In this work, ZrB_2 - 20vol.% MoSi_2 (named as ZM) composite coatings were fabricated by atmospheric plasma spray (APS) and vacuum plasma spray (VPS) techniques, respectively. Phase composition and microstructure of the composite coatings were characterized. Their oxidation behaviours and microstructure changes at 1500°C were comparatively investigated. The results showed that VPS-ZM coating was composed of hexagonal ZrB_2, tetragonal and hexagonal MoSi_2. While certain amount of ZrO_2 existed in APS-ZM coating. The oxide content, surface roughness and porosity of VPS-ZM coating were apparently lower than those of APS-ZM coating. The mass gain of APS-ZM coating was maximum at the beginning (1500°C, 0 h) and then decreased with extending the oxidation time. While the mass of VPS-ZM coating gradually increased with increasing the oxidation time from 0 h to 10 h. VPS-ZM coating had much better oxidation resistance than APS-ZM coating, presenting potential application as high-temperature protecting materials. The possible reasons for the difference of the two kinds of coatings were analysed.
展开▼
