High-purity ultrafine yellow tungsten oxide, or high-purity ultrafine tungsten trioxide is a yellow or light green powder with purity higher than 99.99% and apparent density of 0.28~0.3g/cm3. High-purity ultrafine tungsten trioxide has good catalytic property to be used as a catalyst for petrochemicals. Also, it has good photochromic property and gas sensitivity.
Vapor Phase Method to Produce Yellow Tungsten Oxide
Generally in the air atmosphere, pressure of the evaporation system is controlled under 133.3~1199.9P, and the tungsten wire is heated so that tungsten reacts with oxygen in the air to obtain yellow tungsten oxide powder.
Powder with small grain size can be obtained by this method. And it is suitable for yellow tungsten oxide with special required performance. But, it has high requirement for equipment and big investment. What is worse, the reacting process is hard to control.
Vapor phase method is by using gas or turning article into gas to have physical or chemical reaction under gas status. And it will form into micro particle or nano micro particle powder in the cooling process.
More details, please visit:
http://www.yellow-tungsten-oxide.com/index.html
