钛表面钛钯合金层耐蚀性能及耐蚀机理研究

摘要:

采用磁控溅射沉积钯膜层+热扩散技术在工业纯钛表面制备Ti-Pd合金层,研究了Ti-Pd合金层的耐蚀性能,用重量法评价了合金层的腐蚀速率,分析了不同样品经腐蚀后的表面形貌和成分。结果表明:Ti-Pd合金层在37%(质量分数,下同) HCl溶液和80%H_2SO_4溶液中的腐蚀速率比纯钛降低了2个数量级。Ti-Pd合金层经37%HCl腐蚀后,表面含有Ti、Pd、O元素,表面有微小的点蚀坑。Ti-Pd合金层经80%H_2SO_4腐蚀后,表面含有Ti、Pd、S、O元素,表面有亚微米级的点蚀坑。提出了Ti-Pd合金层的耐蚀机理:微量的Pd和Ti O2组成的钝化膜使表面腐蚀电位提高,产生耐蚀效果。

Abstract:

The Ti-Pd alloyed layer was prepared on pure titanium by the technique of depositing palladium film and thermal diffusion. The corrosion resistance of Ti-Pd alloyed layer was studied. The corrosion rate of the alloy layer was evaluated by gravimetric method. The surface morphologies and composition of different samples after corrosion were analyzed. The results show that the corrosion rate of the Ti-Pd alloyed layer in 37% HCl and 80% H2SO4 is two orders of magnitude lower than that of pure titanium. It is found that after the alloyed layer is corroded by 37% HCl,the surface contains Ti,Pd,O elements,and the surface has tiny pitting pits. On the other hand,after the Ti-Pd alloyed layer is corroded by 80% H2SO4,the surface contains Ti,Pd,S,O elements,and the surface has submicron pitting pits. According to the experimental results,the corrosion resistance mechanism of the Ti-Pd alloyed layer is proposed in this paper. A small amount of Pd and TiO2 constitute a passive film,which improves the surface corrosion potential,thereby improving the corrosion resistance of the material.