Systematic investigation of square wave pulsating overpotential (SWPO) treatment of a chromic acid solution is presented. Some preliminary potentiodynamic scans, potentiostatic deposits, potential steps and capacitance vs. potential curves were measured in order to establish the practical range of the SWPO signal parameters. The results show that properly adjusting the electrochemical parameters of the cyclic alternating potential perturbation it is possible to obtain cracked or crack free metallic chromium or chromium oxide/hydroxide mixed coatings. The different deposit morphologies were characterized through scanning electron microscopy and their chemical composition and micro hardness was measured. Some insight into the possible mechanisms of coating growth under this potential cycling treatment is given.
About Dr. Walter EgliDr. W. A. Egli
Electroplating and Corrosion Department,
Centre for Paints and Coatings Development,
Scientific Research Commission of Buenos Aires,
Province (CICBA), Argentina
About me: More than 15 years of experience in industrial R&D after obtaining my PhD in the National University of La Plata. Vast experience in Tinplating and Electro galvanizing processes. In the present, the fields of research and development in which I am involved are: cyanide free plating processes (Cu, Zn, brass and bronze), dendritic growth of metal deposits, electro co-deposition of second phases (solid or liquid) within metal coatings, effects of organic additives on metal deposition and temporary protection of metal surfaces with silane films. With my team we provide high level technical advice to companies in the plating and metal working business as well as we deal with general corrosion trouble shooting in the industry.
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