Abstract
Kneading process is an important process in manufacturing lubricating carbon blocks, because a failure occurred during the temperature controlling process sometime gives high friction coefficient to the blocks. Effects of boric acid (H3BO3) addition on reducing the friction coefficient were examined by two introduction methods. A method was toimpregnate the carbonized carbon block with boric acid followed by another heat treatment at 2800°C, which was theproduct with over permissible limit of friction coefficients for the markets (μ<0.3). The impregnation with boric acidgave an improvement in reducing the coefficient with remaining the apparent density and the bending strength constant. Another method was to mix raw materials for the blocks with boric acid followed bycarbonization and graphitization. Addition of 1 wt% of B in the form of boric acid gave a carbon block with a set ofsimilar properties to the marketableproducts, though the kneading temperature employed was as high as the temperature giving failed products for the usualmixture of raw materials. Consequently, addition of boric acid to the raw materials was proved to be an useful foolproofmethod for saving a control in the kneading temperature.
