High-speed fabrication of highly uniform ultra-small metallic microspheres

US6491737B2 · kind B2 · utility

Assignee

• The Regents of the University of California · US

Inventors

• Melissa Orme-Marmerelis · Irvine, US
• Robert F. Smith · Newbury Park, US

Key dates

• Filing date: May 18, 2001
• Grant date: Dec 10, 2002
• Expiry date: May 18, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/12014
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

In a high-speed fabrication process for producing highly uniform ultra-small metallic micro-spheres, a molten metal is passed through a small orifice, producing a stream of molten metal therefrom. A series of molten metal droplets forms from the break up of the capillary stream. Applied harmonic disturbances are used to control and generate satellite and parent droplets. Significantly, the satellite droplets formed are smaller than the orifice, allowing for the production of smaller metal balls with larger orifices. The satellite droplets are separated from the parent droplets by electrostatic charging and deflection or by aerodynamic or acoustic sorting. Preferably, the satellite droplets are cooled before being collected to avoid defects and achieve high uniformity of the resulting metal balls.