In situ construction of water vapor resistant Yb2Si2O7 coatings on SiC fiber

In this work, continuous and dense Yb 2 Si 2 O 7 coating was formed on the surface of SiC fibers by reaction of the Yb 2 O 3 coatings prepared via urea-based homogeneous precipitation with SiO 2 scales formed by fiber oxidation. The effect of SiO 2 to Yb 2 O 3 thickness ratio on the microstructure and morphology of Yb 2 Si 2 O 7 coatings was investigated. Fiber oxidation and defects introduced during coating synthesis cause severe fiber degradation, and pre-deposition of SiC via chemical vapor infiltration can improve the strength retention of the fibers. The Yb 2 Si 2 O 7 coatings can protect fibers from corrosion in water vapor environment at 1200 ℃, showing great resistance to oxidation.