Chemical properties and oxidation reactions of tungsten and molybdenum materials
Various carbon-containing gases and solid carbon (carbon black, coal, graphite) begin to react with tungsten and molybdenum in the range of 1000 to 1200°C to form carbides (W3C, WC and Mo2C, MoC). At 1400 to 1600°C, the reaction intensifies. Even small amounts of carbide impurities in tungsten and molybdenum metals can cause tungsten and molybdenum to become embrittled.
Reaction of tungsten and molybdenum with nitrogen: Tungsten does not react with nitrogen when the temperature is lower than 2000°C, but reacts with nitrogen to form nitride WN2 when the temperature is higher than 2000°C. Nitrogen slowly dissolves in molybdenum above 600°C, molybdenum becomes brittle above 1200°C, and molybdenum reacts with nitrogen above 1500°C to form nitrides.
Reaction of tungsten and molybdenum with oxygen and air: Metal tungsten and molybdenum are stable in the air at room temperature. Tungsten and molybdenum product manufacturers say that they begin to oxidize at about 400°C and rapidly oxidize at higher temperatures to form tungsten trioxide. and molybdenum trioxide.
Reaction of tungsten and molybdenum with hydrogen: Until the melting point temperature, hydrogen does not interact with tungsten and molybdenum, making hydrogen an important medium in the heat treatment process of tungsten and molybdenum. But below 1200°C, tungsten slightly absorbs hydrogen.
Reaction of tungsten and molybdenum with chlorine: When metallic tungsten is heated to 500°C, it directly reacts with chlorine to generate WCl6. When the temperature is higher, WCl6 decomposes into WCl5. Iodine vapor has no effect on tungsten.
Reaction of tungsten and molybdenum with water vapor: Tungsten and molybdenum are prone to oxidation reactions with water vapor. Tungsten and molybdenum product manufacturers state that this effect is more severe above 600°C.
