Uses
Lanthanum Boride is mainly made into Lanthanum Boride (LaB6) hot cathode which electronic source is used as electronic source for electron microscopy, electron-beam exposure machine. LaB6 is also used as a size/strain standard in X-ray powder diffraction to calibrate instrumental broadening of diffraction peaks. Lanthanum Boride powder can be further processed to various shapes of rods, tubes, discs and special designed form.
Uses
Lanthanum boride is employed in hot cathodes, which enact and includes electron microscopes, microwave tubes, electron lithography, electron beam welding, X-ray tubes, and free electron lasers. It is administered as a size or strain standard in X-ray powder diffraction to calibrate instrumental broadening of diffraction peaks. It exercises as a superconductor. It has a great potential as a thermionic emitter in renewable energy applications. It is widely used in teleran, electronic industry, instrument, medical equipment, metallurgy and enviromental protection.
Synthesis
Now the preparation of lanthanum hexaboride is generally prepared by the thermal reduction method of boron carbide, and its reaction formula is: La2O3+ 3B4C 2LaB6+ 3CO; due to the introduction of the reaction of boron carbide as the raw material for the reaction, it is difficult to control the carbon content of the product, and due to the high hardness of the boron carbide and the large particle size, it is easy to produce the phenomenon of uneven mixing, which will cause the deviation from the chemical composition of the product.
The second is elemental synthesis method, using high-purity boron powder and lanthanum metal as raw materials, to obtain high-purity products, this method of synthesis of high purity, easy to control the process, but the two raw materials are expensive, so that its cost is very high.
The third is the self-propagating high-temperature synthesis method, using raw materials for magnesium powder, lanthanum oxide, boron trioxide, which is the only method that does not require the use of high-temperature equipment in all the methods, lower energy costs, but the disadvantages of this method of post-processing process is more cumbersome, the product purity is a little lower, but it has the advantage of the particle size.
The fourth is halide boron thermal reduction method, this method uses lanthanum chloride, boron powder as the reaction raw material, the product is lanthanum hexaboride and the gas phase product boron chloride, the product is a single phase, it is relatively easy to deal with, it is also easier to get higher purity.
The successful development of high-purity lanthanum hexaboride can provide high-quality and stable products for the application of high-purity boride in China and reduce the dependence on foreign products. The process in the production process, due to the boron powder price is more expensive, to a certain extent, restricts the development of the process, but because of the characteristics of the process, so that its quality is better than the existing lanthanum hexaboride synthesis process, so that it still has certain advantages.
