Oxidation and ablation protection of graphite materials by monolayer MoSi2–CrSi2–SiC–Si multiphase coating. Issue 16 (November 2018)

• Record Type: Journal Article
• Authors: Jiang, Yan; Chang, Longfei; Ru, Hongqiang; Wang, Wei; Zhang, Cuiping
• Is Part Of: Ceramics international. Volume 44:Issue 16(2018)
• Page Start: 20275
• Page End: 20284
• Publication Date: 2018-11
• Subjects: Graphite -- MoSi2–CrSi2–SiC–Si coating -- Slurry impregnation -- Reactive infiltration -- Oxidation resistance -- Ablation resistance; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.08.013
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: A monolayer MoSi2 –CrSi2 –SiC–Si multiphase coating was designed and prepared by slurry impregnation combined with reactive infiltration of gaseous silicon onto a graphite substrate. The phase composition and microstructure of the as-prepared coating were studied by X-ray diffraction analysis and scanning electron microscopy. Oxidation and oxyacetylene flame tests were performed to evaluate the anti-oxidation and anti-ablation performance of the MoSi2 -CrSi2 -SiC-Si coating. Results showed that the as-prepared coating can withstand long–duration oxidation at low temperature (900 °C) for 1320 h and at high temperature (1600 °C) for 1190 h with mass gains of 0.06% and 1.24%, respectively. The compact structure of the coating, which had a thickness of approximately 600 µm, resulted in the excellent anti-oxidation behavior at 900 °C, whereas the excellent oxidation resistance at 1600 °C is attributed to the formation of an oxide layer with slow oxygen diffusivity on the coating surface and the presence of dispersed MoSi2 and CrSi2 in the coating. Further, the as-prepared coating displayed good ablation resistance, after ablation for 60 s, the mass and linear ablation rates of the coated sample were 0.31 mg/s and 0.33 µm/s, respectively. Under an oxyacetylene flame, active oxidation of silicon carbide and severe evaporation of oxides, for instance, gaseous silica, molybdenum oxide, and chromium trioxide, were the main causes of damage to the MoSi2 –CrSi2 –SiC–Si coating.