ISO/TC 150/SC 1/WG 3 - Ceramics

This document specifies the characteristics of, and corresponding test methods for bio-stable ceramic-bone-substitute material based on a zirconia-reinforced, high-purity alumina matrix composite for use as bone spacers, bone replacements and components in orthopaedic joint prostheses. This document is intended for composite materials which are based on an alumina matrix, i.e. alumina as the dominating phase in the composite with a mass fraction of >60 %, similar to the material described in ISO 6474‑1, but extended by means of a certain amount of zirconia and other defined ingredients. NOTE The required properties in this document differ from those in 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 document, 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 document does not cover biocompatibility (see ISO 10993‑1). 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 document.

This document specifies methods of test for the chemical analysis, assessment of crystallinity ratio and phase composition of hydroxyapatite-based materials such as powders, coating or bulk products. NOTE These tests are intended to describe properties of the material and to communicate these between organizations. These tests are not written with the objective of replacing a company's internal operational and assessment tests although they could be used as such.

This document specifies requirements for single layer thermally sprayed hydroxyapatite coatings applied to metallic surgical implants. These requirements are intended to describe properties of the materials and to communicate these between organizations. These requirements are not written with the objective of replacing a company's internal operational and assessment requirements although they could be used as such. NOTE 1 For thin coatings with a thickness of less than 50 µm, some of the test methods described in this document might be difficult to apply without modification. NOTE 2 The requirements of the hydroxyapatite layer of dual-layer coatings (consisting of a lower layer of metallic coating and an upper layer of hydroxyapatite coating) can follow this document; however, testing methods referred to in this document cannot be applied to dual layer coatings. If this document is taken in reference for the requirements of the hydroxyapatite layer of dual layer coatings, a rationale on how the single-layer tested coupons are representative of the dual-layer coated implant might be considered necessary. This document does not cover coatings made from glasses, glass ceramics, alpha- and beta-tricalcium phosphate, biphasic calcium phosphate or other forms of calcium phosphate. NOTE 3 While the requirements in this document are intended to be used as specifications of a thermally sprayed coating of hydroxyapatite, it might be necessary to establish routine control procedures specifying control tests and their time intervals to make sure the characteristics of the coating stay within specified limits. NOTE 4 This document was developed with a focus on plasma sprayed coating of hydroxyapatite. It might also be used to characterize other thermally sprayed coatings of hydroxyapatite. However, thermally sprayed coatings that do not have a history of clinical use might present different risks and might need additional characterizations beyond those identified in this document.

This document specifies a test method for measurement of the adhesion strength of hydroxyapatite coatings intended for use on metallic-substrate components of surgical implants. NOTE Requirements for the competence of testing laboratories can be found in ISO/IEC 17025.