Zirconia

Zirconia Crucibles (ZrO2) offer three advantages over their alumina crucible counterparts: they are more refractory, having a melting point some 500oC above alumina. They are readily machined and give a high quality surface finish and are a useful oxygen anion conductor for use in sensors and fuel cells. However, they are considerably more expensive than alumina.

Zirconium dioxide has the complication of being metastable and needs to be stabilised before it can be put to use. The addition of small quantities of stabilising oxides such as CaO, MgO and best of all Y2O3 allow the high temperature cubic phase to stabilise itself. Partially stabilised zirconia can also be used as a toughening agent in alumina.

Fully stabilised zirconia (FSZ) produces a high-density ceramic on sintering. The grain size is relatively large at 10-50µm (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 Partially Stabilised Zirconia Fully Stabilised Zirconia
Density g.cc-1 ASTM C20 5.7 6.0
Colour ** ** IVORY WHITE
Elastic Modulus GPa ASTM C848 200 200
Flexural Strength MPa ASTM F417 620 900
Compressive Strength MPa ASTM C773 1750 2500
Fracture Toughness Range MPa NOTCHED BEAM 11 13
Hardness GPa ROCKWELL 45N 77 83
Thermal Conductivity W/mK ASTM C20 2.2 2.2
CTE 25-1000 10(-6)/0C/ ASTM C372 10.1 10.3
Thermal Shock delta Tc NOTE3 350 350
Dielectric Strength ac-kv/mm (6.25mm) ASTM D116 9.4 9.4
Dielectric Loss 250C@1MHz ASTM D2520 0.001 0.001
Volume Resistivity 1000C ohm-cm ASTM D1829 <10^2 <10^1
  • 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.

View our full range of Zirconia Crucibles.

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