丙烯酸粉末涂层在模拟海洋大气环境中的腐蚀行为研究  

Study on Corrosion Behavior of Acrylic Powder Coating in Simulated Marine Atmospheric Environment

作　　者：余强 向继明 张力文 张黎明 周和荣[2] YU Qiang;XIANG Ji-ming;ZHANG Li-wen;ZHANG Li-ming;ZHOU He-rong(Research Institute of Hunan Valin Lianyuan Iron and Steel Co.,Ltd.,Loudi 417009,China;School of Materials and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]湖南华菱涟源钢铁有限公司研究院,湖南娄底417009 [2]武汉科技大学材料与冶金学院,湖北武汉430081

出　　处：《材料保护》2022年第8期22-30,共9页Materials Protection

摘　　要：丙烯酸粉末涂料具有优异的耐老化功能常作为环保型面漆,为了解其防腐性能及防腐机制,以拓展其应用,采用CASS试验、浸泡试验和交流阻抗法研究了丙烯酸粉末涂层缺陷和完整涂层在海洋环境中的腐蚀行为和机制。结果表明:2种厚度(80μm和120μm)的透明丙烯酸粉末涂层试样经240 h CASS试验后划痕边沿有少量起泡,120μm粉末涂层划痕处腐蚀产物的最大腐蚀宽度约为3.5 mm,最小腐蚀宽度约为0.5 mm,表面附着力为0级,其耐CASS性能较强;浸泡30 d后,涂层厚度为120μm试样划痕处的腐蚀产物数量比厚度为80μm试样的少,其耐浸泡性能较强;划痕试样在0.6 mol/L NaCl溶液中的EIS谱显示双电层电容随浸泡时间的延长先迅速降低后趋于稳定,腐蚀速率随浸泡时间的延长不断增大。完整丙烯酸粉末涂层试样在0.6 mol/L NaCl溶液中浸泡720 h后其阻抗由10^(10)~10^(11)Ω·cm~2降至10~6Ω·cm~2数量级,至360 h后2种厚度涂层的阻隔效果基本相同。丙烯酸粉末涂层涂装的铝合金材料的耐蚀性能较差,不适合单独作为轿车铝轮毂或铝合金材料的涂装体系,建议采用复合涂层体系作为汽车铝合金轮毂的涂装方案。Acrylic powder coating has excellent anti-aging function and often used as an environmentally friendly topcoat coating.In order to understand its anti-corrosion performance and anti-corrosion mechanism for the purpose of expanding its application,the corrosion behavior and mechanism of intact acrylic powder coatings in marine environment and the defect of acrylic powder coating had been investigated using CASS test,immersion test and AC impedance method.Results showed that the transparent acrylic powder coatings with a thickness of 80 μm and 120 μm respectively had a few blisters on the edge of the scratch after treated by a 240 h CASS test.For the powder coating with a thickness of 120 μm,the maximum and minimum widths of corrosion products around the scratch were about 3.5 mm and 0.5 mm respectively,and the adhesion to the surface was level 0,indicating that the coating had good CASS resistance.After an immersion of 30 d,the amount of corrosion products generated around the scratch of 120 μm coating was smaller than that of 80 μm coating,revealing that 120 μm coating had better immersion resistance.Furthermore,the EIS of scratch specimens in 0.6 mol/L NaCl solution showed that the electric double layer capacitance decreased rapidly firstly and then tended to be stable,and the corrosion rate increased with the prolonging of immersion time.The impedance of the intact acrylic powder coating decreased from about 10^(10)~10^(11)Ω·cm^(2 )to 10~6 Ω·cm~2after an immersion in 0.6 mol/L NaCl solution for 720 h.The barrier effect of these two kinds of coatings was basically the same after a 360 h immersion.Besides,as the aluminum alloy material covered with acrylic powder coating had poor corrosion resistance,the acrylic powder coating was not suitable to be used alone as the coating system for the automobile aluminum wheel hub or the alumimum alloy material.Hence,it is recommended to use composite coating system as the coating scheme for automobile aluminum alloy wheel hub.

关 键 词：丙烯酸粉末涂层 CASS试验 浸泡试验 交流阻抗 

分 类 号：TG172.3[金属学及工艺—金属表面处理]