Mechanical polishing relies on the grinding and rolling of very small polishing powders to remove a very thin layer of metal on the grinding surface of the sample. If there are deeper wear marks on the grinding surface before polishing, it is difficult to remove only by mechanical polishing. Because if the wear scars are thrown away, it is necessary to increase the concentration of the polishing liquid, increase the pressure applied during polishing for a long time or increase the flow and disturbance of the surface metal on the ground surface, and the deformation layer on the ground surface of the sample is thickened, so that Phases fall off. Especially when the hardness of the aluminum alloy is not too large, the surface oxidation of the abrasive surface will be more severe, which will affect the structure observation. Therefore, the specimens subjected to mechanical polishing are allowed to leave only fine grinding marks uniformly in one direction after fine grinding.
Polishing can be used to enhance and restore the appearance of certain metal parts or against vehicles such as automobiles, armrests, cookers, kitchenware and construction metals. In other applications, such as pharmaceuticals, dairy products, and specialty pipes, the tubes are polished to help prevent corrosion and elimination, where bacteria or mold can reside. Polishing is also used to make light reflectors.