SILVER POWDER, METHOD FOR PRODUCING IT AND METHOD OF MAKING ALLOY FOR PRODUCING SILVER POWDER Russian patent published in 2003 - IPC

FIELD: silver powder production, possibly in electrical engineering for making electrode materials, metal-ceramic contacts, secondary chemical electric current sources. SUBSTANCE: method comprises steps of melting charge containing 30-70 mas.% of magnesium; after melting increasing temperature of melt for 3-5 min up to 700-750 C; pouring melt at temperature 600-630 C into ingot mold whose dimensions provide relation of ingot height to its cross section in range 5-10; cooling ingot under flux in atmosphere of elegas; breaking alloy; leaching magnesium in 10% acetic acid at temperature which is increased for first 15 min from 15-15 C until 75-80 C and then it is lowered until 35-50 C for 1.5-3 h; mechanically working powder. Melting, pouring and cooling are realized under flux in atmosphere of elegas. Powder according to invention containing less than 0.2 mas.% of magnesium consists of porous irregular shape particles with size 1-500 micrometers and with pore size of particles 0.05-7 micrometers; it has specific surface 0.05-10 sq. m/g, bulk density 0.7-2 g/cu.cm and fluidity value 2.5-5 g/cu.cm. Porous particles of powder may be formed of poreless spheric crystals with size 0.05-0.4 micrometer. Powder may contain mixture of magnesium oxide and hydroxide with particle size 0.005-0.01 micrometer in quantity 0.01-0.5 mas. %. EFFECT: enhanced effectiveness and manufacturability of ecologically safe process, improved technical characteristics of powder, possibility for controlling chemical and phase content, structure and properties of powders due to changing content and structure of initial alloys. 11 cl, 1 dwg