| 摘要 |
PURPOSE:To maintain the amt. of remaining doping agents constant and to obtain W powder having stabilized quality and characteristics of W material by adding K2O and SiO2 doping agents to a blue oxide of W and subjecting the mixture to reduction with hydrogen. CONSTITUTION:First, 0.05-0.7% KCl and 0.05-0.7% K2SiO3 (as SiO2) are added respectively as aq. solns. or together with diluting water to a blue oxide of W (W4O11). The pH of the resultant mixed aq. soln. is controlled to 2-3. After the resultant slurried compsn. is dried to a slightly wet state, an aq. AlCl3 soln. is added under thorough stirring in such a way as to be contained at 0.001-0.2% expressed in terms of Al2O3 in the W4O11 while pH is controlled to 1-2. Such compsn. is heated and dried for 2-6hr in air to remove moisture and HCl; further, the compsn. is heated for 3-10hr at 600-900 deg.C in an H2 atmosphere, whereby the blue oxide of W is reduced. The doping agents in the resultant W powder is stable, and the drooping resistance of the W products produced by molding and calcining said powder is excellent. |
