DEPENDENCE OF THERMAL EXPANSION OF BONDED CARBONS ON THE HEAT-TREATMENT TEMPERATURE

Abstract

Samples of four types of carbons were prepared from (1) soft coke filler and soft binder, (2) soft filler and hard binder, (3) hard filler and soft binder and (4) hard filler and hard binder, and heat treated to different temperatures in the range 500°C to 3000°C. The average thermal expansion in the range from temperature to 200°C was determined using a dilatometer with a Linear Variable Differential Transformer and an appropriate electronic circuit. The obtained curves show a decrease during baking, a hump around 1200°C and a decrease or a respective increase in the higher temperature range. Information about the difference in the behavior of the soft and hard carbons and about the relative contribution of the filler and the binder to the thermal expansion is extracted from the data obtained. Curves of volume shrinkage vs. heat-treatment temperature are also presented for the four types of carbon rods listed above.