Ultrasonic Behaviour of Paraffin Wax during Melting and Solidification Processes

The sound velocity of paraffin wax and its attenuation were measured in the solid phase and the liquid phase near the melting point, using the pulse transmission method. An interior transducer-type cell was used for the measurement. The experiment was in the temperature range from 10°C to 80°C, and the frequency of sound waves was 1 MHz. The melting point of the specimen was 44–46°C. In the melting process, a large absorption of ultrasonic waves was observed. During the solidification process, the sound velocity and the attenuation gradually changed with elapsed time. Noticeable changes in sound velocity and attenuation occur in the solid with a microscopical quantity of liquid melt.