TC4钛合金微弧氧化-SiC复合膜的膜层结构及摩擦磨损行为

目的通过微弧氧化共沉积工艺,获得摩擦磨损性能优良的微弧氧化-SiC复合膜。方法在硅酸钠-六偏磷酸钠-钨酸钠-多聚磷酸钠体系的微弧氧化电解液中加入2.0 g/L SiC微粒,以直流脉冲模式制备TC4钛合金微弧氧化-SiC复合膜。利用KH-7700型三维视频显微镜、XRD、SEM,对复合膜的表面、截面微观形貌和结构进行了观察分析,采用CFT-1型显微磨损试验仪检测了其在室温干摩擦条件下的摩擦磨损性能。结果 SiC复合膜层中的微孔数量明显少于不含SiC相的氧化膜层,复合膜表面分布着SiC相、金红石、锐钛矿TiO_2相、Al2Ti O5相以及非晶态的P、Si、W化合物。在干摩擦磨损条件下,微弧氧化-SiC复合膜的摩擦系数为0.26,比磨损率为0.72×10~(-6) mm~3/(N·m),微弧氧化-SiC复合膜只发生轻微的粘着磨损和磨粒磨损。结论得到了摩擦磨损性能优良的复合膜,复合膜中的SiC新相改变了氧化膜的表面形貌,降低了复合膜的摩擦系数和磨损率。

Film Structure and Frictional Wear Behaviour of TC4 Titanium Alloy Micro Arc Oxidation-SiC Composite Coating

The work aims to obtain micro arc oxidation-SiC composite coating of excellent friction and wear properties by micro arc oxidation deposition technology. 2.0 g/L SiC particles were added to micro arc oxidation electrolyte which is com-posed of sodium silicate-sodium hexametaphosphate calgon-sodium tungstate-sodium polyphosphate. TC4 titanium alloy micro arc oxidation-SiC composite coating was prepared in the mode of DC pulse. KH-77003D video microscope, XRD and SEM were used to observe and analyze surface, cross section morphology and structure of the composite coating. The friction and wear properties under dry friction wear at room temperature were tested with CFT-1 microscopic wear tester. Microvoidsin SiC composite coating was less than that without SiC phase. SiC, rutile and anatase TiO2 phase, Al2TiO5 phase some amorphous P, Si, W compounds were distributed on the surface of composite coating, but also contains appear in the composite film. Provided with dry frictional wear, friction coefficient of the micro arc oxidation-SiC composite coating was 0.26, specific wear rate was 0.72×10-6 mm3/(N·m), and slight adhesive wear and abrasive wear were present in micro arc oxidation-SiC composite coating. Morphology of the oxide films changed by the new SiC phase in the composite film, friction coefficient and wear rate of the composite film are reduced and composite coating of excellent friction and wear properties is obtained.