ZTA (zirconia-toughened alumina) and ATZ (alumina-toughened zirconia) ceramics differ in their composition, one containing a majority of alumina, the other a majority of zirconia. These two configurations allow the properties to be adapted as required: ZTA for better hardness and chemical resistance, and ATZ for higher toughness. However, these composites are still expensive to produce and require precise control of the sintering processes to guarantee a homogeneous microstructure. They can also be sensitive to thermal shock, depending on the proportions of alumina and zirconia used.

Alumina-zirconia ceramics have a wide range of applications in sectors such as the biomedical industry for implants (hip prostheses), aeronautics for engine parts and thermal coatings, and industrial tooling where wear resistance is essential. This composite material offers an excellent compromise between hardness, strength and toughness, making it indispensable in extreme environments and high value-added applications.

The alumina or zirconia content mainly determines the mechanical properties: a higher alumina content (ZTA) improves hardness and chemical resistance, while a higher zirconia content (ATZ) increases toughness and impact resistance. Yttrium oxide is often added to stabilize zirconia, thus preventing degradation under thermal and mechanical stress.