National Research Development Corporation

Havard J Prosser

Alan D Wilson

David M Groffman

William M Allen

Bernard F Sansom

Anthony J Dunsdon

Gary S Sayers

Pauline J Brookman

John C Skinner

A sustained release device which comprises a source of at least one trace chemical element incorporated in a cement and releasable therefrom on contact with an aqueous medium. The trace chemical element is exemplified by selenium, cobalt and iodine and the cement is exemplified by a phosphate cement.

Sustained release composition

A body having a substrate surface which comprises corrodible material and on which substrate surface is present a coherent protective layer of an anti-corrosion composition which comprises a solid matrix of electrical conductivity .gtoreq.10.sup.-6 mho cm.sup.-1 and formed by reaction between at least water-soluble Bronsted acid and at least one Lewis base in which matrix is incorporated an elemental metal, or an alloy thereof, the matrix and metal being effective in service as electrolyte and sacrificial anode, respectively.

Coated substrates

A hardenable composition which comprises (i) a poly(carboxylic acid) or precursor thereof (as herein defined); (ii) a particulate ion-leachable silicate, aluminosilicate or metal oxide reactable with (i) in the presence of water to set to a hardened composition; and (iii) a compound comprising at least one phosphorus-carbon or phosphorus-boron covalent bond, in an amount effective in service to extend the working time of the composition.

Cement-forming compositions

A sustained release device which comprises a source of at least one trace chemical element incorporated in a cement and releasable therefrom on contact with an aqueous medium. A preferred cement is copper phosphate cement.

Growing community of inventors

Royston, United Kingdom

Havard J Prosser