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1.
Al-SiC powder preparation for electronic packaging aluminum composites by plasma spray processing 总被引:2,自引:0,他引:2
Powders of pure aluminum (Al) with 55 and 75 vol.% SiC particles were ball milled in a conventional rotating ball mill with
stainless steel and ZrO2 balls for 1–10 h. The morphology and microstructure of the milled powders have been observed and analyzed by scanning electron
microscopy (SEM) and energy dispersive x-ray (EDX). The milled powders were plasma sprayed onto a graphite substrate to obtain
Al matrix composites with high SiC volume fraction. SiC particles in the milled powders existed in two forms; i.e., the combination
of Al into composite powder and individual. Plastic Al particles were broken during ball milling, and fine Al particles can
be coated onto the surface of SiC particles. Iron contamination in the milled powders occurred when stainless steel balls
were used. The iron level can be effectively controlled by using ZrO2 ball media. The milling efficiency by ZrO2 balls is inferior to that by stainless steel balls. Longer milling time was required with ZrO2 balls to achieve the same effect as obtained with stainless steel balls. SiC particles in the sprayed composites from the
milled powders exhibited a reasonably uniform distribution and high volume fraction. 相似文献
2.
Ni-WC composites are ideal protective coatings against wear and are often fabricated using laser cladding and thermal spray processes, but the high temperatures of these processes result in decarburization, which deteriorates the performance of the coating. Cold spray has the potential to deposit Ni-WC composite coatings and retain the composition of the initial WC feedstock. However, the insignificant plastic deformation of hard WC particles makes it difficult to build up a high WC content coating by cold spray. By using three different WC powder sizes, the effect of feedstock powder size on WC retention was tested. To improve WC retention, a WC/Ni composite powder in mixture with Ni was also sprayed. Microstructural characterization, including the deformed structure of Ni splats, retention, distribution, and fragmentation of WC, was performed by scanning electron microscopy. An improvement in WC retention was achieved using finer WC particles. Significant improvement in WC particles retention was achieved using WC/Ni composite powder, with the WC content in the coating being close to that of the feedstock. 相似文献
3.
Since the spontaneous infiltration of molten AZ91 Mg alloy into a powder bed containing SiC particles occurred at 700 °C for
1 h under a nitrogen atmosphere, it was possible to fabricate Mg alloy composites reinforced with SiC particles. Since the
fabrication conditions (e.g. temperature, time, and atmosphere) of the composite are different from those of the other fabrication
route, reaction products formed during the composite fabrication were investigated in detail using field emission scanning
electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HRTEM). From the analysis results, we could
identify the formation of MgAl2O4 and AlN, as well as MgO in fabricated composite. 相似文献
4.
5.
E. Garcia J. Mesquita-Guimar?es P. Miranzo M. I. Osendi C. V. Cojocaru Y. Wang C. Moreau R. S. Lima 《Journal of Thermal Spray Technology》2011,20(1-2):83-91
Mullite-based systems have been considered as environmental barrier coatings (EBCs) for high temperature protection of Si-based ceramic (Si3N4, SiC) substrates against water vapor corrosion, for application in forthcoming turbine engines. Graded mullite/Y-ZrO2 composites plasma sprayed over Hexoloy SiC substrates were analyzed as EBCs. All feedstock materials were purposely prepared and singular spraying conditions were used to assure superior crystallization. The different coated specimens were subjected to temperatures of 1300???C for 100-500?h under water vapor environment. The effect of water corrosion on the exposed coatings was investigated by focusing on their phase and microstructure changes. 相似文献
6.
N.F. Fahim 《Surface & coatings technology》2008,202(9):1696-1703
W/SiC metal matrix composites were produced by gas tunnel type plasma spraying (GTPS) using a mixture of 12 wt.% SiC-88 wt.% W feedstock powder. This work aimed at the optimization of the plasma gun current for deposition of a W/SiC composite with fine microstructure on AISI 304 substrate. Characterization of deposits was performed in order to assess microstructure, micro-hardness, thermal diffusivity and thermal conductivity. WO3 was detected in the composite deposits, which indicated that the tungsten partially oxidized during plasma spraying. Also, the deposit composite was dense and nearly free of pores due to the little mismatch between the coefficient of thermal expansion (CTE) for W and SiC. Microhardness values gradually decreased as a function of input current due to the formation of WO3 and the decomposition of SiC particles in high temperature flame region. The thermal conductivity as high as ∼ 59 W/mK was obtained at gun current 80 A. It was found that both tungsten oxide and structure imperfections have a significant influence on the thermal conductivity and mechanical properties. 相似文献
7.
Friction stir processing (FSP) was utilized to produce surface composites by incorporating nano-sized cerium oxide (CeO2) and silicon carbide (SiC) particles individually and in combined form into the Al5083 alloy matrix. The study signified the role of these reinforcements on microstructure and wear behavior of the resultant surface composite layers. The wear characteristics of the resultant mono and hybrid surface composite layers were investigated using a pin-on-disc wear tester at room temperature. The microstructural observations of FSPed regions and the worn out surfaces were performed by optical and scanning electron microscopy. Considerable grain refinement and uniform distribution of reinforcement particles were achieved inside the nugget zone. All the composite samples showed higher hardness and wear resistance compared to the base metal. Among the composite samples, the hybrid composite (Al5083/CeO2/SiC) revealed the highest wear resistance and the lowest friction coefficient, whereas the Al5083/SiC composite exhibited the highest hardness, i.e., 1.5 times as hard as that of the Al5083 base metal. The enhancement in wear behavior of the hybrid composites was attributed to the solid lubrication effect provided by CeO2 particles. The predominant wear mechanism was identified as severe adhesive in non-composite samples, which changed to abrasive wear and delamination in the presence of reinforcing particles. 相似文献
8.
K. A. Khor F. Y. C. Boey Y. Murakoshi T. Sano 《Journal of Thermal Spray Technology》1994,3(2):162-168
There has been increasing use of Al-Li alloys in the aerospace industry, due mainly to the low density and high elastic modulus
of this material. However, the problem of low ductility and fracture toughness of this material has limited its present application
to only weight- and stiffness-critical components. Development of Al-Li/ceramic composites is currently being investigated
to enhance the service capabilities of this material. The Ti-Al alloy is also of interest to aerospace-type applications,
engine components in particular, due to its attractive high-temperature properties. Preparation of fine powders by plasma
melting of composite feedstock and coatings formed by plasma spraying was carried out to examine the effect of spray parameters
on the microstructure and properties of these materials. Characterization of the powders and coatings was performed using
the scanning electron microscope and image analyzer. Examination of the plasma-sprayed powders and coatings has shown that
in the Al-Li/SiC composite there is melting of both materials to form a single composite particle. The SiC reinforcement was
in the submicron range and contributed to additional strengthening of the composite body, which was formed by a cold isostatic
press and consolidated by hot extrusion or hot forging processes. The plasma-sprayed Ti-Al powder showed four categories of
microstructures: featureless, dendritic, cellular, and martensite-like. 相似文献
9.
Satish Tailor R. M. Mohanty V. K. Sharma P. R. Soni 《Journal of Thermal Spray Technology》2014,23(7):1081-1088
6061Al powder with 15 wt.% SiC particulate (SiCp) reinforcement was mechanically alloyed (MA) in a high-energy attrition mill. The MA powder was then plasma sprayed onto weathering steel (Cor-Ten A242) substrate using an atmospheric plasma spray process. Results of particle size analysis and scanning electron microscopy show that the addition of SiC particles as the reinforcement influences on the matrix grain size and morphology. XRD studies revealed embedment of SiCp in the MA-processed composite powder, and nanocrystals in the MA powder and the coating. Microstructural studies showed a uniform distribution of reinforced SiC particles in the coating. The porosity level in the coating was as low as 2% while the coating hardness was increased to 232VHN. The adhesion strength of the coatings was high and this was attributed to higher degree of diffusion at the interface. The wear rate in the coatings was evaluated using a pin-on-disk type tribometer and found to decrease by 50% compared to the 6061Al matrix coating. The wear mechanism in the coating was delamination and oxidative type. 相似文献
10.
Plasma spraying of Al2O3/ZrSiO4 was performed using spray dried and plasma spheroidised powder feedstock. The mixtures were sprayed using different spray stand-off distances and plasma power levels. X-Ray diffraction (XRD) was used to characterise the phase composition and scanning electron microscopy (SEM) examined the morphology of the sprayed surface and polished cross-sections. The results showed that the plasma spray process parameters played an important role in the final outcome of microstructures of the coatings. The coatings produced with spheroidised powders displayed a much denser structure than those produced with the spray-dried powders. The phase composition analysis showed the presence of amorphous phases in addition to crystalline alumina, zircon and tetragonal (t) zirconia (ZrO2). Transmission electron microscopy (TEM) showed that amorphous phases and t-ZrO2 crystals with particle size 100–200 nm could coexist within a single splat due to the relatively low local cooling rate. 相似文献
11.
《中国有色金属学会会刊》2020,30(4):863-871
Ti-coated SiCp particles were developed by vacuum evaporation with Ti to improve the interfacial bonding of SiCp/Al composites. Ti-coated SiC particles and uncoated SiC particles reinforced Al 2519 matrix composites were prepared by hot pressing, hot extrusion and heat treatment. The influence of Ti coating on microstructure and mechanical properties of the composites was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the densely deposited Ti coating reacts with SiC particles to form TiC and Ti5Si3 phases at the interface. Ti-coated SiC particle reinforced composite exhibits uniformity and compactness compared to the composite reinforced with uncoated SiC particles. The microstructure, relative density and mechanical properties of the composite are significantly improved. When the volume fraction is 15%, the hardness, fracture strain and tensile strength of the SiCp reinforced Al 2519 composite after Ti plating are optimized, which are HB 138.5, 4.02% and 455 MPa, respectively. 相似文献
12.
Previous studies have shown that the fabrication of metal matrix composites (MMCs) by cold spraying is effective and promising. When light materials, such as SiC and Al2O3, were used as reinforcements, it was diffcuclt to obtain a high volume fraction of hard phase in the composite just through the simple powder mixture. Therefore, in this study, a Ni-coated Al2O3 powder, which was produced through hydrothermal hydrogen reduction method, was employed aiming at increasing the volume fraction of ceramic particles in the deposited composite coating. It was found that a dense Ni-Al2O3 composite coating could be deposited with the Ni-coated Al2O3 powder under the present spray conditions. X-ray diffraction analysis indicated that the composite coating had the same phase structures as the feedstock. The volume fraction of Al2O3 in the composite was about 29 ± 6 vol.%, which is less than that in the feedstock (nominal: 40-45 vol.%) due to the rebound of some Al2O3 particulates upon kinetic impacting. The microhardness of the composite coating was about 173 ± 33Hv0.2. 相似文献
13.
原位观测方法能实时、动态、连续地观测SiCf/SiC复合材料的损伤演变过程,对研究SiCf/SiC复合材料在服役环境下的安全运行具有重要的学术价值和工程意义。本文介绍了SEM原位观测、X-CT原位观测、TEM原位观测方法的原理及在研究SiCf/SiC复合材料损伤演变方面的优势、局限性及制样方法,综述了近年来国内外采用SEM、X-CT及TEM 3种原位观测方法分析SiCf/SiC复合材料微裂纹的萌生、扩展过程及微观结构对于不同外部激励信号的动态响应过程的研究工作。最后指出X-CT原位分析技术研究SiCf/SiC复合材料的动态损伤是未来的主要发展方向。 相似文献
14.
采用等离子喷涂技术和亚音速火焰喷涂技术制备了高性能Al/SiC复合材料。利用OM,SEM,TEM,XRD等仪器详细分析了上述两种技术制备的Al/SiC复合材料微观组织。结果显示,亚音速火焰喷涂技术和等离子喷涂技术均可制备出SiC体积分数大于50%的Al/SiC复合材料,所制备的Al/SiC复合材料组织致密、颗粒均匀分布、SiC颗粒和Al之间的界面结合良好。XRD研究表明,等离子喷涂Al/SiC复合材料中存在着Al,SiC,晶体Si等相。亚音速火焰喷涂Al/SiC复合材料中的相是由Al,SiC和少量的Al2O3组成。与等离子喷涂相比,亚音速火焰喷涂Al/SiC复合材料的孔隙率较高,氧化程度较高。此外等离子喷涂Al/SiC复合材料中有一定量纳米尺度的晶粒和颗粒。 相似文献
15.
Aluminium matrix composite (AMC) specimens were prepared using the compocasting technique. The reinforcements used were silicon carbide (SiC) particles with an average size of 30 μm. The influence of reinforced ratio of 10 wt-%SiC on cavitation behaviour was examined. The cavitation resistance of an AMC with SiC (AlSi/SiC) was evaluated using an ultrasonically induced cavitation test method. The mass loss of specimens was measured by an analytical method. The morphology of the damaged surface of tested composite was examined using scanning electron microscopy (SEM). It is shown that the cavitation rate of an AMC with SiC is almost the same as the CA6NM stainless steel, which is largely used in the production of hydraulic machinery components. Because the results show that the composites exhibited very good resistance to the cavitation erosion, this material can be successfully used under conditions where the cavitation resistance is needed. 相似文献
16.
The incorporation of silicon carbide (SiC) and graphite fillers on three-body abrasive wear behaviour of glass–vinyl ester (G–V) composites has been investigated. Dry sand/rubber wheel abrasion tests (RWAT) were carried out at 200 rpm test speed. The tests were carried out at 22 and 32 N loads by varying the abrading distance from 270 to 1080 m in steps of 270 m. The worn surfaces were examined using scanning electron microscopy (SEM). The wear volume and specific wear rate of G–V composite reduces significantly on the addition of SiC filler. Graphite filler, however, performed poorly resulting deterioration in wear performance of SiC-filled G–V composite. The SEM studies indicate the reasons for failure of composites and influencing parameters. 相似文献
17.
Jun LAI Hua-jun GUO Xiang-qun LI Zhi-xing WANG Xin-hai LI Xiao-ping ZHANG Si-lin HUANG Lei GAN 《中国有色金属学会会刊》2013,23(5):1413-1420
Silicon/flake graphite/carbon (Si/FG/C) composites were synthesized with different dispersants via spray drying and subsequent pyrolysis, and effects of dispersants on the characteristics of the composites were investigated. The structure and properties of the composites were determined by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The results show that samples have silicon/flake graphite/amorphous carbon composite structure, good spherical appearances, and better electrochemical performance than pure nano-Si and FG/C composites. Compared with the Si/FG/C composite using washing powder as dispersant, the Si/FG/C composite using sodium dodecyl benzene sulfonate (SDBS) as dispersant has better electrochemical performance with a reversible capacity of 602.68 mA·h/g, and a capacity retention ratio of 91.58 % after 20 cycles. 相似文献
18.
R. Gadow 《Surface & coatings technology》2010,205(4):1157-2056
Thermally sprayed hydroxyapatite (HAp) coatings are widely used for various biomedical applications due to the fact that HAp is a bioactive, osteoconductive material capable of forming a direct and firm biological fixation with surrounding bone tissue.Bioceramic coatings based on nanoscale HAp suspension and microscale HAp powder were thermally sprayed on Ti plates by high-velocity suspension flame spraying (HVSFS) technique and atmospheric plasma spraying (APS) as well as high velocity oxy fuel spraying (HVOF) technique. HVSFS is a novel thermal spray process developed at IMTCCC, for direct processing of submicron and nano-sized particles dispersed in a liquid feedstock.The deposited coatings were mechanically characterized including surface roughness, micro hardness and coating porosity. The bond strength of the layer composites were analyzed by the pull-off method and compared for the different spray techniques. Phase content and crystallinity of the coatings were evaluated using X-ray diffraction (XRD). The coating composite specimen and initial feedstock were further analysed by scanning electron microscope (SEM) and rheology analysis. 相似文献
19.
Titanium carbide nanoparticle-reinforced nickel-based alloys (Ni-TiCNP composites) with ball milling time ranging from 8 to 72 h were prepared by ball milling and spark plasma sintering. Transmission electron microscopy (TEM) and scanning electron microscopy equipped with electron backscatter diffraction were used to characterize the microstructures. Their hardness and tensile properties were measured using the Vickers pyramid method and tensile tests. TEM results showed that a slight coarsening of TiCNP occurred during the ball milling process. The grain sizes of the Ni-TiCNP composites with various ball milling times were different, but they were all much smaller than those of the pure Ni. In all cases, the Ni-TiCNP composites showed higher strengths and hardness values than the unreinforced pure nickel. Furthermore, the strength of the Ni-TiCNP composites increased initially and then decreased as a function of ball milling time. The maximum strengths occurred in the 24-h ball milling sample, which presented the lowest average grain size. The Hall-Petch strengthening was suggested to be the main reason responsible for such variations in mechanical properties. Additionally, the elongation percentage of the Ni-TiCNP composites decreased gradually with ball milling time. This may be caused by the change of microvoids in the composite as the ball milling time varies, which is also related to their fracture behavior. 相似文献
20.
An aluminum base composite (Al-SiC) powder has been developed for producing plasma sprayed coatings on Al and other metallic
substrates. The composite powders were prepared by mechanical alloying of 6061 Al alloy with SiC particles. The concentration
of SiC was varied between 20 and 75 vol%, and the size of the reinforcement was varied from 8 to 37 μm in the Al-50 vol% SiC
composites. The 44 to 140 μm composite powders were sprayed using an axial feed plasma torch. Adhesion strength of the coatings
to their substrates were found to decrease with increasing SiC content and with decreasing SiC particle sizes. The increase
in the SiC content and decrease in particle size improved the erosive wear resistance of the coatings. The abrasive wear resistance
was found to improve with the increase in SiC particle size and with the SiC content in the composite coatings. 相似文献