镁合金基体超音速等离子喷涂Al-Al_(2)O_(3)复合涂层组织与耐腐蚀性能研究  

Study on Microstructures and Corrosion Resistance of SPS Al-Al_(2)O_(3)Composite Coatings on Magnesium Alloy Substrate

作　　者：任东亭 王文权[1] 张新戈 杜文博 朱胜 REN Dongting;WANG Wenquan;ZHANG Xin’ge;DU Wenbo;ZHU Sheng(Key Laboratory of Automobile Materials of Ministry of Education,School of Materials Science and Engineering,Jilin University,Changchun 130025,China;China Institute for Radiation Protection,Taiyuan 030006,China;National Key Laboratory for Remanufacturing,Army Academy of Armored Forces of PLA,Beijing 100072,China)

机构地区：[1]吉林大学材料科学与工程学院,汽车材料教育部重点实验室,长春130025 [2]中国辐射防护研究院,太原030006 [3]中国人民解放军陆军装甲兵学院,装备再制造技术国防科技重点实验室,北京100072

出　　处：《材料导报》2024年第16期207-213,共7页Materials Reports

基　　金：国防科技重点实验室基金(6142005200301)。

摘　　要：镁合金的耐腐蚀性能差,在工程应用中往往因腐蚀而发生失效,通过表面工程技术对镁合金进行表面改性或防护,是工程应用中采用的重要手段。本工作采用超音速等离子喷涂(Supersonic plasma spray,SPS)工艺在AZ61镁合金表面制备Al-Al_(2)O_(3)复合涂层,其中Al_(2)O_(3)的质量分数分别为30%、50%和70%(下文简称AA30、AA50、AA70)。研究了Al_(2)O_(3)含量对Al-Al_(2)O_(3)复合涂层微观组织、孔隙率、电化学性能以及盐雾耐腐蚀性能的影响。结果表明,涂层的表面呈现熔滴铺展堆叠形成的浪花状形貌,粉末熔化充分,涂层内部结合紧密,各涂层均由Al、α-Al_(2)O_(3)和γ-Al_(2)O_(3)三种物相组成。AA70涂层的孔隙率较AA30和AA50明显升高,达到了6.71%;电化学极化试验研究表明,各涂层比AZ61镁合金基体表现出更高的电极电位和较低的自腐蚀电流密度,AZ61镁合金基体自腐蚀电流密度为5.144 mA·m^(-2),而AA30、AA50和AA70的自腐蚀电流密度分别为2.950 mA·m^(-2)、3.084 mA·m^(-2)和2.496 mA·m^(-2),三种涂层相比母材AZ61表现出较低的电化学腐蚀速率。电化学阻抗测试结果表明,三种涂层的R ct达到了AZ61镁合金基体的两倍左右,显示出较低的阳极溶解活性。在盐雾试验中,AZ61镁合金基体产生大量的腐蚀产物和龟裂纹;涂层AA30和AA50由于腐蚀产物的积累产生了大量裂纹,在涂层与基体的界面处发生了电偶腐蚀,最终随着基体表面的腐蚀,涂层产生了剥落;涂层AA70腐蚀程度最小,表现出最佳的抗腐蚀性能。Magnesium alloy corrosion resistance is poor,in engineering applications often due to corrosion and failure,through surface engineering technology to magnesium alloy surface modification or protection,is an important means used in engineering applications.In this work,the supersonic plasma spray(SPS)process was used to prepare Al-Al_(2)O_(3)composite coating on the surface of AZ61 magnesium alloy,in which the mass fractions of Al_(2)O_(3)were 30%,50%and 70%(hereinafter referred to as AA30,AA50 and AA70),and the effects of Al_(2)O_(3)content on the microstructure,porosity,electrochemical properties and corrosion resistance of Al-Al_(2)O_(3)composite coatings were studied.The results show that the surface of the coating presents a wave-like morphology formed by the spread and stacking of molten droplets,the powder is fully melted,and the internal bonding of the coating is tight.And the coating was composed of Al,α-Al_(2)O_(3)andγ-Al_(2)O_(3)phases.The porosity of AA70 coating was significantly higher than that of AA30 and AA50,reaching 6.71%.In the electrochemical polarization test,each coating showed higher electrode potential and lower self-corrosion current density than that of AZ61 magnesium alloy.The test revealed that AZ61 self-corrosion current density was 5.144 mA·cm^(-2),while AA30,AA50 and AA70 self-corrosion current densities were 2.950 mA·cm^(-2),3.084 mA·cm^(-2)and 2.496 mA·cm^(-2),respectively.The coatings of AA30,AA50 and AA70 showed a lower corrosion rate than that of the base metal AZ61.The electrochemical impe-dance test results showed that the R ct of the three coatings reached about twice that of the AZ61 magnesium alloy matrix,showing lower anodic solubilization activity.In the salt spray test,a large number of corrosion products and cracks are produced on the surface of AZ61 magnesium alloy.Coatings AA30 and AA50 have a large number of cracks in the coating due to the accumulation of corrosion products,and galvanic corrosion occurs at the interface between the coating and the substrate.E

关 键 词：超音速等离子喷涂 Al-Al_(2)O_(3)复合涂层 镁合金 孔隙率 耐腐蚀性能 

分 类 号：TG174.44[金属学及工艺—金属表面处理]