When we actually grind and polish the sample, the greater the Hardness of the sample, the easier it is to obtain a good observation surface. High hardness materials are less prone to scratches, deformation, and embedding. In this way, the metallographic polishing cloth is easy to choose, but it is prone to phenomena such as chamfers, protrusions, cracks, and breakage. We need to use a uniform, flat, and delicate polishing surface.

Firstly, cutting: Pay attention to cutting the sample at an appropriate position, ensuring that there is sufficient margin to remove the affected area, and also be aware that high hardness ceramics are difficult to polish, and excessive margin will consume a long time.

Secondly, inlay: High hardness ceramics have many pores and are relatively brittle. Generally, cold inlay is used to avoid excessive pressure during hot inlay, which may cause cracks or damage to the ceramic. Meanwhile, high hardness ceramic specimens require better edge preservation. Due to the high hardness and brittleness of ceramics, it is necessary to embed materials that can protect their edges as much as possible from damage and fragmentation, while also having sufficient hardness to avoid chamfers and protrusions. Insufficient hardness of the inlay material can cause the inlay material to be worn off, while the ceramic is fine (not worn off).

Next is polishing: ordinary silicon carbide metallographic sandpaper may not work, and at this time, products such as sandpaper, grinding discs, and thin films with diamond as the medium can be used.

Next comes polishing: polishing cloth and polishing agent are both important, but high hardness ceramics are not sensitive to metallographic polishing cloth. It is recommended to use a lint free or short polishing cloth. It is necessary to use diamond as a polishing agent, but only a 1 micron level diamond polishing agent is needed to obtain a scratch free polishing surface.

After completion, clean the sample with anhydrous ethanol and blow dry. At the same time, it is important to clean the sample, hands, and fixtures well between the preparation steps.

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