Removal of chemisorbed lubricant on the surface of silver flakes by chemicals

Lubricants generally are used in the milling process of silver powders to flakes to nullify the forces of welding and thereby inhibit agglomeration. The study was carried out to fully understand the interaction of silver flakes with a commonly used lubricant, oleic acid. Silver flakes were prepared by ball milling of precipitated fine silver powders with oleic acid in amounts about 1.0 wt.%. Thermal properties of lubricated silver flakes and silver flakes treated by several chemicals were studied; the efficiency of the lubricant removal was estimated by the DSC exothermic peak in air. It was found that a mixture of solvent and diluted sulfuric acid can fully remove the lubricant on the surface of silver flakes. The morphology of silver flakes before and after treatment by a mixture of alcohol and diluted sulfuric was observed by scanning electron microscopy; the lubricant removal was also confirmed.