Tungsten Oxide

Nano tungsten oxide is considered to be one of the most promising new oxides gas sensing materials that detects nitrogen oxides, hydrogen sulfide, and acetone and other harmful gases. The preparation methods of nano tungsten oxide mainly include hydrothermal method, sputtering method, sol gel method and gas phase deposition method. Compared with other synthetic methods, as a new method for composing nano-materials, low heating solid phase chemical reaction has the characteristics of simple operation, friendly environment and mild conditions.  Mix sodium tungstate and sodium sulfate for 30min, the sample was placed in a cone bottle and placed for 24h to obtain the precursor. Then put the precursor calcined at 600°C in the muffle furnace 2h, nano tungsten carbide was obtained.  Based on the product of nano tungsten carbide test, the material in the lower working temperature of low concentration acetone gas showed the performance of fast response, high selectivity and high sensi...

Electrochromic is the phenomenon that the optical properties of materials change stably and reversibly under the action of applied electric field. It can cause light penetration through the electric field, changing color with the environment, and no longer need to curtain. WO 3  thin film is one of the most promising electrochromic materials. WO 3  thin films have been widely used in photochromic, photochromic, filter, dye sensitized solar cells and so on.  With the implantation and extraction of ions, the dissolution and ion residues of WO 3  thin films will occur, and the electrochromic properties will decline obviously, which limits the wide use of electrochromic devices. TiO 2  has excellent stability, and has excellent transmittance in wide waveband. The doping of electrochromic films with TiO 2  composite WO 3  can improve the stability and lifetime of devices.  Pure Ti/WO 3  composite films were prepared by radio frequency sputtering m...

Tungstic acid can be roughly divided into yellow tungstic acid and white tungstic acid. More and more practice has shown that tungstic acid not only has an important use in tungsten chemistry, but also has great value in tungsten metallurgy. Powdery white tungstic acid can compose tungsten niobium and tungsten tantalum Heteropoly salt. Tungsten phosphoric acid and tungstic acid can also be composed. The heteropoly acid prepared from powdered white tungstic acid has better catalytic performance than that prepared with tungstic acid.  The preparation of white tungstic acid is to drop Na 2 WO 4  solution into dilute acid. In the middle of the process, there is no acid anion, so the precipitation rate is high. In the Na 2 WO 4  solution tungsten exists as monomeric WO42-form. The presence of dilute acid immediately results in protonation and formation of tungstic acid precipitation. Generally, the prepared white tungstic acid is a mixture of mono - tungstic acid and poly - t...

Microwave absorbing material is an important stealth form in stealth technology. High temperature absorbing composites with new wave absorbing materials should be a kind of structure and function integrated material, which can replace metal parts and realize dual functions of bearing and stealth. Fullerene is characterized by cage-like structure, hollow in the middle, and the most common fullerene is C 60 . Because of the particularity of inorganic fullerene hollow cage-like structure, it is found that the inorganic fullerene’s structure has excellent resistance to compression and wave absorption. Its maximum compressive resistance is up to 25Gpa, which is the most hard molecular cage structure found recently, and its compressive resistance performance is better than other carbon cage like structures. Even when it under lower pressure, the collapse or transformation to other diamond structures will occur. Therefore, when inorganic fullerene structure is used as wave absorbing material,...

Tungsten disulfide is an excellent solid lubricant material, it has high application value in the field of super solid lubrication. Tungsten disulfide membrane have layered structure, it has lower hardness and better stability under high temperature, it is suitable to be used as a solid lubricant for friction parts in special environment. There are three main methods for preparing tungsten disulfide membrane which include RF sputtering method, reactive magnetron sputtering method, chemical deposition method. The method of RF sputtering crystal growth is the method of using RF sputtering to make the components of the crystal material gasified and then recrystallized to grow the crystal. RF sputtering is a sputtering deposition method suitable for all kinds of metal and nonmetal materials, the frequency range is 5~30MHz, the frequency of 13.56MHz is commonly used internationally. It is mainly used to prepare thin membranes and also to prepare small size crystals. WS2 powder with 99.99% ...

  Solid lubrication is a method of coating or plating on the surface of the friction pairs to form a thin film and reducing friction. The technique of using solid lubricants to lubricate is called solid lubrication.  Tungsten disulfide and molybdenum disulfide are excellent solid lubricating materials, in the field of ultra-solid lubrication has a very high value, this technology is applied to the hard disk drive bearing of computer, such as rotation and sliding in ultra high vacuum system. Molybdenum disulfide has a graphite-like structure, molybdenum and sulfur through the covalent bond to form a hexagonal structure, each molybdenum is surrounded by six sulfur atoms, the molecular layer surface only sulfur atoms, each layer molecular layer thickness of 0.626nm. The thermal stability of MoS 2  is better in the air environment lower than 400 degrees. When the temperature is higher than 400 degrees, MoS 2  will be oxidized to MoS 3  in a short time, MoS 3  i...

The structure of tungsten disulfide is a hexagonal layered structure with excellent electrical properties. In tungsten disulfide, the interaction between the W atoms in the layer and the surrounding S atoms is strong, and the interaction between the tungsten disulfide layer and the layer is weak. The thermal stability of two tungsten sulfide is stronger than that of molybdenum disulfide. The temperature range is wide, and it is not easy to decompose. Oxidation occurs at 539 degrees centigrade. Therefore, tungsten disulfide is an excellent semiconductor material for indirect bandgap semiconductors. When the thickness of tungsten disulfide is reduced to a single layer, it changes into a direct band gap, which means that tungsten disulfide can effectively pass through the bandgap transition absorb or emit photons. The band gap of monolayer tungsten disulfide is about 2eV. This electrical performance characteristic is the main advantage of tungsten disulfide in semiconductor tubes, transi...