Suchergebnisse

The plasma electrolytic oxidation is an innovative method for the surface treatment of titanium and its alloys. This review provides an overview of the historical development of the process and summarizes the current state of the art. The chemical as well as the electro- and plasma-chemical basics of the layer forming mechanisms, which comprises the substrate/electrolyte interface before discharge initiation and the different types and stages of plasma electrolytic discharge phenomena are explained within the context of titanium-based materials. How these phenomena can be influenced by the use of suitable electrolytes and controlled by the electrical regime is described. Subsequently, the microstructures and composition of the layers are described in detail, and the properties for specific applications are then discussed. The resistance of a PEO coating to corrosive environments, tribological factors, and alternating mechanical stress is viewed critically, and the extensive functional properties such as physiological compatibility, photocatalytic activity, and decorative properties are revealed. Finally, examples of various practical applications in the medical engineering, aviation, automotive, and environmental technology fields, as well as other branches of industry, are presented. ; M. Aliofkhazraei acknowledges comments received from Prof. A. Yerokhin during intial steps of preparation of this review paper. D.D. Macdonald gratefully acknowledges the support of the FUTURE (Fundamental Understanding of Transport Under Reactor Extremes), an Energy Frontier Research Center funded by the U.S. Department of En- ergy (DOE), Office of Science, Basic Energy Sciences (BES). E. Matykina would like to thank the support of the RTI2018-096391-B-C33 (MCIU/ AEI/FEDER, UE) and S2018/NMT-4411 (Regional Government of Madrid and EU Structural and Social Funds). S.V. Gnedenkov ac- knowledges the support of the Russian Science Foundation (No. 20-13- 00130).