Tungsten billet mainly refers to pure tungsten, thorium tungsten, cerium tungsten, lanthanum tungsten, yttrium tungsten, zirconium tungsten, ternary composite (lanthanum, yttrium, cerium) and quaternary complex (lanthanum, yttrium, cerium, zirconium), is the production of tungsten electrodes and other raw materials rod.

At present, the main method of decomposition of tungsten containing materials is "sodium carbonate decomposition". Sodium carbonate is decomposed with sodium carbonate, which is corrosive to iron equipment, and its operating environment is general, and its scope of application is narrow (only for dissolving scheelite). The decomposition agent is expensive and extremely uneconomical. In the market, we need a process to treat tungsten containing materials without corrosive equipment, good operation environment, low cost and high tungsten recovery.

In the existing technology, the industrial preparation methods of APT are mainly acid, caustic soda or soda decomposition method, and ion exchange or extraction after evaporation and crystallization, the overall evaluation, the existing methods are not used or semi circular circulation process system, must set a waste water outlet, the water pollution can not be completely eradicated.

Tungsten copper alloy phase composed of tungsten and copper is not uniformly distributed solid solution and compound forming a kind of composite material, high thermal conductivity, both copper and tungsten, high melting point, low thermal expansion properties, electronic industry is preferred heat sink and package material.

Tungsten oxide varistor ceramics refers to semiconducting ceramics in which the resistance value changes significantly with the applied voltage. It has non-linear volt-ampere characteristics. At a certain critical voltage, the resistance of the varistor ceramic is very high and there is almost no current. But when this threshold voltage is exceeded, the resistance will change drastically. And there is current through. With a little increase in voltage, the current will increase rapidly.

To further elucidate the effect of hydrogenation and determine the surface chemical state of tungsten oxide, we performed X-ray photoelectron spectroscopy analysis on tungsten oxide. Shown are the XPS full spectrum, W-4f spectrum and O-1s spectrum of three tungsten oxide samples. As can be seen from the figure, the three tungsten oxide samples contain W element, O element and a small amount of C element. The presence of the C-1s peak is attributed to unnatural hydrocarbons from the XPS instrument itself. And from the full spectrum of view, the three samples showed no significant change in each peak.

Plasma resonance is a physical optical phenomenon. It utilizes the disappearance of light penetrating into the tungsten oxide film when total internal reflection occurs at the interface between the glass and the tungsten oxide film, causing free electrons in the tungsten oxide to generate surface plasma. In the past few decades, the local surface plasmon resonance effect has been simply considered as the optical properties of noble metal nanoparticles. However, with the discovery of LSPR in semiconductor and oxide nanocrystals, this view is changing. The plasma resonance effect on semiconductors and tungsten oxide materials is mostly achieved by doping noble metals.

High-temperature annealing in a hydrogen atmosphere is an effective way to obtain a non-stoichiometric tungsten oxide structure containing oxygen vacancies. However, it should be noted that hydrogen is a flammable and explosive gas, which is more likely to explode at high temperatures. The high temperature conditions are indispensable, it played to overcome the activation energy barrier.

To further investigate the morphology and structural changes of the samples after hydrogenation, tungsten oxide can be characterized by transmission electron microscopy. It can be seen from the figure that when the hydrogenation temperature is 300 ° C, the W-300 maintains a good morphology and is about 100 nm in size. The hydrogenation temperature is 400 ℃, W-400 size significantly smaller, are below 50nm.

The forming mechanism of tungsten oxide thin nanosheet is since the critical fluids have the characteristics of small viscosity, strong solubility, high diffusion performance, and easy control. So, tungsten oxide thin nanosheets can be widely used in industrial production. Tungstic acid has a small solubility in a mixed solution of ethanol / water, and the surfactant has a strong hydrophobic interaction as a surfactant with tungstic acid.