What factors affect the thermal stability of Heavy High Aluminum Brick?

Heavy High Aluminum Brick is a refractory material with alumina as the main component. It is widely used in high-temperature industries such as metallurgy, chemical industry, and glass. Its thermal stability directly affects its service life and ability to adapt to harsh environments. Thermal stability refers to the ability of a material to maintain its physical, chemical, and mechanical properties at high temperatures, especially whether it can avoid cracking, deformation, or damage when the temperature changes sharply.

1. Alumina content
The main component of Heavy High Aluminum Brick is alumina (Al₂O₃). The higher its content, the better the high temperature resistance and thermal stability of the brick. The high melting point of alumina (over 2000°C) enables high-alumina bricks to remain stable in extremely high temperature environments. The low thermal expansion coefficient of alumina makes its volume change less at high temperatures, reducing the thermal stress caused by temperature changes. If the alumina content is low, the refractoriness and thermal shock resistance of the brick will be reduced accordingly. Therefore, ensuring a high alumina content is the key to improving the thermal stability of high-alumina bricks.

2. Crystal structure
The microscopic crystal structure of Heavy High Aluminum Brick plays a vital role in its thermal stability. Alumina and other minerals form a dense crystal structure during high-temperature sintering, which can disperse the stress caused by temperature changes and reduce the risk of cracks inside the brick. In addition, the dense crystal structure also reduces the porosity of the material, thereby improving its resistance to thermal shock. If the crystal structure in the brick is uneven or the porosity is high, the material is prone to local stress concentration at high temperatures, resulting in cracking or peeling, affecting its thermal stability.

3. Manufacturing process
The manufacturing process of Heavy High Aluminum Brick has a direct impact on its thermal stability. The molding process of the brick body requires high-pressure pressing to ensure the density of the material. The higher the pressing density, the better the thermal stability of the brick body at high temperature, because its internal pores are less and the thermal stress distribution is more uniform. The firing temperature is also very critical. Generally speaking, the firing temperature of high-aluminum bricks is between 1400℃ and 1600℃. If the firing temperature is too low, the material is not dense enough, which can easily lead to uneven thermal expansion coefficient; if the firing temperature is too high, it may destroy the balance between alumina and other components, thus affecting thermal stability.

4. Thermal expansion coefficient
The thermal expansion coefficient of a material is an important parameter that affects its thermal stability. The smaller the thermal expansion coefficient, the smaller the size change of the brick during temperature changes, and the thermal stress is also reduced accordingly. Heavy High Aluminum Brick has a higher alumina content, which gives it a lower thermal expansion coefficient and makes it have better dimensional stability under high temperature conditions. Therefore, the brick can maintain structural integrity in a high temperature fluctuation environment and will not crack due to expansion or contraction. If the thermal expansion coefficient of the material is large, the stress generated during temperature fluctuations will be greater, resulting in a decrease in thermal stability.