Thermal Conductivity Characteristics of SiCp/Al Composites Fabricated by Atmospheric Plasma Spraying

摘要

Feedstock for plasma spraying was prepared by ball milling with Al-55 vol. percent SiC and Al-75 vol. percent SiC powder mixtures in different conditions. The average size of SiC particles was varied from 8 to 30 mu m. Freestanding SiCp/Al composites were fabricated by atmospheric plasma spraying onto a graphite substrate. Thermal conductivity of the plasma-sprayed composites was measured at room temperature of 25 deg C by the laser flash method. Thermal conductivity of the sprayed composites was significantly lower than that of conventionally cast SiC_p/Al composites. Thermal conductivity was varied considerably with respect to the SiC size and feedstock preparation method. The deterioration mechanism of thermal conductivity in the sprayed composites was elucidated, and numerical analyses based on theories of Maxwell and thermal boundary resistance were carried out.