A study of liquid metal atomization using close-coupled nozzles, part 1: gas dynamic behavior

The preparation of spherical metal powders using the high-temperature remelting spheroidization technology

The present invention relates to a silicon powder, which is characterised in that it is produced by gas atomizing of molten silicon and having a particle size between 0.1 and 1000 µm, a specific area between 0.001 and 1 m²/g, and the following chemical composition in percent by weight: 0.1 - 1% iron, 0.01 - 1% aluminium, 0 - 8% copper, 0 - 1% calcium, 0 - 1% zinc, 0 - 1% tin, 0 - 5% boron, 0 - 0.5% phosphorus, 0 - 0.5% sodium, 0 - 0.5% lithium, 0 - 0.5% potassium, 0 - 0.5% magnesium, 0 - 0.5% strontium, 0 - 0.5% barium, 0 - 0.5% beryllium, the rest being silicon and less than 0.3% impurities as Ti, V, Cr, Mo, W and Zr. The silicon powder is produced continuously by a method comprising the following steps: a) continuous production of silicon in an electric smelting furnace, b) refining and alloying of the molten silicon in a metal treatment vessel, c) continuous supply of molten silicon from the metal treatment vessel to a holding furnace, d) continuous supply of molten silicon to a closed atomising apparatus wherein the molten silicon is atomised by means of an inert gas supplied from a pressure vessel or a compressor unit, e) continuous removal of atomised silicon powder from the atomising apparatus, f) separation of atomised silicon powder and inert gas in a solid/gas separator, g) screening of the silicon powder into preset particle size fractions, h) supply of the different particle size fractions of silicon powder to closed product silos, i) filtration of the inert gas from step f) for removing any remaining solid particles from the inert gas, j) cooling and compressing the inert gas from step i) and recycling of the compressed inert gas to the pressure vessel or directly to the atomising apparatus.

Silicon powder and method for its production

Methods of fabricating powders of electrically conductive particles supersaturated with grain growth control additives are described. A molten admixture of an electrically conductive material and a grain growth control additive is atomized by spraying an inert atmosphere forming fine molten particles which rapidly cool to form solid particles which are supersaturated with the grain growth control additive. The supersaturated particles are heated to form an electrical conductor having grain sizes less than about 25 microns. The supersaturated particles can be combined with a binder to form an electrical conductor forming paste. Patterns of the paste can be embedded in a green ceramic which can be sintered to form a semiconductor chip packaging substrate having electrical conductors with controlled grain size. During sintering of the combination of ceramic precursor and conductor forming paste, the grain growth control additive results in a substantially void free and crack free via filled with metal having a fine grain morphology.

Supersaturation method for producing metal powder with a uniform distribution of dispersants method of uses thereof and structures fabricated therewith

In-situ de-wetting assisted fabrication of spherical Cu-Sn alloy powder via the reduction of mixture metallic oxides

Gas atomising is placed into context as a production technology by comparison with other methods of producing powder. Data obtained from the commercial production of powder in a wide range of alloys are characterised in terms of mean particle diameter and standard deviation and used to assess the efficiency of the atomiser in producing powder within the particle size distribution required for a particular end application. PM/0484

R. I. L. Howells

Papers

Production of Gas Atomised Metal Powders and Their Major Industrial Uses