How to deal with the oxidation of tungsten and its alloys?
Tungsten and its alloys have high mechanical properties at high temperatures and are good high-temperature structural materials, but their applications need to be implemented in a protective environment, such as hydrogen, vacuum, and argon. The oxidation problem is a key problem that hinders the wide application of tungsten and tungsten alloys at high temperatures, because tungsten has begun to oxidize in atmospheric air at 300~400℃, and volatilizes above 850℃. As the temperature further rises, oxidation tends to become serious , Above 1000°C, WO3 volatilizes and will cause "catastrophic" oxidation.
There are two main ways to solve the tungsten oxidation problem:
1. Starting from the alloy itself, develop an alloy with high-temperature oxidation resistance. However, the degree of alloying of tungsten is very small. When the addition of elements to improve the oxidation resistance of the alloy increases, the workability of the alloy will become poor or There is no room temperature plasticity at all, so there is not much room for maneuver to develop anti-oxidation tungsten alloys
2. Add anti-oxidation protective layer on tungsten and its alloy.
The use of tungsten and its alloys as high-temperature structural materials is meaningful only at high temperatures above 1649°C, so the lower limit of the oxidation resistance temperature of the tungsten protective layer shall not be lower than this temperature. The preparation process of the tungsten protective layer includes electrochemical methods, such as electroplating, and physical and chemical methods, such as chemical vapor deposition, sintering, and thermal diffusion of slurry spraying.
