A CaO-MgO-Al2O3-SiO2 amorphous ceramic material was fabricated by a high-temperature melting method, and calcium magnesium aluminum silicate ceramic coating was prepared on 45# steel substrate via high-speed grinding and plasma spraying. The phase composition, microhardness, and microstructure of monolithic ceramics and coatings were analyzed, and the bonding strength of the coatings was tested through tensile experiments. The corrosion resistance and mechanism of the coating were investigated through salt solution immersion corrosion experiments. The results indicate that the porosity of the calcium magnesium aluminum silicate ceramic coating is 7.93%±3.27%, without an obvious layered structure. The microhardness value of the coating is 6.63 GPa, which is only 3.89% lower than that of monolithic materials. The non-porous area has the microstructure and mechanical properties of monolithic ceramic materials. The bonding strength of the coating is (16.25±2.11) MPa, and the fracture occurs at the interface between the coating and the metal transition layer, which is equivalent to the bonding performance of other plasma spraying ceramic coatings. The corrosion rate of the coated sample is 0.102 6?偆bg瘙
簚m-2瘙
簚h-1, which is reduced by 12.3 times, compared to the substrate sample, indicating a good corrosion resistance through a 1 000?偆bh-immersion-corrosion-experiment. Based on the analysis of the corrosion cross-section, the dense structure of the coating plays a mechanical isolation role in corrosion. The dissolution rate of corrosion products accumulated on the pores and crack surfaces of the coating is balanced with the rate of corrosion liquid penetrating into the substrate, reducing the corrosion.