热膨胀系数准确测量方法及其标准物质研究

Development of Accurate Measurement Method for Coefficient of Thermal Expansion and Related Certified Reference Materials

热膨胀系数是评价材料热稳定性的重要指标,其测量准确性直接影响材料的加工和应用。对热膨胀系数准确测量的方法进行了研究,探索了其量值溯源途径和热历史影响,选择了最优的静态力值和升温速率。以该方法为定值方法研制了两种热膨胀系数标准物质,分别为GBW(E)130779铝热膨胀系数标准物质和GBW(E)130780聚醚醚酮热膨胀系数标准物质。联合研究院所、高校和仪器厂商等6家单位为标准物质定值,定值结果的平均值为标准物质的认定值。经过研究,铝热膨胀系数标准物质和聚醚醚酮热膨胀系数标准物质认定值分别为24.7×10^(-6)K-1和53.9×10^(-6)K-1,相对扩展不确定度分别为2%和3%(k=2)。

The coefficient of thermal expansion is an essential index for evaluating the thermal stability of materials. Its accurate measurement directly affects the processing and application of materials. In this paper, the precise measurement method of the coefficient of thermal expansion was studied, the traceability of the quantity value and the influence of thermal history were explored, and the optimal experimental conditions of static force value and heating rate were selected.To establish an accurate measurement method of coefficient of thermal expansion, two kinds of certified reference materials(CRM) for the coefficient of thermal expansion, GBW(E) 130779 of aluminum and GBW(E) 130780 of polyetheretherketone(PEEK), have been developed. 6 Institutions, including research institutes, universities, and instrument manufacturers, characterized the CRMs, and the average value of the characterization results was the certified value of the CRMs. The certified values of aluminum and PEEK coefficient of thermal expansion were 24.7×10-6K-1and 53.9×10-6K-1,with relative extended uncertainty of 2% and 3%(k=2).