This International Standard specifies the characteristics of, and corresponding test methods for, a bio-compatible and bio-stable ceramic bone substitute material based on zirconia reinforced high purity alumina matrix composite for use as components of orthopaedic joint prostheses. This part of ISO 6474 is intended for composite materials which are based on an alumina matrix similar to the material described in Part 1 of ISO 6474. This International Standard is applicable for a composition of the material as described in ISO 6474-1, extended by means of a certain amount of zirconia and other defined ingredients. NOTE – The required properties in this International Standard ISO 6474-2 differ from ISO 6474-1 with respect to strength and fracture toughness. Furthermore, there are requirements specifically applicable for zirconia containing materials (see ISO 13356). In the material composition as defined in this International Standard, additional additives are listed. Typical additives for alumina or zirconia ceramics are Mg, Y, Ce and others. Such additives can be useful in order to improve the mechanical properties and/or the chemical stability of the alumina-zirconia composite material. This International Standard does not cover the biocompatibility of these inorganic additives in the human body. It is the responsibility of the manufacturer to evaluate the biocompatibility of the specific ceramic composite material which is produced within the framework of this International Standard.