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采用超音速火焰喷涂(high velocity oxy-fuel,HVOF)技术在Q235钢基体上制备了Cr3C2-Ni Cr涂层,借助X射线衍射(XRD)和扫描电镜(SEM)等方法分析了涂层的相组成和微观组织,研究涂层与镀铬层在质量分数为3.5%Na Cl溶液中的腐蚀性能.结果表明,涂层主要由Cr3C2,Cr7C3和Ni Cr等相组成,涂层的致密度高,层状结构明显,含少量孔隙.阻抗谱曲线表明,Cr3C2-Ni Cr涂层对基体的保护作用良好,在Na Cl溶液中浸泡时间40 d后,极化电阻为2.8 kΩ,而镀铬层失效严重,极化电阻为300Ω.极化曲线表明,Cr3C2-Ni Cr涂层在浸泡周期内腐蚀电位平稳,腐蚀电流缓慢增加.镀铬层的腐蚀电位下降较快,腐蚀速率成倍增加.孔洞是影响Cr3C2-Ni Cr涂层耐蚀性的重要原因,影响镀铬层耐蚀性的主要原因是裂纹.
Cr3C2-Ni Cr coating was prepared on Q235 steel substrate by HVOF technique. The phase of the coating was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) The results show that the coating mainly consists of Cr3C2, Cr7C3 and NiCr phases, and the coating has high density and the layer The results show that the Cr3C2-Ni Cr coating has a good protective effect on the matrix, the polarization resistance is 2.8 kΩ after soaking time in NaCl solution for 40 d, The polarization resistance is 300Ω.The polarization curves show that the corrosion potential of Cr3C2-Ni Cr coating is stable and the corrosion current is slowly increased during the soaking cycle.The corrosion potential of the chrome-plated layer decreases rapidly and the corrosion rate multiplies.The porosity is the effect of Cr3C2- Ni Cr coating corrosion resistance of the important reasons that affect the chrome layer corrosion resistance is the main reason for cracks.