Investigation of influence function model and polished surface characteristics during belt polishing polycrystalline aluminate magnesium spinel (PAMS) ceramics

Polycrystalline aluminate magnesium spinel (PAMS) ceramic is a polycrystalline ceramic material with excellent optical and mechanical performance. It offers potential applications in laser and IR windows, missile domes, and transparent armors. A belt polishing system, aimed to polish deep and thin optical components fabricated with spinel, was developed based on an ultra-precision machine tool. The influence function model was established for the belt polishing system based on Preston's law and modified for spinel based on the spot polishing experiments. The modified model has a deviation ratio of less than 2%, indicating that its stability was acceptable. The surface defects of polished spinel were characterized by white light interferometry and microscope imaging. The effect of polishing parameters of the belt polishing on the spinel was discussed. Moreover, it can be found that the primary defect of large grain spinel caused by polishing is grain spalling pits. The belt polishing with loose abrasive is less efficient yet obtains a polished surface with fewer surface defects.