White LED is a new solid-state lighting electric light source (SSL). Its principle and structure are different from those of previous vacuum electric light sources such as incandescent lamp and fluorescent lamp. SSL light source has many advantages, especially high light efficiency, energy saving, long life and pollution-free. It has great application value and prospects.

The traditional method of preparing tungsten carbide-titanium carbide solid solution is to use industrial titanium dioxide and WC as raw materials, carbon black as reducing agent, mix with ball mill, and react in graphite tube electric furnace at the temperature of 2000-2300 ℃. The preparation method has the following shortcomings: first, the ball mill has low ball milling efficiency, mainly mixing effect on raw materials and little crushing effect. Second, the high reaction temperature makes the sintering growth of the prepared tungsten carbide-titanium carbide solid solution obvious.

SCR denitrification technology has the advantages of high denitrification efficiency, over 90%, good selectivity and reliable technology. Catalyst is the core of SCR denitrification technology. At present, the commonly used SCR denitrification catalyst is based on titanium dioxide as carrier, V₂O₅ as active component, WO₃ or MoO₃ as structural promoter. The activity of catalyst directly determines the efficiency of denitrification.

At present, the main methods for preparing Ti-W alloys are high temperature vacuum melting, powder metallurgy and mechanical alloying. However, these methods have some disadvantages, such as high production cost, complex process or low purity of products, which reduce the properties of Ti-W alloys and greatly limit their application.

Tungsten oxide is a semiconductor photocatalyst with visible light response. Tungsten oxide particles can absorb most of the visible light occupying the room space. However, because the conduction band is located at the energy level of oxygen-specific oxidation-reduction, oxygen can not be reduced in the electrons stimulated by the conduction band, and the amount of reactive oxygen species is insufficient. Therefore, tungsten oxide can not show high photocatalytic activity in the environment of visible light irradiation but not ultraviolet light irradiation.

With the rapid development of economy, the demand for tungsten and cobalt in machinery manufacturing, geology, mining, construction, electronics and chemical industries is increasing. As rare metal elements, tungsten and cobalt are also the main raw materials of cemented carbide. Therefore, it is very meaningful to recycle tungsten and cobalt from scrap cemented carbide.

Photocatalytic technology can oxidize organic pollutants into inorganic substances, and the reaction system can convert the absorbed light energy into chemical energy under photocatalysis. This discovery has become a current academic hot spot, especially in the field of organic pollutant treatment and hydrogen analysis.

The application of hard surface material in surface engineering is to coat it on metal or workpiece surface by thermal spraying and other thermal technology, so as to improve the wear resistance, impact resistance, high temperature resistance, corrosion resistance and other properties of the surface, significantly prolong the service life of the workpiece, and save a lot of metal materials and production costs.

Tungsten carbide is one of the most important materials in transition metal carbides. It has excellent properties such as high melting point, hardness, thermal stability and mechanical stability. It is widely used in making cemented carbide materials and has important applications in cermet, mechanical processing, metallurgical minerals, aerospace and other fields.

Fuel cell is an electrochemical device that directly converts chemical energy into electrical energy. One of its key materials is electrode catalyst. For a long time, precious metals such as platinum and ruthenium have been widely used because of their excellent catalytic performance. Alloy catalyst can reduce the Pt loading and improve the catalytic efficiency, but the stability of catalyst needs to be improved.