the sintering submodel concerns the phenomena of coalescence and air diffusion. It describes the melting kinetics of grains, driven by surface tension and the release of entrapped gases inside powder bed. Finally, the granular dynamics submodel concerns the motions and contacts between particles when depositing a new layer of powders. The coupling between these submodels leads to propose a global numerical framework, validated by comparing the results to both simulated and experimental ones from literatures. A parametric study is then proposed for model validation and process analysis. The Influence of different material and process parameters on the evolution of temperature, relative density and materials structure and characteristics are investigated. The results exhibit accurate modeling of the complex phenomena occurring during the SLS process, and the work constitute a great potential in modeling and optimization of additive processes
Talamantes-Silva, Jose. "Liquid phase sintering of austenitic stainless steel 316L powder using tin and nickel." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287168.
Повний текст джерелаHiser, Matthew A. "Powder Processing and Characterization of W-3Ni-1Fe Tungsten Heavy Alloy." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/42512.
Повний текст джерелаMaster of Science
Bergman, Ola. "Studies of oxide reduction and nitrogen uptake in sintering of chromium-alloyed steel powder." Licentiate thesis, KTH, Materials Science and Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9555.
Повний текст джерелаThe powder metallurgy (PM) process route is very competitive for mass production of structural steel components with complex shape, due to efficient material utilisation, low energy consumption, and short overall production time. The most commonly used alloying elements are the processing friendly metals Cu, Ni and Mo. However, the prices for these metals are today high and volatile, which threatens to make the PM process less competitive compared to conventional metal forming processes. Consequently, there is a strong desire in the PM industry to increase the use of less costly alloying elements. Cr is an attractive alternative since it, besides low cost, provides high hardenability and also recyclable components. The drawback is that Cr has high affinity for oxygen, which makes oxidation and oxide reduction in PM processing of Cr-alloyed materials a challenging issue. Furthermore, the interaction between nitrogen and Cr-alloyed powder during processing is important to consider, since Cr also has high nitrogen affinity and is prone to form nitrides.
The aim of the research work presented in this thesis was to study oxide reduction and nitrogen uptake in sintering of Cr-alloyed steel powder. Water-atomized powder grades pre-alloyed with 1.5-3% Cr were used as test materials. Sintering experiments were performed in N2/H2 (90/10) atmospheres with test bars pressed to density 7.0-7.2 g/cm3. The oxygen content of the sintering atmosphere was varied and different sintering temperatures and cooling rates were applied. The experimental study has been complemented with thermodynamic calculations using the software Thermo-Calc.
The oxygen partial pressure should be below 4 x 10-18 atm in order to have reducing conditions during sintering at 1120°C of steel powder pre-alloyed with 3% Cr. With graphite added to the powder, conditions are reducing at higher oxygen partial pressures (up to 10-16 atm) due to favourable conditions locally in the material. Sintering at 1120°C for 30 minutes leads to incomplete reduction of Cr-oxides in the Cr-alloyed PM grades, but remaining oxides are not detrimental for mechanical properties of the PM components. Increased sintering temperature is beneficial for the oxide reduction kinetics and practically all oxides are reduced after sintering for 30 minutes above 1200°C. Nitrogen uptake by Cr-alloyed steel powder from N2-based sintering atmospheres is strongly dependent on the cooling rate applied after sintering. No nitrides appear in the sintered material and mechanical properties are not affected when normal cooling rates (0.5-1°C/s) are applied. Very low cooling rates (such as 0.05°C/s) may lead to grain boundary precipitation of Cr-nitrides in the sintered material.
Deceuster, Andrew Isaac. "Investigation of Joining Micro-Foil Materials with Selective Laser Sintering and Laser Powder Deposition." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/434.
Повний текст джерелаSchultz, Jeffrey Patrick. "Modeling Heat Transfer and Densification during Laser Sintering of Viscoelastic Polymers." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/11091.
Повний текст джерелаPh. D.
Saha, Deepak. "De-lubrication during sintering of P/M compacts : operative mechanism and process control strategy." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-10014-233109.
Повний текст джерелаLi, Tao. "Reaction-bonding of Crâ†2Oâ†3 ceramics." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318804.
Повний текст джерелаYouseffi, M. "Some aspects of the injection moulding of alumina and other engineering ceramics." Thesis, Loughborough University, 1992. https://dspace.lboro.ac.uk/2134/7227.
Повний текст джерелаDemir, Vedat. "Development and application of vacuum heat-treated silicon nitride ceramics." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310039.
Повний текст джерелаSaha, Deepak. "De-lubrication during sintering of P/M compacts: Operative mechanism and process control strategy." Digital WPI, 2004. https://digitalcommons.wpi.edu/etd-theses/1049.
Повний текст джерелаPozzi, Francesco. "Direct metal laser sintering of steel with high vanadium content." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13548/.
Повний текст джерелаYoussef, Toni. "Modélisation multiphysique d'un assemblage de puissance haute température destiné à l'environnement aéronautique." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0167/document.
Повний текст джерелаToday’s main challenge for aeronautical equipment manufacturers is to respond to the more electrical aircraft regulations. Moreover, there are many applications in aircraft area where high temperature technologies are needed. Nowadays, the replacement of hydraulic systems for electric ones leads to place the power inverters in a harsh environment, for example in the engine nacelle. The equipment is under high constraints such as high and low temperatures, wide temperature cycling, high humidity and low pressure. Combined to these environmental constraints, the new aircraft system is submitted to weight and operating cost reduction. As a consequence, efforts shall be done to reduce weight and volume of the power converter without losing its performance. To reach such a goal, the design of the converter must enable a high level of integration, efficiency and reliability. In particular, fatigue damage has a significant influence on such modules electrical power performance. And fatigue-related performance testing remains a costly endeavor for aeronautical equipment. A finite number of destructive tests can be carried out in specific facilities for a fairly low number of configurations. The purpose of these destructive tests is to investigate the failure modes appearing regarding this accelerated ageing. Therefore numerical simulations have been envisaged since non-destructive, easily evolving and usable for a high number of configurations, though needing data from experimental assays. In this study, we propose a method dealing with the main constraints for such equipment, i.e. electrical, thermal and mechanical simulation. Those three physical problems have different characteristic time and are strongly coupled with a non-trivial behavior. To optimize the resources usage and have a relevant representation of the problem, a 1D electrical / 3D thermal / 3D mechanical coupled method has been implemented over a co-simulation bus. Different time steps, different abstraction levels and different skills are used to provide predictions of the multiphysical fatigue behavior of power modules
Caliskan, Necmettin Kaan. "Powder Metallurgy Of W-ni-cu Alloys." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607576/index.pdf.
Повний текст джерелаthe effects of the powder metallurgical parameters such as the mixing method, compaction pressure, initial tungsten (W) particle size, composition, sintering temperature and sintering time on the sintering behavior of selected high density W-Ni-Cu alloys were investigated. The alloys were produced through conventional powder metallurgy route of mixing, cold compaction and sintering. The total solute (Ni-Cu) content in the produced alloys was kept constant at 10 wt%, while the copper concentration of the solutes was varied from 2.5 wt% to 10 wt%. Mainly liquid phase sintering method was applied in the production of the alloys. The results of the study were based on the density measurements, microstructural characterizations including optical and scanning electron microscopy and mechanical characterizations including hardness measurements. The results showed that the nature of the mixing method applied in the preparation of the powder mixtures has a considerable effect on the final sintered state of W-Ni-Cu alloys. Within the experimental limits of the study, the compaction v pressure and initial W particle size did not seem to affect the densification behavior. It was found that the sintering behavior of W-Ni-Cu alloys investigated in this study was essentially dominated by the Ni content in the alloy and the sintering temperature. A high degree of densification was observed in these alloys with an increase in the Ni content and sintering temperature which was suggested to be due to an increase in the solubility and diffusivity of W in the binder matrix phase with an increase in these parameters, leading to an increase in the overall sintering kinetics. Based on the results obtained in the present study, a model explaining the kinetics of the diffusional processes governing the densification and coarsening behavior of W-Ni-Cu alloys was proposed.
陳冠宇. "Sintering of Microcrystalline Silver Powder and Its Application in Hydrogen Separation Membrane." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/63240298168362903253.
Повний текст джерела國立清華大學
材料科學工程學系
88
Permeation of hydrogen in transition metals is an important catalytic reaction. The preparation and properties of hydrogen permeable membranes have been studied in energy technologies for many years. The palladium-silver alloy membrane has been extensively studied in recent years due to the absence of α→βphase transition and embrittlement associated with hydrogen permeation. In addition to the application for ultra high purity hydrogen separation, it is also widely utilized in recovery or purification of hydrogen in petroleum industry, hydrogen reactor in fuel cells, and methane stream reforming. In the present work, microcrystalline silver powder was used as the substrate material. Porous silver substrate was obtained after sintering at 350oC in air for 1hr. Prior to deposition, the surface was filled with nanocrystalline Pd70Ag30 particles to reduce the pore size, followed by deposition with a Pd70Ag30 alloy film. The palladium-silver alloy film was sputter deposited on the substrate as a separation membrane. The surface and cross-section morphologies of the sintered silver substrates were examined by scanning electron microscopy. Besides, the permeation rate of hydrogen at 250oC was measured by a gas permeation apparatus. A new rotation design was also built for sputter coating on tube substrates. It was observed that a dense and continuous film of a thickness 10μm could be achieved on the modified substrate. The hydrogen permeation flux through the membrane increases monotonically with the pressure but deviates from the Sievert’s law. A rotation design was made and a copper tube was tested. The uniformity of thickness was fairly good.
Wu, Wei, and 吳惟. "The Effet of the Silver-Palladium Powder Characteristics on Sintering Property of its Thick Film." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/87315701858371380380.
Повний текст джерелаTrung, Le Manh, and 黎孟忠. "Optimization Sintering on Fiber Laser Sintering of Metallic Powder." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/15072777316117271182.
Повний текст джерела明新科技大學
精密機電工程研究所
99
Nowadays, increasing competition requires companies to substantially reduce product development time and rapidly respond to market demands. Rapid prototyping technologies have attracted significant interests from both industry and academia. However, problems in model accuracy \ product quality and material properties have limited their applications. In order to apply these technologies to a wide range of industrial and medical applications, the manufacturing processes of rapid prototyping must be improved. Selective laser sintering (SLS) is one among many different rapid prototyping processes where the parts are built in a layer by layer fashion. Recently, SLS has gained importance due to its ability to process a wide variety of materials. SLS can produce functional prototypes and rapid tooling components, which necessitates the production of high-quality parts. The majority of its applications are in aerospace and rapid tooling, where high accuracy levels have to be met in order to ensure proper functional requirement. Due to this new constraint imposed on SLS in terms of part quality, there is a need to study the process in detail and to improve part accuracies. The objective of this thesis is to investigate the effect of various parameters on rapid prototyping parts for processes of sintering metallic powder using Ytterbium Fiber Optic Laser via the design of experiments (DOE) method. Experiments based on the DOE method were utilized to determine the optimal parameter setting for achieving a minimum amount of porosities in specimens on the SLS process. Analysis of variance (ANOVA) was further conducted to identify significant factors. A regression model predicting percentages of porosities under various conditions was developed when the traditional Taguchi’s approach failed to identify a feasible model due to strong interactions of controlled factors. The significant factors to the process were identified by ANOVA. Four controlled factors including laser power, speed (scan rate), pulse frequencies and scan line spacing (air gap) had significant influence on the sintering process. Future investigation planned to be carried out for achieving multiple quality targets such as the hardness and the density for 3D parts.
Liu, Su Hao, and 劉書豪. "Constrained sintering of silver paste." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/98998346123891965994.
Повний текст джерелаLin, Jiou-Wei, and 林久瑋. "3D metal powder printing sintering parameter studies." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/vbf7f7.
Повний текст джерела國立虎尾科技大學
機械與電腦輔助工程系碩士班
105
In the current industry, integrated manufacturing is highly competitive. As 3D printing continue to develop, the techniques and output value are also expending. In the present domestic market, 3D printing with PLA or ABS filament wires are the most common materials. Due to the low-cost and easy operation, the machine is often purchased by schools as a teaching tool. As for the metal 3D printing, it needs to insert protective gas in a closed off space, through laser sintering and stack-build to create an object with metal powder, although such techniques can produce complex parts, very few technical developments are found in the domestic market due to the high cost. The purpose of this study is to focus on the research of 3D metal powder sintering techniques and process. Through laser sintering experiments with different metal powder mixtures to confirm possible powder sintering, then use different laser power, scanning speeds, frequencies and path spacing parameters to conduct powder sintering experiments under different experimental conditions. By using optical microscope and Vickers Hardness tester to verify sintering products and using Taguchi method to find out best parameter combinations. The conclusions of the study are summarized as follow 1.In this study, the powder mixing mechanism was designed and used, the ratio of copper and tin powder for the mixing mechanism was 18: 1 2.If the scanning rate is higher than 30mm/s, the powder indicates insufficient temperature and shows a splash phenomenon which is not conducive to sintering. This will subsequently impact on the porosity and hardness analysis experiments. 3.Through Taguchi analysis, the best combine parameters for pore-space were found. The best pore-space is 4.712%, the laser power is 80%, and the scanning speed is 7mm/s, the frequency is 30k, and the path-space is 0.05mm. 4.Through Taguchi analysis, the best combine parameters for Vickers Hardness were found. The best pore-space is 134.423HV, the laser power is 100%, the scanning speed is 7mm/s, the frequency is 33K, and the path-space is 0.07mm.
Huang, Guo-Lun, and 黃國倫. "Study on photonic sintering of silver particles." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/86133709735449343460.
Повний текст джерела國立中興大學
材料科學與工程學系所
105
By utilizing the drastically reduced sintering temperature of nano-sized particles (NPs), one of the trends in microelectronic packaging is to manufacture highly conductive interconnections at a low processing temperature using metallic nanoparticles. With respect to ligand-protected NPs, the protect shell must be thermally or chemically eliminated, and the NPs need to join together to form continuous conductive networks in order to generate electrical conductance. Considering the increasing demands for interconnects on flexible and stre substrates, this study aims to develop innovative photonic sintering for nano/submicrom Ag nanoparticles on PI substrates using pulsed flash and NIR. Experimental results show that carboxylate-capped Ag NPs with an average diameter of less than 10 nm can be well sintered together and reached an electrical resistivity of 10.2µΩ•cm. If the same NP deposits were exposed with flash light (energy density: 4.7W/cm2) on the deposit side or substrate side for 9 pulses, the electrical resistivities were 11.2µΩ•cm and 8.3µΩ•cm respectively. It was demonstrated that the desorption of carboxylate by photonic means was through the decomposition by the oxidation of CH2 rather than debonding of CO2-. Photonic sintering of NPs by flash pulses might be through melting and resolidifying due to the heat generated from surface plasmon resonance. On the other hand, NIR exposure on NPs brought about a uniformly coarsened sintered structure. Worthy of notice is that submicron-sized Ag particles (SMPs) with an average size of about 250 nm were the first time to be adopted for photonic sintering. Pulsed-flash-sintered SMPs can reached 9.9 •cm, while the electrical resistivity of the optimized mixture of SMPs and NPs subjected to pulsed-flash-sintering can be lowered to 7.32 •cm. Subjected to bending cycles up to 104 times (bending radius of 10 mm, 0.5 Hz), all those sintered structures on PI substrates remained excellent electrical conductance. The increase in electrical resistivity was less than 50%.