Application of multiphase composite ceramics covers a wide range between mechanical engineering and biomedical. These ceramics are e.g. applied in cutting tools for machining of metals to ceramic implants for hip and knee arthroplasty. The IFKB focuses on alumina/zirconia based materials exploiting the effect of transformation toughening. These new ATZ and ZTA ceramics offer an improved combination of mechanical properties such as hardness, toughness and bending strength. Low temperature degradation, an effect feared in biomedical implants, is inhibited by alumina addition. Even higher toughness and damage tolerance is introduced by platelet reinforcement with hexaaluminates. These rod- or platelet shape dispersions are formed in situ during sintering and lead to various additional reinforcement effects.