Heavy-metal oxide glasses might arbitrarily be defined as those containing over 50 cation percent of bismuth and lead which participate in the glass structure as network formers. Glass systems based on these heavy-metal oxides in silicates, borates, phosphates, germanates, and ferrites are surveyed. Gallate systems are emphasized since they have a unique ability to form stable glasses while maintaining key properties, such as the best infrared transmission and the highest nonlinear optical susceptibilities and diamagnetic Verdet constants for oxide glasses.

Heavy-Metal Oxide Glasses

Copper metal powders, methods for producing copper metal powders and products incorporating the powders. The copper metal powders have a small particle size, narrow size distribution and a spherical morphology. The method includes forming the metal particles in a continuous manner.

Copper powders methods for producing powders and devices fabricated from same

The present work critically reviews the scientific and patent literature on low melting bismuth based oxide glass frits in materials for electronics, sensors and related applications such as sealing glasses, solar cells, architectural and automotive glass, the main motivation being to replace lead based materials by environmentally more benign ones. Due to similar glass forming properties of Bi and Pb, Bi based glasses are the closest ‘drop-in’ alternative for lead bearing formulations, and are therefore actually replacing them in many applications, helped also by previous experience with Bi containing materials in thick film technology and component metallisations. The outstanding issues are discussed, e.g. matching the lowest processing temperatures achieved by the classical lead based glasses without sacrificing durability and stability, as well as stability versus chemical reduction. Finally, consideration is also given to special ‘heavy’ glasses (often containing Bi and Pb together) that are ...

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Review of Bi2O3 based glasses for electronics and related applications

A metallizing composition comprising a gold powder having spherical particles with a particle diameter within the range of 1-10 microns wherein the powder has a bulk density within the range of 5-9 gms./cc. and prepared by precipitating the gold from solution with selected reducing agents under controlled conditions.

Gold metallizing compositions

A silver metallizing paste for attachment of silicon semi-conductive devices in lead-frame packages, specifically ceramic packages, which is less expensive than a gold preform but useable in hermetic packages, and provides better electrical and thermal conductivity, and higher bond strength, than silver polyimides. From 25 to 95% of silver is blended with a low-melting glass, preferably one having 95-96% PbO, and a paste or ink is formed with a suitable vehicle at 75-85% solids. Use of the paste follows conventional practice. Selection of Ag:glass ratio depends on the type of die bonding to be used. The paste is particularly useful in MOS technology, where low contact resistance is required, and also finds applications as a solder substitute and bonding chip capacitors. It is most advantageous in attachment of larger-area integrated circuits in that stress cracking associated with the gold-silicon eutectic is avoided.

Silver-filled glass

Powdered alloys of Pd-Au, Pt-Au, Ag-Au, Ag-Pt or Pd-Pt are prepared by co-reduction of a solution of compound of the metals by the addition of a reducing agent. The soluble compounds of the metals may be bromides, chlorides (except in the case of silver containing alloys) cyanides or nitrates and the solvent may be water or another polar solvent (e.g. chlorinated hydrocarbons for chloride salts). Suitable reducing agents are hydrazine, zinc dust, hypophosphorus acid, sodium hydrosulphite, hydroquinone, sulphurous acid, sodium sulphite, ferrous sulphate or sodium borohydride. Pairs of reducing agents, more efficacious for the different metals, may be used in combination. The pH of the solution is preferably adjusted to between 4.5 and 6.5 prior to precipitation. The average particle size of the powder is preferably 0.1 - 0.5 microns.

Method for the production of finely divided metals

Vitreous enamel frit

Copper/vanadium oxide compositions,noble metal metalizing compositions containing vanadium oxide additives,and electrical conductor elements made therewith

Lewis C Hoffman

Papers

Method for the production of finely divided metals

Vitreous enamel frit

Copper/vanadium oxide compositions,noble metal metalizing compositions containing vanadium oxide additives,and electrical conductor elements made therewith

Low melting glass and compositions containing the same

Vitreous enamel, article and method