Abstract
“The Perfect Finish” is something that the industry has been seeking for years. It is an elusive concept for which millions of dollars have been spent in developing, testing and qualifying possible alternative finishes, but most of these efforts are futile. In order for engineers to be most effective, a realization must be made that each finish, from phosphate to cadmium, has strengths and weaknesses that must be weighed in considering each application. It is with these considerations that progress can be made toward using the materials that have the closest resemblance to the qualities of cadmium and, in turn, accepting their weaknesses.
This paper describes a research study conducted on eight finishes that are potential replacements for cadmium. Information is specific to fasteners with regards to clamp load and corrosion, both cosmetic and galvanic. The scope was broadened to understand many different elements of each finish to give engineers information that is vital to recommending their usage as cadmium substitutes and exposing weaknesses of each finish. One inorganic alternative was found to be a drop-in replacement for cadmium, and another two were found to closely resemble performance of cadmium in all respects except for electrical conductivity.
