摘要
利用磁致伸缩空蚀实验机研究了 2 0SiMn低合金钢在蒸馏水和 3%NaCl溶液中的空蚀行为。利用扫描电镜(SEM)跟踪观察了试样表面的空蚀形貌 ,测量了静态和空蚀条件下的极化曲线和腐蚀电位变化 ,分析了腐蚀因素的影响。结果表明 :空蚀使 2 0SiMn的自腐蚀电位正移近 2 0 0mV ,使电化学腐蚀速率增大 5 4倍 ;3%NaCl溶液中最大失重率约为蒸馏水中的 3倍。两种介质中的空蚀形貌相似 ,空蚀破坏首先在铁素体相以及相界和晶界发生 ,在空蚀初期 ,材料的失重主要来源于铁素体相区的小片剥落 ,随着空蚀的进行 ,由于裂纹的扩展和连接导致材料大块脱落。
The cavitation erosion behavior of 20SiMn low alloy steel in both distilled water and 3%NaCl solution was investigated by using a magnetostrictive-induced cavitation facility.The micrographs of damaged surfaces were observed by scanning electron microscope (SEM).The role of corrosion was analyzed by the measurements of polarization curve and free-corrosion potential with or without cavitation.The results showed that the cavitation shifted free corrosion potential to the positive direction by 200 mV.The electrochemical corrosion rate in the presence of cavitation was 53 times higher than that in absence of cavitation.The maximum cavitation erosion rate in 3%NaCl solution was almost three times as fast as that in distilled water,while the morphologies of damaged surfaces in 3%NaCl solution were similar to that in distilled water.The ferrite area,grain boundaries and ferrite-pearlite phase boundaries were preferential sites for cavitation attack,which attributed to the low hardness of ferrite phase.The mass loss came from the detachment of small pieces in the ferrite area in the early stage and from the removal of massive chunks by the propagation and connection of cracks in both ferrite and pearlite area in the following test period.
出处
《中国腐蚀与防护学报》
CAS
CSCD
2003年第4期206-210,共5页
Journal of Chinese Society For Corrosion and Protection
基金
国家重点基础研究专项经费 (G19990 6 5 0 )
