为了提高纯钛在强酸中的耐蚀性能,采用双层辉光等离子渗金属技术对纯钛表面渗钽;使用电化学扫描法和失重法对比研究了钽改性层及纯钛基体在硫酸中的耐腐蚀性能,并通过扫描电镜观察其腐蚀形貌.结果表明:改性层厚约15 μm,由沉积层和扩散层组成,与基体形成了冶金结合,钽呈梯度分布;在质量分数10%和40%硫酸中,钽改性层年腐蚀速率分别只有纯钛的30%和1.2%,在75%硫酸中改性层年腐蚀速率依然很小,只有0.008 8 mm·a-1;纯钛基体在浓硫酸中腐蚀120 h后,腐蚀表面已出现许多腐蚀坑,而钽改性层腐蚀前后的试样表面没有明显变化,整个改性层依然完整致密.

In order to improve corrosion resistance of pure titanium in strong acid solution,tantalum modified layer was formed on pure titanium surface by double glow plasma surface alloying technique.The corrosion resistances of the tantalum modified layer and pure titanium substrate in H2SO4 solution were investigated by immersion test and electrochemical techniques respectively,and the corrosion morphology was observed by scanning electron microscopy.The results indicate that the thickness of the tantalum modified layer was about 15 μm.The layer was composed of deposition layer and diffusion layer,which combined closely with substrate by metallurgy method.The tantalum element distributed gradiently.The annual corrosion rate of the modified layer was only 30% and 1.2% of pure titanium at the same condition in 10wt% and 40wt% H2SO4 solution,and the rate of the modified layer was still small in 75wt% H2SO4 solution,which was only 0.008 8 mm·a-1.After the pure titanium substrate was corroded in concentrated sulfuric acid for 120 h,its corrosion surface already had a lot of corrosion pits,while there was no significant difference on the surface of the tantalum modified layer before and after corroded.The whole modified layer was still integrated and compact.