Agfa Gevaert Nv

H. C. Starck, Gmbh & Co Kg

Hermann C. Starck Berlin Gmbh & Co Kg

Gerhard Winter

Nikolaas C De Jaeger

Jan E Van Havenbergh

Guy Damen

Paul Moltgen

Dietmar Fister

Fister Dietmar

A method for the production of a radiographic screen comprising the following steps: 1) dispersing phosphor particles in an organic liquid in the presence of a charge controlling agent that charges said phosphor particles with a positive or negative net charge, 2) arranging said dispersion between a pair of electrodes, wherein one of said electrodes is or carries a conductive support of said radiographic screen, 3) applying and maintaining between said electrodes a sufficiently high direct current voltage to deposit charged phosphor particles onto said conductive support, and 4) separating said support carrying electrophoretically deposited phosphor particles from said organic liquid, wherein the dispersing of said phosphor particles proceeds by means of an organic surface active compound acting as dispersing agent for said phosphor particles, and said phosphor particles are electrostatically charged through adsorption thereon of ionic components of said organic surface active compound and/or through adsorption of cations or anions stemming from an ionic inorganic compound incorporated in said liquid.

Method for the production of a radiographic screen

A method for the production of a radiographic screen comprising the following steps:

Colored corundum composite with a matrix of .alpha.-Al.sub.2 O.sub.3, as formed by sol-gel process ending in sintering and size reduction steps with addition of oxide pigments (or precursors of such oxide pigments, formable to the oxide pigment in sinter heating) added to the sol before full gelation thereof.

Colored corundum composite and processes for its production and its use

Sintered composite abrasive material useful in abrasives (grinding wheels, abrasive discs and paper, etc.) and cutting tools, comprising an .alpha.-Al.sub.2 O.sub.3 matrix of sub-micron crystallite size made by sol-gel processing with a dispersed phase therein of mechanically resistant material, preferably essentially isotropic grains, added directly to the sol or gel stage of matrix formation.

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Goslar, Germany

Gerhard Winter