Tribological Properties of Nano-structured Titania

对高压低温烧结法制备的纳米二氧化钛陶瓷和等离子烧结法制备的纳米二氧化钛陶瓷在较宽的接触载荷和滑动速度范围内进行了块-环滑动磨损试验。块状试件为二氧化钛，环状材料为轴承钢。主要研究结果如下：(1)研究了不同烧结条件(压力0.5-1.5 Gpa，温度400-500ﾟC)制备的纳米二氧化钛的摩擦学性能。结果表明，n-TiO2体损量随烧结压力的增加而减小，并与样品的密度、晶粒度和金红石相的含量有关。(2)等离子烧结法制备的TiO2光陶瓷，在v=10m/S时，磨损率随滑动速度的增加而增加，但在高速下磨损率下降。它随着载荷的增加而单调增加。在v=0.1m/S条件下，与A1203和碳化硅相比，二氧化钛陶瓷具有较高的耐磨性，其摩擦学性能主要取决于热应力引起的脆性断裂。基于这些结果，可以预期纳米结构的二氧化钛陶瓷将在先进的摩擦应用中发挥重要作用。

Nanocrystalline TiO2 ceramic which was produced by sintering under high-pressure and low temperature (grain size<100nm) and TiO2 ceramic produced by plasma sintering technique were studied by the block-on-ring sliding wear tests under the wide range of contact load and the sliding velocity in room air. A block specimen was TiO2 and a ring material was bearing steel. The following results were obtained.(1) The tribological properties of nanociystalline TiO2 which was manufactured under various sintering conditions (pressure of 0.5-1.5GPa and temperature of 400-500ﾟC) were discussed from the view points of grain size and handness. The volume loss of n-TiO2 was found to decrease with sintering pressure, and was also related to the density, the grain size and the % rutile phase in the samples.(2) For TiO2 ceramic produced by plasma sintering technique, the wear rate increases with sliding velocity until v=10m/s -but then decreases at high velocity. It increases monotonously with load. TiO2 ceramic shows high wear resistance compared with A1203 and SiC under v=0.1m/s. The tribological properties of TiO2 ceramic depend on the brittle fracture caused by thermal stress. Based on these results, it is expected that nano-structured TiO2 ceramic will play an important role in advanced tribo-applications.