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Certain electroless gold plating procedures are autocatalytic in nature, while gold can also be used as an activator or initiator in the autocatalytic plating of plastics and of other non-conducting materials by metals such as nickel and copper. This paper describes the scientific basis of autocatalytic plating, and reviews electroless gold plating procedures. The effectiveness of gold as an activator in the autocatalytic plating of plastics is also briefly surveyed.The literature relating to so-called "electroless" plating is confusing, not only because it tends to be largely of an empirical nature, but also because the term "electroless" has often been used to describe processes which are different in character. True "electroless" or autocatalytic plating should not be confused either with electrochemical displacement deposition, or with homogeneous chemical reduction processes, such as silvering. In the former, deposition is accompanied by dissolution of the basis metal, which must therefore be less noble than the metal being plated. It does not, therefore, occur on gold. Moreover, deposition ceases immediately access of plating metal ions to the basis metal is not possible. Only thin platings can therefore be expected by this procedure. In the latter, deposition occurs indiscriminately over all objects in contact with the solution. After initial deposition has occurred, however, autocatalytic deposition may constitute the main plating process.

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