Application of Pulse Calorimetry to Metal Systems

The pulse calorimeter developed as a part of the author's masters thesis was used extensively in the doctoral research to determine the electrical resistivity and specific heat of Ni, Ni₄Mo, Fe-A1 alloys and Ni-A1. The temperature range of measurements varied with different specimens but in general were between 375 K to 1300 K.

The pulse calorimeter essentially consists of a specimen in series with a standard resistor and a programmable power supply. The specimen is inside a vacuum chamber. The programmable power supply can be triggered from the computer to send a specific current to the specimen for a specific time. As the specimen heats, its temperature rises. Three signals - current, voltage and temperature (thermoelectric voltage) are acquired into the computer program to be processed later to determine the specific heat and electrical resistivity as functions of temperature. The specimen is allowed to cool from a high temperature and the temperature-time data are acquired as a function of time. This cooling data are used later to correct for the heat losses during heating.

A knife-edge apparatus was designed to determine the separation distance between the voltage taps on a specimen. This apparatus was also used to determine the room temperature electrical resistivity of specimens.

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