1. Smooth it, use 320grit sandpaper to cool it in water, and grind it for 2 to 3 minutes to remove the damage layer caused by cutting and make the surface of the sample flat. Use 320grit SiC sandpaper, water cooling, rotation speed 240 RPM, rotation in the same direction*, pressure: 27N (6lbs)/each sample, until the sample is flat.

Note: The removal of the cutting damage layer is the basic task of polishing. If the removal is not clean, the direct result is that the observed phenomenon may be an illusion.

2. For rough polishing, apply 9μm metaDI diamond polishing paste on the perforated TEXMET polishing cloth in advance, use distilled water as the cooling lubricant, and polish for 10-15 minutes. Rough polishing process: 9μm metaDI diamond polishing fluid + metaDI polishing lubricant, using ULTRA-PAD to polish the surface, rotating speed 120 RPM, reverse rotation**, pressure: 27N (6lbs)/each sample, time 10min.

3. For final polishing, use MICROCLOTH or MASTERTEX polishing cloth, add MASTERMET silica suspension polishing liquid, and polish for 10-15 minutes. Final polishing process: On the MICROCLOTH polishing surface, use MASTERMET silica polishing liquid, rotating speed 120 RPM, reverse rotation, pressure: 27N (6lbs)/each sample, time 10min.

Note: During the polishing process, the sample needs to be rotated regularly. Most metal alloys have hard phases. If the direction is not rotated, the polished sample will have a black "long tail" on the hard phase, which will affect the quality of the metallography. The key to the "long tail" problem is the direction of turning the sample. It can be rotated 90 degrees or 180 degrees each time.