Influence of Temperature and Current on the Contact Electrical Resistivity of Graphite

The article presents the results of an experimental study of the contact electrical resistivity of MPG-7 graphite in the 700–1300 K range of change in the determining temperature. The case of one fixed contact surface is studied. The experiment was carried out by passing a direct electric current through a cylindrical sample installed vertically. The studies were done in vacuum at a pressure of 10^–4 Pa. The experimental data comprised the actual temperature and voltage drop distributions measured along the longitudinal axis of the cylinder at equal distances from the contact surface. For the first time, the dependences of the contact electrical resistivity, related to the electrical resistance of graphite, on the current strength and determining temperature in the 700–1300 K range are presented. It is shown that the contact electrical resistivity in the contact plane exceeds the electrical resistance of graphite by 11.5 times at a temperature of 700 K and by 6 times at 1300 K.