Zirconia-toughened alumina (ZTA) shows a considerable improvement in strength and more importantly toughness. As a result, these ceramics can be used in areas of extreme mechanical abrasion and thermal shock.

Fully stabilised zirconia (FSZ) produces a high-density ceramic on sintering. The grain size is relatively large at 10-40µm (microns) and the ceramics are often translucent in appearance. Recent optimisation of zirconia powders have resulted in a readily sinterable high-purity product.

Material Properties

Please note that the information set forth herein is offered for comparison only, and is not to be construed as absolute engineering data or constituting a warranty or representation for which we assume legal responsibility.

Property Unit Test Zirconia Toughened Alumina
Density g.cc-1 ASTM C20 4.0
Colour ** ** WHITE
Elastic Modulus GPa ASTM C848 360
Flexural Strength MPa ASTM F417 450
Compressive Strength MPa ASTM C773 2900
Fracture Toughness Range MPa NOTCHED BEAM 5-6
Hardness GPa ROCKWELL 45N 85
Thermal Conductivity W/mK ASTM C20 27
CTE 25-1000 10(-6)/0C/ ASTM C372 8.2
Thermal Shock delta Tc NOTE3 300
Dielectric Strength ac-kv/mm (6.25mm) ASTM D116 9.0
Dielectric Loss 250C@1MHz ASTM D2520 0.0005
Volume Resistivity 1000C ohm-cm ASTM D1829 10^6
  • DATA MEASUREMENTS – All data measurements are typical and made at room temperature unless otherwise noted.
  • THERMAL SHOCK RESISTANCE – Tests are run by quenching samples into water from various elevated temperatures. The change in temperature where a sharp decrease in flexural strength is observed is listed as ‘delta Tc’.
  • CHEMICAL RESISTANCE – Although all alumina and zirconia ceramics are highly resistant to chemical attack, it is recommended that specific applications are discussed with Almath Crucibles to ensure optimum ceramic selection.

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