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Alumina

Family Overview

Aluminas (aluminum oxide, Al2O3) are the most commonly used technical ceramics due to their generally useful properties and good price/performance ratio. Alumina ceramics are commonly subdivided according to their alumina content ranging from 80% to more than 99%. Higher purity alumina demonstrates enhanced wear and corrosion resistance — creating a continuous scale of various alumina grades, compositions, and performance.

Aluminas are used in both general use and specialized applications. A grade is selected to fit the application environment. Alumina compositions and microstructures can be formulated to meet the specific performance requirements of more demanding applications. 

  • General use
  • Wear resistance
  • Electrical insulator
  • Dielectric strength
  • Low dielectric loss

Ceramic Expertise

CoorsTek has developed over 100 unique alumina compositions, optimized for specific application requirements. Let our experts help you determine the best-fit material for your application.

Brochure Downloads

Download the Advanced Alumina brochure

Download the Advanced Alumina for Semiconductor brochure

Technical Ceramic Chemical Properties iconTechnical Ceramic Electrical Properties iconTechnical Ceramic Mechanical Properties iconTechnical Ceramic Thermal Properties icon

Alumina properties

 

    AD-94 AD-96 FG-995 AD-995 PLASMAPURE
AD-998
PLASMAPURE-UC
ALUMINA
Properties Units Nom. 94% Al2O3 Nom. 96% Al2O3 Nom. 98.5% Al2O3 Nom. 99.5% Al2O3 Nom. 99.8% Al2O3 Nom. 99.9% Al2O3
Density g/cm³ 3.70 3.72 3.80 3.90 3.92 3.92
Color WHITE WHITE WHITE IVORY IVORY IVORY

4-PT Flexural Strength
(MOR) 
(20° C)

MPa
(psi x 10³)
308 343 298 300 320 360
Elastic Modulus
(20° C)
GPa
(psi x 106)
303 303 350 370 380 386
Poisson’s Ratio
(20° C)
0.21 0.21 0.22 0.22 0.22 0.22
Compressive Strength
(20° C)
MPa
(psi x 10³)
2103 2068 2500 2600 2650 2700
Hardness
(Knoop 1000gm)
GPa
(kg/mm²)
11.5 11.5 13.7 14.1 14.1 14.5
Fracture Toughness
(K(I c))
MPa m1/2 4 - 5 4 - 5 4 - 5 4 - 5 4 - 5 4 - 5
Thermal Conductivity
(20° C)
W/m 22.4 24.7 27.5 30.0 31.0 33.0
Coefficient of Thermal Expansion (25-1000°C) 1x10-6/°C 8.2 8.2 8.2 8.2 8.2 8.2
Specific Heat
(100° C)
J/kg*K 880 880 880 880 880 870
Dielectric Strength
(6.35mm)
ac-kV/mm
(ac V/mil)
8.3 8.3 8.7 8.7 8.7 8.7
Dielectric Constant
(1 MHz)
25° C 9.1 9.0 9.6 9.7 9.8 9.8
Dielectric Loss (tan delta)
(1 MHz 25° C)
25° C 0.0004 0.0002 0.0002 0.0001 < 0.0001 <0.0001
Volume Resistivity
(25° C)
ohm-cm >1014 >1014 >1014 >1014 >1014 >1015
(500° C) ohm-cm 4 x 109 4 x 109 2 x 1010 2 x 1010 2 x 1011 1 x 1012
(1000° C) ohm-cm 5 x 105 1 x 106 2 x 106 2 x 106 2 x 107 1 x 107