?Refractory zircon mullite brick can improve the structure of mullite by introducing ZrO2 into A12O3-SiO2 series bricks, which can improve the chemical corrosion resistance, thermal shock resistance and reduce the expansion coefficient of mullite. It is also produced by the sintering method.
refractory zircon mullite brick is a special refractory made by using industrial alumina and zircon concentrate as raw materials and introducing zirconia into the mullite matrix through the reaction sintering process.
Refractory zircon mullite brick introduces zirconia into mullite bricks, and the high-temperature mechanical properties of mullite materials can be greatly improved by using the phase transformation toughening of zirconia. Zirconia can promote the sintering of mullite materials. The addition of ZrO2 can accelerate the densification and sintering process of ZTM materials due to the generation of low melting point compounds and the formation of vacancies. When the mass fraction of ZrO2 is 30%, the relative theoretical density of the green body fired at 1530? reaches 98%, the strength reaches 378MPa, and the toughness reaches 4.3MPa·m1/2.
Refractory zircon mullite brick are made from industrial alumina and zircon by reaction sintering. Because the reaction and sintering are carried out at the same time, the process control is difficult. Usually, Refractory zircon mullite bricks are heated at 1450 °C to make them densified and then heated to 1600 °C for reaction. ZrSiO4 is decomposed into ZrO2 and SiO2 at greater than 1535 °C, and SiO2 and Al2O3 react to form mullite. Due to the decomposition of ZrSiO4, a part of the liquid phase appears, and the decomposition of ZrSiO4 can refine the particles and increase the specific surface area, thereby promoting sintering.
