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 put a coat on the high temperature material, which can effectively protect the flake graphite from oxidation at high temperature. To find this kind of flake 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 Furuite graphite editors share the methods to prevent flake graphite from being oxidized at high temperature:
1. Use materials with vapor pressure less than 0.1333MPa(1650℃) and good comprehensive properties.
2. Choose the glass phase material that meets the performance requirements as the self-sealing material, and make it become the crack sealing material at the working temperature.
3. According to the function of the standard free energy of the reaction with oxygen with temperature, at the steelmaking temperature (1650-1750℃), the materials with higher affinity to oxygen than carbon-oxygen are selected to take oxygen first, so as to oxidize themselves and protect the 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 an oxidation barrier.
4. At the working temperature, a large number of inclusions such as Al2O3, SiO2 and Fe2O3 in molten steel can be adsorbed, which react with themselves to sinter, so that various inclusions from molten steel gradually enter the coating.
Furuite graphite reminds us that the oxidation temperature of flake graphite in China’s main producing areas is 560815℃ 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 600815℃ and that of graphite with less than 90% carbon content is 62075℃. The more crystalline flake graphite is, the higher the oxidation peak temperature is, and the less the oxidation weight loss at high temperature is.
Post time: Jan-19-2023