钛表面不同厚度氧化钛纳米管层的摩擦磨损行为*

为了改善钛的摩擦学性能,采用阳极氧化法在钛表面制备了纳米管径约100nm,厚度分别为500nm、1 000nm和1 500nm的TiO2纳米管层,并在450℃保温3h进行热处理。对试样的表面形貌、显微硬度和粗糙度进行测试。利用摩擦磨损试验考察了热处理前后不同试样在大气环境下的摩擦磨损行为。结果表明:干摩擦下,纳米管层的存在降低了钛与GCr15轴承钢球之间的摩擦系数;随TiO2纳米管层厚度的增加,试样的摩擦因数逐渐降低,磨损逐渐下降;热处理使纳米管由无定型氧化钛转变为锐钛矿晶型,进一步降低了摩擦因数,增加了钛的耐磨性能;纳米管层的磨损机制为磨粒磨损,接触疲劳磨损和粘着磨损。

Friction and Wear Behavior of Titania Nanotube Layers with Different Thicknesses on Titanium Surface

To improve the tribological properties of titanium,anodic oxidation was used to fabricate a series of nanotube layers on Ti surface with the same inner diameter about 100 nm and different thicknesses of 500 nm,1 000 nm and 1 500 nm.Specimens were heat-treated at 450 ℃ for 3 h.Morphology,micro-hardness and roughness of specimens surface were measured.The friction and wear properties of the specimens treated before and after heat-treatment in atmosphere were investigated by friction and wear experiments.The results indicate that in dry friction condition,the friction coefficients between Ti and GCr15 bearing steel ball decrease due to the existence of nanotube layers.The friction coefficients and wear rates decrease with the increase of the nanotube thickness.Amorphous titania nanotubes transform into anatase through heat-treatment,which reduces the friction factor and increases the wear resistance of titanium.The wear mechanisms of the nanotube layers involve abrasive wear,fatigue wear and adhesive wear.