A turbine blade is the essential part in a steam turbine. Turbine blades are subjected to high temperature and high pressure steam, and they are subjected to large bending moments during operation. The moving blades in high speed operation are also subjected to high centrifugal force; the blades in the wet stream areaare subject to electrochemical Corrosion and water droplets impinge on moving blades are also subject to very complex exciting forces. Therefore, the steel for blade should meet the following requirements: high temperature mechanical properties and anti-creep property; high resistance to vibration damping; high structural stability; good corrosion and erosion resistance.

Physical vapor deposition (PVD) is widely used in optical industry, electronic industry, and information industry. The applications of PVD include integrated circuits, liquid crystal displays (LCD), industrial glass, camera lenses, information storage, ships, chemicals, etc. The alloy target used in PVD is one of the most important raw materials in the manufacturing process of integrated circuits and liquid crystal displays.

Thin-film-transistor (TFT) film has the advantages of high responsivity, high brightness and high contrast. It is one of the basic materials in many industries. Therefore, it is widely used in the fields of solar cells, liquid crystal displays and plasma displays. In recent years, along with the rapid development of high-end displays, tungsten Molybdenum alloy rotary targets have become an important material for the preparation of TFT films.

Ammonium paratungstate hydrate is an intermediate for the production of tungsten metal, tungsten-containing catalysts, tungsten-based hard materials (such as tungsten carbide) or sputtering targets. The preparation is carried out mainly by digesting or melting a slag containing tungsten concentrate or tungsten with acid or base, followed by purification, and the purification stage includes a precipitation process and a liquid-liquid extraction. The purified solution is usually concentrated by evaporation to finally crystallize the ammonium paratungstate hydrate.

In recent years, research on tungsten trioxide (WO3) nanofilm has attracted more and more attention. WO3 is an n-type semiconductor material with a narrow band gap (2.4-2.8eV), is capable of responding to visible light, and has similar characteristics to TiO2 photocatalyst, namely stable, non-toxic, photo-resistant, low-cost and low-priced. The potential of the belt is high and the photo-generated holes are highly oxidizing.

Tungsten is a very important non-ferrous metal. It has the properties of high density and high hardness. It is commonly used in counterweight materials, shielding materials and military materials. Tungsten-zirconium alloy has a broad application prospect in the military field due to its strong resistance to corrosion.

Heterojunctions have become an essential element of the modern semiconductor industry, and they play an important role in high-speed electronic devices and optoelectronic devices. Two-dimensional layered materials, including graphene and transition metal disulfide, can serve as a constituent unit of a heterostructure due to their unique electrical and optical properties.

Nitrogen oxides (NOx) are recognized as one of the major sources of atmospheric pollution, including combustion fumes and automobile exhaust. Monolithic vanadium-titanium-based catalysts have been widely used for the removal of NOx from combustion fumes or automobile exhaust, and NOx is removed by selectively catalyzing the reduction of NOx by NH3 to N2. The catalyst uses TiO2 as a carrier (usually 80-90% of the total mass), V2O5 as an active component (1-2%), and WO3 as a co-catalyst (5-10%).

At present, ammonium paratungstate can completely dissolve for 1~4 hours at a temperature of 120~160°C with high concentration of ammonia, some enterprises promote the decomposition of ammonium paratungstate and even through high temperature roasting to get tungsten oxide, then ammonium tungstate solution is dissolved in ammonia water, and some enterprises use sodium hydroxide and other strong alkali to dissolve ammonium paratungstate. The ammonium tungstate solution is regenerated from sodium tungstate solution, the process is complex and costly. Therefore, it is necessary to develop a new low-cost and simple dissolution process for ammonium paratungstate / tungsten trioxide.

Tungsten trioxide is an important type of N type semiconductor oxide. It is widely used in chemical sensors, photocatalysis, energy conversion system and other fields. When WO₃ is used as negative material, its structure and volume will change greatly during charge / discharge process. It destroys the stability of electrode materials and eventually leads to the cyclic performance of the electrode. As a result, the actual capacity is often lower than the theoretical capacity.