Porcelain | High Alumina | Steatite | Cordierite | Mullite | Macor | Zirconia | Ceramic Coating | Silicon Carbide | Titanium Dioxide | ZTA (Zirconia Toughened Alumina)


Property Units (S.I.) Minimum Value (S.I.) Maximum Value (S.I.)
Atomic Volume (average) m3/kmol 0.0057 0.007
Density Mg/m3 3.97 4.05
Bulk Modulus GPa 209.1 218.1
Compressive Strength MPa 660 3675
Hardness MPa 9330 10290
Modulus of Rupture MPa 140 441.2
Tensile Strength MPa 333.3 367.5
Maximum Service Temperature K 1840 1910
Melting Point K 2103 2123
Thermal Conductivity W/m.K 4.8 11.8
Thermal Expansion 10-6/K 8.4 11.8
Dielectric Constant 10 85

ZTA (Zirconia Toughened Alumina)

The main advantage of Zirconia Toughened Alumina (ZTA) is the additional strength and toughness over alumina with a lower cost than zirconia (YTZP, MSZ, CSZ).

The combination of aluminum oxide and 10-20% zirconium oxide provides a much higher strength, toughness, hardness and wear resistance than alumina alone.

The 20-30% increase in strength often provides the design criteria needed at a much lower cost than using zirconia.

A process called transformation toughening is the phenomenon that increases the fracture toughness of ZTA. When placed under stress, the zirconia particles change their crystal structure from a tetragonal to a monoclinic structure, causing a volume expansion that compresses the surrounding crack in the alumina matrix.

ZTA should be considered for any application where structural strength is needed that exceeds the standard alumina properties.

Prime Features
Higher strength than alumina Lower cost than zirconia
High corrosion resistance High erosion resistance
High fracture toughness Capable of a very fine surface finish
Typical Applications
Standoffs Pump piston sleeves
Insulators Instrument
Probe bodies Sensor bulbs
Pump components Valve seals
Bushings Impellers
Fluid delivery system components Analytical instrument columns
Application Limitations
ZTA does provide a higher strength than alumina but the temperature limitation of 1500 C (2732 F) must be observed. Above this temperature the strength contribution of the zirconia is reduced. Use in moist environments at temperatures above 250C also must be carefully considered as the zirconia is subject to low temperature degradation.