SiC/(SiC+glass)/glass coating for carbon-bonded carbon fibre composites

Abstract

An oxidation resistant coating for highly porous carbon-bonded carbon fibre composites (CBCFs) was prepared by slurry method. The compositionally and structurally gradient coating consists of a carbon fibre reinforced SiC inner layer, a SiC with CaO-MgO-Al 2 O 3 -SiO 2 (CMAS) glass inter layer, and a dense CMAS glass outer layer. The effectiveness of the S-SG-G coating in protecting the CBCFs from degradation at 1000 °C in air has been evaluated. The results indicated that the coating could protect CBCFs from oxidation for 100 min with the weight loss of 20.7%. In contrast, the uncoated CBCFs were completely combusted after 50 min. Good oxidation resistance of the coating is mainly attributed to high temperature stability of SiC, CMAS glass sealant, and good adhesion within the coating layers and with the substrate.

Ceramic Matrix Composites: Classifications, Manufacturing, Properties, and Applications

“…Bond, active, and outer layers are frequently present, with the outer layer acting as an oxygen-and corrosion-resistant layer [89]. In SiC/C composites, the bond layer is fabricated on top of SiC, and either SiC or Si 3 N 4 makes up the outer layer [90,91]. In the functional layer (central layer), combinations from the Si-B-C system are present; the three layers may also show signs of self-healing [77].…”