Zirconia Toughened Alumina (ZTA) is a composite ceramic with excellent mechanical properties and a very attractive performance to price ratio. It is produced by the addition of Zirconia to the main Alumina matrix before sintering.
The main advantages of Zirconia Toughened Alumina (ZTA) over Alumina are that provides additional strength, fracture toughness, elasticity, hardness, and wear resistance for temperatures below 1500 C, and has fairly improved thermal shock resistance. Also ZTA crucibles exhibit better surface finish than Alumina making them an excellent choice for bio-compatible and analytical grade application. The mechanical robustness compared to Alumina is attributed to the phase transformation of the metastable tetragonal Zirconia grains when the material is stressed. The stress concentration at a crack tip can cause a transformation from a tetragonal crystal structure to a monoclinic one, which has an associated volume expansion of Ziroconia. This volume expansion effectively pushes back the propagation of the crack and results in higher toughness and strength.
Thermansys t-ceramics ZTA crucibles are offered without significant additional cost compared to pure Alumina crucibles, retaining its prices much lower than Fully Yttria Stabillized Zirconia (8YSZ), while have improved some of the properties where Yttria Stabilized Zirconia outbalance Alumina. Thus ZTA crucibles are presenting a cost effective alternative to YSZ for temperatures up to 1500C.