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The most common material used for structural ceramic parts is alumina. It is used in applications from aerospace to medical, to bearings to analytical instrumentation. High purity alumina ceramics lends itself well to corrosive environments.

Download the properties chart here.

PropertyASTM MethodUnitsAL74AL95AL95BAL96AL96PAL98AL995AL998AL998E
% Alumina-% Al2O373.895.195.995.895.497.899.599.899.6
Color- whiteivorywhitewhitepurplewhiteivory-whiteivoryivory
Gas Permeability--gas tightgas tightgas tightgas tightgas tightgas tightgas tightgas tightgas tight
DensityC 20-97g/cc3.033.653.683.713.683.783.883.913.90
Hardness-Mohs Scale999999999
Water AbsorptionC 20-97%000000000
Flexural StrengthF417-87psi35k45k51k52k48k57k49k55k50k
Tensile Strength-psi17k22k27k29k23k32k25k29k25k
Compressive Strength-psi200k265k300k300k285k325k310k325k310k
Elastic ModulusC848psi x106254446454550555555
Shear ModulusC848psi x106101819191920222222
Poisson's RatioC848none0.
C.T.E., 25 - 100°CC372-96x10-6/°C5.
C.T.E., 25 - 300°C--
C.T.E., 25 - 600°C--
Thermal Conductivity, 25°CC 408W/m-K41922232129303030
Max Use Temperature-°F280030003100310031003100305030503050
Dielectric Strength (.125" thick)D149-97AV/mil225250250250250260270290255
Dielectric Constant
@ 1MHz
Dielectric ConstantD2520-95-n/a9.
@GHzD2520-95 n/a@11.0@10.6@10.9@10.8@9.8@9.8@9.6n/a
Dielectric Loss @ 1MHzD150-98-0.00120.00060.00060.00040.00060.00060.0002<0.00010.0007
Dielectric LossD2520-95-n/a0.00090.00070.00070.00060.0005<0.0001<0.0001n/a
@GHzD2520-95 n/a@12.5@10.6@10.9@10.8@9.8@9.8@9.6n/a
Volume Resistivity,
D 257ohms-cm>1E + 14>1E + 14>1E + 14>1E + 14>1E + 14>1E + 14>1E + 14>1E + 14n/a
Volume Resistivity, 300°C--4E + 105E + 121E + 123E + 121E + 118E + 111E + 133E + 12n/a
Volume Resistivity, 700°C--2E + 091E + 122E + 111E + 121E + 109E + 105E + 126E + 09n/a

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.

NOTE: In addition to the above compositions, STC offers a wide range of alternative materials. Please contact one of our applications engineers for material requirements that may not be shown above.