Influence of Silicon-Modified Al Powders (SiO2@Al) on Anti-oxidation Performance of Al2O3-SiO2 Ceramic Coating for Carbon Steel at High Temperature

In this paper, silicon-modified Al powders (SiO2@Al) were prepared by tetraethyl orthosilicate (TEOS) hydrolysis under alkaline conditions. Using SiO2@Al as additives, a new Al2O3-SiO2 ceramic coating (ASMA) was formed on carbon steel to prevent carbon steel from oxidization at 1250 °C for 120 min. Compared with the Al2O3-SiO2 ceramic coating without additive (AS), ASMA showed a remarkably better anti-oxidation performance, especially during the temperature-rise period. According to the characterization conducted by TG-DTA, XRD and SEM-EDS, it was found that the metallic Al in ASMA melted at 660 °C and reacted with SiO2 on its surface, which generated local high temperature and accelerated the sintering of ceramic raw materials. The mullite and hercynite formed in ASMA also played a major role for enhancing the anti-oxidation performance of ceramic coating.