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Zirconia-Toughened Alumina (ZTA)

ZTA is a grade of alumina. It has the highest strength compared to the other variants of alumina. The graph bars on the material properties cards below compare ZTA to other oxide-based engineering ceramics (top) and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Compressive (Crushing) Strength

2750 MPa 400 x 103 psi

Elastic (Young's, Tensile) Modulus

360 GPa 51 x 106 psi

Flexural Strength

430 MPa 63 x 103 psi

Fracture Toughness

7.2 MPa-m1/2 6.5 x 103 psi-in1/2

Knoop Hardness


Poisson's Ratio


Tensile Strength: Ultimate (UTS)

290 MPa 42 x 103 psi

Thermal Properties

Maximum Temperature: Mechanical

1530 °C 2780 °F

Maximum Thermal Shock

300 °C 580 °F

Melting Onset (Solidus)

2040 °C 3700 °F

Specific Heat Capacity

870 J/kg-K 0.21 BTU/lb-°F

Thermal Conductivity

25 W/m-K 14 BTU/h-ft-°F

Thermal Expansion

8.2 µm/m-K

Other Material Properties


4.1 g/cm3 260 lb/ft3

Dielectric Constant (Relative Permittivity) At 1 MHz


Dielectric Strength (Breakdown Potential)

8.9 kV/mm 0.35 V/mil

Electrical Dissipation At 1 MHz


Electrical Resistivity Order of Magnitude

13 10x Ω-m

Common Calculations

Stiffness to Weight: Axial

48 points

Stiffness to Weight: Bending

57 points

Strength to Weight: Axial

19 points

Strength to Weight: Bending

24 points

Thermal Diffusivity

6.9 mm2/s

Thermal Shock Resistance

7.1 points

Followup Questions

Further Reading

Ceramic and Glass Materials: Structure, Properties and Processing, James F. Shackelford and Robert H. Doremus (editors), 2008

Ceramics and Composites: Processing Methods, Narottam P. Bansal and Aldo R. Boccaccini (editors), 2012

Springer Handbook of Condensed Matter and Materials Data, W. Martienssen and H. Warlimont (editors), 2005