US Patent 7413771 Coating solder metal particles with a charge director medium

A method for preparing particles to retain a charge such that the particles are rendered electrostatically or electrokinetically mobile. The method involves coating the particles with a coating medium which facilitates attachment of a charge director material, and contacting the particles with the coating medium thereon with a charge director medium to impart a positive or negative charge thereto and thereby render the particles electrostatically or electrokinetically mobile. Electrostatically and electrokinetically mobile particles for use in an electrostatic or electrokinetic deposition process. The particles include a coating medium and a charge director on particle bodies.