Patent ID: 7648557

Claim:
A method for the formation of very high solids, highly ordered, finely divided, and controlled morphology silver powder particles comprising the sequential steps of: (a) preparing an aqueous solution of a silver salt wherein said aqueous solution comprises a silver salt dissolved in de-ionized water; (b) preparing a reducing solution comprising: (i) de-ionized water; (ii) nitric acid; (iii) a reducing agent consisting of ascorbic acid; (iv) a particle surface morphology modifier chosen from the group consisting of potassium sulfate, sodium sulfate, potassium phosphate, sodium phosphate, potassium carbonate and sodium carbonate; (v) a surface modifier chosen from the group consisting of gum arabic, ammonium stearate, stearate salts, salts of polynaphthalene sulfonate formaldehyde condensate, polyetheylene glycol with molecular weight 2100 to 8000, and mixtures of these surfactants; (vi) a particle modifier chosen from the group consisting of gold colloid, silver colloid and sodium borohydride; and (c) mixing together the aqueous solution of silver salt and said reducing solution to form silver powder particles in a final aqueous solution wherein said final aqueous solution has a pH of less than or equal to 6.