ABSTRACT
The effects of the applied voltage on the morphology, composition and corrosion behaviour of Ti7Cu5Sn coated were investigated. At applied voltages lower than 250 V, the composite coatings consist of anatase-TiO2, rutile-TiO2, DCPD(CaHPO4·2H2O) and a small amount of amorphous calcium phosphate phase. When the applied voltage is increased, the ceramic coatings transform from DCPD (CaHPO4·2H2O) to HA (Ca10(PO4)6(OH)2, 300 V), and new phases of Ca2P2O7, CaTiO3 and TCP(Ca3(PO4)2) form at 350 V. The passive current densities at body potential are one order of magnitude lower than that of the uncoated sample, indicating better corrosion resistance. The MAO film is a tri-layer system: a compact inner layer, a mesosphere porous oxide layer, and an outer layer.
Acknowledgements
SEM was performed by the Precision Instrument Center of the National Pingtung University of Science and Technology, Taiwan.
Disclosure statement
No potential conflict of interest was reported by the author.
Notes on contributor
Lung-Chuan Tsao, professor is the National Pingtung University of Science and Technology, College of Engineering, Department of Materials Engineering. He received his BS in industry education/Nation Taiwan normal University, MS in Engineering/National Center University and PhD in Material Science/National Taiwan University. His research interests cover multi-disciplinary aspects of electronics packaging, special joining, biomaterial, 3D powder and art-material, with emphasis on materials characterization and the application of materials and mechanical engineering fundamentals to sound product design. His current research interests are in the areas of special solders filler, biomaterial and art-material.