BS ISO 6474-2:2019 pdf free

BS ISO 6474-2:2019 pdf free.Implants for surgery一Ceramic materials
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 amount of specimens and micrographs.
NOTE 1 ASTM E112 cannot be applied as it is not intended for composite materials.
NOTE 2 The linear intercept grain size is inevitably smaller than the genuine grain size. Further details and references to literature are given in EN 623-3.
For improved contrast and grain boundary detection of zirconia and alumina, it is recommended that a secondary electron detector in a scanning electron microscope (SEM) at a high acceleration voltage be used.
Within the scope of this document, it is assumed that the wear behaviour could be affected by surface degradation of the material due to hydrothermal ageing, which is considered to be a specific material property. It is thus required that wear behaviour be tested before and after accelerated hydrothermal ageing of the ceramic components.
The wear test shall be selected in accordance with the intended application, in particular considering the materials used for the wear couple of the implant. Either a simulation of the intended application [e.g. ISO 14242-1 (hip) or ISO 14243-1 (knee)] or a simplified wear test (e.g. ring on disc, pin on disc) shall be used.
The wear performance shall be determined quantitatively, e.g. the wear volume or weight loss of both components of the wear couple. If there is an increase in wear after accelerated ageing, the limits given in Table 2 shall be met.
In ISO 13356, the accelerated ageing test is combined with measurement of the monoclinic phase content. An upper limit of monoclinic phase content after ageing is defined for pure zirconia materials.Such a limit is not required within the scope of this document because the total volume of zirconia in the composite is approximately 20 % or less. This applies also to the theoretical case where all the zirconia is monoclinic, in which case the total proportion of the monoclinic phase in the composite is ≤20 %. However, it is recommended that the manufacturer also analyse the monoclinic-phase content after ageing and discuss the results with respect to the mechanical test results.BS ISO 6474-2 pdf free.