Metrology and Measurement Systems

Abstract

On the basis of induction heating, radiation heating and liquid nitrogen refrigeration, high-temperature, medium-temperature, normal-temperature and low-temperature heating/refrigeration furnaces were designed, respectively. An apparatus with a wide temperature range and high accuracy applied to test oxidation resistance of materials has been developed based on the thermogravimetric method and the heat transfer principle. The apparatus consists of four heating/cooling systems, a specimen fixture positioning unit, a laser positioning unit, vertical and horizontal moving guide rails, and a high-precision weighing balance. The apparatus, based on the thermogravimetric method, is able to test oxidation resistance of materials. In the test, the temperature range was −180∼3000 • C (the highest temperature is determined by material properties). The temperature control accuracy was ±5 • C. The accuracy of on-line weighing was ±0.1 mg. The measurement uncertainty was 0.2 mg. Compared with other relevant devices, this apparatus has its own advantages: simple operation, wide heating/cooling temperature range, sufficient specimen heating, high sensitivity and precision, and short heating/cooling time. The experimental results show that the developed apparatus presented in this study not only can be used for isothermal thermogravimetric tests, but also for thermal cycling tests and multi-step oxidation tests. With the effective integration of multiple heating apparatus and refrigeration apparatus, the apparatus breaks through the limitations of the heating/cooling temperature range of the existing devices, accomplishes the high-precision oxidation resistance test of materials in a wide temperature range, and will play a great role in improving the research of materials.