BS ISO 6474-1:2019 pdf download – Implants for surgery — Ceramic materials Part 1: Ceramic materials based on high purity alumina 5 Preparation of specimens Specimens shall be produced equivalent to the regular production of the implants. The same feedstock, comparable shaping technology (e.g. axial pressing, isostatic pressing), high temperature process (e.g. sintering, hot isostatic pressing) and hard machining (e.g. grinding, polishing) shall be applied. The shaping of specimens shall be accomplished according to the requirements of the test. The manufacturer shall declare and justify whether the production of the specimens can be assessed as equivalent to the regular production. Finished products or portions of them can be used for the evaluation of material properties. However, due to geometric restrictions and the risk of damage during specimen preparation, it is not recommended to produce specimens as portions of finished products for evaluation of the following material properties: a) strength (see 6.4); b) fracture toughness (see 6.6); c) cyclic fatigue (see 6.9). 6 Test methods 6.1 Bulk density The bulk density shall be determined in accordance with ISO 18754 or EN 623‑2. 6.2 Chemical composition The chemical composition shall be determined in accordance with EN 725‑1 or either by X‑ray fluorescence in accordance with ISO 12677 or by Inductively Coupled Plasma‑Optical Emission Spectroscopy (ICP‑OES) or Inductively Coupled Plasma‑Mass Spectroscopy (ICP‑MS). The upper limits of impurities (total amount of SiO 2 + CaO + Na 2 O) shall have a % mass fraction in accordance with the requirements specified in Table 1. 6.3 Microstructure For determination of the alumina grain size, ISO 13383‑1 or EN 623‑3 or ASTM E112 shall be applied (linear intercept method). Five test specimens shall be used for the determination of microstructure. NOTE The linear intercept method reveals a nominal average grain size for the selected position of the micrograph, not the distribution of the size of individual grains. For selection, preparation and evaluation of the specimen, the following guidelines shall be followed: a) the wall thickness of the selected specimens shall represent maximum and minimum of the manufacturer’s products; b) the position of the micrographs shall represent regions at the centre and at the skin of the selected specimens; c) the specimen selection shall reflect the possibility of temperature deviation in the furnace; d) using regular products as specimens for microstructure evaluation is recommended; if other specimens are used, they shall be produced equivalent to the normal...
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