摘要
应用扫描Kelvin探针原位研究盐雾和干湿周浸环境中缺陷涂层膜下的腐蚀行为.结果显示:在两种腐蚀环境中,缺陷涂层均分为缺陷、阴极剥离及完好涂层区域;Kelvin电位的分布相同,缺陷处最高,完整涂层处最低.Kelvin电位分布峰的直径随时间的延长而增大,表明剥离区域扩大.干湿周浸环境中,Kelvin电位的最大值Vmax随时间变化不明显,Vmin在逐渐下降后达到谷值,随后升高;盐雾环境中由于电解质溶液持续扩散和盐雾颗粒极强的腐蚀性,Kelvin电位随时间的变化规律为Vmin在起始阶段达到最小值,随后升高.由Vmax-Vmin的变化规律得出,干湿周浸环境下腐蚀倾向性在试验开始5h后达到最大,而在盐雾环境下,试验开始阶段腐蚀倾向性就达到最大,且要高于干湿周浸环境.
The corrosion behavior under coatings with a point defect was investigated in situ by means of scanning Kelvin probe in both salt spray test and cyclic wet-dry immersion test.The results showed that the Kelvin potential distribution was identical in both the tests due to the same division of coating surfaces：defect area with the highest potential,delaminated area,and intact area with the lowest potential.Through monitoring the augment of diameter of Kelvin potential peaks with time,the expansion of the delaminated area was revealed.In cyclic wet-dry immersion test,the highest Kelvin potential Vmax did not change obviously with time while the lowest potential Vmin increased after reaching at the valley.On the other hand,in salt spray test,different from the rule in cyclic wet-dry test,Vmin was minimized at the first stage of the test resulted from the continued diffusion of the electrolyte and the corrosive ability of slat spray particles.Based on the changing pattern of Vmax-Vmin,it was concluded that in cyclic wet-dry immersion test,the tendentiousness of corrosion got the highest level when the test kept going for 5 h.However,in salt spray test,it achieved the highest level just at the beginning of the test and was more intensive than that in cyclic wet-dry immersion test.
出处
《北京科技大学学报》
EI
CAS
CSCD
北大核心
2010年第9期1169-1174,共6页
Journal of University of Science and Technology Beijing
基金
科技部国家科技基础条件平台建设资助项目(No.2005DKA10400)
关键词
涂层
缺陷
电化学腐蚀
扫描KELVIN探针
coatings； defects； electrochemical corrosion； scanning Kelvin probe；
