离子喷涂W-Cu电子封装材料的组织与性能

采用等离子喷涂工艺制备了W Cu电子封装材料，并对该电子封装材料的微观组织和热物理性能进行了研究. 结果表明，在内部送粉条件下，复合材料中钨的收得率要高于外部送粉条件下复合材料中钨的收得率；在内部送粉条件下，功率对铜氧化的影响并不明显；而在外部送粉条件下，随着功率的提高，铜的氧化明显增多；由于氧化物和孔隙等的存在，利用大气等离子喷涂工艺制备的复合材料的导热率远远低于根据混合法则计算的理论值. 这为后续实验研究提供了重要的参考依据.     

等离子喷涂W-Cu电子封装材料的组织与性能

采用等离子喷涂工艺制备了W-Cu电子封装材料，并对该电子封装材料的微观组织和热物理性能进行了研究．结果表明，在内部送粉条件下，复合材料中钨的收得率要高于外部送粉条件下复合材料中钨的收得率；在内部送粉条件下，功率对铜氧化的影响并不明显；而在外部送粉条件下，随着功率的提高，铜的氧化明显增多；由于氧化物和孔隙等的存在，利用大气等离子喷涂工艺制备的复合材料的导热率远远低于根据混合法则计算的理论值．这为后续实验研究提供了重要的参考依据．     

Experimental study on thermophysical properties of C/C composites at high temperature

Ablationthermalprotectivecompositesarethekeystructureofspacevehiclesprotectingthemfromaerody namicheatingduringtheirreentryintotheaerosphere.Thecarbonmatrixcompositesarethemostpromisingablationmaterialsusedinthisenvironmentduetotheirpotentiallyfavorablepr…     

Thermal expansion and mechanical properties of middle reinforcement content SiCp/Al composites fabricated by PM technology

Middle reinforcement content SiCp/Al composites(Vp=30%, 35% and 40%) for precision optical systems applications were fabricated by powder metallurgy technology. The composites were free of porosity and SiC particles distributed uniformly in the composites. The mean linear coefficients of thermal expansion(20-100 ℃) of SiCp/Al composites ranged from 11.6×10-6 to 13.3×10-6 K-1 and decreased with an increase in volume fraction of SiC content. The experimental coeffi cients of thermal expansion agreed well with predicted values based on Kerner's model. The Brinell hardness increased from 116 to 147, and the modulus increased from 99 to 112 GPa for the corresponding composites. The tensile strengths were higher than 320 MPa, but no signifi cant increasing trend between tensile strength and SiC content was observed.     

Mechanical,electrical, and thermal expansion properties of carbon nanotube-based silver and silver-palladium alloy composites

The mechanical, electrical, and thermal expansion properties of carbon nanotube（CNT）-based silver and silver–palladium（10：1, w/w） alloy nanocomposites are reported. To tailor the properties of silver, CNTs were incorporated into a silver matrix by a modified molecular level-mixing process. CNTs interact weakly with silver because of their non-reactive nature and lack of mutual solubility. Therefore, palladium was utilized as an alloying element to improve interfacial adhesion. Comparative microstructural characterizations and property evaluations of the nanocomposites were performed. The structural characterizations revealed that decorated type-CNTs were dispersed, embedded, and anchored into the silver matrix. The experimental results indicated that the modification of the silver and silver–palladium nanocomposite with CNT resulted in increases in the hardness and Young＇s modulus along with concomitant decreases in the electrical conductivity and the coefficient of thermal expansion（CTE）. The hardness and Young＇s modulus of the nanocomposites were increased by 30%？40% whereas the CTE was decreased to 50%-60% of the CTE of silver. The significantly improved CTE and the mechanical properties of the CNT-reinforced silver and silver–palladium nanocomposites are correlated with the intriguing properties of CNTs and with good interfacial adhesion between the CNTs and silver as a result of the fabrication process and the contact action of palladium as an alloying element.     

Spark Effect on the Densification of SiCp/Al Composites by SPS

1 IntroductionSiCp/Al composites have aroused considerable inter-ests in manyfields of industry due to their tailorable me-chanical and thermophysical properties .SiCp/Al compos-ites have been developed mainly as structural materials inapplicationfor automobile industries and aerospace indus-tries . However ,thermal management applicationsin elec-tronic packaging,such as substrates ,heat slugs and heatspreads have been focused on. Electronic componentsused in thermal management applications …