深海环境对纯镍腐蚀行为的影响Ⅲ-静水压力对纯镍点蚀机制的影响

Influence of Deep-sea Environment on Corrosion Behavior of Pure Nickel III-Influence of Hydrostatic Pressures on Pitting Mechanism for Pure Nickel

利用光学显微镜、扫描电子显微镜和电化学测量方法研究纯镍在3.5%NaCl溶液中,挣水压力为常压和8MPa条件下的腐蚀行为.结果表明,在常压和挣水压力为8MPa条件下,纯镍钝化膜均为二维形核;8MPa的静水压力对纯镍的腐蚀行为有三方面的影响:(1)降低纯镍的钝化膜形成速度;(2)抑制点蚀形成的B1过程,促进A3过程;(3)降低点蚀的产生概率.

The effect of hydrostatic pressure on the corrosion behavior of nickel in 3.5%NaCl solution was investigated by electrochemical measurements and OM/SEM observation.The results showed that passive film on nickel formed by instantaneous 2D nucleation both under atmospheric and 8 MPa pressures.The higher hydrostatic pressure 8 MPa showed effect on the corrosion behavior of nickel in terms of：（1）hindering the passive film formation rate;（2）retarding the B1 process and accelerated the A3 process and（3）decreasing the pitting growth probability.