合金元素铁对钛缝隙腐蚀性能的影响

用浸泡腐蚀试验及电化学测试技术研究了合金元素铁对钛抗缝隙腐蚀性能的影响。试验结果表明，加入铁使缝隙腐蚀再钝化电位ＥＲ变负，缝隙腐蚀诱导期缩短，腐蚀率增大。通过电子探针分析和ＳＥＭ观察发现，铁以ＴｉＦｅ形式在晶界析出，腐蚀优先在ＴｉＦｅ析出物上发生，并且沿晶界向内部发展。由此得知，缝隙腐蚀起源于ＴｉＦｅ析出物，继而成长并促进了缝内活性溶解。

INFLUENCE OF IRON AS ALLOYING ELEMENT ON CREVICE CORROSION BEHAVIOR OF TITANIUM

The effect of iron as alloying element on the crevice corrosion resistance of titanium was studied using immersion test,electrochemical measurement, SEM and EPMA techniques.The results indicated that the addition of iron into titanium decreased repassivation potential for crevice corrosion (ER), reduced the incubation time of crevice corrosion and increased the crevice corrosion rate. The potentiostatic tests showed that ER is in accordance with critical potential of crevice corrosion.The EPMA analysis and SEM observation showed that the intermetallic compound TiFe precipitated at intergranular boundaries in titanium.Corrosion occurred preferentially st these places and penetrated along the intergranular path to the interior.TiFe induced the crevice corrosion and promoted active active dissolution inside the crevice.