Al-Mg_2Si复合涂层在3.5%NaCl水溶液中的腐蚀磨损性能研究  

Corrosion Wear Properties of Al-Mg_2Si Composite Coatings in 3.5wt.% NaCl Solution

作　　者：范春[1] 龙威[1] 周小平[1] FAN Chun;LONG Wei;ZHOU Xiao-ping(Hubei Provincial Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan 430068, Chin)

机构地区：[1]湖北工业大学绿色轻工材料湖北省重点实验室,武汉430068

出　　处：《表面技术》2018年第4期260-266,共7页Surface Technology

基　　金：国家自然科学基金资助(51171062)~~

摘　　要：目的研究Al-Mg_2Si复合涂层在3.5%NaCl溶液中的腐蚀-磨损性能。方法用电化学工作站(CHI660E)、腐蚀-磨损试验机测试试样的电化学行为及实时监测在3.5%NaCl溶液中的开路电位、摩擦系数和干摩擦性能,并采用扫描电镜(SEM)、超景深三维显微镜对磨痕特征进行表征。结果镁合金自腐蚀电位为-1.4888V,腐蚀电流密度为2.817×10^(-3) A/cm^2。与镁合金基体相比,Al-Mg_2Si复合涂层的自腐蚀电位正移了0.5288V,腐蚀电流密度降低了3个数量级。腐蚀磨损过程中,Al-Mg_2Si复合涂层的开路电位(OCP)为-0.9202 V,比镁合金基体高0.5713 V。干摩擦过程中,复合涂层的稳定摩擦系数为0.28,比镁合金低0.07。复合涂层干、湿磨损率相差44.72×10^(-4) mm^3/(N?mm),其值是镁合金基体干、湿磨损率相差值的0.52倍,且均远远大于各自纯机械磨损率。结论在腐蚀磨损过程中,腐蚀是造成磨蚀损失的主要原因,且Al-Mg_2Si复合涂层的耐磨蚀性能优于镁合金基体。This work aims to study corrosive wear properties of Al-Mg2Si composite coating in 3.5 wt.% NaCl solution. Electrochemical behavior of the samples was tested, and open circuit potential, friction coefficient and dry friction of the sam- ples in 3.5%NaCl solution were monitored in real time with electrochemical workstation （CHI660 E） and corrosive wear tester. Characteristics of grinding cracks were characterized with scanning electron microscope （SEM） and ultra-depth three-dimen- sional microscope. Self-corrosion potential of magnesium alloy was -1.4888 V, and corrosion current density was 2.817×10^-3 A/cm^2. Compared with the substrate magnesium alloy, self-corrosion potential of the A1-MgzSi composite coating shifted positively by 0.5288 V, and corrosion current density of the composite coating decreased by 3 orders of magnitude. During the pro- cess of corrosive wear, open circuit potential （OCP） of the Al-Mg2Si composite coating was -0.9202 V, 0.5713 V higher than that of the substrate magnesium alloy. During the process of dry friction, stability friction coefficient of the coating was 0.28, 0.07 lower than that of the magnesium alloy. Difference between dry and wet wear rate of the Al-Mg2Si composite coating was 44.72×10^-4 mm^3/（N·mm）, 0.52 times as large as that of AZ31B magnesium alloy, and was far greater than corresponding pure mechanical wear rate. Corrosion is the main cause of abrasion loss during corrosive wear process, and the Al-Mg2Si composite coating exhibits better corrosive wear properties than magnesium alloy.

关 键 词：AZ31B镁合金 Al-Mg2Si复合涂层 腐蚀磨损 干摩擦 摩擦系数 

分 类 号：TG172[金属学及工艺—金属表面处理]