摘要
用电弧喷涂技术在Q235钢板上喷涂锌铝合金涂层,用硬脂酸/乙醇的表面修饰技术在锌铝合金涂层表面构筑了一层超疏水膜。用接触角测量仪(OCA-20),扫描电子显微镜(SEM)和智能型傅立叶红外光谱仪(ATR)等手段表征了涂层修饰前后的润湿性、表面形貌以及化学结构,并用三电极体系电化学工作站(Solartron analytical)对硬脂酸表面修饰前后锌铝涂层进行了阻抗谱和极化测试。结果表明:热喷涂锌铝涂层具有微/纳复合结构,修饰前涂层表现为亲水性,因为金属涂层具有高表面能;经过硬脂酸表面修饰后涂层的静态接触角达到153.2°,滚动角小于10°;红外分析结果表明,锌铝涂层表面由大量的疏水性烃基长链组成,有超疏水作用;腐蚀测试结果表明,修饰处理能明显提高锌铝涂层的防腐蚀性。涂层表面形成的超疏水膜阻碍了界面电化学反应腐蚀产物的脱落与溶解,提高了电荷转移电阻,降低了电流腐蚀密度,从而提高了涂层的防腐蚀性。
A superhydrophobic ZnAl coating was prepared by the electric arc spraying technology and then surface modification by stearic acid/ethanol. The surface wettability, morphology and chemical structure of the ZnAl coating before and after modification were characterized by contact angle measurement（OCA-20）, scanning electron microscope（SEM） and artificial FTIR spectrometer（ATR）, respectively. The impedance spectrum and polarization curves of the coatings were measuared by electrochemical workstation（Solartron Analytical） with three electrodes system. The results show that the as sprayed ZnAl coating consists of irregular micro-and nano-sized alloy particles and pores, and exhibits clear hydrophilicity, which may be ascribed to the high surface energy of metallic coating. After the surface modification with stearic acid, the static contact angle of the coating reached 153.8° with a rolling angle less than 10°, because there exsited a large number of hydrophobic long alkyl chains on the surface of the modified Zn Al coating. In addition, the surface modification could significantly enhance the corrosion resistance of ZnAl coating due to that the thin hydrophobic film plays an important role in supression of the fall off and dissolution of corrosion products on the ZnAl coating, leading to the increase of charge transfer resistance and the corrosion current density.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2015年第7期523-528,共6页
Chinese Journal of Materials Research
基金
国家重点基础研究发展计划2014CB643302
国家自然科学基金重点项目51335010
中国博士后科学基金2014M551784
浙江省博士后科研择优资助项目BSH1401040
金属强度国家重点实验室开放课题20141605
浙江省重点科技创新团队项目2011R50006
宁波市自然科学基金2014A610010资助~~
关键词
材料失效与保护
热喷涂锌铝合金涂层
表面修饰
疏水机理
腐蚀行为
materials failure and protection
thermal spraying Zn-Al coating
surface modification
hydrophobicity
corrosion behavior
