Abstract: An improved scandate cathode having an increased emission density is prepared from a porous tungsten billet that has been impregnated with Ba.sub.3 Al.sub.2 O.sub.6 by coating the top surface of the impregnated billet with a mixture of Sc.sub.6 WO.sub.12,Sc(WO.sub.4).sub.3, and W in the mole ratio of 1:3:2, heating the billet to about 1000.degree. C. in a vacuum to cause BaWO.sub.4 and Sc to form in the billet in a molar ratio of 1:1, removing the billet and cleaning in a jewelers lathe, and preparing the billet for a cathode environment.

Abstract: An improved scandate cathode is made from a hollow cylinder of a metal that ill not react with Sc.sub.2 (WO.sub.4).sub.3. The first step in making such a cathode is to insert a metal plug at the bottom of the cylinder to a height that will allow the remaining volume of the cylinder to be filled with the reactants WO.sub.3 and Sc.sub.2 O.sub.3. Next, the reactants are heated in a vacuum to about 1100.degree. C. to form the reaction product Sc.sub.2 (WO.sub.4).sub.3. The plug is then removed from the cylinder, the cylinder is inverted, and BaH.sub.2 is added to the volume of the cylinder that had been occupied by the plug. Finally, the cylinder is heated to decompose the BaH.sub.2.

Abstract: A long life high current density cathode is made from a mixture of aluminum xide and tungsten oxide powders by processing the powders into a fused powder, adding barium hydride to the fused powder, inverting the fused powder and heating to decompose the barium hydride and obtain barium metal.

Abstract: A long life high current density cathode is made from a mixture of tungsten nd iridium powders by processing the mixture of powders with an activator into a porous billet, and then impregnating the billet with a quaternary compound including barium, oxygen, a metal selected from the group consisting of osmium, iridium, rhodium, and rhenium, and a metal selected from the group consisting of strontium, calcium, scandium and titanium, by firing the billet in a dry hydrogen furnace at a temperature at which the impregnant melts.

Abstract: A cathode is made from tungsten powder using as an impregnant the product rmed from adding about 1 mole of a member selected from the group consisting of zirconium, zirconium dioxide, hafnium, hafnium dioxide, uranium, uranium dioxide, titanium, and titanium dioxide to about 50 to about 100 moles of a compound selected from the group consisting of Ba.sub.3 Al.sub.2 O.sub.6, Ba.sub.3 WO.sub.6, and Ba.sub.4 Al.sub.2 O.sub.7.

Abstract: A long life high current density cathode is made from a mixture of tungsten nd iridium powders by processing the mixture of powders with an activator into a porus billet, and then impregnating the billet with a mixture of barium peroxide and a coated emitter by firing the billet in a dry hydrogen furnace at a temperature at which the impregnant melts.

Abstract: A cathode is made from a mixture of tungsten and iridium powders using a ction product formed from reacting barium peroxide with an excess of tungsten as the impregnant.

Abstract: A tungsten-iridium billet is impregnated with a chemical mixture of barium xide, strontium oxide, and aluminum oxide, the impregnated billet heated, and the surface of the impregnated billet desired for emission exposed to an overcoating of rhodium.

Abstract: A cathode is made from a mixture of tungsten and aluminum powders.

Abstract: A long life high current density cathode is made from a mixture of tungsten nd iridium powders by processing the mixture of powders with an activator into a porous billet, and then impregnating the billet with a low melting point impregnant by firing the billet in a dry hydrogen furnace at a temperature at which the impregnant melts.

Abstract: A cathode is made from a mixture of tungsten and iridium powders using a ium iridiate formed from barium peroxide and iridium oxide as the impregnant.

Abstract: A cathode is made from a mixture of tungsten and iridium powders using a ium peroxide containing material as the impregnant.

Abstract: A long life high current density cathode is made from a mixture of tungsten nd iridium powders using a bariumaluminoiridiate as the impregnant.

Abstract: A long life high current density cathode is made from a mixture of tungsten nd iridium powders using a barium iridiate as the impregnant by processing the mixture of powders with an activator into a porous billet, and then impregnating the billet with a barium iridiate by firing the billet in a dry hydrogen furnace at a temperature at which the impregnant melts.

Abstract: A long lived high current density cathode is made from a mixture of tungs and iridium powders by processing the mixture of powders with an activator into a porous billet, and then impregnating the billet with a chemical mixture of barium oxide, strontium oxide, and aluminum oxide by firing the billet in a dry hydrogen furnace at a temperature at which the impregnant melts.

Abstract: Non laminating anisotropic boron nitride is prepared by reacting a boron halide with ammonia at a temperature of from 1100.degree. C. to 1600.degree. C. in the presence of a small amount of a volatile oxygen containing compound. The small amount of volatile oxygen containing compound is sufficient to prevent lamination yet small enough to prevent the finalized product from losing its anisotropy.

Abstract: A high current density cathode is made by first forming an active porous h purity tungsten pellet by the steps of:(A) mixing tungsten powder with about 1 to 5 percent by weight of the mixture of an activator powder and compacting the powders at a pressure of about 35 tons per square inch to form a pellet,(B) sintering the pellet in a non-oxidizing atmosphere at about 1800 degrees C. for about 11/2 to 31/2 hours to the desired porosity,(C) filling the porous pellet with a filler material,(D) machining to the desired size and shape,(E) removing the filler material, and then forming the cathode by impregnating the pellet with Ba.sub.5 Sr(WO.sub.6).sub.2 at about 1700 degrees C. in an inert atmosphere and subsequently firing for 2 minutes at 1800 degrees C. in dry hydrogen.

Abstract: A cathode is made from a mixture of tungsten and iridium powders using a ontium peroxide containing material as the impregnant.