示差扫描热量计测量结果不确定度的评定

2019-12-19陈扬

科技创新与应用 2019年35期

陈扬

摘要：示差扫描热量计是在程序控制温度下，测量试样与参比物之间的加热功率差或温差的仪器。根据仪器测量原理的不同，可分为功率补偿式示差扫描热量计和热流式示差扫描热量计。示差扫描热量计是一种多功能的量热仪器，可测定物质的熔融热、相变热、结晶热等，广泛用于化工、纺织、药物、高分子等领域，也适用于新材料热物性和化学性质的测定。示差扫描热量计测量的温度和热量的准确与否，直接影响试样的检测结果。文章依据JJG 936-2012《示差扫描热量计》检定规程，对示差扫描热量计测量结果进行不确定度分析评定。

关键词：示差扫描热量计;标准物质;不确定度评定

中图分类号：TH81 文献标志码：A 文章编号：2095-2945（2019）35-0016-02

Abstract： The differential scanning calorimeter is an instrument for measuring the heating power difference or temperature difference between the sample and the reference under the temperature controlled by the program. According to the different measuring principle of the instrument， it can be divided into power compensation differential scanning calorimeter and heat flow differential scanning calorimeter. Differential scanning calorimeter is a multi-functional calorimetric instrument， which can measure the melting heat， phase change heat， crystallization heat and so on. It is widely used in the fields of chemical industry， textile， medicine， polymer and so on. It is also suitable for the determination of thermophysical and chemical properties of new materials. Whether the temperature and heat measured by the differential scanning calorimeter is accurate or not directly affects the test results of the sample. According to the verification regulation of JJG 936-2012 "Differential Scanning Calorimeter"， this paper analyzes and evaluates the uncertainty of the measurement results of differential scanning calorimeter.

Keywords： differential scanning calorimeter; reference material; uncertainty evaluation

1 温度示值误差测量结果的不确定度评定

1.1 测量过程简述

1.1.1 测量依据：JJG 936-2012《示差扫描热量计检定规程》

1.1.2 测量环境条件：温度（15～30）℃，相對湿度不大于85%

1.1.3 测量标准：热分析标准物质铟（In）、锡（Sn）、铅（Pb）、锌（Zn）、硝酸钾（KNO3）、二氧化硅（SiO2），不确定度U=（0.06～0.94）℃（k=2）

1.1.4 被测对象：示差扫描热量计。

1.1.5 测量方法：在规定的条件下，用In进行测量，测量2次，2次的算术平均值与标准值之差值为温度示值误差。

1.2 数学模型

1.2.1 数学模型

3 结束语

用示差扫描热量计检定装置检定/校准示差扫描热量计，温度误差的不确定度为U=（0.2～1.0）℃（k=2），热量误差的不确定度为U=（0.20～1.4）J/g（k=2）。