Silver and copper nanoparticle composites

A non-aqueous silver-containing dispersion, comprising:

• silver composite nanoparticles that are present in the non-aqueous silver-containing dispersion in an amount of up to 80 weight %, the silver composite nanoparticles comprising silver metal, (e) ascorbic acid adsorbed on the silver metal, and (a) one or more polymers adsorbed on the silver metal in an amount such that the weight ratio of silver to the (a) one or more polymers is at least 5:1 and up to and including 20:1, the (a) one or more polymers being selected from one or more of cellulose acetate, cellulose acetate phthalate, cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate trimellitate, hydroxypropylmethyl cellulose phthalate, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropylmethyl cellulose, and carboxymethyl cellulose;
• and
• one or more (c) hydroxylic organic solvents, each of which has a boiling point of at least 100° C. and a Hansen parameter (δTSolvent) equal to or greater than a total Hansen parameter (δTPolymer) of the one or more (a) polymers, and
• the non-aqueous silver-containing dispersion comprises less than 1 weight % of water, based on the total weight of all solvents in the non-aqueous silver-containing dispersion,
• wherein the non-aqueous silver-containing dispersion has a viscosity of at least 1 centipoise and up to and including 50 centipoise, as measured at 25° C., and
• wherein the non-aqueous silver-containing dispersion contains 0 mol % and up to 10 mol % reducible silver ions based on the total silver present in the non-aqueous silver-containing dispersion.