摘要
目的通过化学浸泡法在黄铜表面获得植酸钝化膜,并研究其成膜机理。方法采用硝酸点滴、中性盐雾试验和极化曲线测试,研究植酸钝化膜的耐蚀性。通过SEM、XRD对植酸钝化膜的形貌和组成进行分析,并测试黄铜试样钝化过程的电位-时间曲线,推测植酸钝化膜的成膜机理。结果与铬酸盐转化膜对比,黄铜表面植酸钝化膜的自腐蚀电流密度小于铬酸盐转化膜,腐蚀速率比重铬酸盐钝化膜小。经测试,植酸钝化膜的外观平整,结构致密,主要成分为植酸盐、Al_2O_3和ZnO。钝化过程的电位-时间曲线显示,黄铜试样的电位在前60 s从-0.172 V迅速升高到-0.157 V,随后电位升高的速度逐渐变缓,在150 s后电位变化微小。结论在黄铜表面形成的植酸钝化膜具有良好的耐腐蚀性能。植酸钝化膜的成膜过程分为黄铜表面的溶解和植酸钝化膜的形成两个过程。
The phytic acid passivation film were acquired on the brass surface by Chemical immersion technology, and studied the film formation mechanism. The corrosion resistance of the phytic acid passivation film were studied by nitric acid droplet test, Neutral salt spray test and polarization curves, the morphology and components were analised by SEM and XRD. The potential-time curve were tested in the process of passivation on the brass specimen to speculate the Film-forming mechanism of phytic acid passivating film. Compared with chromate conversion, The corrosion current density of the phytic acid passivation on the brass surface is smaller than that of the chromate conversion film, and the corrosion rate is smaller than the chromate conversion. SEM and XRD results show that the surface of the passivation film is smooth and compact, and the main components are phytate, A1203 and ZnO. The poten-tial-time curve show that the brass sample potential rise rapidly from -0.172 V to -0.157 V in the 60 s in the process of passivation. Then the speed of the potential rise gradually slow, finally, potential changes in tiny after 150 s. The phytic acid passivation film on the brass surface has good corrosion resistance, the process of film formation of phytate passivation film included two processes： dissolu- tion of brass surface and formation ofphytic acid passivation film.
出处
《表面技术》
EI
CAS
CSCD
北大核心
2017年第9期197-202,共6页
Surface Technology
基金
国家自然科学基金(51561008)
江西省科技厅重点工业项目(20161BBE50030)~~
关键词
黄铜
钝化膜
植酸
成膜机理
brass
passivation film
phytic acid
film formation mechanism
