表面镀锡活塞
Piston with Tin on the Surface
   在活塞表面用化学方法镀覆05.-3的锡层，多孔的锡层有软金属的良好润滑特性，能吸附较多润滑剂，降低了活塞与气缸音的摩擦功.
   Piston plated by 0.5-3u tin on the surface in chemical way ,the tin layer with little hole has the lubri-cative quality of soft metal .it can absorb more lubricative oil to drop the friction between the piston and cylinder.