AZ31镁合金表面低偏压磁控溅射TiAlN薄膜的结构与耐蚀耐磨性能

Structure,Corrosion Resistance and Wear Resistance of Low Bias Magnetron Sputtering TiAlN Films on AZ31 Mg Alloy

针对镁合金不抗蚀、不耐磨2大问题,采用直流磁控溅射的方法,通过对基体施加偏压调控,在AZ31镁合金表面制备了TiAlN薄膜。借助XRD和SEM等方法研究了薄膜的微观结构,通过电化学工作站和销盘式摩擦磨损试验机评估了薄膜的耐腐蚀和耐磨性能。结果表明:施加偏压后的镀膜基体结构发生很大变化,薄膜由岛状生长模式转变为层状生长模式,由等轴晶转变为柱状晶结构。当偏压增大到-30 V后的薄膜开始在(111)择优生长,薄膜主要为柱状晶结构。镀膜后基体的腐蚀电位明显提高,腐蚀电流密度下降了2个数量级,表明其具有良好的耐蚀性能,-30 V偏压的薄膜的耐腐蚀性能最佳。薄膜的摩擦系数在0.19~0.30范围,磨损率在10-6 mm^(3)/(N·m)数量级,薄膜的摩擦系数和磨损率从小到大对应的偏压依次为-30 V<-15 V<-45 V<0 V。

Aiming at the two problems of non-corrosion and non-wear resistance of magnesium alloy,TiAlN thin film was prepared on AZ31 Mg alloy by DC magnetron sputtering with bias control applied to the substrate.The microstructure of the films was studied by means of XRD and SEM,and the corrosion resistance and wear resistance of the films were evaluated by means of electrochemical workstation and pin type friction and wear testing machine.Results showed that the substrate structure of coating film changed greatly after the bias voltage is applied,the grow pattern of films changed from the island growth mode without bias to the layered growth mode,and from exquiaxed crystal to columnar crystal.The film began to grow preferentially in(111)when the bias voltage increased to-30 V,and the film was mainly columnar crystal structure.The corrosion potential of the coated substrate increased obviously,and the corrosion current density decreased by two orders of magnitude,indicating a good corrosion resistance,the film controlled at-30 V bias had the best corrosion resistance.The friction coefficients of the film ranged from 0.19 to 0.30,and the wear rate was in the order of 10-6 mm^(3)/(N·m).The bias voltages corresponding to the friction coefficient and wear rate of the films from smallest to largest were-30 V<-15 V<-45 V<0 V.