Tribofilm Formation by Tribo-Sintering of Nanometer-Sized Particles

当具有高表面能的纳米颗粒被人为提供给摩擦表面时，表面形成了耐磨的摩擦膜。前人的研究表明，添加高扩散速率的纳米氧化物，如Fe_2O_3、SnO_2、CuO或Bi2O_3，可以诱导滑动距离向轻微磨损转变。轻微的磨损是由于摩擦钢表面形成了耐磨的摩擦膜，观察证实摩擦膜是由提供的氧化物颗粒摩擦烧结而产生的。因此，即使表面不存在颗粒，也有望通过纳米颗粒的供应产生摩擦膜来减少磨损。本课题的目的是研究在钢表面供应纳米颗粒产生的摩擦膜的磨损行为。利用销盘式磨损机在空气和真空(8x10^&lt；-4&gt；Pa.)中制备了摩擦膜。销盘试件材料为正火的0.45质量%碳钢。在空气气氛中，供给粒子为CuO(平均粒径为48 nm)、Fe_2O_3(30 Nm)、SnO_2(21 Nm)或Bi2O_3(51 Nm)氧化物；在真空气氛中，供给粒子为CuO(50 nm，1μm)。尤其是在Bi2O_3氧化物颗粒的作用下，摩擦膜的轻微磨损转变的滑动距离最长，总磨损量较小。

When nanometer-sized particles, which have high surface energy, are artificially supplied on rubbing surfaces, wear-protective tribofilms are formed on the surfaces. The previous study has demonstrated that the supply of nanoparticles of an oxide of high diffusion rate, such as Fe_2O_3, SnO_2, CuO, or Bi_2O_3, induced transition to mild wear with sliding distance. The mild wear was due to the formation of the wear-protective tribofilms on the rubbing steel surfaces, and observations confirmed that the tribofilms were produced by tribo-sintering of the supplied oxide particles. Therefore, it is expected that the tribofilms produced by the supply of nanoparticles reduce wear even if no particles exist on the surfaces.The purpose of this project is to study wear behavior of the tribofilms produced by the supply of nanoparticles on the steel surfaces. Particularly, the influences of the type and size of supplied particles on the wear of the produced tribofilms have been investigated in detail.Tribofilms were produced in air or vacuum(8x10^<-4> Pa) by using a pin-on-disc wear machine. The pin and disc specimen material is normalized 0.45 mass% carbon steel. The supplied particles were CuO(mean particle diameter : 48nm), Fe_2O_3(30nm), SnO_2(21nm) or Bi_2O_3(51nm) oxide in the case of air atmosphere, and Cu(50nm, 1μm) in the case of vacuum atmosphere.It was found that the tribofilms produced by the supply of nanoparticles on the rubbing surfaces reduced the wear considerably, depending on the type of the supplied particles. Particularly the sliding distance of the mild wear transition was the longest for the tribofilms by the supply of Bi_2O_3 oxide particles, resulting in low total wear volume.