ZrB2-SiC-ZrC coating on ZrC ceramics deposited by plasma spraying

Abstract

The ZrB2-SiC-ZrC coating free of adhesion layer was successfully prepared by plasma spraying. Fine ZrB2-SiC-ZrC sprayed composite powders were pre-synthesized by muti-step hot pressing. The X-ray diffraction (XRD) analysis showed that as-sprayed coating was primarily composed of ZrB2, SiC, ZrC and a small quantity of SiO2 and ZrO2, which corresponds with the composition of spraying composite powders. The microstructure of the coating exhibited the characteristics of stacking of fully melted and partially melted particles. The coating was continuous and well bonded with ZrC substrate without adhesion layer. However, a few pores were found in the sprayed composite coating, which was attributed to incomplete melting of some of ZrB2-SiC-ZrC composite powders during plasma spraying. Keywords: ZrC, ZrB2-SiC-ZrC coating, Plasma spraying, Adhesion