In order to enhance the oxidation resistance of graphite mould and prolong its service life, it is necessary to reduce the gasification reaction rate of graphite material at high temperature. Under normal circumstances, there are three factors affecting the gasification reaction of graphite materials:
(1) graphitization degree of carbon graphite material increased, the activity of gas decreased, gasification reaction rate was slow. The higher the heat treatment temperature of carbon materials, the higher the temperature of the starting oxidation.
(2) the state of the surface of the structure is loose and porous carbon graphite material, easy to react with the gas, and the surface of carbon graphite material, not easy to react with gas. For example, after 3200 degrees of heat treatment of the surface of the dense pyrolytic graphite, starting in the air temperature of up to 850 degrees C.
(3) the impurities impurities in the catalysis of carbon materials have great influence on the gasification reaction, such as oxidation of iron, lead, manganese, copper and other elements of carbon materials have a catalytic effect to reduce the impurity content of carbon graphite materials, can improve its antioxidant properties.
Therefore, to make use of carbon graphite products raw material of ultrafine particle size, and try to improve the graphitization temperature, can greatly reduce the porosity of carbon graphite products rate, stomatal aperture and impurity content, improve the graphitization degree, so as to improve the anti oxidative properties of carbon graphite products, reduce the oxidation speed.
