Key words: sampling, cutting, inlay, coarse grinding, fine grinding, rough polishing, medium polishing, fine polishing.
Let's talk about the conclusion first, the metallographic sample grinding and polishing proposal is divided into four steps.
After the laboratory completes the preparation work of sampling, cutting, and mosaicing, it enters the grinding and polishing process. Grinding and polishing can be divided into two stages, one is to polish with metallographic sandpaper, and the other is to polish with metallographic polishing cloth. These two stages should also be broken down.
Let's talk about metallographic sandpaper polishing first. Generally speaking, if the surface of the sample is good, direct fine grinding (P1000 or P1200) is sufficient. However, in practice, it is difficult to be so ideal, and coarser sandpaper is generally needed to smooth out the sample. Therefore, you can choose the appropriate coarse sandpaper, generally the coarsest sandpaper chooses P180 or P240, such sandpaper is relatively rough. The most common option is to start with the P800 and then connect to the P1200. In rare cases, a step is added to the P2500.
As for polishing. From coarse to fine, metallographic polishing cloth is divided into three categories: coarse polishing, medium polishing and fine polishing, and the polishing cloth should be used with polishing liquid. There are also many polish options, ranging from 9 m for coarse and 0 for fine05µm。Generally speaking, after the P1200 sandpaper is grinded, it is directly polished, and the polishing cloth is polished + 3 micron diamond polishing slurry. After the end of the middle polishing, fine polishing, fine polishing cloth +005 micron alumina polishing slurry. However, P800 sandpaper is recommended to be followed by a rough polishing cloth + 9 micron diamond polishing slurry, and then polished in the middle and fine polished. If the sample requirements are very high, you can try P800, P1200, P micron medium polishing, 1 micron fine polishing, 005 micron fine polishing.
If you have a lot of experience in sample preparation, you can completely reduce the number of preparation steps and shorten the preparation time. We also favor experimenters to give full play to their subjective initiative and explore more efficient, more economical and more effective sample preparation schemes.