초록 ▼

Amorphous or microcrystalline alloy powder is prepared by the rapid quenching of ultrafine metallic spheroids generated from the molten metal state. The molten metal droplets are formed when an intense electric field (105 V/cm) is applied to the surface of liquid metal held in a suitable container.

Amorphous or microcrystalline alloy powder is prepared by the rapid quenching of ultrafine metallic spheroids generated from the molten metal state. The molten metal droplets are formed when an intense electric field (105 V/cm) is applied to the surface of liquid metal held in a suitable container. The interactions between the intense electric field and liquid surface tension disrupts the metal surface, resulting in a beam of positively charged droplets. The liquid metal spheres generated by this electrohydrodynamic process are subsequently cooled by radiative heat transfer. Rapid cooling of the droplets may be accomplished by heat transfer to a low pressure gas by free molecular heat conductivity. Quenching rates exceeding 106 °K./sec are possible using this technique. Thin film coatings are prepared by electrohydrodynamically spraying a beam of charged droplets against a target (substrate). The target can be electrically controlled to effect the charged particles impact. The materials to be sprayed electrodynamically can be varied in both throughput and species such that a target can have multimaterial layers being deposited coincidentally or sequentially. The ultra small droplet size will enhance the physical properties by reducing skin stresses and enhance the optical properties by reducing the growth of crystallites in the film. Precise layers can be deposited from extremely thin films to thick filters for optical characteristics into the infrared. All materials that can be molten and contained can be electrohydrodynamically sprayed and controlled for depositions upon a substrate material.

대표청구항 ▼

A method of forming high melting temperature metal alloys in the form of ultrafine particles ranging in size from sub-micron to about 100 microns by electrohydrodynamic spraying which comprises: liquefying the metal alloy; pneumatically feeding the molten metal alloy to a capillary nozzle to form a

A method of forming high melting temperature metal alloys in the form of ultrafine particles ranging in size from sub-micron to about 100 microns by electrohydrodynamic spraying which comprises: liquefying the metal alloy; pneumatically feeding the molten metal alloy to a capillary nozzle to form a liquid meniscus at the tip of the nozzle; applying a positive electric field to the molten metal alloy to create electrostatic forces which are high enough to overcome the surface tension of the liquid meniscus to thereby generate a beam of positively charged ultrafine droplets of said metal alloy; solidifying the ultrafine droplets; and collecting the resulting ultrafine metal alloy particles.