An environmental barrier coating system was applied on SiC

f

/SiC composite specimens with the silicon bond coat and mullite intermediate coat sprayed using APS processes and the ytterbium silicate topcoat sprayed using a PS–PVD process. The sprayed environmental barrier coating system is dense in microstructure and the PS–PVD ytterbium silicate topcoat possesses lamellar structure with a porosity less than 1%. The static oxidation

cyclic oxidation

water vapour corrosion and thermal impact resistances of the environmental barrier coating system were investigated. It was demonstrated that the environmental barrier coating sprayed on the SiC

f

/SiC composite specimens had a desirable oxidat

ion resistance as it kept intact with no obvious evidence of spallation observed after 100h static oxidation

100h cyclic oxidation test at 1200℃ and 1300℃. Moreover

the coating had a thermal impact resistance life more than 100 cycles as heated to a high temperature of 1300℃ by a hot gas stream and it had a preferable corrosion resistance at 1200℃ in an environment containing 15% H

2

O water vapour.