BS ISO 21713:2020 pdf download – Fine ceramics (advanced ceramics, advanced technical ceramics) — Determination of elastic modulus of ceramics at high temperature by thin wall C-ring method

BS ISO 21713:2020 pdf download – Fine ceramics (advanced ceramics, advanced technical ceramics) — Determination of elastic modulus of ceramics at high temperature by thin wall C-ring method 5.2 Heating system 5.2.1 General A furnace shall be capable of heating the test fixture and test piece as well as maintaining a uniform and constant temperature during the test, by which a vacuum environment shall be available for test requirements. If a vacuum chamber is used, and it is necessary to transmit the load through a seal, bellows or a fitting, it shall be verified that load losses or errors are less than 1 % of the applied loads. 5.2.2 Test piece temperature stability The furnace shall be controlled by a device for maintaining a constant temperature within ±2 °C or better within the working space of the furnace, during the time that the test piece is loaded in the range of elasticity. 5.2.3 Test temperature uniformity The furnace shall be capable of maintaining the test piece at a uniform temperature. The temperature of the test piece shall not vary by more than 10 °C after a 15-min holding time at the required temperature. 5.2.4 Furnace heating rate The furnace control device shall be capable of controlling the heating rates of the furnace and preventing temperature overshoots. 5.2.5 Furnace stability The time for the system to reach thermal equilibrium at the test temperature shall be determined. 5.3 Temperature-measuring and indicating instruments 5.3.1 General The thermocouple temperature-measuring equipment shall have a resolution of at least 1 °C and an accuracy of 5 °C or better. The optical pyrometer, if used, shall have a resolution of at least 5 °C and an accuracy of 10 °C or better. 5.3.2 Thermocouples Thermocouples in accordance with IEC 60584-1 shall be used. The thermocouples shall exhibit low thermal inertia (the diameter of the wires shall be not greater than 0,5 mm). The thermocouples shall have a sufficient length within the furnace (with respect to heat conduction along the wires). The measuring thermocouple tip shall be as close as possible to the test piece. 5.3.3 Verification of the thermocouple temperature-measuring system Thermocouples shall be checked periodically as their output may drift with usage or contamination. 5.4 Vacuuming machine A suitable vacuuming machine capable of applying a suitable vacuum environment shall be used. The low vacuum degree (<10 Pa) shall be accomplished by a mechanical pump, while the...