Crystalline tungsten grown by reducing vapor-deposited tungsten oxide

Monocrystalline particles and whiskers of tungsten grown by the reduction of vapor-deposited tungsten oxide with 1-3 x 10-2 Torr hydrogen were investigated with the aid of a transmission electron microscope. Particle growth was caused by abrupt oxide evaporation starting at approximately 1250 K, while the whiskers formed slightly below this temperature. The particles increased in size and decreased in population with increasing source temperature. The large particles produced at the higher temperatures tended to have well-developed [110] planes. The whiskers were very thin with an average diameter of approximately 300 A and generally were <110> oriented. (Auth.)