**Influence of Silicon-Modified Al Powders (SiO 2@Al) on Anti-oxidation Performance of Al 2 O 3-SiO 2 Ceramic Coating for Carbon Steel at High Temperature**

#### **Bo Yu 1,2, Guoyan Fu 1,3, Yanbin Cui 1, Xiaomeng Zhang 1, Yubo Tu 1,2, Yingchao Du 1,2, Gaohong Zuo 1,4, Shufeng Ye 1 and Lianqi Wei 1,\***


Received: 24 January 2019; Accepted: 26 February 2019; Published: 4 March 2019

**Abstract:** 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.

**Keywords:** ceramic coating; anti-oxidation; SiO2@Al additive; carbon steel
