Available Grades of Zirconia

Yttria Partially Stabilized Zirconia (Y-PSZ)

Yttria Partially Stabilized Zirconia (Y-PSZ) is doped with Yttrium oxide (Y2O3) as a stabilizing agent which stresses the internal grain structure and makes the material stronger by changing it from a monoclinic to tetragonal phase. It is a fine grain material that has one of highest flexural strength among all ceramic materials. It has very high impact and wear resistance while offering a low thermal conductivity, often making it a suitable material to replace metals.The addition of Yttrium oxide (Yttria) enables the material to undergo transformation toughening which is responsible for the high toughness. As the material is stressed, it becomes more energetically favorable for the crystal structure to revert back to transforms from tetragonal to monoclinic phase, resulting in a highly localized volume increase of 3% – 5%. This increase in volume puts crack under compression which reduces its ability to grow and propagate into more cracks. This characteristic accounts for the material’s low susceptibility to stress fatigue and high flexural strength.

While Y-PSZ is excellent for demanding mechanical applications, it may not be suitable for very high temperature applications because it suffers from grain boundary sliding; this occurs when prolonged exposure to heat causes the material to transform form the strong tetragonal phase to the weaker monoclinic phase. Similarly, it may not be suitable for warm and moist conditions since its properties deteriorate when it is exposed to water vapor. YSZ is therefore best suited when it is operating in dry and moderate temperature conditions. For more information on hydrothermal aging of Zirconia please contact us.

Magnesia Partially Stabilized Zirconia (MSZ)

Doping of Zirconia with Magnesium oxide (MgO) also leads to a stressed internal matrix, however, this structure is cubic. M-PSZ has better temperature and moisture resistant properties because it does not suffer from phase migration. M-PSZ maintains its strength even in moist high temperature environments where YSZ mechanical properties begin to deteriorate.