Novel post treatment of nano-particle reinforced metallic coatings

S.L. Tay, C. Goode
Cirrus Materials Science,
New Zealand

Keywords: nano-composite coatings, dopant, electroplating, nanoparticles, dispersion strengthening


Electrochemical co-deposition of metallic coatings with a second phase material have been widely applied in industry to improve the properties of coatings. A variety of hard oxide, carbide, nitride, and ceramic nanoparticles have been successfully co-deposited within different metal matrices. These nano-composite coatings are generally prepared by dispersing the secondary phase particles as a powder in a plating bath by means of vigorous agitation; however, this process is not simple to industrialize and present an environmental hazard if nano materials become airborne. Patented Dopant™ technology from Cirrus Materials Science offers a means to create high value nano-composite coatings without the implementation and process drawbacks of powder mixing. Cirrus Dopant™ is an aqueous form of precursor nano-structured material that supports in-situ creation of nanoparticles during the plating process. This technology is applicable to commercial baths for a large variety of electrolytic and electroless coatings. The improved mechanical properties of nano-reinforced coatings were generally created by refining the microstructure and dispersion strengthening engendered by the presence of the nano-particle. To achieve to optimum results, a customised Dopant™ formulation and dosing regime is required for each bath. Recently, Cirrus discovered that a novel post-treatment process for coatings reinforced with the Cirrus Dopant™ improves the hardness and ductility of the coating by >40%. To date, all the coating created using Cirrus Dopant have shown better mechanical properties after post treatment. This paper discusses the process and latest results for nano-doping commercially relevant coating baths.