Synthesis Nano-SiCp/MoSi2 Composites by in-situ Reaction Sintering and Low Temperature Oxidation Behavior

摘要

Nano-SiCp/MoSi2 composites with different SiC volume fraction have been synthesized by in situ reactive hot press sintering with the milled Mo,Si and C elements powders.The X-ray diffraction (XRD) detection shows the composites are composed of α-MoSi2 and β-SiC,and transmission electron microscopy (TEM) shows that the particle sizes of β-SiC formed by in situ reaction are in range of 20-100nm,and most of the them locate in grain boundary and some particles embed in MoSi2 grain.The isothermal oxidation and thermal cycling test of nano-SiCp/MoSi2 composites were carried out in air at temperatures of 500°C.The pest phenomenon was not found during oxidation and cyclic oxidation at 500°C for 500 hours and 50 cycles,respectively.All the composites have both excellent oxidation resistant and good cyclic oxidation resistant.The mechanisms of oxidation at low temperature were discussed also.