诱导方式对锌凝固温坪的影响OA北大核心CSTPCD

The zinc freezing point is the defining fixed-point of the International Temperature Scale of 1990(ITS-90).Also,it is an important reference point for calibrating standard platinum resistance thermometers(SPRT).In order to improve the level of realization of the zinc freezing point,the zinc fixed point cell with metal shell was used to study the influence of different inducing methods on the zinc freezing plateaus and supercoolings.The Overall Maximum Estimate(OME)method was adopted to determine the impurity concentration.The reliability of the cell was evaluated using the changes of the impurity concentrations and the differences between the melting plateaus and freezing plateaus.The results showed that the zinc fixed point cell with metal shell had good reliability;under different induction times,the value of zinc freezing plateaus obtained by using quartz,stainless steel and nickel inducation rods was consistent in the range of 0.15 mK,that is,the different inducing methods can obtain good zinc freezing plateaus;and the inducing methods had no effect on the supercoolings of high purity zinc.