Achieving a super-smooth surface of stainless bearing steel with chemical mechanical polishing via controlling corrosive wear of Fe and Cr

9Cr18Mo stainless bearing steel is commonly used to manufacture rolling bearings in aerospace. Excellent surface quality is required to improve the service performance of bearings. In this study, chemical mechanical polishing (CMP) was employed. The results reveal that Cr has a significant impact on the CMP performance. The higher the Cr content, the lower the material removal rate (MRR). When polishing with the slurry containing the complexing agent glycine and the oxidant H2O2, the 9Cr18Mo steel surface is uneven, probably caused by unequal removal of Fe and Cr. A super-smooth 9Cr18Mo steel surface can be achieved by excluding glycine and adding 1 wt% H2O2. The surface roughness S-a is 0.63 nm, and no surface defects can be observed. During CMP, a uniform thin surface film mainly composed of evenly distributed iron oxides and chromium oxides can be formed. On the one hand, the iron oxides and chromium oxides can be removed simultaneously with a close MRR. On the other hand, the passive oxides can inhibit corrosion and protect recessed areas. Therefore, a super-smooth surface can be achieved. The findings provide an enhanced understanding of attaining a smooth surface for the material consisting of multiple chemical elements.