Plating Hydrogen

Cathodic activation examined with reference to the cold fuslon developments (controversy). Historically cathodic activation has been used for plating preparation of p a s s i v e (o x i d e) s u r f a c e s e.g. nickel/chromium alloys, niobium and powdered metals. More recent results of work employing cathodic activation for preparing aluminum for plating will be presented e.g. process parameters, deposit adhesion; suggesting a mechanism of oxide reduction. Data on theoretical energy requirements to reduce oxide will be given. The cathodic activation Joule energy input used in this work on aluminum was considerably less than the theoretical energy required to reduce oxide. In the spirit of a common sense Baltimore AESF approach a simplified environmentally improved method of chromium plating aluminum will be discussed. The process is based on cathodic activation (reduction of surface aluminum oxide) to achieve an adherent electro deposit. Also the mechanism of cathodic hydrogen has lead the author to stay current with the work being reported outside the plating industry as "cold fusion" which claim excess energy from cathodic hydrogen. History of Cathodic Reduction The industry uses baths with low plating efficiency which results in significant hydrogen evolution e.g. 98%.-Copper cyanide strike for steel-"Woods" Nickel strike for stainless steel-Activates to plate nickel on nickel chromium on chromium-Activate niobium for plating-Activate aluminum for plating Theory of Cathodlc Hydrogen Reduction As Applied to Aluminum Formation of hydrides at cathode' Here is a possible explanation for achieving necessary temperature to cause aluminum oxide reduction. At low or normal temperatures, hydrogen will not reduce aluminum oxide. An additional reaction is necessary to provide the extremely high temperatures required. However, a study of the variation with temperature of the free energy of metal oxide formation (Fig. 1) indicates the mechanism wherein hydrogen can reduce aluminum oxide at elevated temperatures. By examining the curves in Fig. 1, any metal reduces the oxide of a metal whose curve lies below. When the net change in free energy is negative, as traced in Fig. 1, oxide reduction takes place. The free energy gets more negative with increases in temperature or stays basically flat, with very little change, thereby intercepting the aluminum line at some elevated temperature (N55OoC).