| 摘要 |
1,231,713. Tungsten oxides; carbon. COMPAGNIE GENERALE D'ELECTRICITE. 2 June, 1969 [26 June, 1968], No. 27879/69. Heading C1A. [Also in Division H1] Tungsten oxide, WO 3 , may be prepared by heating tungsten powder in oxygen at 400‹ C. On heating WO 3 in hydrogen at 600‹ C., WO 2 is formed. The tungsten oxides are not stable and develop towards a formula WO x , where 2#x#3. The heating can be carried out so that a coating of the tungsten oxides is formed on the tungsten. Tungsten oxide may be deposited on a support of pulverulent carbon or tungsten or a thin sheet of C, Ti or Ta by impregnating the support with a tungstate, followed by a thermal decomposition under hydrogen. Alternatively, a " vapour plating " process may be used in which WCl 6 is volatilized by heating to 400‹ C., then cracked in the presence of the support to be coated by heating up to 700-800‹ C. using hydrogen as carrier gas. |
