HU Qing 1, TAN Guangfan 1, TANG Huidong 1, JIANG Weihui 1, 2, LIU Jianmin 2, CHEN Ting 1,
JIANG Feng 1, FENG Guo 2
(1. Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi, China; 2. National Engineering Research Center for Domestic and Building Ceramics, Jingdezhen 333001, Jiangxi, China)
Abstract: Zirconium silicate (ZrSiO4) thin film was prepared on the SiC substrate by non-hydrolyzed sol-gel process combined with dip-coating using zirconium n-propoxide and ethyl orthosilicate as zirconium source and silicon source, respectively, using n-propanol as solvent and anhydrous citric acid as auxiliary additives. The effect mechanism of anhydrous citric acid-assisted ZrSiO4 synthesis as well as the effects of anhydrous citric acid addition and coating times on the synthesis of ZrSiO4 and the morphology of the film and the oxidation resistance of the film were studied via XRD, FT-IR, SEM, EDS and other methods. The results showed that anhydrous citric acid could promote the dissolution of the lithium fluoride (LiF) in n-propanol, resulting in the formation of pure ZrSiO4 phase. When the amount of anhydrous citric acid added (molar ratio to zirconium n-propoxide) was 1.1 : 1 and the number of coating times was 5, dense ZrSiO4 film with the thickness of 500 nm without cracking could be obtained on the SiC substrate. After oxidizing at 1450 °C for 60 h, the weight gain per unit area of uncoated SiC substrate was 7.2354×10-4 g/cm2, while that of the sample coated with ZrSiO4 film was only 2.2283×10-4 g/cm2. The surface of the sample was relatively flat and free of cracks after oxidizing process, indicating that the ZrSiO4 film had excellent high temperature oxidation resistance.
Key words: ZrSiO4 thin film; non-hydrolyzed sol-gel; anhydrous citric acid; oxidation resistance