Microstructure and isothermal oxidation of 3Al2O3·2SiO2/SiC coating on high and low density carbon-carbon composites
来源期刊：中南大学学报(英文版)2013年第1期
论文作者：L. GBOLOGAH XIONG Xiang (熊翔) HAO Han-lin(郝安林) Zeng Yi(曾毅) Zhang Wu-zhuang (张武装)
文章页码：30 - 36
Key words：mullite; carbon-carbon composite; slurry coating; isothermal oxidation
Abstract: Carbon-carbon composite (C/C) materials are prone to severe oxidation and volatilization problems. To address these issues, mullite (3Al2O3·2SiO2)/silicon carbide (SiC) coatings were deposited on C/C composite substrates characterized into high and low densities. The coatings were applied by a two-step approach: pack cementation and silica sol based slurry coating processes. The relationship between the microstructure of 3Al2O3·2SiO2/SiC coatings and C/C substrates during isothermal oxidation cycle at 1 500 ºC was investigated using X-ray diffractometer (XRD) and scanning electron microscope (SEM) mounted with energy dispersive spectrometer (EDS). The results indicate that the density of the substrates has a marked effect on the coatings. Dense, thick and well-bonded coatings are obtained in the high density substrate. After 106 h of isothermal oxidation, the high density substrate with 3Al2O3·2SiO2/SiC coating offers effective protection as compared to low density substrate suffering recession.
L. GBOLOGAH1, XIONG Xiang (熊翔) 1, HAO Han-lin(郝安林)2, Zeng Yi(曾毅) 1, Zhang Wu-zhuang (张武装) 1,
(1. State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China;
2. Anyang Institute of Technology, Anyang 455000, China)
Abstract:Carbon-carbon composite (C/C) materials are prone to severe oxidation and volatilization problems. To address these issues, mullite (3Al2O3·2SiO2)/silicon carbide (SiC) coatings were deposited on C/C composite substrates characterized into high and low densities. The coatings were applied by a two-step approach: pack cementation and silica sol based slurry coating processes. The relationship between the microstructure of 3Al2O3·2SiO2/SiC coatings and C/C substrates during isothermal oxidation cycle at 1 500 ºC was investigated using X-ray diffractometer (XRD) and scanning electron microscope (SEM) mounted with energy dispersive spectrometer (EDS). The results indicate that the density of the substrates has a marked effect on the coatings. Dense, thick and well-bonded coatings are obtained in the high density substrate. After 106 h of isothermal oxidation, the high density substrate with 3Al2O3·2SiO2/SiC coating offers effective protection as compared to low density substrate suffering recession.
Key words:mullite; carbon-carbon composite; slurry coating; isothermal oxidation
