45~#钢表面Al-Cr复合强化层的耐腐蚀性能

Corrosion Resistance of Al-Cr Composite Strengthening Layer on the Surface of 45~# steel

针对海工装备中常用45~#钢表面耐腐蚀性不足的问题,采用离子注入技术(PII)注Al和双辉等离子表面冶金技术(DGPSM)渗Cr复合处理,在基体45~#钢表面制备Al-Cr复合强化层。利用X射线衍射(XRD)、光电子能谱(XPS)、原子力显微镜(AFM)、扫描电镜(SEM)和能谱(EDS)等对试样的元素分布、物相结构进行表征。并采用极化曲线和电化学阻抗谱,对比分析Al-Cr复合涂层、注Al涂层和基体在3.5%NaCl溶液中的耐腐蚀性,研究其腐蚀机理。结果表明,采用复合技术制备所得Al-Cr涂层的耐腐蚀性最佳,其表面形成Cr_2O_3和Al_2O_3复合钝化膜,涂层内部形成具有优异耐腐蚀性Fe_2AlCr和Al_8Cr_5相,阻碍Cl^-的腐蚀作用;注Al层耐腐蚀性次之,其表面形成致密Al_2O_3钝化膜,延缓了Cl^-对基体的腐蚀作用;基体耐腐蚀性最差。

Aiming at improving the corrosion resistance of 45-# steel used in maritime works,Al-Cr composite strengthening layer was deposited on the surface of 45-# steel via a composite technique of plasma ion implantation（PII）and double glow plasma surface metallurgy（DGPSM）.The element distribution and phase structure of the Al-Cr composite strengthening layer were investigated via X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,atomic force microscope（AFM）,scanning electron microscope（SEM）and energy dispersive spectroscopy（EDS）.Polarization curves and electrochemical impedance spectroscopy（EIS）were used to study the corrosion resistance and corrosion mechanisms of the Al-Cr composite strengthening layer,Al implanted layer and 45-# steel in 3.5 wt%NaCl solution.The results show that the Al-Cr composite strengthening layer reveals the best corrosion resistance.Cr_2O_3 and Al_2O_3 form on the surface of the Al-Cr composite strengthening layer as a passive film,and they hinder the corrosion of Cl--effectively together with the inner Fe_2AlCr and Al_8Cr_5 phases which have excellent corrosion resistance.The Al implanted layer exhibits moderate corrosion resistance due to the formation of Al_2O_3 passive film.The substrate of 45-# steel shows the worst corrosion resistance.