High Temperature Chlorine Corrosion Resistance and Heat Erosion Resistance of Silica Sol Reinforced Phosphate Ceramic Coating

Silica sol reinforced phosphate ceramic coating was prepared on the surface of 12Cr1MoV steel by adding different content of silica sol into phosphate ceramic coating. The surface morphology and phase composition of the coating were analyzed by scanning electron microscopy and X-ray diffraction. The effects of silica sol content on the surface drying time, hardness, high temperature chlorine corrosion resistance and heat erosion resistance of the coating were studied. The results show that the silica sol improved the hygroscopicity of the phosphate ceramic coating. The higher the silica sol content, the shorter the surface drying time. Adding an appropriate amount of silica sol improved the surface forming quality and hardness of the coating. The corrosion rate of the coating sample decreased first and then increased with the increase of silica sol content. When the mass fraction of silica sol was 6%, the high temperature chlorine corrosion resistance of the coating was relatively good. When the mass fraction of silica sol was 6% and 9%, the wear depth of the coating was about 30 μm, which was nearly 45% lower than the thickness loss of the pure phosphate ceramic coating sample, showing better heat erosion resistance.