What are the benefits of pressed mullite for high-temperature applications?

Pressed mullite (3Al2O3.2SiO2), with a density of approximately 2.8 g/cm³ and a flexural strength of 180 MPa, has an excellent chemical and mechanical stability up to 1,700°C, and also offers an excellent thermal shock resistance and low thermal conductivity (2.2 W/(m.K). Its low expansion coefficient (5.3×10-6/K) limits deformation due to temperature. Its corrosion resistance and oxidisation resistance are higher than those of steatite and cordierite. Final Advanced Materials recommends mullite for industrial ovens, burner components and high-temperature chemical applications requiring stability and durability.

FAQs From Same Category
What is the difference between cordierite, steatite and mullite in terms of their properties?

Pressed cordierite, with a density of 2.1 g/cm3, has a low thermal expansion coefficient (2–4.5×10-6/K), providing excellent thermal shock resistance and resistance to rapid thermal cycling. Steatite, with a density of 2.7 g/cm3, has a high dielectric strength (~15 kV/mm) but a lower thermal shock resistance. Mullite, with a density of 2.8 g/cm3, stands out for its stability at high temperature (up to 1,700°C) and its chemical resistance. To help you choose the type of pressed ceramic best suited to your requirements, Final Advanced Materials takes into account the application, but also the material’s thermal resistance, mechanical resistance and electrical insulation.

Which pressed ceramic has the best dielectric strength for electrical insulation applications?

Pressed steatite has the best electrical insulation, with a dielectric strength of 15 kV/mm and a resistivity of over 105 at 600°C. It withstands temperatures as high as 1,000°C and has excellent dimensional stability. Cordierite and mullite have lower dielectric strengths (10 kV/mm) but are less suited to high tensions. Final Advanced Materials recommends steatite for high-voltage electrical components such as supports, insulators and electrical resistor caps.

Is steatite more or less resistant to thermal shocks than cordierite?

For thermal applications requiring thermal shock resistance, it is recommended to use porous pressed ceramics. Porous steatite, with a density of approximately 1.8 g/cm3 and a thermal expansion coefficient of approximately 8-9x10-6/K, can resist to temperatures up to 1,000°C. Porous cordierite, with a density of approximately 1.9 g/cm3 and a thermal expansion coefficient of approximately 4-6x10-6/K, can resist to temperatures up to 1,200°C. Porosity slightly improves the resistance to thermal shock, but steatite has a higher thermal expansion coefficient than cordierite. Final Advanced Materials therefore recommends porous cordierite rather than porous steatite for applications requiring thermal shock resistance.