Study on anti-oxidation performance of the magnesium phosphate ceramic coating on steel at high temperatures

Ceramic coating technology has garnered significant attention in the manufacturing and utilization of steel products to enhance their physicochemical properties. Among various ceramic coating techniques, magnesium phosphate ceramic coating has emerged as a promising solution due to its economic viability and excellent corrosion resistance and high-temperature characteristics. In this study, we apply magnesium phosphate ceramic coating to a metal surface and investigate its oxidation behavior at high temperatures. To achieve the phosphate ceramic coating, we employed the 1-liquid spray coating method. We examined the influence of the crystallinity and purity of commercial MgO powder on the phosphate reaction during the preparation of the coating slurry, along with an analysis of the oxidation behavior on the coated steel surface at elevated temperatures. The oxidation characteristics of the magnesium phosphate ceramic-coated steel surfaces were analyzed by studying the oxidation resistance under varying CO/CO₂ ratios. Additionally, we observed the morphology of the oxidation scale and the presence of oxidation cracks on the metal surface using scanning electron microscopy (SEM) and optical microscopy (OM). The results of the study confirm that high purity and crystallinity of MgO are crucial for achieving excellent oxidation resistance on high-temperature steel surfaces. The ceramic coating technology, offering advantages in industrial-scale coating, holds great potential for the application of magnesium phosphate ceramic coating.