基于阴极沉积Mg(OH)_(2)薄膜的镁合金超疏水表面改性及其耐蚀性研究  

Study on the Superhydrophobic Surface Modification and Corrosion Resistance of Mg(OH)_(2)Films on Magnesium Alloys by Cathodic Deposition

作　　者：黄仕高 陈洪世 马展雄 张宏亮 姚金钰 张永君[3] HUANG Shigao;CHEN Hongshi;MA Zhanxiong;ZHANG Hongliang;YAO Jinyu;ZHANG Yongjun(Guangdong Yue Power Zhanjiang Biomass Power Co.,Ltd.,Zhanjiang 524300,China;China Southern Power Grid Power Technology Co.,Ltd.,Guangzhou 510600,China;School of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]广东粤电湛江生物质发电有限公司,广东湛江524300 [2]南方电网电力科技股份有限公司,广东广州510600 [3]华南理工大学机械与汽车工程学院,广东广州510641

出　　处：《材料保护》2024年第8期175-182,共8页Materials Protection

基　　金：广东省自然科学基金(2023A1515011202)。

摘　　要：为延长镁合金的使役寿命,通过阴极沉积和超疏水改性在ME20M稀土镁合金表面制备超疏水涂层,采用硬脂酸乙醇基溶液对阴极沉积Mg(OH)_(2)薄膜的镁合金进行化学修饰,通过单因素试验分别考察硬脂酸浓度、溶液温度、浸泡时间对表面润湿性的影响规律,确定最优修饰工艺。对典型试样,采用点滴实验、全浸腐蚀实验及现代电化学测试技术评估其耐蚀性,采用划格法评价膜/基结合力,采用SEM、FT-IR及XRD分析试样表面微观形貌及成分。结果表明:阴极沉积Mg(OH)_(2)薄膜经低浓度硬脂酸溶液短暂浸泡即可获得超疏水性,蒸馏水静态接触角SCA高达151.5°,滚动角SA低至1.0°,呈低黏性。阴极沉积/疏水改性复合处理可显著改善镁合金的耐蚀性,与空白试样相比,复合处理试样的点滴液变色时间延长近25倍,在3.5%NaCl溶液中的自腐蚀电流密度Jcorr降低3个数量级,特征阻抗模值|Z|_(0.1 Hz)提高4个数量级。经疏水处理的阴极沉积Mg(OH)_(2)薄膜呈刀片状微纳结构,试样的红外光谱中出现明显的-CH_(3)和-CH_(2)-吸收峰。In order to prolong the service life of magnesium alloys,superhydrophobic coatings were prepared on the surface of ME20M rare earth magnesium alloy through cathodic deposition and superhydrophobic modification.A stearic acid ethanol solution was used for chemical modification of the cathodically deposited Mg(OH)2 films on the magnesium alloy.Single-factor experiments were conducted to investigate the effects of stearic acid concentration,solution temperature and immersion time on surface wettability,in order to determine the optimal modification process.The corrosion resistance of typical samples was evaluated using drop tests,full immersion corrosion tests and modern electrochemical testing techniques.The adhesion strength of the film to the substrate was assessed by the cross-cut method,and the surface microstructure and composition of the samples were analyzed using scanning electron microscopy(SEM),fourier transform infrared spectrometer(FT-IR)and X-ray diffraction analyzer(XRD).Results showed that the cathode deposited Mg(OH)_(2)film could be rendered superhydrophobic by brief immersion in a low-concentration stearic acid solution,achieving a static contact angle(SCA)of up to 151.5°with distilled water and a rolling angle(SA)as low as 1.0°,exhibiting low viscosity.The combined treatment of cathodic deposition and hydrophobic modification could signifi-cantly improve the corrosion resistance of magnesium alloys.Compared with the blank sample,the discoloration time of the droplet on the com-posite treated sample was extended by nearly 25 times,the self-corrosion current density Jcorr in 3.5%NaCl solution was reduced by nearly 3 orders of magnitude,and the characteristic impedance modulus|Z|0.1 Hz was increased by nearly 4 orders of magnitude.The surface micromor-phology of cathodic deposition Mg(OH)_(2)thin film with hydrophobic treatment showed a sword-like structure at the micro/nano scale.There were obvious absorption peaks of-CH_(3) and-CH_(2)-in the infrared spectrum of the sample.

关 键 词：镁合金 阴极沉积 Mg(OH)_(2)薄膜 超疏水 耐蚀性 

分 类 号：TG174.4[金属学及工艺—金属表面处理]