热处理对等离子喷涂铁基非晶合金涂层微观结构和耐腐蚀性能的影响

Effect of Heat Treatment on Microstructure and Corrosion Resistance of Plasma Sprayed Fe-based Amorphous Alloy Coating

采用等离子喷涂技术在Q235钢基体上制备Fe48Cr15Mo14C15B6Y2非晶合金涂层,之后对涂层进行200,300,500,600,700℃热处理,研究了热处理对涂层微观结构、耐电化学腐蚀性能和耐均匀腐蚀性能的影响。结果表明:随着热处理温度的升高,涂层的非晶含量降低,孔隙率先减小后增大,经300℃热处理后涂层的孔隙率最低,且低于未热处理涂层的;热处理后涂层中的晶体相主要包括α-Fe,Fe-Cr,Fe63Mo37,Fe3C等;随着热处理温度的升高,涂层的自腐蚀电流密度先减小后增大,经300℃热处理后,自腐蚀电流密度最小,涂层的耐电化学腐蚀性能最好;经过热处理后,涂层在NaCl溶液中浸泡31d后的单位面积质量损失减小,且热处理温度越高,单位面积质量损失越小,涂层的耐均匀腐蚀性能提高。

Fe48Cr15Mo14C15B6Y2 amorphous alloy coating was prepared on Q235 steel substrate by plasma spraying technique,and the coating was heat treated at 200,300,500,600,700℃.The effect of heat treatment on the microstructure,electrochemical corrosion resistance and uniform corrosion resistance of the coating was studied.The results show that with the increase of heat treatment temperature,the amorphous phase content in the coating decreased,and the porosity decreased first and then increased;the porosity of the coating heat-treated at 300℃was the lowest,and lower than that of the unheat-heated coating.The crystal phases in the coating after heat treatment mainly includedα-Fe,Fe-Cr,Fe63Mo37,Fe3C.With the increase of heat treatment temperature,the free corrosion current density of the coating decreased first and then increased;the free corrosion current density of the coating heat-treated at 300℃was the smallest,and the electrochemical corrosion resistance was the best.After heat treatment,the mass loss per unit area of the coating immersed in NaCl solution for 31 ddecreased;the higher the heat treatment temperature,the smaller the mass loss per unit area,indicating the uniform corrosion resistance of the coating was improved.