氮化硼含量对热化学反应法制得陶瓷涂层耐高温氯腐蚀性能的影响

Effect of BN Content on High Temperature Chlorine Corrosion Resistance of Ceramic Coating Prepared by Thermochemical Reaction Method

采用热化学反应法以复合磷酸盐为黏接剂,在Q235钢基体上制备了不同氮化硼(BN)含量的氧化铝基陶瓷涂层;运用扫描电子显微镜和X射线衍射仪研究了BN含量对热化学反应陶瓷涂层形貌和组织结构、热膨胀系数和耐高温氯腐蚀性能的影响。结果表明:热化学反应涂层与基体反应产生了新相Al0.67Fe0.33PO4,随着陶瓷涂层中BN含量的增加,涂层表面的裂纹和孔隙先减少后增加,30%BN-Al_(2)O_(3)和50%BN-Al_(2)O_(3)陶瓷涂层的热膨胀系数分别为7.9×10-6和7.7×10^(-6),与基体材料Q235的较为接近;热化学反应涂层显著改善了Q235钢的耐高温氯腐蚀性能,其中50%BN-Al_(2)O_(3)陶瓷涂层的耐高温氯腐蚀性能最好。

Alumina-based ceramic coatings with different content of boron nitride(BN)were prepared on Q235 substrate using a thermochemical reaction method and composite phosphate as the adhesive.The effects of BN content on the morphology and microstructure,thermal expansion coefficient,and high-temperature chloride corrosion resistance of thermochemical reactive ceramic coatings were studied using scanning electron microscopy and X-ray diffraction.The results indicate that a new phase of Al_(0.67)Fe_(0.33)Po_(4) was formed by the reaction between the thermochemical reaction coating and the substrate.As the BN content in ceramic coatings increased,the cracks and pores on the coating surface first decreased and then increased.The thermal expansion coefficients of 30%BN-Al_(2)O_(3) and 50%BN-Al_(2)O_(3) ceramic coatings were 7.9×10^(-6)and 7.7×10^(-6)respectively,which were relatively close to the matrix material Q235.Ceramic coatings significantly improved the high temperature chlorine corrosion resistance of Q235 steel,and 50%BN-Al_(2)O_(3) ceramic coating had the best high temperature chlorine corrosion resistance.