Palladium is an interesting element in surface chemistry. It is a noble metal and an active catalyst in many  reactions. Palladium or palladium alloys are used in the fields of catalysts, electronics or hydrogen seperation or purification. One special application is its use as a catalyst for metallising non-conductors like platic materials. In this paper the literature concerning the deposition of catalytic palladium for the surface activation prior to the deposition of electroless nickel and other metals is reviewed.

Link: Electroless Deposition of Palladium – Part 2