The individual grains are completely tetragonal. The transformation toughened zirconias are characterized by high strength and fracture toughness approaching that of the cemented carbides. The characteristics result from stress induced phase transformations of the tetragonal crystals to the monoclinic phase with a corresponding change in volume and local stress field. The Mg-PSZ s retain their desirable properties at temperatures approaching 1100 . ZrO2 is available in a wide variety of shapes and sizes and amenable to a wide variety of cold and hot forming techniques.
Zirconia is stable in oxidizing and mildly reducing atmospheres.
It reacts with carbon, nitrogen and hydrogen at temperatures above 2200 . It is inert to acids and bases at room temperature with the exception of HF and does not react with the refectory metals up to 1400 . However, the capability is strongly dependent upon the type and quantity of stabilizer used in the ceramic. Superior fracture toughness and high mechanical strength.average thermal shock resistance. Best suited applications bellow 800 and minimum thermal cycling.