In fact, the alumina ceramic normal pressure sintering method is the entire process of sintering the green body under atmospheric conditions. This method will have a higher sintering temperature, so the requirements for the kiln are higher, and energy is wasted. It is also very large.

Industrial ceramic is a polycrystalline inorganic material, generally composed of grains, grain boundaries, pores and so on. In general, the opacity of ceramics is caused by the discontinuity of the refractive index between the grains due to the randomness of the non-equiaxed crystal grains in the alignment orientation, and the scattering caused by factors such as grain boundary effects and pores.