Apparatus for coating powders

US6149785A · kind A · utility

Assignee

• The Regents of the University of California · US

Inventors

• Daniel M. Makowiecki · Livermore, US
• John A. Kerns · Livermore, US
• Craig S. Alford · Tracy, US
• Mark A. McKernan · Livermore, US

Key dates

• Filing date: Jan 20, 1998
• Grant date: Nov 21, 2000
• Expiry date: Jan 20, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23C14/352
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A process and apparatus for coating small particles and fibers. The process involves agitation by vibrating or tumbling the particles or fibers to promote coating uniformly, removing adsorbed gases and static charges from the particles or fibers by an initial plasma cleaning, and coating the particles or fibers with one or more coatings, a first coating being an adhesion coating, and with subsequent coatings being deposited in-situ to prevent contamination at layer interfaces. The first coating is of an adhesion forming element (i.e. W, Zr, Re, Cr, Ti) of a 100-10,000 .ANG. thickness and the second coating or final coating of a multiple (0.1-10 microns) being Cu or Ag, for example for brazing processes, or other desired materials that defines the new surface related properties of the particles. An essential feature of the coating process is the capability to deposit in-situ without interruption to prevent the formation of a contaminated interface that could adversely affect the coating adhesion. The process may include screening of the material to be coated and either continuous or intermittent vibration to prevent agglomeration of the material to be coated.