摘要
为了研究316L不锈钢自然点蚀的生长规律,发展基于声发射技术的小孔腐蚀监测方法,利用声发射技术原位研究了316L奥氏体不锈钢在pH=1.0和中性(pH=6.7)的3.5%NaCl溶液中的自然点蚀状况,同时监测了开路电位E_(OCP);通过扫描电镜对试验后样品的表面形貌进行表征,并通过Matlab平台对声发射信号进行聚类分析。结果表明:316L奥氏体不锈钢的自然点蚀具有不同的孕育周期,声发射信号的获取跟E_(OCP)的变化具有较好的对应关系。在点蚀快速发展阶段,声发射信号具有较高的绝对能量。在Matlab平台上建立了一套信号处理程序,并对声发射信号进行重新定义,对处理后的信号进行声发射信号参数分析,得到了3类较好的声发射信号聚类,来源于不同腐蚀现象或阶段。其中,在点蚀的快速发展阶段主要以高持续时间高计数和高持续时间低计数2类谐振信号为主。
In order to understand the evolution behavior of natural pitting on stainless steel and develop monitoring methods of pitting corrosion, the acoustic emission （AE） technique was applied to investigate the pitting corrosion of 316L austenitic stainless steel in sodium chloride solu- tions with different pH values（ pH = 1.0 and pH = 6.7） , along with the open circuit potential monitoring. The corrosion micromorphology was characterized with scanning electron microscope. Clustering analysis of AE signals was studied by Matlab platform. Results showed that natural pitting corrosion of 316L austenitic stainless steel had different propagation periods. There was a good corresponding relationship between acquirement of AE signals and change of Eoce. In the rapid development stage of pitting corrosion, AE signals had high absolute energy. Three types of AE signals were classified by waveform parameters clustering after the performing of a novel AE waveform processing, corresponding to different corrosion phenomena or stages. In the propagation stage of pitting corrosion, the two main types of resonance signals were high duration and high count, and low duration and low count, respectively.
出处
《材料保护》
CSCD
北大核心
2017年第10期73-77,88,共6页
Materials Protection
基金
四川省科技厅应用基础研究项目基金(2017JY0044)
四川省青年科技创新研究团队基金(2015TD0007)资助
关键词
点蚀
316L奥氏体不锈钢
原位监测
开路电位
声发射
聚类分析
pitting corrosion
316L austenitic stainless steel
in-situ monitoring
open circuit potential
acoustic emission
clustering analysis
