稀土铒和铬离子注入对电机护环钢SCC性能的影响

研究了解和铬离子高、中能量重迭注入对５０Ｍｎ１８Ｃｒ４电机护环钢ＳＣＣ性能的影响．ＳＣＣ对比试验结果表明：（１）在ＱＨＪ－７９标准硝酸盐介质中，离子注入试样的ＳＣＣ出现时间（ｔｆ）比不经注入试样的延长了６倍以上，致钝和维钝电流密度下降了一个数量级；（２）在阴极充氢条件下，两种试样均对氢致开裂（ＨＩＣ）不敏感，但离子注入可抑制氢诱发腐蚀．用ＡＥＳ－ＰＲＯ、ＲＢＳ、ＸＰＳ－ＰＲＯ、ＥＤＡＸ、金相及电化学方法分析讨论了护环钢在ＱＨＪ－７９标准介质中的ＳＣＣ机理和离子注入改善ＳＣＣ抗力及抗氢锈发腐蚀性能的机制．

EFFECTS OF ION IMPLANTATION WITH RARE-EARTH ERBIUM AND CHROMIUM ON SCC BEHAVIOUR FOR GENERATOR RETAINING RING STEEL

he effeCts of overlap-implanting rare-earth erbium and chromuim ions with high-medium energy on stress corrosion cracking (SCC) have been studied for generator retaining ring steel 50Mn18Cr4. The results of comparstive SCC tests show that: (1) The time to SCC appearance if in the nitrate solution prepared according to QHJ-79 standard for implanted specimens is postponed averagely over 6 times, and the critical current densities required to cause and maintain passivation decrease by one order of magnitude. (2) In the medium for cathodally charging of hydrogen, the steel is insensitive to hydrogeninduced corrosion (HIC); the HIC resistance can be improved by Er Cr implantation remarkably. The mechanism of SCC for the steel in QHJ-79 standard solution and of improvement of resistance to SCC and HIC by ion-implantation is discussed on the basis of the results of AES-PRO, RBS, XPS-PRO, EDAX, metallography and electrochemistry tests.