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.