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Method for the electrolytic preparation of tungsten carbide.
Gomes-JM; Baker-DH Jr.; Uchida-K
U S Pat 3 589 987 1971 Jun; :
Coarse crystalline tungsten carbide was produced by electrolysis of a melt containing alkali tungstate 1, alkali halide 14-22, alkali hydroxide 1-1, and b2o3 0.8-1.2 Moles with a graphite anode at 1,000 deg.-1,050 Deg. C at a cathode current density of 10-150 a/dm2 and an anode C.D. of 3.5 A/dm2. At a b2o3/tungstate mole ratio of <1:8 no carbide is deposited; at a ratio of 1.5:1, W2c and w are deposited; and at a ratio of at least 2:1 w borides are formed. No deposit formed in the absence of b2o3. Below 1,000 deg. C excess carbon was deposited. The b could also be introduced as metaborate or tetraborate. For example, a melt containing na2wo4 1, nacl 14, naf 7, naoh 2, and b2o3 1 mole was electrolyzed at 1,000 deg. C, at a w cathode with a C.D. of 150 a/dm2 to form 99 pct pure wc, 15.9 G/cm3, particles 85 pct +60 mesh, in 85 pct yield based on na2wo4. The wc is useful for making cermets.
U.S. Pat. 3,589,987; June 29, 1971; Chem. Abstr. 75:83,590Q
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