Comparison Between Melting and Freezing Points of Aluminum and Silver

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Comparison Between Melting and Freezing Points of Aluminum and Silver (218.11 KB)

For metal fixed point cells, it will be convenient if the melting points can be used instead of the freezing points in calibration of standard platinum resistance thermometers (SPRTs) because of easier realization and longer plateau duration of melting plateaus. Experimental research was carried out to compare the melting and freezing points of aluminum and silver by using the inter-comparison method with SPRTs. The influence of the furnace maintenance temperature on the performance of melting and freezing plateaus were investigated and discussed. Differences in results between the melting points and the freezing points are shown. Uncertainty budget analysis of the melting points and freezing points is presented. The experimental results show that it is possible to replace the freezing point with the melting point of aluminum cell in the calibration of SPRTs in secondary-level laboratories if the optimal methods of realization of melting points are used.