Tungsten Oxide

Scientists discovered that VO 2   has a distinctive phase change function long time ago. When the phase transition temperature is 68°C, it can change reversibly from low temperature monoclinic system to high temperature tetragonal system. The physical properties such as resistivity, optical transmittance, permeability and so on have changed greatly. Doping method is an effective method to change the phase transition temperature of VO 2 . The preparation methods of doped VO 2  films include sol-gel doping method, hydrothermal synthesis doping method, sputtering doping method, metal organic compound vapor deposition doping method, pulse laser deposition process, inorganic sol-gel doping method, and microwave plasma method. We prepare it by microwave plasma method. Another main content of the preparation of doped VO 2  thin film is the selected doping compounds. Weigh a certain amount of pure V 2  O 5  powder and W 2 O 3  into the pot, then stirring, put in th...

Violet tungsten oxide is kind of short rod fine crystal and between these short rod fine crystals there have many voids, particle size distribution is relatively loose. Which are conducive to discharge water and help hydrogen into the crystal particles, therefore, not only the restore process can take place inside also can restore on the surface, violet tungsten oxide advantageous for the producing ultrafine tungsten powder. Besides the reduction process conditions during the reaction should able to better control, such as low dew point of hydrogen, flow rate, amount of loading the boat. After studies showed with the development of reduction reaction, the oxygen atom reduce and  oxygen vacancies increase of violet tungsten oxide, tungsten dioxide particles becomes more dense than γ- tungsten oxide’s. This is bad for hydrogen gas get into interior particles and the water which producing by reaction particles are not easily discharged. During the restore process, the reac...