How to reduce the sintering temperature of alumina ceramics and prepare high-performance alumina wear-resistant ceramics

Alumina as an important inorganic non-metallic material, in addition to being widely used as anti-wear materials, but also because of its high mechanical strength and large insulation resistance and other excellent characteristics, often used in the manufacture of vacuum devices, circuit substrates and other electronic components; because of it's good high temperature resistance, can be applied to the manufacture of crucibles, sodium fluorescent lamps and other high temperature equipment parts; Based on its stable chemical properties, it can be used as bioceramic in biomedical field and catalytic carrier in chemical catalysis field.

In order to reduce the sintering temperature of alumina ceramics and prepare high-performance alumina wear-resistant ceramics, research and practice are mainly carried out from the following three technical levels:

Selection of fine raw material powder with small particle size and high surface activity is one of the key steps. From the point of view of material science, the finer the powder particles, the more crystal defects they have, and the higher the corresponding surface activity. This high activity is conducive to promoting the diffusion and fusion of substances between particles during the sintering process, thereby improving the strength of the ceramics produced.

In addition, the minute particles can effectively disperse the stress concentration phenomenon caused by the difference in linear expansion coefficient between the corundum phase and the glass phase, and significantly reduce the risk of crack generation. The fine grain structure can also hinder the further propagation of microcracks and reduce the probability of transgranular fracture, which has a positive effect on improving the fracture toughness of ceramic materials and also helps to enhance the wear resistance of materials. Therefore, reducing the particle size of Al₂O₃ powder is the core point of preparing high-performance Al2O3 ceramic powder.

Reasonable Optimization of Sintering Method In the preparation of ceramic materials, the choice of sintering method is very important. Pressurized sintering process is a common sintering process in traditional ceramic production. Compared with special sintering process, its production cost is relatively low, so it is still widely used in industrial production. However, the atmospheric sintering method has certain limitations, such as higher sintering temperature, higher performance and quality requirements of the furnace, and higher energy consumption in the sintering process.

In contrast, thermoforming sintering technology is not only dependent on diffusion mass transfer in the process of heating and pressurizing the green body. By adopting the hot sintering technology, not only can the sintering temperature of alumina ceramic bodies be significantly reduced, energy is effectively saved, but also excessive growth of crystal grains can be well inhibited, so that alumina ceramic products with dense structure and high crystallinity can be obtained, especially suitable for sintering high-end ceramic products such as transparent alumina ceramics and microcrystalline corundum ceramics.

The scientific application of additives relies solely on the use of ultra-fine particles, non-agglomerated and uniformly dispersed powders with good sintering activity to achieve densification and low temperature sintering of materials. Although technically feasible, the cost is relatively high.

By introducing appropriate sintering additives, that is, adding appropriate additives to ceramic materials, these additives can form liquid phase or solid solution with the matrix material, thereby enhancing the diffusion rate between atoms, and thus promoting the densification of materials and reducing the sintering temperature. The advantage of this method is that it can reduce the harsh requirements for raw material powder, effectively reduce production costs, and has been widely used in various fields of current ceramic industry production.

To sum up, by selecting raw materials with small particle size and large surface activity, adopting appropriate sintering technology and reasonable use of additives to reduce the sintering temperature of ceramic materials, these three methods cooperate and cooperate with each other, which can reduce the sintering temperature of alumina ceramics under the premise of effective cost control, and successfully prepare high-performance alumina wear-resistant ceramics, which provides solid technical support for the application of alumina ceramics in more fields.