Gte Products Corporation

Osram Sylvania Inc.

Gte Sylvania Incorporated

Richard G Gingerich

Clarence D Vanderpool

Richard A Scheithauer

Joseph E Ritsko

Michael J Miller

Kenneth T Reilly

Martin B MacInnis

Charles F Chenot

Ronald E Karam

Robert P McClintic

John A Arbie, Sr

Douglas M Jackson

Richard R Borchardt

Michael J Cheresnowsky

Chen-Wen Fan

James N Christini

Dale E Benjamin

Robin W Munn

Howard L Acla

Martin C Vogt

Brice E Martin

Mary A Fedorchak

Christopher S Poss

James Morse

Leslie F Trudeau

Franz Kummer

An electroluminescent phosphor containing an effective amount of bismuth to increase the half-life of the phosphor compared to the half-life of the phosphor without the bismuth. The phosphor is produced by the method comprising the steps of preparing the electroluminescent phosphor; adding granular, elemental bismuth to the bottom of a quartz reaction vessel; covering the bismuth with a layer of quartz wool; placing the phosphor on top of the quartz wool; evacuating the reaction vessel to about 750-760 mm Hg and sealing the vessel; and heating the vessel to between about 500 to 700.degree. C. for about 24 to 72 hours.

Electroluminescent phosphor with extended life and method of making same

A method for forming a continuous, conformal non-particulate coating of boron oxide on individual phosphor particles is provided. The method involves reacting a boron-containing precursor with an oxidizing gas in a fluidized bed of phosphor particles. The boron oxide coated phosphor exhibits an increased quantum efficiency under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation.

Boron oxide coated phosphor and method of making same

A fine, largely beta phase calcium pyrophosphate powder for, e.g., a diffuser coating for the interior surface of lamp envelopes. The powder is useful for electrostatic deposition of such coatings under varying conditions of environmental humidity. A process for the synthesis of the calcium pyrophosphate is also disclosed. Dibasic calcium orthophosphate (monetite) is dissolved in a dilute aqueous hydrochloric acid solution and spray-dried to form a calcium phosphate powder of spherically shaped hollow particles. The calcium phosphate powder is fired in air to convert the calcium phosphate powder to a spherical calcium pyrophosphate powder including the beta phase as a major component and the gamma phase as a minor component. For a diffuser coating, the poder is sonicated to fragment a portion of the hollow particles.

Synthesis of beta phase spherical calcium pyrophosphate powder

Disclosed is a large size Y.sub.2 O.sub.3 :Eu lamp phosphor as a red component for a water degradation resistant blend of fluorescent phosphors having large sized green phosphor particles and the method for making by blending yttrium oxide and europium oxide with fluxing agents, firing, milling the fired phosphor; sieving the milled phosphor to obtain a phosphor with an average particle size greater than about 5 by Coulter Counter to produce a sieved phosphor, and encapsulated a conformal coating of gamma alumina on said sieved phosphor by vapor chemical vapor deposition to form a resulting coated Y.sub.2 O.sub.3 :Eu phosphor with additional phosphor components including a green phosphor to form a lamp phosphor blend, and applying the blend to a lamp as a water based suspension.

Europium-doped yttrium oxide phosphor

A method of making an unactivated yttrium tantalate x-ray phosphor containing an aluminum additive wherein a high brightness phosphor is obtained without the use of a lithium chloride containing flux. The method includes using a high surface area aluminum oxide as the source of the aluminum additive and a lithium sulfate flux.

Method of making an unactivated yttrium tantalate x-ray phosphor

Composite electroluminescent phosphor particles may be made by forming, on a substrate, a composite layer comprising at least one layer of a dielectric or conductive material and at least one layer of an electroluminescent phosphor, physically removing the composite layer from the substrate, and pulverizing the composite layer to obtain composite electroluminescent phosphor particles.

Composite electroluminescent phosphor

A process for recovering tungsten as an ammoniacal tungstate which comprises reacting a tungsten containing material with sodium hydroxide to produce sodium tungstate and forming a first aqueous sodium tungstate solution therefrom, crystallizing sodium tungstate from the first aqueous sodium tungstate solution, dissolving the resulting sodium tungstate crystals in an aqueous medium to form a second aqueous sodium tungstate solution, extracting tungsten from the second aqueous sodium tungstate solution with an organic extracting agent wherein the extracting agent containing tungsten is capable of being stripped of the extracted tungsten by ammonia, and thereafter stripping the extracted tungsten from the organic extracting agent with ammonia to form an ammoniacal tungstate solution, crystallizing a portion of the tungsten contained in the ammoniacal tungstate solution to form a two phase system wherein an ammoniacal tungstate compound comprises the first phase and wherein the resulting mother liquor containing the balance of the contained tungsten comprises the second phase, and repeating the process using the mother liquor as at least a portion of the aqueous medium to dissolve the sodium tungstate crystals.

Process for recovering tungsten as an ammoniacal tungstate compound in

Method of making a composite electroluminescent phosphor

A phosphor composition consisting essentially of particles of zinc sulfide electroluminescent phosphor activated with from about 0.7% by weight of about 1.3% by weight of manganese, based upon the total weight of the phosphor composition, wherein the electroluminescent emission of the phosphor has an x color coordinate value of from about 0.522 to about 0.532 and a y color coordinate value of from about 0.460 to about 0.470 and an efficiency of greater than about 5.6 lumens per watt at 115V/400 Hz. A solid state process for producing the foregoing phosphor comprises a multiple firing in order to incorporate manganese, chloride and copper ions into the zinc sulfide lattice. Controlled levels of manganese yield highly efficient electroluminescent phosphors.

Process for producing electroluminescent yellow zinc sulfide phosphors

A cadmium-free cathodoluminescent phosphor composition consists essentially of zinc sulfide activated with from about 0.019% by weight to about 0.024% by weight of copper and from about 0.01% by weight of about 0.02% by weight of aluminum wherein the emission of the phosphor upon stimulation by cathode rays has CIE values of x of from 0.287 to 0.291 and y from 0.616 to 0.620. The process involves solid state heating of the various raw materials wherein a first relatively pure zinc sulfide and a second zinc sulfide containing chloride ions are mixed with the appropriate levels of and alkali metal chloride and sources of copper and aluminum activators and then heated in a nitrogen-carbon disulfide atmosphere for about 3 hours at 1775.degree. C. to about 1825.degree. C.

Method for producing cadmium free green emitting CRT phosphor

A method is disclosed for producing alkaline earth halophosphate stir-in phosphors which comprises forming a mixture of about 55% to 75% calcium monohydrogen phosphate, about 15% to 35% calcium carbonate, about 2% to 20% ammonium chloride, about 1% to 15% manganese carbonate, about 1% to 15% antimony trioxide, and about 2% to 10% by weight calcium fluoride, wherein the average particle size of the calcium monohydrogen phosphate by Fisher subseive size is about 4.6 to 6.8 micrometers in diameter and the 50% Coulter Counter size is about 9.0 to 11.5, firing in a non-reacting atmosphere at 600.degree. C. to 1300.degree. C., milling in acid, wet screening through a first screen of greater than 300 mesh, removing the acid, suspending the material in water, screening through a second screen of greater than 350 mesh, adding base to form a slurry, removing the liquid phase from the slurried phosphor material, drying, transferring the material by vacuum to holding means, and transferring the material by gravity from the holding means to a vibratory feeder, transferring the material from the vibratory feeder by gravity to a third screen of greater than 350 mesh, and passing the material through the third screen wherein vacuum pulls the material to and through the screen and at the same time a flow of air behind the third screen results in vibration of the particles of the material as they pass through the third screen, and thereafter passing the particles under vacuum to collecting means.

Method for producing alkaline earth halophosphate stir-in phosphors

A process is disclosed for producing an electroluminescent phosphor which comprises blending a chloride flux, a copper source, and zinc sulfide to form a relatively uniform admixture, heating the admixture at a temperature of from about 1000.degree. C. to about 1300.degree. C. for about 2 to about 8 hours to convert at least a portion of the admixture to a crystalline material containing zinc sulfide, at least some chloride ions, and copper ions, washing the material with sufficient water to remove at least a major portion of the water soluble material from the crystalline material, drying the material to produce a relatively moisture-free material which is low intensity milled for a sufficient time to change the crystallographic structure of at least a portion of the moisture-free material, blending the milled material with zinc sulfate and copper sulfate, with or without manganese carbonate depending on whether manganese is desired as an activator, to form a second admixture, which is heated at a temperature of from about 750.degree. C. to about 850.degree. C. for about 1.5 to about 3 hours to form an activated material which is cooled for a period of time of from about 10 minutes to about 20 minutes followed by immediately quenching in water, removing the water from the cooled and quenched activated material, washing the material with reactive aqueous solutions to remove residual fluxes and excess activator materials, and drying the material to form an electroluminescent phosphor.

Process for producing electroluminescent phosphors of improved brightness

In the manufacture of an alkaline earth halophosphate phosphor, the phosphor ingredients are mixed, fired, wet milled and dried. By sieving the material part way through the wet milling process and by sifting the dry phosphor powder, the phosphor powder weight in fluorescent lamps can be reduced.

Method of making alkaline earth halophosphate phosphor

A process is disclosed for producing pure cobalt metal powder. The process involves contacting a cobaltous salt with a sufficient amount of an alkaline earth halide in an aqueous solution at a sufficient temperature for a sufficient time to form a solution which is essentially cobaltous halide and a solid which consists essentially of a salt of the alkaline earth and the anion of the cobaltous salt. The cobaltous halide solution is removed from the solid and the ions in the solution are complexed with ammonia in the presence of a catalyst to form a cobaltic hexammine ion. The resulting solution is treated with an acid in the presence of halide ions to form a cobaltic hexammine halide precipitate which is removed from the resulting mother liquor and dissolved in an aqueous solution to form a relatively pure solution which is treated with a sufficient amount of a metallic hydroxide to form a cobalt containing precipitate which is reduced to cobalt metal.

Process for producing cobalt metal powder

A process is disclosed for recovering cobalt from an alloy containing other metals as chromium, tungsten, etc. The process involves first adding the alloy to fused sodium hydroxide at a temperature of from about 750.degree. C. to about 1000.degree. C. to form a reaction mixture, the amount of sodium hydroxide being sufficient to subsequently form sodium salts which are essentially those of chromium and tungsten and hydroxides which are essentially those of cobalt and nickel. The reaction mixture is then heated at a sufficient temperature for a sufficient time while introducing an oxidizing gas into the reaction mixture to form a melt which consists essentially of the sodium salts and the hydroxides, followed by cooling the melt. The cooled melt is then contacted with sufficient water to form a solution containing the major portion of the sodium salts and a solid containing the major portion of the hydroxides, followed by separating the solid from the solution. The solid is then washed with sufficient water to remove the remaining portion of the sodium salts and other water soluble impurities and then separated from the resulting wash water.

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Towanda, PA, United States of America

Richard G Gingerich