Used primarily for its low cost and good thermal shock properties, Mullite is an easily machinable technical ceramic.


Relative Cost of Material


Machining Degree of Difficulty


Mullite is a technical ceramic known primarily for its thermal shock resistance and insulatory properties. It has relatively low CTE when compared to other materials such as parially stabilized zirconia, and good oxygen resistance as well. In addition to these properties, Mullite is also a low-cost and easily machinable material, so component manufacture in this material is generally very cost-effective. Although the machinability of Mullite makes tight tolerance or complex component manufacture achievable, the fact that its mechanical properties are inferior to many other technical ceramics (with correspondingly higher manufacturing costs) translates to more complex components frequently being made from other materials. Mindrum Precision has decades of experience with Mullite, and click here for our contact information or to request a quote today.


Mullite is used primarily for two purposes; either as a low-cost insulator, or for applications where thermal shock is a pressing concern, such as in refractories. While it is not among the most common ceramics used in the industry, there are a number of defense and aerospace applications that involve Mullite as well. 


Material PropertyMullite
Density (g/cm^3)2.8
Hardness (Knoop)1450
Tensile Strength (MPa)132
Modulus of Elasticity (GPa)91 - 220
Flexural Strength (MPa)170
Compressive Strength (MPa)550 - 1320
Poisson's Ratio0.24
Dielectric Strength (ac-kV/mm)9.8
Dielectric Constant (@1MHz)6.5
Volume Resistivity (ohm-cm @25°C)>1.0E13
Coefficient of Thermal Expansion (1 x 10^-6/°C)5.4
Thermal Conductivity (W/m K)6
Specific Heat (J/kg*K)250
Maximum Working Temperature (°C)1800
*Note: Properties vary by manufacturer. The above information should be used for general reference purposes only.

related Materials

  • Alumina – Technical ceramic with excellent mechanical and insulatory properties and good corrosion resisitance.
  • Macor – Easily machinable ceramic with similar electrical resistivity
  • Aluminum Nitride – Softer ceramic with good thermal insulation and electrical resistivity

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