在本研究中，先在预磨机上进行预磨，然后在150、320、600和1000号砂纸上依次水磨，在抛光机上进行机械抛光后，置于4 ml HNO3 + 96 ml CH3CH2OH混合溶液浸蚀15~25 s，采用FEI Quanta650热场发射扫描电子显微镜分析。

In this study, pre-grinding was carried out on a pre-grinding machine, and then water grinding was carried out on sand paper 150, 320, 600 and 1000 in turn. After mechanical polishing on a polishing machine, it was immersed in 4 mL HNO3 + 96 mL CH3CH2OH mixed solution for 15-25 s. FEI Quanta650 thermal field emission scanning electron microscope was used for analysis.