Alumina ceramics is a structural ceramic material with a-Al2O3 as the main crystal phase. Because of its high melting point, high hardness, heat resistance, corrosion resistance, and electrical insulation characteristics, it can be used under harsher conditions . The price of alumina ceramics is low, and the production process is mature. It is currently one of the ceramic materials with the largest output and the most widely used. It is mainly used in the fields of cutting tools, wear-resistant parts and bioceramics. In addition, it is also widely used in energy, aerospace, chemical, chemical and electronic fields.

However, due to the low toughness and brittleness of ordinary alumina ceramics, its application fields are limited. In addition, the high sintering temperature is also a major reason for its limited application. To obtain ceramic materials with higher hardness and crystallinity, sintering must be carried out at a relatively high sintering temperature, which will inevitably lead to an increase in energy consumption.
In recent years, due to higher and higher requirements for material properties, people have proposed various methods to improve the properties of alumina ceramics, including hot pressing sintering, spark plasma sintering, microwave sintering, and adding additives. After taking some new measures, the performance of alumina ceramics in terms of bending strength and hardness has been greatly improved.
As a special functional material, nano alumina has many excellent characteristics such as high hardness, high strength, corrosion resistance, wear resistance, high temperature resistance, high insulation, high oxidation resistance, etc., so it is widely used in precision ceramics, bio-ceramics, Chemical catalysts, refractory materials, integrated circuits and aerospace.

Nano-alumina and alumina are the same substance, but the particle size is different. So, what is the effect of adding a certain amount of nano-alumina to alumina ceramics?

1, the impact on the body
A certain amount of nano-alumina is added when preparing alumina ceramics. During the molding process, the nano-powder can be fully filled into the voids of the alumina powder, reducing the porosity, increasing the strength of the molded body, and facilitating sintering.

2. Influence on sintering temperature
Due to the small size of nano-alumina and high surface activity, adding a certain amount of nano-alumina can effectively increase the diffusion rate on the surface of the blank, reduce the sintering temperature, and improve the densification of the sintered product.
This is because nano-alumina has a large number of interfaces, provides a short-range diffusion path and a higher diffusion rate, and makes the sintering driving force of the material increase sharply, greatly accelerating the entire sintering process, and greatly reducing the sintering temperature.

3. Effect on crystallinity
While reducing the sintering temperature of alumina ceramics, the crystallinity will not be reduced. The so-called crystallinity is the degree of crystallization of the material in a certain regular arrangement of atoms during the sintering process, that is, the percentage of the mass or volume of the crystalline part to the total mass or volume, in other words the proportion of the crystalline area of the product after sintering. The degree of crystallinity is different, the physical and mechanical properties of the material are different, and the electrical and optical properties of the material are also affected by the degree of crystallinity to a considerable extent.

4. Influence on mechanical properties
Improve the hardness of alumina ceramics.
Improve the strength of alumina ceramics.
The elastic modulus of alumina ceramics is increased, and the toughness is improved.

In comparison, the physical properties of pure nano-alumina ceramics are much better than ordinary alumina ceramics, but the preparation process of nano-alumina is complicated and the cost is higher. Moreover, alumina ceramics themselves have very excellent properties. In some cases, some nano-alumina can be selectively added to improve performance, which not only guarantees product quality, improves production efficiency, but also reduces production costs.

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