新制标准铂电阻温度计退火特性理论模型及验证

根据再结晶动力学理论,对新制标准铂电阻温度计(SPRT)首次退火过程中水三相点电阻值随时间的变化规律建立了理论模型,得出无量纲电阻值变化具备指数函数特征及双对数无量纲电阻值变化函数的线性特性。基于15支SPRT在660℃退火的实验数据获得了退火参数和退火指数变化范围及平均值。理论模型计算结果表明,1000h后的SPRT稳定性可以达到约1mK。SPRT退火平均值稳定性曲线在一定程度上可以反映出温度计退火稳定性的变化规律,可为合理制定退火工艺时间提供理论预测和参考。

Theoretical Model and Verification of Annealing Characteristic of the New Standard Platinum Resistance Thermometer

According to the theory of recrystallization kinetics, two theoretical models were established for the change law of the triple point resistance of water with time during the first annealing of a new standard platinum resistance thermometer (SPRT), it was concluded that that the dimensionless resistance value change have the dimensionless resistance value change has the characteristics of an exponential function and the linear characteristic of the double logarithmic dimensionless resistance value change function. Based on the experimental data of 15 SPRTs annealed at 660 ℃, the range and average value of annealing parameters and annealing index were obtained. The calculated results of theoretical model showed that the stability of SPRTs could reach about 1mK after 1 000 hours. The annealing average stability curve of SPRT could reflect the change law of the annealing stability of the thermometer to a certain extent, and could provide a theoretical prediction and reference for the reasonable annealing process.