The impact of sintering temperature and holding time for refractory materials

refractory

Sintering temperature and holding time is an important external sintering refractory material. With the increase of temperature, the vapor pressure of the material increases, the diffusion coefficient increases, and the viscosity of the liquid phase decreases, thus facilitating the process of material transfer such as evaporation-aggregation, diffusion of ions and vacancies, particle rearrangement, viscous and plastic flow. So that sintering speed. Prolonging the sintering time can also promote the completion of sintering. However, in the latter stage of sintering, unreasonably prolonging the sintering time can sometimes aggravate the secondary recrystallization, but can not obtain a sufficiently dense product.
The firing temperature of refractory products should be controlled within the sintering temperature range, at this temperature should maintain the appropriate sintering time to complete the sintering, if continue to increase the temperature deformation of the body.

The impact of the atmosphere:
Atmosphere directly affects the firing effect and product quality. Burning atmosphere can be divided into general oxidizing atmosphere, neutral atmosphere and reducing atmosphere. Different materials for the green body should choose a different atmosphere to ensure the physical and chemical reactions in the body smoothly. At the end of sintering, the atmosphere (the type of gas in the pores) has an influence on the sintering when the pores are closed. Study of Al2O3 sintering found that when the gas solubility in the lattice is small and slow diffusion, the isolated pores is not easy to discharge from the body. For example, Al2O3 is sintered in argon and air. On the contrary, when the diffusion rate of gas in the lattice is fast enough, the atmosphere has no effect on the sintering end. If the atmosphere to control the defect structure has a certain role, you can speed up the proliferation and conducive to sintering.

It must be pointed out that the influence of firing atmosphere depends on the material composition, sintering conditions, the type and amount of additives, and other factors. Therefore, specific analysis should be conducted for different temperatures.

In the actual sintering process, the impact of the above factors are interrelated and mutually restrictive. The factors that play a major role under different conditions may be different.


More refractory material:
http://www.ruizhirefractory.com/
Email: sales@ruizhirefractory.com