Articles de revues : « SURFACE COMPOSITE VIA »

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Yuvaraj, N. « Improving the Wear Properties of Aluminum 6082 Alloy by Surface Compositing with Zro2 Ceramic Particles Via Friction Stir Processing ». Material Science Research India 15, n^o 1 (30 mars 2018) : 68–74. http://dx.doi.org/10.13005/msri/150108.

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Aluminum based metal matrix composites are given more attention in fabrication of surface engineering applications due to their excellent mechanical and wear properties. In this study, Friction stir processing (FSP) method was used to fabricate the surface composite with inserting different volume % of ZrO2 reinforcement particles in the Aluminum 6082 alloy. The hardness and triblogical characteristics of fabricated surface composites and base alloy were investigated. The higher volume content of reinforcement surface revealed higher hardness and higher wear resistance compared to the lower volume content reinforcement surface and base material. The wear worn-out of composite surfaces and base alloy were examined through SEM for understanding the wear mechanisms.

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Hou, Yacong, Yubo Liu, Lei Chen, Ding Weng, Yuan Ma, Yadong Yu, Yang Wu et Jiadao Wang. « Controllable Friction of an Epoxy Composite via Thermal Treatment ». Applied Sciences 13, n^o 17 (1 septembre 2023) : 9899. http://dx.doi.org/10.3390/app13179899.

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Smart surfaces with controllable friction have generated considerable attention lately. However, most composites prepared with traditional fillers cannot achieve “real-time” friction conversion. Herein, a new smart surface was designed to achieve different friction coefficients (0.65 and 0.12). Different coefficients of friction were reversibly and precisely controlled via heating. Via friction and heating, 1H,1H,2H,2H-perfluorohexyl hexadecane (PHHD), a kind of phase-change material—paraffin wax—was released from the microcapsules, and a stable and complete film was formed. It changed the interface from “solid-solid” to “solid-liquid” in a dry friction state. The composite contains microcapsules that prevent phase separation between PHHD and matrix, which enables the composite to have a long service time and switchable friction performance. In addition, this composite can maintain its extraordinary ability even in harsh environments like UV irradiation. By demonstrating switchable friction based on changes in the interactions between contact interfaces, this work provides a new principle for designing smart tribological composites.

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Skoura, Eva, Peter Boháč, Martin Barlog, Helena Palková, Martin Danko, Juraj Šurka, Andreas Mautner et Juraj Bujdák. « Modified Polymer Surfaces : Thin Films of Silicate Composites via Polycaprolactone Melt Fusion ». International Journal of Molecular Sciences 23, n^o 16 (15 août 2022) : 9166. http://dx.doi.org/10.3390/ijms23169166.

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Polymer/layered silicate composites have gained huge attention in terms of research and industrial applications. Traditional nanocomposites contain particles regularly dispersed in a polymer matrix. In this work, a strategy for the formation of a composite thin film on the surface of a polycaprolactone (PCL) matrix was developed. In addition to the polymer, the composite layer was composed of the particles of saponite (Sap) modified with alkylammonium cations and functionalized with methylene blue. The connection between the phases of modified Sap and polymer was achieved by fusing the chains of molten polymer into the Sap film. The thickness of the film of several μm was confirmed using electron microscopy and X-ray tomography. Surfaces of precursors and composite materials were analyzed in terms of structure, composition, and surface properties. The penetration of polymer chains into the silicate, thus joining the phases, was confirmed by chemometric analysis of spectral data and changes in some properties upon PCL melting. Ultimately, this study was devoted to the spectral properties and photoactivity of methylene blue present in the ternary composite films. The results provide directions for future research aimed at the development of composite materials with photosensitizing, photodisinfection, and antimicrobial surfaces.

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Marzuki, Haslan Fadli Ahmad, Mawarni Mohamad, Engku Ahmadhilmi Engku Ubaidillah, Mohd Nasha’ain Nordin, Mohd Fadzlee Zainal Abidin, Norazlan Roslani, Yusli Mohamad Junos, Salleh Omar et Mariatti Jaafar. « Effect of Anodizing on Strength of Carbon-Fibre Aluminium-Laminated Composites ». Advanced Materials Research 748 (août 2013) : 216–21. http://dx.doi.org/10.4028/www.scientific.net/amr.748.216.

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Fibre-metal-laminated composites that consist of aluminium and carbon fibre/epoxy was widely use in engineering fields such as in aerospace and civil application. An issue arise for this laminate systems is that aluminium surfaces must be treated to ensure the effectiveness of load transfer mechanism in the interfacial region. In this research, the effect of anodized layer on the aluminium surface towards strength of the carbon fibre-aluminium-laminated composites was studied. Aluminium 6061-T6 was anodized using phosphoric acid as electrolyte and different anodizing voltage to produce different surface morphology. The surface roughness and morphology were determined via Atomic Force Microscopy and its wettability was determined by Static Contact Angle. Then, anodized aluminium was laminated with carbon fibre/epoxy system via vacuum bagging techniques. It shows that the strength of laminated composite with anodized surface increases up to 26% compared to laminates without anodized surfaces. Furthermore, the failure mechanism of laminated composite with anodized surface resulted in partial adhered failure instead of adhesive failure. These show that anodized surfaces contributes to the effectiveness of load transfer mechanism in fibre-metal-laminates composites.

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Alamaria, Abdulhakim, et Ghazali Nawawi. « Dehydration Pervaporation of Ethyl Acetate-Water Mixture via Sago/PVA Composite Membranes Using Surface Methodology ». Chemistry & ; Chemical Technology 9, n^o 4 (15 décembre 2015) : 479–84. http://dx.doi.org/10.23939/chcht09.04.479.

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Wang, Yilong, Hong Xu, Weili Qiang, Hongchen Gu et Donglu Shi. « Asymmetric Composite Nanoparticles with Anisotropic Surface Functionalities ». Journal of Nanomaterials 2009 (2009) : 1–5. http://dx.doi.org/10.1155/2009/620269.

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Asymmetric inorganic/organic composite nanoparticles with anisotropic surface functionalities represent a new approach for creating smart materials, requiring the selective introduction of chemical groups to dual components of composite, respectively. Here, we report the synthesis of snowman-like asymmetric silica/polystyrene heterostructure with anisotropic functionalities via a chemical method, creating nanostructure possibly offering two-sided biologic accessibility through the chemical groups. Carboxyl group was introduced to polystyrene component of the snowman-like composites by miniemulsion polymerization of monomer on local surface of silica particles. Moreover, amino group was then grafted to remained silica surface through facile surface modification of the composite nanoparticles. The asymmetric shape of these composites was confirmed by TEM characterization. Moreover, characteristics of anisotropic surface functionalities were indicated by Zeta potential measurement and confocal laser microscopy after being labeled with fluorescent dyes. This structure could find potential use as carriers for biological applications.

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Kim, Daeyoung, Heon Kang, Donghyun Bae, Seungjin Nam, Manuel Quevedo-Lopez et Hyunjoo Choi. « Synthesis of reduced graphene oxide/aluminum nanocomposites via chemical-mechanical processes ». Journal of Composite Materials 52, n^o 22 (21 février 2018) : 3015–25. http://dx.doi.org/10.1177/0021998318760152.

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The present study employed a combination of solution-based synthesis and mechanical milling to develop reduced graphene oxide/aluminum composites, in order to achieve uniform dispersion of reduced graphene oxide and strong interfaces between reduced graphene oxide and aluminum. First, spherical aluminum powder was flattened via mechanical milling to afford a large specific surface area and many reaction sites for the graphene oxide. A hydrophilic surface was then created by coating the aluminum powder with polyvinyl alcohol. The polyvinyl alcohol-coated aluminum slurry was mixed with a graphene oxide suspension, thereby inducing a reaction between graphene oxide and polyvinyl alcohol via hydrogen bonding. After thermal reduction, the composite powder was further ball milled and hot-pressed at 500℃ to produce a reduced graphene oxide/aluminum composite. The dispersion of reduced graphene oxide in the composite, as well as the mechanical and thermal behaviors of the composite, improved with increased flattening and specific surface area of the starting aluminum powder.

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Parreño, Ronaldo P., et Arnel B. Beltran. « Hybrid composite of Nafion with surface-modified electrospun polybenzoxazine (PBz) fibers via ozonation as fillers for proton conducting membranes of fuel cells ». RSC Advances 12, n^o 16 (2022) : 9512–18. http://dx.doi.org/10.1039/d2ra00830k.

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Nafion compatibility in the preparation of hybrid composites with electrospun Polybenzoxazine (PBz) surface-modified fibers via ozonation by evaluating the effects on the surface and structure of the composite.

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Wang, Pengjie, Qiang Cao, Yuping Yan, Yangtian Nie, Sheng Liu et Qing Peng. « Graphene Surface Reinforcement of Iron ». Nanomaterials 9, n^o 1 (4 janvier 2019) : 59. http://dx.doi.org/10.3390/nano9010059.

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Graphene is an ideal material in the reinforcement of metal-matrix composites owing to its outstanding mechanical and physical properties. Herein, we have investigated the surface enhancement of iron via a computational nanoindentation process using molecular dynamics simulations. The findings of our study show that graphene can enhance the critical yield strength, hardness and elastic modulus of the composite to different degrees with the change of the number of graphene layers. In the six tested models, the composite with trilayer graphene on the surface produces the strongest reinforcement, with an increased magnitude of 432.1% and 169.5% in the hardness and elastic modulus, respectively, compared with pure iron. Furthermore, it is revealed that high temperature could weaken the elastic bearing capacity of the graphene, resulting in a decrease on the elastic mechanical properties of the graphene/Fe composite.

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Dahotre, Narendra B., et Arvind Agarwal. « Refractory ceramic-composite coatings via laser surface engineering ». JOM 51, n^o 4 (avril 1999) : 19–21. http://dx.doi.org/10.1007/s11837-999-0073-z.

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Mazov, I. N., V. L. Kuznetsov, D. V. Krasnikov, N. A. Rudina, A. I. Romanenko, O. B. Anikeeva, V. I. Suslyaev, E. Yu Korovin et V. A. Zhuravlev. « Structure and Properties of Multiwall Carbon Nanotubes/Polystyrene Composites Prepared via Coagulation Precipitation Technique ». Journal of Nanotechnology 2011 (2011) : 1–7. http://dx.doi.org/10.1155/2011/648324.

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Coagulation technique was applied for preparation of multiwall carbon nanotube- (MWNT-)containing polystyrene (PSt) composite materials with different MWNT loading (0.5–10 wt.%). Scanning and transmission electron microscopies were used for investigation of the morphology and structure of produced composites. It was shown that synthesis of MWNT/PSt composites using coagulation technique allows one to obtain high dispersion degree of MWNT in the polymer matrix. According to microscopy data, composite powder consists of the polystyrene matrix forming spherical particles with diameter ca. 100–200 nm, and the surface of MWNT is strongly wetted by the polymer forming thin layer with 5–10 nm thickness. Electrical conductivity of MWNT/PSt composites was investigated using a four-probe technique. Observed electrical percolation threshold of composite materials is near to 10 wt.%, mainly due to the insulating polymer layer deposited on the surface of nanotubes. Electromagnetic response of prepared materials was investigated in broadband region (0.01–4 and 26–36 GHz). It was found that MWNT/PSt composites are almost radiotransparent for low frequency region and possess high absorbance of EM radiation at higher frequencies.

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Abdulmalik, Samir Sani, et Rosli Ahmad. « Fabrication of AA6061-0/RHA Surface Composite via Friction Stir Processing ». Applied Mechanics and Materials 660 (octobre 2014) : 214–18. http://dx.doi.org/10.4028/www.scientific.net/amm.660.214.

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Friction stir processing is a novel process evolved to fabricate surface metal matrix composites. Rice husk ash (RHA) is an agro-industrial waste and by product of rice husk. The feasibility of incorporating RHA powder into aluminium alloy AA6061-0 as reinforcement particles to make surface matrix composite via FSP is reported in this paper. The optical micrographs revealed a homogeneous distribution of RHA particles which were well bonded with the matrix in both first and fourth-passes of the FSP due to mechanical stirring. Microhardness of the stir zone SZ with the RHA particles of I-pass increased to about 106 HV, 40% higher than that of the base material 66 HV by dispersed RHA particles.

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Wang, Xiang-Qin, Bin-Jie Xin et Jian Xu. « Preparation of Conductive PANI/PVA Composites via an Emulsion Route ». International Journal of Polymer Science 2013 (2013) : 1–6. http://dx.doi.org/10.1155/2013/903806.

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A facile and novel strategy for preparing polyaniline/polyvinyl alcohol (PANI/PVA) composite emulsion is reported wherein the reaction is carried out via the emulsion polymerization using ammonium peroxydisulfate (APS) as the oxidizing agent and dodecylbenzene sulfonic acid (DBSA) as the protonic acid. The PANI/PVA composite membranes have been characterized using optical microscope, scanning electron microscope (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and electrochemical workstation. It is interesting that the electrical conductivity of the PANI/PVA composites is estimated to be as high as 1.28 S/cm. The experimental results show that the surface of PANI/PVA composite membranes exhibits good integrity. The PANI particles at the nanoscale are dispersed in the PVA matrix, and the electrochromic behaviors of PANI/PVA composites obtained at different polymerization temperatures can be compared based on cyclic voltammetry (CV) curves, revealing that PANI/PVA composites synthesized at room temperature are better than those synthesized at low temperature.

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Hu, Ke, Quan Xin Xu et Xiao Long Yang. « Fabrication of Superhydrophobic Surfaces on Copper Substrates via Brush Plating Technique ». Advanced Materials Research 834-836 (octobre 2013) : 662–69. http://dx.doi.org/10.4028/www.scientific.net/amr.834-836.662.

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Superhydrophobic surfaces on metal substrates are often prepared via roughing the surfaces and lowering their surface energy. Composite brush plating technique is developed to prepare superhydrophobic n-SiO2/Ni brush plating composite coating on copper surfaces. Under the better process parameters, the water contact angle of the obtained superhydrophobic surface is approximately 160°, and the water sliding angle is less than 10°. The influences of plating voltage and plating time on the coating surface structure and hydrophobicity were discussed. The surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).The results show that the prepared surfaces have the appearance of the uniform micron papilla-like structures, which are composed of submicron globular Ni particles covered with n-SiO2nanoscale villiform structures. These hierarchical micro/nanostructures are similar to the lotus leaf and play an important role in gaining superhydrophobicity. It is expected that this sample technique will be widely used for large-scale production of superhydrophobic engineering materials.

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Jahanzad, Fatemeh, Siobhan Mobberley, Basu Saha et Brian W. Brooks. « Composite polymer particles via concentrated emulsification ». Colloids and Surfaces A : Physicochemical and Engineering Aspects 302, n^o 1-3 (juillet 2007) : 286–92. http://dx.doi.org/10.1016/j.colsurfa.2007.02.045.

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Wen, Shi Bao, Guo Wei Li et Qi Ye Wu. « Preparation of Conductive PANI/Modified CIP Composites via In Situ Polymerization ». Advanced Materials Research 557-559 (juillet 2012) : 295–99. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.295.

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A conductive PANI/CIP composite with core/shell structure was prepared by in-situ polymerization of Aniline(Ani). In order to reduce the acid corrosion on carbonyl iron powders(CIP) in polymerization of Ani, the surface of CIP was modified by (3-aminopropyl)-triethoxysilane (APTES) before the polymerization. The influences of modification on Ani polymerization, the morphology changes of core/shell structure and conductivity of PANI/CIP composites were characterised and discussed. The results show that after CIP modified by APTES, the reaction process of Ani polymerization is more stable; the PANI particles on the surface of CIP are smaller, and more uniform and more compact; The coating effect of PANI on the surface of CIP is significantly improved; The composite conductivity changes slightly with the modification.

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Zhang, Qing, Lin Lu, Meina Liang, Dunqiu Wang, Daolin Huang et Yinian Zhu. « Efficient treatment of lead-containing wastewater using bagasse biochar modified via hydroxylapatite ». BioResources 17, n^o 1 (5 janvier 2022) : 1205–31. http://dx.doi.org/10.15376/biores.17.1.1205-1231.

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A hydroxylapatite bagasse biochar composite was prepared via the hydrothermal chemical precipitation method with bagasse as the primary raw material. The adsorption capacity of hydroxylapatite bagasse biochar composite for Pb(II) was determined using a series of batch adsorption experiments. The results showed that the point of zero charge value was near neutral pH, and the optimal pH ranged from 4.0 to 7.0. Langmuir isotherms were suitable for fitting the isothermal adsorption process of Pb(II) by the hydroxylapatite bagasse biochar composite. The maximum adsorption capacity of hydroxylapatite bagasse biochar composite in terms of Pb(II) was 210 mg·g-1 at 25 °C. Fourier transform infrared spectrometry analysis indicated that oxygen-containing functional groups were abundant on the external and internal surfaces of the composite sample, which provided numerous chemical sorption sites and resulted in an increase in the adsorption capacity of the composite sample. The Pb(II) removal mechanism of the hydroxylapatite bagasse biochar composite primarily utilized surface diffusion, electrostatic attraction, surface complexation, ion exchange, and a dissolving-coprecipitation reaction. The composite sample was suitable for the treatment of lead-contaminated water (containing zinc, arsenic, cadmium, etc.), which was a promising environmentally friendly material.

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Raja, R., Sabitha Jannet et Titus Thankachan. « Investigation of hybrid copper surface composite synthesized via FSP ». Materials and Manufacturing Processes 36, n^o 12 (26 avril 2021) : 1377–83. http://dx.doi.org/10.1080/10426914.2021.1914841.

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Sun, Ning, et Diran Apelian. « Composites Fabrication via Friction Stir Processing ». Materials Science Forum 690 (juin 2011) : 125–28. http://dx.doi.org/10.4028/www.scientific.net/msf.690.125.

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Friction stir processing (FSP) is a post-processing method that locally manipulates the microstructure by imparting a high level of energy in the solid state giving rise to improved mechanical properties. Additionally, FSP has emerged as an advanced tool to produce surface composites and synthesize the second phase into the matrix. In the current study, FSP was investigated for the manufacture of localized zones of composite materials made by the emplacement of a second phase into cast A206 Al alloy matrix. Both the discontinuously reinforced aluminum (DRA) and some encapsulated powders (nano-sized SiC or Ta) were used for the second phase emplacement. Through SEM and EDS mapping, the morphology and distribution of second phase particles have been studied. The work shows that friction stir processing is a viable means of producing localized composite zones in Al components.

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Zhang, M. Y., L. Z. Liu, L. Weng, W. W. Cui et K. S. Hui. « Fabrication and characterization of polyimide/Al2O3 composite films via surface modification and ion exchange technique ». Pigment & ; Resin Technology 45, n^o 1 (4 janvier 2016) : 30–37. http://dx.doi.org/10.1108/prt-01-2015-0009.

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Purpose – The aim of this study was to fabricate polyimide (PI)/Al2O3 composite films via surface modification and ion exchange techniques, and examine their properties. Design/methodology/approach – The method involves hydrolyzing the PI film double surface layers in an aqueous potassium hydroxide (KOH) solution and incorporating aluminium ions (Al3+) into the hydrolyzed layers of the PI film via subsequent ion exchange, followed by a treatment of the Al3+-loaded PI films with an aqueous ammonia solution, which leads to the formation of Al(OH)3 in the surface-modified layers. After a final thermal annealing treatment in ambient air, the Al(OH)3 decomposes to Al2O3, and forms composite layers on both surfaces of the re-imidized PI film. Findings – The PI/Al2O3 composite film obtained with a 6 hours of KOH treatment exhibited excellent thermal stability, good mechanical properties and better electric breakdown strength and corona-resistance properties than the pristine PI film. Practical implications – The method for obtaining the composite films in this paper is worth consideration, but additional research will be needed. Furthermore, this method is of general importance for the fabrication of composite PI films with tailored properties. Originality/value – This study showed that surface modification and ion-exchange techniques are powerful methodologies for the fabrication of PI/Al2O3 composite films.

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Wachowski, Marcin, Justyna Zygmuntowicz, Robert Kosturek, Paulina Piotrkiewicz, Radosław Żurowski, Anna Więcław-Midor et Lucjan Śnieżek. « Study on Manufacturing via Slip Casting and Properties of Alumina-Titanium Composite Enhanced by Thialite Phase ». Materials 16, n^o 1 (22 décembre 2022) : 79. http://dx.doi.org/10.3390/ma16010079.

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This paper aims to study the Al2O3/Ti ceramic-metal composite obtained by the slip casting method. Samples containing 50% volume of the solid phase, including 10% volume of the metallic phase, were investigated. The rheological properties were analyzed. Thermogravimetric analysis was performed. The properties of the obtained composite determined the phase composition using and SEM/EDS microstructural analysis and the XRD method. The size of the titanium particles equals 20.6 ± 10.1 mm, which corresponds to 27.5% of the initial size and indicates significant fragmentation of the titanium powder during the manufacturing of the composite. The relative density of the fabricated composites was equal to 99%. The slip casting method allows to obtain the proposed composite additionally enhanced by the presence of TiO2 and Al2TiO5 (thialite). Research results revealed a non-Newtonian character of the composite suspension flow with clear thinning under the influence of increasing shear forces. The obtained composites are characterized by the lack of visible defects (cracks, microcracks and delamination) on the surface.

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Imai, Hisashi, Katsuyoshi Kondoh et Junko Umeda. « Mechanical Properties of PM CNT-Dispersed Cu Composite ». Key Engineering Materials 737 (juin 2017) : 320–25. http://dx.doi.org/10.4028/www.scientific.net/kem.737.320.

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Microstructural and mechanical properties of powder metallurgy (PM) with carbon nanotube (CNTs) dispersed copper (Cu) composites were investigated in detail. Pure copper powder was coated with un-bundled CNTs by using the zwitterionic surfactant solution containing CNTs. The powder rolling process was applied to increase the powder surface area to be coated with CNTs. The total rolling reduction of Cu-CNT composite powder by 5 steps rolling was about 75%. With increasing the number of rolling steps, the content of CNTs coated on the Cu powder surface increased because of the increment of the flat surface area of flaky Cu rolled powder. As a result, the CNT content was 0.67mass% after 5 steps powder rolling. It was about twice as that of as-coated Cu-CNT composite powder without rolling. The grain size of PM extruded Cu-CNT composite was about one fifth of that of the extruded monolithic Cu material without CNT. Yield stress of the extruded Cu-CNT composite via the rolling process was 192 MPa, which is about twice that of the extruded monolithic Cu material (88 MPa). CNTs distributed at primary particle boundaries were effective to prevent the grain coarsening by their pinning effects, and this grain refinement was the main strengthening factor of the Cu-CNT composite via rolling process.

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Li, Mei Juan, Qiang Shen, Fei Chen, Lian Meng Zhang et L. F. Yao. « Effects of Coated Nano-BN Particles on Microstructure and Properties of BN-AlN Composite ». Advanced Materials Research 66 (avril 2009) : 89–92. http://dx.doi.org/10.4028/www.scientific.net/amr.66.89.

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Surface coating has been used to prepare nano-particle BN-AlN composite powder. Nano-BN was synthesized via in-situ reaction, coating on the surface of AlN particles. The effects of coated nano-BN on the microstructure and properties of BN-AlN composites have been investigated. Results indicate that the microstructure and properties of BN-AlN composites are very different from the origin composite powders. Nano-BN particles cause the homogeneous microstructure and reinforce the grain boundary of BN-AlN composites. They exhibit similar regularity of reinforce effect of ceramic nano-particle and enhances remarkably the composites’ mechanical strength. But nano-BN will introduce more grain interfaces, more oxygen-related defects in grain lattice to increase phonon scattering and reduce the thermal conductivity of BN-AlN composites.

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Ali, Mohamed E. A., Fathy M. Hassan et Xianshe Feng. « Improving the performance of TFC membranes via chelation and surface reaction : applications in water desalination ». Journal of Materials Chemistry A 4, n^o 17 (2016) : 6620–29. http://dx.doi.org/10.1039/c6ta01460g.

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We modified TFC membranes via a series of chemical and surface reactions. A nascent polyamide (PA) active layer was prepared by interfacial polymerization and composited with GO nanosheets then reacted with CuCl₂·2H₂O. Finally, the composite membrane was treated with NH₄OH solutions.

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Kawajiri, Yohei, Hiroshi Ikeda, Yuki Nagamatsu, Chihiro Masaki, Ryuji Hosokawa et Hiroshi Shimizu. « PICN Nanocomposite as Dental CAD/CAM Block Comparable to Human Tooth in Terms of Hardness and Flexural Modulus ». Materials 14, n^o 5 (3 mars 2021) : 1182. http://dx.doi.org/10.3390/ma14051182.

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Polymer infiltrated ceramic network (PICN) composites are an increasingly popular dental restorative material that offer mechanical biocompatibility with human enamel. This study aimed to develop a novel PICN composite as a computer-aided design and computer-aided manufacturing (CAD/CAM) block for dental applications. Several PICN composites were prepared under varying conditions via the sintering of a green body prepared from a silica-containing precursor solution, followed by resin infiltration. The flexural strength of the PICN composite block (107.8–153.7 MPa) was similar to a commercial resin-based composite, while the Vickers hardness (204.8–299.2) and flexural modulus (13.0–22.2 GPa) were similar to human enamel and dentin, respectively. The shear bond strength and surface free energy of the composite were higher than those of the commercial resin composites. Scanning electron microscopy and energy dispersive X-ray spectroscopic analysis revealed that the microstructure of the composite consisted of a nanosized silica skeleton and infiltrated resin. The PICN nanocomposite block was successfully used to fabricate a dental crown and core via the CAD/CAM milling process.

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Zhu, Chenkai, Lei Nie, Xiaofei Yan, Jiawei Li et Dongming Qi. « Ramie fiber reinforced composites with flame retardant structure design : flammability, smoke suppression, and mechanical properties ». Journal of Polymer Engineering 42, n^o 1 (29 novembre 2021) : 9–17. http://dx.doi.org/10.1515/polyeng-2021-0221.

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Abstract In this work, the structure of composite was designed as Core Stack and Surface Stack, which was treated with the expandable graphite (EG) and metal oxides such as iron oxide (IO), hydroxyapatite (HA), and aluminum tri-hydroxide (ATH). The mechanical performance of composites was characterized via flexural performance and interlaminar shear strength analysis. The flame retardance and smoke suppression of composite was explored in detail by LOI, UL-94, and cone calorimeter test. The findings presented that flexural properties of composites were observed to decrease due to delamination of surface stack, whilst no significant effect on interlaminar shear strength. In comparison with control composite, the loading of metal oxide into composite Surface Stack led to the reduction of peak heat release rate, total heat release, and fire growth index effectively. Moreover, the remarkable decrease in total smoke production could be observed due to the addition of iron oxide and the flame retardant mechanism was discussed. This study was the preliminary exploration of composite with flame retardant design which could be potential solution to improve flame retardancy and smoke suppression of composite with better mechanical structure preservation.

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WANG, Teng, Zhaofu MENG, Xinxin WANG, Amjad ALI, Xuewen CAO et Lin LIU. « Mechanism of nitrogen-fluoride co-doped TiO2/bentonite composites removing tetracycline : A study in the co-doping ratio ». Environmental Engineering Research 26, n^o 6 (3 décembre 2020) : 200440–0. http://dx.doi.org/10.4491/eer.2020.440.

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N-doped and N-F co-doped TiO2/bentonite composites were synthesized via the gel-sol method. The morphology, structure and surface charge of the composite before and after adsorption were used to determine the effect N/F doping ratio on TC removal. The results showed that, compared with undoped samples, the TC adsorption on N doped composites was reduced by 24.44% on average. N-F co-doping significantly increased the TC adsorption when the Ti-N-F molar ratio was 1:1: 0.01, reaching a maximum TC adsorption of 64.00 mmol·kg<sup>-1</sup>. The coverage of the N doped TiO2 increases as the N doping ratio increases; the specific surface area increased by 2.03 % on average, but the number of surface negative charges decreased by 36.24 % on average. FT-IR results confirmed that N doping reduced the number of -OH groups on the N-doped composites. Additionally, fluorination of N-F co-doped TiO2 and bentonite surfaces inhibits hydrogen bonding and π-π interactions between the TC and the composites. As the N doping ratio increased, the coverage of N-F co-doped TiO2 on the composite surface increased, resulting in the TC adsorption decrease with the increases N doping ratio.

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Kim, Kiho, Seokgyu Ryu et Jooheon Kim. « Highly dispersible laser activate particles via surface modification for laser direct structuring and electroless plating application ». Journal of Composite Materials 53, n^o 10 (3 septembre 2018) : 1377–86. http://dx.doi.org/10.1177/0021998318798453.

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A composite of laser-activate particles and the super engineering plastic of polyphenylene sulfide was fabricated via melt-mixing. The laser-activate particle surfaces were modified using hydroperoxide and three different silane coupling agents. The laser-activate particles dramatically deteriorate the mechanical properties of polyphenylene sulfide because of its low compatibility with the polymer. However, surface modification, especially via amino silane treatment, effectively prevented the degradation of thermal and mechanical properties upon adding laser-activate particle, while modification with phenyl silane had the reverse effect. In order to confirm the different effects, solubility parameters obtained by theoretical calculation via the group contribution method were compared. Thermally and mechanically enhanced laser-activate particle/polyphenylene sulfide composites were fabricated for laser direct structuring and electroless plating applications.

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Shamsipur, Ali, Seyed-Farshid Kashani-Bozorg et Abbas Zarei-Hanzaki. « Surface Modification of Titanium by Producing Ti/TiN Surface Composite Layers via FSP ». Acta Metallurgica Sinica (English Letters) 30, n^o 6 (14 février 2017) : 550–57. http://dx.doi.org/10.1007/s40195-017-0529-z.

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Zhang, Ju Xian, Long Liang et Jin Jun Feng. « Preparation of AlN-BN Composite by Composite Powders ». Materials Science Forum 546-549 (mai 2007) : 1559–62. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.1559.

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AlN-BN composite Powders with the microstructure of micrometer-sized AlN particles coated with BN particles were prepared via a chemical reaction, which used a mixture of boric acid (H3BO3) and urea (CO(NH2)2) as reactants coated on the surface of the AlN particles to react in nitrogen ambient. The XRD and TEM studies showed that the coating layer (BN) was composed mostly of amorphous BN particles at the reaction temperature of 850oC ~1100oC. When the composite powders formed into pellets using cold isostatic-pressing, then, sintered at pressureless sintering, the relative density of the composites that contained 15wt% BN reached above 98%, and there was homogeneous microstructure.

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Anwar ul Haq Ali Shah, Anwar ul Haq Ali Shah, Saima Shaheen Saima Shaheen, Muhammad Kamran Muhammad Kamran et Humaira Seema Rizwan Ullah and Salma Bilal Humaira Seema Rizwan Ullah and Salma Bilal. « Synthesis of Soluble and Highly Thermally Stable Polyaniline- Titanium Dioxide Composite via Inverse Emulsion Polymerization ». Journal of the chemical society of pakistan 41, n^o 6 (2019) : 921. http://dx.doi.org/10.52568/000809/jcsp/41.06.2019.

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Polyaniline (PANI)/Titanium dioxide (TiO2) composites were prepared by polymerization of aniline in the presence of TiO2 using inverse emulsion polymerization protocol. In this method 2-butanol and chloroform were used as dispersing media and the materials were tested for corrosion protection of stainless steel in Indian Ocean water. The amount of aniline, oxidant (Benzoyl peroxide), Dodecylbenzenesulphonic acid (DBSA) surfactant and metal oxide (TiO2) were varied in the reaction bath for optimum yield. The as-synthesized PANI and PANI-TiO2 composites were soluble in a number of common organic solvents and characterized with Ultravilot-visivble (UVand#172;-Vis) and Fourier Transform Infra-Red (FT-IR) spectroscopies. The surface morphology, particle size and crystinality were determined with Scanning Electron Microscopy (SEM) and X-Rays Diffraction (XRD) analysis. Thermogravimetric analysis (TGA) was employed to determine thermal stability of the composite. The total mass loss was found to be 58% in PANI as compared to 22% in PANI-TiO2 showing comparatively higher thermal stability of the composites. The composites were electrochemically active in acidic medium and reduced corrosion rate of steel to 0.9083 mm/ year Indian Ocean water. Finally it was concluded that PANI-TiO2 composites could be employed as anticorrosive coatings for steel in aggressive corrosive environment

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Yang, Zhe Wei, Xin Fan, Li Ang Guo et Wei Ting Wei. « Graphene Oxide/Fe₃O₄ Composites Prepared via In Situ Precipitation ». Advanced Materials Research 904 (mars 2014) : 150–54. http://dx.doi.org/10.4028/www.scientific.net/amr.904.150.

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The graphene oxide/Fe3O4 composites were prepared by in situ precipitation method in this article. The microstructure and surface morphology of composites were characterized by Fourier transform infrared spectrum, X-ray diffraction and scanning electron microscopy, respectively. Cyclic voltammetry was employed for the determination of specific capacitance and other electrochemical performances. It was shown that there was the chemical bonding force between GO and Fe3O4 particles. And the surfaces of GO were wrapped by the Fe3O4 particles precipitated on the surfaces of GO sheets and no impurities were detected. Furthermore, the specific capacitance of GO/Fe3O4 composite electrodes decreased as Fe3O4 particles reduced and the redox peaks became weaker owing to the addition of nonconductive Fe3O4 particles.

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He, Mingping, Jianguang Li, Wanli Xu, Zhenqiang Dong, Yuechao Wu et Liang Lv. « Carbon Nanotubes/MnO2 Composite Fabricated via Laser Welding and Electrodeposition as Flexible Electrode for Supercapacitors ». Nano 14, n^o 06 (juin 2019) : 1950074. http://dx.doi.org/10.1142/s1793292019500747.

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Carbon nanotubes (CNTs) were welded on the surface of thermoplastic polypropylene (PP) substrate by laser irradiation and then manganese dioxide (MnO2) was deposited on the surface of CNTs by electrochemical method to prepare CNTs/MnO2 flexible electrodes (L-CM). The microstructure and morphology of CNTs/MnO2 composites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The results showed that CNTs were welded on the surface of the substrate, adhering to each other to form a porous network structure. In addition, there were distinct small protrusions on the surface of CNTs, indicating that MnO2 had been successfully deposited on the surface of CNTs. Cyclic voltammogram (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques were employed to investigate the electrochemical performance of the composites. Compared with CNTs/MnO2 composite prepared via compaction (denoted as C-CM), L-CM composite prepared under the laser power of 0.75[Formula: see text]W (denoted as L-CM75) showed a larger capacitance of 214.6[Formula: see text]F[Formula: see text]g[Formula: see text] at the current density of 0.5[Formula: see text]A[Formula: see text]g[Formula: see text] and displayed excellent bendability, demonstrating capacitance retention of approximately 89.6% after 1000 bending cycles. The excellent performance of L-CM75 may be attributed to the fact that the CNTs welded on the substrate have formed an effective conductive network whose porous structure can facilitate easy access of electrolytes to the electrode, which results in enhancement of the electrochemical performance of L-CM75.

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Xie, Hongbin, Weimian Guan, Hao Lv, Huiya Yang, Mingyu Gao, Youtong Fang, Jiabin Liu et Hongtao Wang. « W–Cu/Cu composite electrodes fabricated via laser surface alloying ». Materials Characterization 185 (mars 2022) : 111715. http://dx.doi.org/10.1016/j.matchar.2021.111715.

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Bisadi, Hossein, et Asghar Abasi. « Fabrication of Al7075/TiB2 Surface Composite Via Friction Stir Processing ». American Journal of Materials Science 1, n^o 2 (31 août 2012) : 67–70. http://dx.doi.org/10.5923/j.materials.20110102.10.

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Guo, Xiaomin, Bin Zheng et Jinlei Wang. « Controllable Synthesis of Metal-Organic Framework/Polyethersulfone Composites ». Crystals 10, n^o 1 (15 janvier 2020) : 39. http://dx.doi.org/10.3390/cryst10010039.

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Composite materials that contain metal-organic frameworks (MOFs) as a filler and a polymer matrix have attracted attention because they present a combination of high porosity and structural integrity. Phase compatibilities of the MOF and polymer play a vital role in the formation of the composites. In particular, the stiff polymer cannot easily adapt to penetrate into the surface pore of MOF and mainly depends on chemical attractions to form the MOF/polymer composites. We report the synthesis of MOF/polyethersulfone (Young’s modulus = ~2.6 GPa) via different fabrication methods, different MOF types and particle sizes, and different solvents. The formed network structures are robust, monolithic composites with 60% MOF loadings; also, the MOF surface area and porosity were fully preserved. The study explored the formation of the composite between MOF and a stiff polymer and encourages the design of more MOF/polymer composite materials across a wide range of applications.

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Lee, Daiheon, Hirotaka Maeda, Akiko Obata, Keiichi Inukai, Katsuya Kato et Toshihiro Kasuga. « Aluminum Silicate Nanotube Modification of Cotton-Like Siloxane-poly(L-lactic acid)-vaterite Composites ». Advances in Materials Science and Engineering 2013 (2013) : 1–6. http://dx.doi.org/10.1155/2013/169721.

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In our earlier work, a cotton-like biodegradable composite, consisting of poly(L-lactic acid) with siloxane-containing vaterite, has been prepared by electrospinning. In the present work, the fibers skeleton of the cotton-like composites was modified successfully with imogolite, which is hydrophilic and biocompatible, via a dip process using ethanol diluted solution to improve the cellular initial attachment. Almost no change in the fiber morphology after the surface modification was observed. The surface-modified composite showed the similar calcium and silicate ions releasabilities, for activating the osteoblasts, as an unmodified one. Cell culture tests showed that the initial adhesion of murine osteoblast-like cells on the surface of the fibers was enhanced by surface modification.

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Katcharava, Zviadi, Anja Marinow, Rajesh Bhandary et Wolfgang H. Binder. « 3D Printable Composite Polymer Electrolytes : Influence of SiO2 Nanoparticles on 3D-Printability ». Nanomaterials 12, n^o 11 (29 mai 2022) : 1859. http://dx.doi.org/10.3390/nano12111859.

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We here demonstrate the preparation of composite polymer electrolytes (CPEs) for Li-ion batteries, applicable for 3D printing process via fused deposition modeling. The prepared composites consist of modified poly(ethylene glycol) (PEG), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) and SiO2-based nanofillers. PEG was successfully end group modified yielding telechelic PEG containing either ureidopyrimidone (UPy) or barbiturate moieties, capable to form supramolecular networks via hydrogen bonds, thus introducing self-healing to the electrolyte system. Silica nanoparticles (NPs) were used as a filler for further adjustment of mechanical properties of the electrolyte to enable 3D-printability. The surface functionalization of the NPs with either ionic liquid (IL) or hydrophobic alkyl chains is expected to lead to an improved dispersion of the NPs within the polymer matrix. Composites with different content of NPs (5%, 10%, 15%) and LiTFSI salt (EO/Li+ = 5, 10, 20) were analyzed via rheology for a better understanding of 3D printability, and via Broadband Dielectric Spectroscopy (BDS) for checking their ionic conductivity. The composite electrolyte PEG 1500 UPy2/LiTFSI (EO:Li 5:1) mixed with 15% NP-IL was successfully 3D printed, revealing its suitability for application as printable composite electrolytes.

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Zuo, Hong-mei, Dian-sen Li, David Hui et Lei Jiang. « The multiscale enhancement of mechanical properties of 3D MWK composites via poly(oxypropylene) diamines and GO nanoparticles ». Nanotechnology Reviews 8, n^o 1 (31 décembre 2019) : 587–99. http://dx.doi.org/10.1515/ntrev-2019-0052.

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AbstractInterfacial bonding between the fibers and matrix plays a large role in mechanical properties of composites. In this paper, poly(oxypropylene) diamines (D400) and graphene oxide (GO) nanoparticles were grafted on the desized 3D multi axial warp knitted (MWK) glass fiber (GF) fabrics. The surface morphology and functional groups of modified glass fibers were characterized by scanning electron microscopy (SEM) and fourier transform infrared spectra (FT-IR). Out-of-plane compression properties and the failure mechanisms of composites at different temperature were tested and analyzed. The results revealed that GO nanoparticles were successfully grafted on fibers under the synergistic effect of D400. In addition, D400-GO-grafted composite possessed the highest mechanical properties than desized composite and GO-grafted composite. Their strength and modulus were improved by 10.16%, 10.06%, 8.92%, 8.75%, 7.76% and 40.38%, 32.74%, 29.85%, 26.98%, 25.16% compared to those of desized composites at 30∘C, 60∘C, 90∘C, 120∘C, 150∘C, respectively. The damage to D400-GO-grafted composite was yarns fracture accompanied with fibers breakage, matrix cracking, interface debonding. At higher temperature, interlayer slipping with matrix plasticization was the main failure mode.

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Cavdar, Kadir, et Mahmut Bingol. « Investigation of Mechanical Properties of Basalt Particle-Filled SMC Composites ». International Journal of Polymer Science 2016 (2016) : 1–6. http://dx.doi.org/10.1155/2016/1231606.

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Basalt particles have been investigated as a novel additive for the production of glass fibre reinforced composite using sheet moulding compound (SMC) method. Compared to the CaCO3that are widely used as filler in the SMC composite, the resulting composites exhibit improved mechanical properties. The tensile strength increased by approximately 15%, whereas the flexural strength was enhanced by 8% in SMC composites prepared by basalt particles. Examination of the surface morphology and interfacial debonding of the specimens is also performed via scanning electron microscopy. Superior strength properties are observed in the basalt particle-reinforced composites compared to those with the CaCO3fillers.

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Rodzeń, Krzysztof, Mary Josephine McIvor, Preetam K. Sharma, Jonathan G. Acheson, Alistair McIlhagger, Mozaffar Mokhtari, Aoife McFerran, Joanna Ward, Brian J. Meenan et Adrian R. Boyd. « The Surface Characterisation of Fused Filament Fabricated (FFF) 3D Printed PEEK/Hydroxyapatite Composites ». Polymers 13, n^o 18 (15 septembre 2021) : 3117. http://dx.doi.org/10.3390/polym13183117.

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Polyetheretherketone (PEEK) is a high-performance thermoplastic polymer which has found increasing application in orthopaedics and has shown a lot of promise for ‘made-to-measure’ implants via additive manufacturing approaches. However, PEEK is bioinert and needs to undergo surface modification to make it at least osteoconductive to ensure a more rapid, improved, and stable fixation that will last longer in vivo. One approach to solving this issue is to modify PEEK with bioactive agents such as hydroxyapatite (HA). The work reported in this study demonstrates the direct 3D printing of PEEK/HA composites of up to 30 weight percent (wt%) HA using a Fused Filament Fabrication (FFF) approach. The surface characteristics and in vitro properties of the composite materials were investigated. X-ray diffraction revealed the samples to be semi-crystalline in nature, with X-ray Photoelectron Spectroscopy and Time-of-Flight Secondary Ion Mass Spectrometry revealing HA materials were available in the uppermost surface of all the 3D printed samples. In vitro testing of the samples at 7 days demonstrated that the PEEK/HA composite surfaces supported the adherence and growth of viable U-2 OS osteoblast like cells. These results demonstrate that FFF can deliver bioactive HA on the surface of PEEK bio-composites in a one-step 3D printing process.

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Kulkova, Julia, Niko Moritz, Hannu Huhtinen, Riina Mattila, Ivan Donati, Eleonora Marsich, Sergio Paoletti et Pekka K. Vallittu. « Bioactive glass surface for fiber reinforced composite implants via surface etching by Excimer laser ». Medical Engineering & ; Physics 38, n^o 7 (juillet 2016) : 664–70. http://dx.doi.org/10.1016/j.medengphy.2016.04.003.

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De Nino, Antonio, Fabrizio Olivito, Vincenzo Algieri, Paola Costanzo, Antonio Jiritano, Matteo Antonio Tallarida et Loredana Maiuolo. « Efficient and Fast Removal of Oils from Water Surfaces via Highly Oleophilic Polyurethane Composites ». Toxics 9, n^o 8 (5 août 2021) : 186. http://dx.doi.org/10.3390/toxics9080186.

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In this study we evaluated the oil adsorption capacity of an aliphatic polyurethane foam (PU 1) and two of its composites, produced through surface coating using microparticles of silica (PU-Si 2) and activated carbon (PU-ac 3). The oil adsorption capacity in diesel was improved up to 36% using the composite with silica and up to 50% using the composite with activated carbon with respect to the initial PU 1. Excellent performances were retained in gasoline and motor oil. The adsorption was complete after a few seconds. The process follows a monolayer adsorption fitted by the Langmuir isotherm, with a maximum adsorption capacity of 29.50 g/g of diesel for the composite with activated carbon (PU-ac 3). These materials were proved to be highly oleophilic for oil removal from fresh water and sea water samples. Regeneration and reuse can be repeated up to 50 times by centrifugation, without a significant loss in adsorption capacity.

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Shinkaryov, Alexander S., Dmitriy Yu Ozherelkov, Ivan A. Pelevin, Sergey A. Eremin, Vyacheslav N. Anikin, Maxim A. Burmistrov, Stanislav V. Chernyshikhin, Alexander A. Gromov et Anton Yu Nalivaiko. « Laser Fusion of Aluminum Powder Coated with Diamond Particles via Selective Laser Melting : Powder Preparation and Synthesis Description ». Coatings 11, n^o 10 (5 octobre 2021) : 1219. http://dx.doi.org/10.3390/coatings11101219.

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This work aims to study the possibility of obtaining Al–C composite from AlSi10MgCu aluminum matrix with the addition of 500 nm-sized diamond particles by selective laser melting (SLM) process. Al–C composite powder was prepared by mechanical mixing to form a uniform cover along the surface of aluminum particles. The diamond content in the resulting AlSi10MgCu-diamond composite powder was equal to 0.67 wt %. The selection of the optimal SLM parameters for the obtained composite material is presented. For materials characterization, the following methods were used: scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) was applied after SLM printing for a detailed investigation of the obtained composites. The presence of carbon additives and the formation of aluminum carbides in the material after the SLM process were demonstrated.

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Kondoh, Katsuyoshi, Thotsaphon Threrujirapapong, Hiroyuki Fukuda et Junko Umeda. « Un-Bundled Carbon Nanotubes Reinforced Light Metal Composites via Powder Metallurgy Route ». Materials Science Forum 690 (juin 2011) : 339–42. http://dx.doi.org/10.4028/www.scientific.net/msf.690.339.

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By using light metal (Mg, Al, Ti) powders coated with un-bundled multi-wall carbon nanotubes (MWCNTs) via wet process, powder metallurgy (P/M) light metal matrix composite reinforced with un-bundled nanotubes was prepared by spark plasma sintering (SPS) and subsequently hot extrusion process. The microstructure and mechanical properties of the composites were evaluated. In the case of pure titanium, the distribution of CNTs and in-situ formed titanium carbide (TiC) compounds during sintering was investigated by optical and scanning electron microscopy (SEM) equipped with EDS analyzer. The mechanical properties of TMC were significantly improved by the additive of CNTs. For example, when employing the pure titanium composite powder coated with CNTs of 0.35 mass%, the increase of tensile strength and yield stress of the extruded TMC was 157 MPa and 169 MPa, respectively, compared to those of extruded titanium materials with no CNT additive. Fractured surfaces of tensile specimens were analyzed by SEM, and the uniform distribution of CNTs and TiC particles, being effective for the dispersion strengthening, at the surface of the TMC were obviously observed. In the case of Mg-Al alloys, in-situ formation of Al2MgC2compounds at the interface between CNTs and Mg-matrix occurred and effective for the tensile transfer loading, and resulted in the increment of tensile strength of the composite material.

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Xiao, Yu Mei, Xu Dong Li, Hong Song Fan, Xiang Dong Zhu, Li Zhao Teng, Zhong Wei Gu et Xing Dong Zhang. « A Novel Preparation Method for Nano-HA/PLA Composite with Grafted PLA ». Key Engineering Materials 309-311 (mai 2006) : 1105–8. http://dx.doi.org/10.4028/www.scientific.net/kem.309-311.1105.

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Good interfacial interaction is crucial for preparation of inorganic-organic materials at a nanometer level. Poly(α-methacrylic acid) (PMAA) was grafted on the PLA surfaces via photooxidization and subsequent UV induced polymerization in an attempt to synthesize nano-hydroxyapatite/poly(lactide) (n-HA/PLA) composites. Grafting of PMAA on the PLA surface was confirmed using FTIR analysis and the size distribution measurement of the grafted-PLA (g-PLA) particles. n-HA/g-PLA composites were in situ synthesized via dropwise addition of Ca2+- and g-PLA containing solution to PO4 3-- solution. The prepared composites were characterized by FTIR, XRD，SEM and TEM means. Analytical results indicated that the g-PLA acts as a template to manipulate the nucleation and growth of n-HA crystals and thereby to control the morphology, size and anisotropy of n-HA crystals and their distribution over the organic phase. Chemical linkages and/or interfacial interactions between the n-HA and the g-PLA in the n-HA/g-PLA composite were further discussed.

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Zheng, Shu-Qin, Shao Ren, Hong-Xia Yu, Jian-Ce Zhang et Wei Zhu. « Synthesis and application of a porous composite material synthesized via an in situ technique ». Clay Minerals 50, n^o 4 (septembre 2015) : 525–35. http://dx.doi.org/10.1180/claymin.2015.050.4.07.

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AbstractNovel composite materials with wide pores were synthesized by an in situ technique using kaolin, palygorskite and pseudoboehmite as raw materials. The characterization results indicated that the synthesis components and conditions influenced the micro-, meso- and macro-porosity of the composite materials. The composites contained 53.5% zeolite Y and had much larger specific surface areas and pore volumes as well as significant hydrothermal stability. Fluid catalytic cracking (FCC) catalysts were prepared based on the composite materials. The results indicated that the as-prepared catalysts possessed a unique pore structure which assisted in diffusion-controlled reactions. In addition, the attrition resistance, activity and hydrothermal stability of the catalyst studied were superior to those of a reference catalyst. The catalyst studied also exhibited excellent nickel and vanadium passivation performance, strong ‘bottoms upgrading’ selectivity and better gasoline and coke selectivity.

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Thäsler, Torsten, Jens Holtmannspötter et Hans Joachim Gudladt. « Surface Topography Influences on the Fatigue Behavior of Composite Joints ». Key Engineering Materials 809 (juin 2019) : 341–46. http://dx.doi.org/10.4028/www.scientific.net/kem.809.341.

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The surface condition of carbon fibre reinforced plastic (CFRP) substrates is decisive to obtain high bond strength and lifetime of adhesively bonded parts. Those surfaces were adjusted in terms of their microscopic topography by means of peel plies and release foils. The subsequent surface treatment via atmospheric pressure plasma jet or vacuum blasting allowed the modification of the microscopic roughness as well as the surface chemistry. Those configuration were assessed using surface analytic methods as well as quasi-static and cyclic fracture tests on single lap shear specimens. The microscopic surface roughness, if at all, only showed a small influence on the bond strength. Despite release agent residues, fracture was found within the fiber-matrix interface, which caused difficulties in evaluating the effect of surface pretreatments on the adhesion strength. Fatigue tests revealed a lifetime reduction of uneven microscopic rough surfaces, which was assigned to stress concentrations at the tip of asperities. The crack propagation was accelerated in case of release agent residues. If surfaces were free of contaminations, no differences between microscopically smooth and slightly structured surfaces were found. Overall, fatigue testing on single lap shear specimens showed an increased sensitivity with regard to the assessment of surface morphology.

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Lo, Jonathan, Xingyue Zhang, Travis Williams et Steven Nutt. « Eliminating porosity via reformulation of a benzoxazine–epoxy resin transfer molding resin ». Journal of Composite Materials 52, n^o 11 (29 août 2017) : 1481–93. http://dx.doi.org/10.1177/0021998317727048.

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Use of benzoxazine resins in composites is limited by volatile-induced porosity, which degrades the thermomechanical properties of the product. In the present study, we demonstrate how to eliminate cure-induced volatilization and volatile-induced defects in benzoxazine composite laminates, using a chemistry-based approach. Like most resins formulated for high-temperature service, benzoxazine and benzoxazine–epoxy blends generally include solvent additives. Consequently, composite parts produced with such resins exhibit higher levels of cure-induced volatile release, often leading to porosity in the final manufactured part. Here, we develop a method to eliminate porosity by analyzing volatile release and the effects of residual solvent in a pre-commercial benzoxazine–epoxy system designed for liquid molding by resin transfer molding. Utilizing thermogravimetric analysis, nuclear magnetic resonance spectroscopy, and dynamic mechanical analysis, we correlate the concentration of residual solvent remaining within the final manufactured part with the Tg, degradation temperature, and dynamic modulus. Lastly, a resin synthesis method is demonstrated that eliminates residual solvent in order to produce composite parts with optimal surface finish and thermomechanical properties. The report outlines a methodology for optimizing blended resin chemistry for production of high-quality composite parts.

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Odiwo, H., K. A. Bello, M. Abdulwahab, A. A. Adebisi et M. A. Maleque. « PROPERTIES OF ALUMINIUM/ELECTROLESS Ni-COATED SiC COMPOSITES - A REVIEW ». FUDMA JOURNAL OF SCIENCES 5, n^o 1 (28 juin 2021) : 381–91. http://dx.doi.org/10.33003/fjs-2021-0501-582.

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The combination of properties of Al/SiC composites make them very attractive materials for applications in automotive and aerospace industries. Several techniques are used in developing Al/SiC composites but stir casting process is most commonly used because it is the simplest and cost effective technique. However, composites produced via stir casting suffer from limitations such as low wettability and inadequate bonding between the molten Al & SiC particulates and the formation of degrading interfacial products like aluminum carbide (Al4C3) which degrades the mechanical properties of the composite. Some of the techniques to improve Al-SiC wettability include addition of surface active elements such as magnesium, heat treatment of particles and application of metallic coating on the reinforcements before addition to the melt. Wetting agents alter the composition of the matrix alloy, while heat treatment of the reinforcement does not completely prevent the formation of Al4C3 when utilized. To reduce the direct interaction and promote wetting between reinforcements and molten aluminum during processing, the surface of SiC particulates can be modified by coating via oxidation, sol-gel and electroless processes. Of all these methods, electroless nickel deposition produces the best coatings with uniform thickness and adequate strength. In the present study, influence of electroless nickel-coating of SiC on the mechanical, corrosion and microstructural properties of Al/SiC composite has been evaluated. Finally, it can be concluded that the Ni and Ni3P intermetallic phases produced via electroless coating improves the wettability between the SiC and molten aluminium leading to enhanced properties of the composite.

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