High Temperature Chlorine Corrosion Resistance of Organopolysilazane Precursor Ceramic Coating

An organopolysilazane precursor ceramic coating was prepared on the surface of TP347 stainless steel sheet. High-temperature HCl gas and KCl heap salt corrosion tests were performed on coated and uncoated samples, and the corrosion mass increase curves of the samples were analyzed by weight gain method. The results show that the prepared coating had a uniform and compact surface and was closely connected with the substrate. In the HCl gas at 500, 525, 550 ℃, the corrosion rates of the coated samples were lower than that of the blank samples. In the KCl heap salt, the mass of the uncoated samples increased first and then decreased with the extension of time. The corrosion resistance of the coated samples was relatively good, and no Cl element was detected in the substrate at 500 ℃. The Cl content in the matrix was high at 550 ℃, indicating that Cl^- gradually diffused into the samples. When the service temperature was below the softening temperature of the coating glass powder, the coating could effectively block the diffusion of Cl^- into the substrate, improving the protective performance of the coating.