Antioxidant activity of different graphite materials
To enhance the oxidation resistance of graphite mold to extend its service life, must be reduced graphite materials under high temperature gasification rate. Typically, the effect of graphite gasification material has the following three factors:
(1) the degree of graphitization of carbon graphite material increased degree of graphitization, decreased activity of the gas, the gasification reaction rate. The heat treatment temperature is higher carbon material, then the starting temperature of the oxidation will be higher.
(2) structural state of the surface porosity and porous carbon graphite material is easy to react with the gas, while the surface dense carbon graphite materials, not react with the gas. After 3200 ℃ heat treatment such as dense pyrolytic graphite surface, begins to be oxidized in air temperatures up to 850 ℃.
(3) the catalytic impurities in the carbon material for gasification reaction impurities have a great impact, such as iron, lead, manganese, copper and other elements on the catalytic oxidation of carbon materials, try to reduce carbon graphite materials impurity content, can improve its antioxidant properties.
Therefore, the use of ultra-fine particle size carbon feedstock to produce carbon graphite products, and to try to improve its graphitization temperature, can greatly reduce the extent of carbon graphite products, porosity, pore size and pore impurities, improve its degree of graphitization , thereby increasing carbon graphite products antioxidant properties, slowing the oxidation burning speed.