摘要
以方波电位着色法在不锈钢表面制备彩色膜,可获得较快的膜生长速率,现有的硫酸方波电位着色研究未涉及着色时间对彩色膜耐蚀性的影响。采用无铬硫酸体系对304不锈钢进行交流方波恒电位电化学着色,运用色差计、扫描电镜及能谱仪、腐蚀加速浸泡试验和交流阻抗测试等方法,重点研究了硫酸介质中交流方波着色时间对着色膜着色性能和膜耐腐蚀性能的影响。结果表明:在高低电位幅值分别为0 V和1 V的方波脉冲条件下,20～120 min的着色时间范围内,膜的厚度随着着色时间增加而增厚,呈现不同色彩;但膜的耐腐蚀性能随时间增加并不呈线性增加关系,着色时间超过80 min,着色膜耐腐蚀性能反而下降,这与膜的双层结构有关:当着色时间超过80 min后,膜层由微孔钝化膜单层结构转变为顶层覆盖岛状富铬氧化物层的双层膜结构,顶层膜小岛之间的缝隙导致膜的微观电化学非均匀性,从而使膜的耐腐蚀性能降低。
The 304 stainless steel was colored by square wave potential pulse polarization method in chromium-free H2 SO4 solution. The effects of coloring time on the coloring performance and corrosion resistance were researched by using colorimeter,scanning electron microscopy,X-ray energy dispersive spectrometer,accelerated corrosion test and electrochemical impedance spectroscopy. Results showed that when the lower potential( 0 V) and higher potential( 1 V) of the square wave were applied,respectively,the obtained colored film showed an increasing trend in thickness and different colors with the coloring time increasing from 20 min to 120 min. However,the corrosion resistance of the colored film did not increase linearly versus the increasing coloring time. When the coloring process exceeded 80 min,the corrosion resistance inversely decreased. This was related to the double-layer structure of the film. While exceeding 80 min coloring,the film changed from microporous single layer structure into double layer structure with covering by a top island-shaped Cr-rich oxide film. The irregular gaps between adjacent islands resulted in the inhomogeneous electrochemical heterogeneity characteristics of the film,leading to the degradation of the corrosion resistance.
作者
秦静
朱凯
屈钧娥
王海人
曹志勇
QIN Jing;ZHU Kai;Qu Jun-e;WANG Hai-ren;CAO Zhi-yong(Key Laboratory of Polymer Materials in Hubei Province-Materials Science and Engineering College,Hubei University,Wuhan 430062,China)
出处
《材料保护》
CAS
CSCD
北大核心
2019年第1期92-95,122,共5页
Materials Protection
关键词
304不锈钢
恒电位方波着色
着色时间
耐腐蚀性能
色彩
304 stainless steel
coloring by potentiostat square wave
coloring time
corrosion resistance
color
