The interfacial stability of the coated-SiC/Fe couple

SiC piece was successfully coated by interaction with chromium powder. When the SiC piece was coated at 1373 K for 1 h, the obtained coating layer of 6 μm is dense and well distributed on the SiC piece. The coating layer is composed of Cr3Si, Cr7C3 and Cr23C6, and in a sequence of Cr3Si/Cr3Si+Cr7C3/Cr7C3/Cr23C6 from the SiC terminal to the growing surface. The coating layer on the SiC piece has high thermal stability, which may improve the thermal stability of the coated-SiC/Fe composite. The interfacial stability between the coated-SiC and Fe was examined by annealing the coated-SiC/Fe couples in the temperature range from 1273 to 1423 K for times from 1 to 22.5 h. The results showed that the coating layer improved the interfacial stability between the coated-SiC and Fe by inhibiting the reaction between SiC and Fe. The interdiffusion of the Fe and the coating layer’s component atoms resulted in the dissolution of coating layer into Fe piece at 1373 K. The dissolution of the coating layer increased with the increasing annealing temperature and time. After annealed at 1423 K for 5 h, the coating layer of the coated-SiC/Fe couple was found to be completely dissolved, and the reaction between SiC and Fe was detected.