脉冲单电源铬镍共渗层耐酸腐蚀性研究

Research on Acid-resistance of Plasma Cr-Ni Surface Alloying Layer Formed by Single Pulse Power Supply

采用脉冲单电源等离子渗金属技术,在Q195钢表面进行铬镍共渗工艺。利用X射线衍射仪、扫描电子显微镜(SEM)及能谱仪(EDS)分析了铬镍共渗层的表面相组成、表面微观形貌和表面成分。采用电化学测量仪测定铬镍共渗层分别在1mol/L H2SO4、1mol/L HNO3溶液中的极化曲线,研究其腐蚀形貌,并与未处理的Q195钢试样进行对比分析。结果表明,铬镍共渗层的主要相成分为Fe-Cr-Ni固溶体;铬镍共渗层的表面呈上凸的胞状组织,排列致密;表面成分的相对含量为Cr 16.14%、Ni 48.16%、Fe 35.7%(质量分数)。在HNO3溶液中,未处理的Q195钢试样表面为严重的面腐蚀,铬镍共渗层表面几乎未被腐蚀,后者比前者的耐蚀性提高了658倍;在H2SO4溶液中,未处理的Q195钢试样表面为严重的点蚀,而铬镍共渗层表面状态良好,后者比前者的耐蚀性提高了90倍。铬镍共渗层耐硝酸腐蚀性能优于耐硫酸腐蚀性能。

Q195 steel was conducted by Cr-Ni surface alloying process using single pulse power supply. The surface phase composition, morphology and contents were analyzed by XRD, SEM and EDS. Polarization curves of Cr-Ni alloying layer in 1mol/L H2 SO4 and lmol/L HNO3 solution were measured by electrochemical measuring instrument. The corrosion morphology was studied and compared with untreated Q195 steel. Results show that, the surface phase component is Fe-Cr-Ni solid solution; the surface of alloying layer is shown as tightly arranged cellular structure; the surface contents are Cr 16. 14%, Ni 48. 16%, Fe 35. 7%. In HNO3 solution, the severe surface erosion happens to the untreated samples; Cr-Ni alloying layer is in good condition and almost no corrosion happens; compared with untreated Q195 steel, the corrosion resistance of chromized layer increases 658 times. In H2 SO4 solution, the severe pitting corrosion happens to untreated samples; while Cr-Ni alloying layer is in good condition; compared with untreated Q195 steel, the corrosion resistance of chromized layer increases 90 times. The corrosion resistance of Cr-Ni alloying layer in HNO3 solution is better than that in H2 SO4 solution.