Why can ceramic grinding balls be able to identify people with light? Many surfaces of ceramic grinding balls are shiny, and some even light can identify people. What’s the secret here? In fact, the factors that determine whether there is light on the surface of ceramic grinding balls are The flatness of the spherical surface; the more lubricated the spherical surface, the better the mirror effect; the rougher the spherical surface, the worse the mirror effect. The main factors that affect the flatness of the spherical surface are the internal structure of the material and the degree of processing outside the spherical surface. In the meantime, the outside processing of the spherical surface is relatively simple to understand. For example, the spherical surface of the grinding ball just after sintering is matt, and the spherical surface may have a mirror effect after polishing. The internal structure of the material includes pores, grain size, liquid phase, etc., and their effects on the flatness of the spherical surface are as follows:
1.Stoma
Because ceramic grinding balls after sintering generally have a high density, and there are few pores caused by sintering, the pores we are talking about here generally refer to major shortcomings caused by molding and other reasons.
For example, the powders for rolling balls include airflow powder, spray-dried powder, granulated powder, etc. They are essentially fake particles composed of countless individual crystal grains. However, because the powdering process is different and the particle strength of the powder is not the same, some false particles may not be completely crushed in the application, resulting in the grains cannot be completely close during the sintering process, resulting in shortcomings such as large holes.
2. Grain size
When the type of material is different, the degree of grinding of the material by each manufacturer is different, and the formula and sintering process are different, it will lead to different grain sizes in the sintered grinding ball. The finer the crystal grains, the flatter the spherical surface; the thicker the crystal grains, the more uneven the spherical surface, just like paving a road with stones and sand.
The zirconia grinding ball crystal grains are mostly 0.3um-0.5um, and the alumina grinding ball crystal grains are mostly 1um-5um. The zirconia crystal grains are finer and the spherical flatness is higher, so the zirconia spherical surface is brighter than the alumina spherical surface.
3. Liquid phase
Taking alumina ceramics as an example, in order to lower the sintering temperature of ceramics, some additives are added in general production. Some of them are additives that can generate liquid phase in high alumina porcelain, such as kaolin, bornite, silica fume, etc., which can form binary, ternary or more complex low-melting eutectics together with other additives. After adding an appropriate amount of additives, on the one hand, the sintering temperature of the ceramic can be lowered to make the crystal grains finer; on the other hand, the liquid phase formed will be the same as the asphalt of the pavement, so that the spherical surface is more flat and the spherical surface is naturally brighter. Up.
