BS ISO 6474-1 pdf free download
BS ISO 6474-1-2019 pdf free 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 GA);
b) fracture toughness (see 6k);
c) cyclic fatigue (see 69).
6 Test methods
6.1 Bulk density
The bulk density shall be determined in accordance with ISO 18754 or EN 623Z.
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 S102 + CaO + Na20) 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 ol 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 manufacturing of the products;
e) the requirement for linear intercept grain size given in Tablc 1 shall be matched at each selected position of the micrographs;
1) the standard deviation of the linear intercept grain size shall be determined from the data of all selected micrographs; the standard deviation shall match the requirement given in Table 1.
The determination of linear intercept grain size shall be organized such that homogeneity of the regular production can be assessed to a sufficient statistical relevance. The manufacturer shall justify the organization of grain size determination for his specific manufacturing process. It is recommended that the manufacturer analyse the reliability, repeatability and maintenance of the manufacturing process with respect to microstructure (e.g. validation) and utilize these data for the organization of the regular production control. If this detailed analysis is accomplished successfully, the regular production control of the microstructure can be performed with a reduced number of specimens and micrographs.
6.4 Strength properties
6.4.1 General
The strength properties shall be determined using either the biaxial flexural strength test, as described in &42 or the 4-point bending strength test (see 6A3). A total of at least 30 specimens for each test shall be used. The data shall be analysed in accordance with Weibull statistics (see 6AA).
It is recommended that the surface finish which was used for the test for ease of data interpretation in terms of the product’s intended use be specified.
For an as-fired surface, specify whether the surface was made by pressing of green machining.
6.4.2 Biaxial flexural strength
The biaxial flexural strength test shall be performed in accordance with ASTM C1499. The surfaces ot the specimen can be as-fired, ground or polished. Within the scope of this document, the dimensions of specimen and test rig listed in Table 2 shall be used.BS ISO 6474-1 pdf download.
