湿度对热镀锌钢材在海洋大气环境中氢脆敏感性的影响

来源期刊：中国有色金属学报2010年第3期

论文作者：张大磊 李焰

文章页码：476 - 482

关键词：热浸镀锌层；氢渗透；大气腐蚀；氢脆,hot-dip galvanized coating; hydrogen permeation; atmospheric corrosion; hydrogen embrittlement

Key words：hot-dip galvanized coating; hydrogen permeation; atmospheric corrosion; hydrogen embrittlement

摘    要：采用改进的双面电解池检测热镀锌钢材在恒温30 ℃、不同湿度条件下的氢渗透电流，并结合慢应变速率拉伸和断口形貌分析，研究其在海洋大气环境中的氢脆敏感性。结果表明：在相对湿度小于70%时，热镀锌钢材未检测到明显的氢渗透电流，但随着湿度的增加，氢渗透电流密度逐渐增大；当镀层存在缺陷时，镀锌层在为钢材基体提供阴极保护的同时也会促进氢向钢材基体中渗透，且氢渗透电流密度的最大值随镀层缺陷面积的增加而降低；氢吸收和氢渗透降低了热镀锌钢材的断后伸长率，导致其断口切边处出现少量撕裂棱，表明热镀锌钢材在高温、潮湿的海洋大气中使用时，其氢脆敏感性将有所提高。

Abstract: The hydrogen permeation and embrittlement behavior of hot-dip galvanized steels exposed to stimulated marine atmospheric environments with different relative humidities(RH) at 30 ℃ were investigated by hydrogen permeation current measurement with modified Devanathan-Stachurski cell, slow strain rate tensile test and scanning electron microscopy technique. The results indicate that hydrogen permeation can be negligible if RH is less than 70%. With RH rising, the permeation curves increase gradually. The hydrogen absorption is accelerated by the cathodic protection of scratched steel surface afforded by zinc coating, and hydrogen permeation flux decreases with the exposed area of steel substrate increasing. Hydrogen absorption and permeation reduce the elongation after fracture of galvanized steel specimens; some lacerated phenomena occur in the fracture fringe, indicating that galvanized steels show higher hydrogen embrittlement susceptivity when being exposed to marine atmospheric environment.

基金信息：国家自然科学基金资助项目
山东省优秀中青年科学家科研奖励基金资助项目