膜厚对粉末润滑层特性影响的试验研究

采用真实接触面积比定量表征粉末层的破坏过程,通过模型研究不同膜厚的粉末层承载和摩擦力分布情况。当膜厚值较小时,承载较小且承载峰值较低,承载不均匀,容易导致载荷集中,粉末层局部破坏严重,真实接触面积比较迅速下降。当膜厚值较大时,承载较大且承载峰值较多,承载均匀,粉末层破坏不严重,润滑效果好。膜厚值大则剪切力较大,粉末层局部被破坏,上下试件之间发生相对滑移,且剪切力较大的粉末层迅速被破坏,粉末层局部破坏扩散较快,真实接触面积比快速下降。

Theoretical Analysis About Effect of Film Thickness on Powder Lubrication Characteristics

Real contact area ratio is used to quantitatively characterize the destruction process of powder layer,and three dimensional model is adopted to analyze the distribution of bearing and friction under different film thickness. The results show that when film thickness is smaller,the bearing capacity is smaller and bearing peak is less;be-cause of uneven bearing,the load concentration occurs easily. Due to serious local damage of the powder layer,re-al contact area ratio drops quickly. When the thickness of the film is large,the shear force is uniform and the bear-ing capacity increases with more bearing peaks. No serious damage to the powder layer,lubrication effect is good. Large thickness of film brings the larger shear force,which means there is local destruction of the powder layer. Af-ter the powder layer is partially destructed,the relative slip between upper and lower specimens exists. The powder layer with larger shear force is rapidly destructed. Diffusion of partial area rapidly increases and the real contact ar-ea ratio declines fast.