Technology of production of hafnium carbide, etc. refractory metals.
The unique technology of production (melting) of hafnium carbide directional electron beam allows to obtain a carbide of hafnium in just a couple of minutes. This approach can be applied to other refractory metals and materials: carbides and borides of tantalum, tungsten, molybdenum, etc.
The traditional method (technology) of obtaining refractory metals, e.g. hafnium carbide is incredibly energy intensive. First get a carbide of hafnium by heating the mixture of powders of hafnium and carbon, then it is ground as fine as possible, pressed and sintered as ceramics, dozens of hours, at the maximum possible temperature.
Russian scientists have created unique technology of production (melting) of hafnium carbide in only a couple of minutes.
In the first phase, the powders of carbon and hafnium is subjected to mechanical activation by scrolling down in a ball mill is a special device for mixing and grinding solids prior to microrasbora. The result is a micropowder of fine particles with alternating layers of carbon and hafnium, the so-called mechanocomposite – processing for the future of the carbide. In this condition increases the reactivity of the material.
Then, on the installation for electron beam welding focused beam of electrons is carried out heating the mixture of the micropowder and run chemical reactions. The formation of hafnium carbide with a melting point of “in itself”: the liquid material is “in the ring” powder. Then use the method of layer-by-layer addition of material used in 3D printing: the pattern is created using electron beam on the first layer of powder, then poured a new layer, the process is repeated, and so until then, until the form is molded in its entirety. This process takes a few minutes.
This approach can be applied to other refractory metals and materials: carbides and borides of tantalum, tungsten, molybdenum, etc.
Hafnium carbide is the most refractory material in the world (the temperature of its melting point 3890 °C, the boiling point is 5400 °C). Properties (refractoriness, high resistance to corrosion, resistance to mineral acids and alkalis) are very promising for use as a thermal barrier coating for Russian space ships. It is also applicable for the manufacture of control rods for nuclear reactors, refractory alloys, special refractory ceramic materials.
– high speed of melting and
– low energy costs,
– a small pick – up- only a couple of minutes.