National Research Development Corporation

International Business Machines Corporation

Peter W McMillan

Ananda H Kumar

Rao R Tummala

Ronald Maddison

Ronald William Jones

A porous glass membrane for reverse osmosis desalination of salt water is made by heating a membrane of a sodium-boron-alumino silicate glass so that it separates into two inter-connecting phases, removing one phase to make the membrane porous, and then coating the pores with a metal oxide to modify the pore size distribution and strengthen the membrane to enable it to withstand the high pressure applied in the reverse osmosis process. The porous glass is first treated with a volatile metal chloride such as titanium chloride, and the resulting surface layer is hydrolyzed to produce the metal oxide coating. A further reduction in pore size with an accompanying increase in strength can be made by partially sintering the treated membrane.

Method of reverse osmosis employing an improved porous glass membrane

Sintered glass-ceramic substrates containing multi-level, interconnected thick-film circuit patterns of highly conductive metals such as gold, silver or copper are provided which can be fired in air (for gold and silver) or in neutral atmospheres (for copper) at temperatures below the melting points of these metals. This has been made possible by the discovery that finely divided powders of certain glasses described herein sinter to essentially zero porosity at temperatures below 1000.degree. C. while simultaneously maturing to glass-ceramics of low dielectric constant, high flexural strength and low thermal expansivity.

Glass-ceramic structures and sintered multilayer substrates thereof with

A fully dense high silica glass is made by taking a silica glass, causing it to phase separate into two inter-connecting phases, then removing one phase to leave a porous high silica glass, forming a layer of metal oxide over the surface of the pores of the glass and finally sintering the metal oxide-coated porous glass. Preferably a titanium oxide layer is formed by first producing a layer of titanium chloride and then hydrolysing this layer to form a surface layer of titanium oxide. The formation of a metal oxide layer on the pores of the glass allows a lower process temperature to be used, for sintering and providing the fully dense high silica glass.

High silica glass

A glass ceramic body having a microcrystalline interior and a relatively amorphous outer surface layer, the composition of said layer comprising ions of at least two alkali metals the ratio of the concentrations of which ions increases from said layer to said interior.

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Leamington Spa, United Kingdom

Peter W McMillan