In order to prevent the corrosion damage caused by the oxidation of flake graphite at high temperature, it is necessary to find a material to coat the high-temperature material, which can effectively protect the flake graphite from oxidation at high temperature. To find this kind of scale graphite anti-oxidation coat, we must first have some characteristics such as high temperature resistance, good compactness, good anti-corrosion performance, strong anti-oxidation ability and high hardness. The following editor of Furuite Graphite shares the method of preventing flake graphite from being oxidized at high temperature:
1. Materials with steam pressure less than 0.1333MPa(1650℃) and good comprehensive properties are adopted.
2. Select the glass phase material that meets the performance requirements as the self-sealing material, and make it become the crack sealing material within the working temperature.
3. According to the change function of standard free energy of reaction with oxygen with temperature, at the steelmaking temperature (1650-1750℃), select materials with higher affinity with oxygen than carbon-oxygen, seize oxygen first, and oxidize themselves to protect flake graphite. The volume of the new phase generated after oxidation is larger than that of the original phase, which is helpful to block the inward diffusion channel of oxygen and form the oxidation barrier.
4. At working temperature, it can absorb a large number of inclusions such as AL2O3,SiO2,Fe2O3 in molten steel, and react with itself to sinter, so that various inclusions from molten steel gradually enter the coating.
Furuite Graphite Xiaobian reminds that the oxidation temperature of flake graphite in China’s main producing areas is 560,815℃ when the carbon content is 88%96% and the particle size is above -400 mesh. Among them, when the particle size of graphite is 0.0970.105mm, the oxidation temperature of graphite with more than 90% carbon content is 600,815℃, and that of graphite with less than 90% carbon content is 6200℃. The better the crystalline flake graphite, the higher the oxidation peak temperature and the less the oxidation weight loss at high temperature.
Post time: Dec-21-2022