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. 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.