TC4钛合金微弧氧化Cr2O3复合膜的结构及摩擦磨损性能

Microstructure and Tribological Properties of Microarc Oxidation Composite Coating Containing Cr2O3 Particles on TC4 Titanium Alloy

摘要:

在硅酸钠-六偏磷酸钠体系中添加1.5 g/L Cr2O3微粒，采用直流脉冲模式在TC4钛合金表面制备了微弧氧化Cr2O3复合膜；利用SEM、EDS、XRD对复合膜的微观形貌和结构进行观察分析，并研究了其在室温干摩擦条件下的摩擦磨损性能。结果表明：复合膜的表层孔隙中填满了微小的Cr2O3颗粒，表面只能看到少量微孔；膜层中除了金红石及锐钛矿TiO2相、Al2TiO5相外，还出现了大量的Cr2O3相，且包含了一些非晶态的P、Si化合物。在相同的摩擦磨损条件下，微弧氧化Cr2O3复合膜的摩擦系数更小、磨损量更低、耐磨性也更好。在10 N载荷下，复合膜只发生轻微的粘着磨损，几乎未发生磨粒磨损；在50 N载荷下，复合膜的磨粒磨损有所加剧，且出现了第二相粒子流失。Cr2O3颗粒主要通过对微弧氧化膜孔隙的填充作用、载荷转移作用及弥散强化作用，来降低复合膜的摩擦系数和表面磨损量，提高其耐磨性

Abstract:

Using DC pulse mode, a microarc oxidation (MAO) composite coating containing Cr2O3 particles on TC4 titanium alloy was prepared by adding 1.5 g/L Cr2O3 microparticles into the Na2SiO3-(NaPO3)6 electrolyte. The morphology and microstructure was analyzed by SEM, EDS and XRD. The dry wear behavior of the composite coating was investigated at room temperature. The results show that the surface pores of composite coating are filled with tiny Cr2O3 particles, and only a small amount of micropores can be observed on the coating surface. The composite coating has a large number of Cr2O3 phase besides rutile-TiO2, anatase-TiO2, Al2TiO5 phase and some amorphous compounds. The MAO composite coating containing Cr2O3 particles has smaller friction coefficient, lower wear loss and better wear resistance under the same wear condition. The composite coating only produces slight adhesive wear, almost without abrasive wear under the load of 10 N. However, the abrasive wear is somewhat intensified, and the loss of second-phase particles appears under the load of 50 N. Cr2O3 particles can reduce the friction coefficient and wear loss and improve the wear resistance of the composite coating by filling the pores of MAO coating, transferring load of Cr2O3 particles and the dispersion strengthening