接触腐蚀.pdf

General Metal Finishing Contact (galvanic) corrosion 关于接触腐蚀 G. Krolik – Guangzhou China – 2015/12/11 What is contact corrosion? 什么是接触腐蚀? Proprietary and Confidential General Metal Finishing Contact corrosion What is contact Corrosion?  Different metals show different chemical behavior 不同金属有不同的化学特性 ‒ Related to environmental conditions与周围环境有关系  Type of electrolyte which surround the metal金属周围的电解液  Ion content离子的含量  pH  Oxigen content 氧气含量  Temperature 温度  etc. 其它...  To compare the metals the electrochemical potential can be measured under different conditions 在不同条件下,金属间的电位差可以通过测量并比较  当不同金属间的电位差100 mV时很有可能发生接触腐蚀 Proprietary and Confidential 3 G. Krolik - Guangzhou China - 2015/12/11 Contact corrosion What is contact Corrosion?  If two or more electrical conencted different metals are dipped in an electrolyte, electrons will flow from the less noble metall to the nobel metal. 当两种或两种以上通电的金属浸泡在 电解液中,电子从活性较强的金属流向相对惰性的金属  The less noble metal become the anode – 活性较强的金属这时做阳极-被溶解  On the nobel metal for example gas will be generated 惰性金属上会有副产物生成，如:气体 e (+) (-) Me1+ H 2 less noble noble Proprietary and Confidential 4 G. Krolik - Guangzhou China - 2015/12/11 Contact corrosion What is contact Corrosion?  Contact corrosion - Oil distribution pipe in humid environment 接触腐蚀-如在潮湿环境中的油管 - Contact of materials with different electrochemical potential 化学电位各不相同的金属接触 Brass 黄铜 Aluminium铝 Unalloyed Steel 非合金钢