PREPARATION AND PROPERTIES OF NANOSIZED PDS DISPERSIONS FOR ELECTROLYTIC PLATING

Aqueous dispersions of PdS particles were prepared by the controlled d ouble-jet precipitation technique using PdCl2 or Na-2[PdCl4] and Na2S solutions. Uniform spherical particles 20-30 nm in diameter were obtai ned in acidic media in the absence and in the presence of surfactants, whereas the reaction in alkaline media yielded particles with a diame ter of 2-5 nm. Surfactants of the AVANEL S series enhanced the deposit ion of PdS particles on the epoxy circuit boards, resulting in a condu ctive layer, which also facilitated the electroplating by copper in ho les. The electrokinetic mobilities of the chloride-containing dispersi ons reveal negative charges over the entire pH range, whereas chloride -free samples display isoelectric points at pH 3.0+/-0.2 or between pH 5 and 6, depending on the preparation conditions. (C) 1998 Elsevier S cience B.V.