Osram Sylvania Inc.

Gte Products Corporation

Robert T McSweeney

Madis Raukas

Thomas M Snyder

Kailash C Mishra

Eric R Mercer

Karlene Zuk

A method of making a haloapatite phosphor having a general formula represented by (CaMnSb)(PO)(FClO), where 0&#x3c;x&#x3c;0.05, 0.004&#x3c;y&#x3c;0.01, and 0&#x3c;z&#x3c;0.1. is provided. The method involves (a) formulating a blend of ingredients to make the haloapatite phosphor, the ingredients including CaHPOas a primary source of calcium and phosphorus, (b) partially substituting an amount of an equimolar combination of an ammonium phosphate compound and calcium carbonate for an equal number of moles of CaHPOin the formulation, (c) combining the ingredients in their formulated amounts to form the blend, and (d) firing the blend to form the haloapatite phosphor. The partial substitution has been found to increase the 100-hour brightness of the haloapatite phosphors.

Method of making haloapatite phosphors

A europium-activated barium aluminate phosphor is described wherein the phosphor is doped with tetravalent ions of Hf, Zr, or Si. Preferably, the phosphor is represented by (BaEu)MgAlO:(Hf,Zr,Si)where 0.05&#x2266;x&#x2266;0.25 and 0&#x3c;y&#x2266;0.05. The tetravalent dopant ions are shown to enhance the stability of the phosphor in UV/VUV applications.

Europium-activated barium magnesium aluminate phosphor

A method is provided for improving the x-ray screen brightness of gadolinium oxysulfide x-ray phosphors. The method applies annealing and acid washing steps in a specific order following deagglomeration of the phosphor in order to ameliorate the loss of brightness caused by the deagglomeration.

Method for improving the screen brightness of gadolinium oxysulfide

In a method of preparing an alkaline earth halophospor having an antimony content greater than about 0.70 weight percent, a uniform mixture of starting raw materials is fired with already fired phosphor of the desired alkaline earth halophosphate so that the already fired phosphor is refired in an inert atmosphere containing volitile species from the uniform mixture of starting raw materials.

Process for making apatitic phosphors

In a method of preparing an alkaline earth halophospor having an antimony content greater than about 0.70 weight percent, a uniform mixture of starting raw materials is fired with already fired phosphor of the desired alkaline earth halophosphate so that the already fired phosphor is refired in an inert atmosphere containing volatile species from the uniform mixture of starting raw materials.

A procedure used to prepare Ba(Ti.sub.1-x),Zr.sub.x)O.sub.3 compositions wherein 0&lt;x&lt;0.25 having a more completely randomized distribution of Ti and Zr atoms on the TiO.sub.2 sublattice of barium titanate is described. In accordance with the present invention there is provided a method for preparing barium titanium zirconium oxide ferroelectic ceramic. The present method comprises mixing tetraalkyl titanate and alkyl zirconate in appropriate amounts to produce (Ti.sub.1-x Zr.sub.x)alkoxide wherein 0&lt;x&lt;0.25; reacting (Ti.sub.1-x Zr.sub.x) alkoxide wherein 0&lt;x&lt;0.25 to form (Ti.sub.1-x Zr.sub.x)O.sub.2 wherein 0&lt;x&lt;0.25 admixing (Ti.sub.1-x Zr.sub.x)O.sub.2 with BaCO.sub.3, said BaCO.sub.3 being added in a molar ratio greater than 1 relative to (Ti.sub.1-x Zr.sub.x)O.sub.2 ; heating the admixture for a period of time and at a temperature sufficient to produce Ba(Ti.sub.1-x Zr.sub.x)O.sub.3 wherein 0&lt;x&lt;0.25. The improved randomization of the Ti and Zr atom distributions results in a ferroelectric ceramic material having squarer electrical polarization hysteresis loops and higher remanent polarization values than can be obtained from conventionally prepared materials of similar composition.

Method of preparing barium, titanium, zirconium oxide ferroelectric

An improved nonlinear dielectric element for use in ferroelectric ceramic capacitors is disclosed which exhibits higher operating temperatures and lower coercive field levels than the compositions presently in use. This new composition is based upon Pb(Mg.sub.0.33 Nb.sub.0.67)O.sub.3 as described by the general formula

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Wakefield, MA, United States of America

Robert T McSweeney