Test No. 102

This Test Guidelines describes several methods and devices to determine the temperature or temperature range of the phase transition from the solid to the liquid state or from the liquid to the solid state. The melting point is defined as the temperature at which the phase transition from the solid to the liquid state at atmospheric pressure takes place. It is considerably affected by impurities. The selection of a particular method depends mainly on the state of physical aggregation of the sample and on whether or not the substance can be pulverized easily, with difficulty, or not at all. The methods are: the capillary/liquid bath, the capillary/metal block, the Kofler hot bar, the melt microscope, the differential thermal analysis and differential scanning calorimetry, the freezing temperature and the pour point.