Abstract
Double-layer oxidation resistant SiC/Cr-Al-Si coating for carbon-carbon composites was prepared by a two-step method of pack cementation and slurry. The phase composition, micro-structure and oxidation resistance of mono-layer SiC coating and double-layer SiC/Cr-Al-Si coating were studied by XRD, SEM, and isothermal oxidation test at 1773 K in air, respectively. Mono-layer SiC coating consists of SiC and Si, which can protect carbon-carbon composites for several hours depending on its thin thickness and porous structure. After adding outer Cr-Al-Si alloy coating, the as-prepared double-layer SiC/Cr-Al-Si coating with a dense surface and about 150 μm thickness showed improved oxidation resistance, which can protect carbon-carbon composites for 197 h with only 0.079 wt.% mass gain. The failure of the double-layer SiC/Cr-Al-Si coating is thought to occur due to the excessive depletion of the outer Cr-Al-Si alloy coating and the appearance of defects in the SiO2 glass layer.
| Original language | English |
|---|---|
| Pages (from-to) | 7842-7846 |
| Number of pages | 5 |
| Journal | Surface and Coatings Technology |
| Volume | 201 |
| Issue number | 18 |
| DOIs | |
| State | Published - 25 Jun 2007 |
Keywords
- Carbon-carbon composites
- Coating
- Cr-Al-Si
- Oxidation