Mullite is an excellent material due to its high temperature stability, strength and creep resistance. It is similar to Cordierite, although it is not as good an  insulator and has a higher coefficient of thermal expansion. It is commonly used in heater exchange parts and electrical insulators.

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Property Charts & Safety Data Sheets
Property ChartsMullite
Master Ceramics Property ChartFull Color
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Safety Data SheetsDense Mullite Ceramic

Materials Property Chart
 PropertyASTM MethodUnitsMullite
ElectricalDielectric Strength (.125" Thick)D 149-97AV/mil250
Dielectric Constant @ 1 MHzD 150-98--6.7
Dielectric ConstantD 2520-95--6.7
@ GigahertzD 2520-95--11.4
Dielectric Loss @ 1 MHzD 150-98--0.003
Dielectric LossD 2520-95--0.003
@ GigahertzD 2520-95--11.4
Volume Resistivity, 25°CD 257ohms-cm> 1 x 1014
Volume Resistivity, 300°CD 1829ohms-cm4 x 1010
Volume Resistivity, 500°CD 1829ohms-cm1 x 109
ThermalC.T.E. 25 - 100° CC 372-96x 10-6/C3.6
C.T.E. 25 - 300° CC 372-96x 10-6/C4.1
C.T.E. 25 - 600° CC 372-96x 10-6/C4.8
Thermal Conductivity @ RTC 408W/m K4
Max Use Temp--Fahrenheit (°F)3100
--Celsius (°C)1700
MechanicalDensityC 20-97g/cc3.00
HardnessVickers 500gmGPa (kg/mm2)10 (1000)
Fracture ToughnessNotched BeamMPam1/23
Flexural Strength (MOR)
(3 point) @ RT
F417-87MPa (psi x 103206 (30)
Tensile Strength @ RT--MPa (psi x 103)138 (20)
Compressive Strength @ RT--MPa (psi x 103)1034 (150)
Elastic ModulusC848GPa (psi x 106)179 (26)
Poisson's RatioC848--0.24
GeneralCrystal Size (Average)Thin SectionMicrons7
Water AbsorptionC 20-97%0
Note: The information in this data sheet is for design guidance only. STC does not warrant this data as absolute values. Forming methods and specific geometry could affect properties. Slight adjustments can be made to some of the properties to accommodate specific customer requirements. Most of the dense materials in the table are resistant to mechanical erosion and chemical attack. STC has performed ASTM testing qualification for certain compositions, in accordance with ASTM D2442. Please consult our technical staff for appropriate material and specific test results.