粉末润滑界面的原位观察及润滑机制

In Situ Observation and Lubrication Mechanism of Powder Lubrication Interfaces

将松散的石墨粉导入面接触的摩擦副间隙中,在轴向力和剪切力作用下形成减摩性能良好的粉末层。利用带有CCD数码相机的光学显微镜对试件表面进行动态观测,分析表面粗糙度、载荷、滑移速率、粉末量对粉末层的破坏形式、破坏过程的影响,采用图像分割技术计算真实接触面积比。结果表明:粉末层的破坏形式包括完整、局部区域破坏、局部破坏区域扩散、粉末黏附、完全破坏5个阶段;黏附阶段存在的必要条件为重载、试件表面具有一定粗糙度,粉末量、滑移速率的增大使黏附加剧。

Loose graphite powder was used to lubricate plane contact tribopairs.A good powder layer with good anti-friction ability was observed under the effects of axial load and shear.Damage forms of powder layers were dynamically observed by optical microscope with CCD digital camera.The influences of surface roughness,load,slip velocity,powder quantity on the damage forms and processes of powder layers were analyzed.Image segmentation was used to calculate real contact area ratio.The results show that damage forms of the powder layers include five stages:complete period,partial area destruction,diffusion of partial area destruction,powder adhesion and complete destruction.The necessary conditions for adhesion stage existence are overload and a certain roughness.The increase of the powder amount and slip velocity may intensify the adhesion.