Metallographic etching has been an analytical tool used by metallurgists for well over 100 years. Polished surfaces are etched, which involves using a strong acid or reagent to remove material from different surface features at different rates. This reveals the grains, phases, and defects of the sample when viewed under a microscope. If these features, such as grains, are allowed to grow large enough through an annealing treatment, etching can make them starkly visible to the naked eye. This "aesthetic etching" process is used on aluminum medallions to create a surface that looks like a layer of shiny silver over a dry, cracked desert. The University of Wisconsin-Madison has developed this technique to make jewelry items such as its "EnginEarrings." Jewelry that showcases these aluminum medallions combines precision science with stunning beauty and is marketable to engineers and socialites alike. This paper will review the science of metallographic etching and present processes to apply this aesthetic property to jewelry manufacturing applications.

Author: Katie Radavich