As a sealing material and sliding material, carbon fiber has a stronger inertia than traditional materials such as asbestos, or fiberglass, when encountering strong acid strongly alkaline substances.At the same time, it has better heat resistance and self-lubricating, and is used as an advanced sealing material. However, although as a high-tech material, carbon fiber materials still face some difficult, such as oxidation reaction, reaction to metal and metal oxides at high temperatures, interlayer compounds.
1. Oxidation reaction
Usually, when heated to 350 degrees in the air, the carbon fiber begins to oxidize slowly, the mass decreases gradually, and the intensity begins to decline. Therefore, the lower the temperature in the manufacturing process, the higher the corresponding oxidation resistance. As a result, graphite fibers have much better antioxidant resistance.
In the carbon fiber manufacturing process, there are Na, K, Ca, MG and other metal elements were added, which promotes the oxidation of carbon fibers, the addition of Phosphorus series materials can effectively prevent oxidation. In addition, oxidizing acids can also cause a certain amount of corrosion to carbon fiber, especially at high temperatures, high concentrations.
2. Reaction with metal or metal oxides at high temperatures
Carbon fibers will start chemical reactions with NA, Li, K, iron oxide at 400-500 degrees, with Fe, AL at 600-800 degrees, with Si, silica, titanium dioxide, magnesium oxide, at 1100-1300 degrees. But it doesn’t matter with Cu、Zn、Mg、Ag、Hg、Au. When used as reinforcing material, the properties of carbon fiber will be severely limited when meeting metals and metal oxides. Therefore, carbon fiber can not be used for the reinforcement of oxide ceramics.
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Post time: Dec-21-2018