采用开路电位测量、电化学阻抗谱及极化曲线测量等方法研究了钛合金Ti70(Ti-2.5Al-2Zr-1Fe)在HF-HNO3体系中的电化学腐蚀行为。结果表明,随着氢氟酸浓度的增加，Ti70合金的腐蚀速率增大; 氢氟酸浓度一定时，随着硝酸与氢氟酸体积比的增大，Ti70合金的开路电位降低，容抗弧增大; 极化曲线由活化向自钝化特征转化。Ti70合金在浸泡初期，其电化学阻抗谱出现低频感抗弧; 随着浸泡时间的延长，溶液中的离子在合金表面进行沉积，形成一层致密的钝化膜，从而出现中高频段的双容抗弧。

The electrochemical corrosion behavior of Ti70 alloy in HF-HNO3 system was investigated by measurements of open-circuit potentials, EIS and polarization curves. The results show that the corrosion rate of Ti70 increased with the HF concentration increasing. When the HF concentration was constant, the open-circuit potential decreased and the capacitance arc increased with increasing the volume ratio of HNO3 to HF. The obvious active-passive transition could be seen in the polarization curves. At the early stage of corrosion, an inductive arc at low frequency appeared. With extending the immersion time, a compact passivated film formed on the alloy surface. Two capacitance arcs appeared at high and medium frequencies respectively.