| 摘要 |
PURPOSE:To produce coarse-grained W powder having superior flowability by sintering a powdery mixture of W powder with powder of a specified binding metal in a liq. phase to form a W alloy, adding a low m.p. metal to the alloy, carrying out melting by heating, and evaporating and removing the low m.p. metal under reduced pressure. CONSTITUTION:W powder as starting material is mixed with powder of one or more kinds of binding metals selected among Ni, Fe, Cu and Co and the powdery mixture is sintered in a liq. phase to form a W alloy contg. coarse- grained W powder. At least one kind of low m.p. metal selected among Zn, Cd and Te is added to the alloy and they are heated to allow all the binding phase to enter into a solid soln. and to convert it into a melt. They are then heated under reduced pressure to evaporate the remove the low m.p. metal and to separate the coarse-grained W powder and alloy powder of the binding phase. The alloy powder is separated from the coarse-grained W powder by sieving, air classification or other method. Thus, high purity coarse-grained W powder obtd. The low m.p. metal is preferably added by an atm. (wt.) 10-30 times the amt. of the binding phase.
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