摘要:
A process is disclosed for producing molybdenum-ruthenium metal powder which comprises forming an ammonium molybdate solution, heating that solution to drive off excess ammonia, and thereafter adding ruthenium dioxide to that heated ammonium molybdate solution to form a slurry of ruthenium dioxide in the ammonium molybdate solution. Molybdenum trioxide and ruthenium dioxide are then crystallized from the slurry to produce a uniform mixture of molybdenum trioxide and ruthenium dioxide which is heated at a temperature of from about 300.degree. C. to about 800.degree. C. for a sufficient time in a reducing atmosphere to reduce the molybdenum trioxide and ruthenium dioxide to their respective metals and form a uniform mixture of the metals. The metal mixture is heated at a temperature of from about 800.degree. C. to about 1200.degree. C. for a sufficient time in a reducing atmosphere to stabilize the mixture at a particle size of -325 mesh, and then cooled in a non-reacting atmosphere.
摘要:
The center electrode of an ignition plug is a unitary cylindrical tungsten rod in which the outer peripheral portion thereof has a higher work function than the core portion.
摘要:
A wire for fabrication of a vibration resistant filament for an incandescent lamp. The wire includes about 0.05-1.00 weight percent lanthanum oxide dispersed in a tungsten matrix and has a microstructure including stringers of fine particles of lanthanum oxide extending parallel to the wire axis. During primary recrystallization of a vibration resistant lamp filament from the filament wire, the stringers produce a microstructure in the filament exhibiting sufficient grain boundary segments extending generally axially along the length of the filament to render the filament resistant to vibration. A method for producing a vibration resistant filament for an incandescent lamp is also disclosed.
摘要:
It has been discovered that potassium retention in NS tungsten processing may be improved by double doping tungsten blue oxide (TBO) prior to reduction. The novel `double-doping` process consists of dry doping standard singly doped K--Al--Si TBO with potassium nitrate, KNO.sub.3, followed by the standard reduction, acid washing, sintering, rolling and drawing steps. In another aspect, the novel method includes an aqueous extraction of heteropolytungstate anion [SiW.sub.11 O.sub.39 ].sup.8- from a sample of the singly doped tungsten blue oxide to predict potassium retention.
摘要:
A wire for fabrication of a vibration resistant filament for an incandescent lamp. The wire includes about 0.05-1.00 weight percent lanthanum oxide dispersed in a tungsten matrix and has a microstructure including stringers of fine particles of lanthanum oxide extending parallel to the wire axis. During primary recrystallization of a vibration resistant lamp filament from the filament wire, the stringers produce a microstructure in the filament exhibiting sufficient grain boundary segments extending generally axially along the length of the filament to render the filament resistant to vibration. A method for producing a vibration resistant filament for an incandescent lamp is also disclosed.
摘要:
A three step process in which a metal alloy selected from a tungsten based alloy and molybdenum based alloys is provided to prevent the decarbonization of the alloys. The process involves a three step sintering process wherein the atmosphere during the initial heating step is a mixture of carbon monoxide and hydrogen, thereafter at a intermediate temperature range the atmosphere is hydrogen and a final heating step at a elevated temperature is employed and the atmosphere is a mixture of inert gas and a source of carbon.
摘要:
In a method of making alloy of tungsten and lanthana, lanthanum hydroxide is blended with tungsten metal powder, the mixture is pressed to form a pressed ingot, optionally presintered, and sintered to form the alloy. The use of lanthanum hydroxide as the source of the lanthana dopant allows the pressed or presintered ingots to be stored in air prior to sintering for prolonged periods without becoming degraded from exposure to atmospheric moisture.
摘要:
The center electrode of an ignition plug is a unitary cylindrical tungsten rod in which the outer peripheral portion thereof has a higher work function than the core portion.
摘要:
A molybdenum-tungsten-titanium-zirconium-carbon alloy system is disclosed having a composition in percent by weight of from about 0.01 to about 0.15 carbon, from about 0.06 to about 0.20 zirconium, from about 0.40 to about 0.75 titanium, from about 10 to about 60 tungsten, and the balance molybdenum.
摘要:
A large-diameter tungsten-lanthana rod having an elongated grain structure substantially parallel to the longitudinal axis of the rod is described. The large diameter rod is produced by rolling at a temperature greater than 1400° C. and less than 1700° C. to achieve at least about a 40% reduction in cross-sectional area. The high strength of the longitudinally elongated grain structure is desirable for applications such as rocket nozzles.