| abstract |
PURPOSE:To produce W powder of good fluidity used as a melt spraying material by adding a compd. of Li to oxide of W then reducing, pickling, washing and drying the same. CONSTITUTION:An aq. lithium nitrate soln. is added to the tungsten blue oxide obtd. by decomposing ammonium paratungstate powder by heating at about 400-500 deg.C in gaseous H2 flow in such a way as to contain 0.02-0.5wt% Li2O basing on WO3, after which this is dried and is reduced at about 700-900 deg.C in H2, whereby W powder is obtained. This W powder is then washed for about 10min in about 2:3 dilute hydrochloric acid, and is further washed until the supernatant attains around 3pH, after which it is dried, whereby desired W powder is obtained. |