Pulse Anodizing—An Overview

Abstract

SUMMARYAnodizing is a versatile method used to prevent a metal from corrosion by forming an oxide coating over its surface. Various power supplies such as D.C., A.C. and A.C. superimposed on D.C. are used in industrial anodizing depending upon the different fields of application. For specific applications, especially for hard anodizing of aluminium containing high copper and silicon, the importance of the pulse current technique has been recognised. This paper reviews the entire history of pulse anodizing of metals such as aluminium, drawbacks of other existing power sources, advancement of pulse power sources and applications of pulse current techniques in various types of anodizing such as general pulse anodizing, pulse hard anodizing and pulse colour anodizing.Keywords: AnodizingPulse currentPulse VoltageDuty Cycle and Frequency Additional informationNotes on contributorsV. RajDr. V. Raj has completed his B.Sc. (1988), M.Sc.(1991) and Ph.D (1999) degrees in chemistry from Madurai Kamaraj University, Madurai. He has 10 years of experience in teaching and research and has worked as a lecturer, SN College, Madurai for one year. Since 1997, he has been working as a scientist at Central Electrochemical Research Institute, Karaikudi. His fields of interest are anodizing, electrochemical and chemical deposition, electrochemical and chemical polishing of metals. He has published 10 research papers and presented thirty research papers at national and international conferences.M. P. RajaramM. P. Rajaram and G. Balasubramanian are in the final year B.Tech, degree in Chemical and Electrochemical Engineering. Both are working on various projects related to electrochemical engineering and each has published 2 research papers.G. BalasubramanianM. P. Rajaram and G. Balasubramanian are in the final year B.Tech, degree in Chemical and Electrochemical Engineering. Both are working on various projects related to electrochemical engineering and each has published 2 research papers.S. VincentSri S. Vincent obtained his B.E. degree from Madurai Kamaraj University, Madurai in Electrical and Electronics Engineering in 1989. He received his M.S. degree from BITS, Pilani in Electronics and Control Engineering in 1994. Presently he is studying for his Ph.D. He has been working in the Electrochemical and Electronics Instrumentation division of Central Electrochemical Research Institute, Karaikudi since 1982. His fields of interest are electrochemical instrumentation, microprocessor and computer based instruments. He has 10 patents to his name and published more than 30 research papers in reputable journals.D. KanagarajDr. D. Kanagaraj, senior scientist, obtained his B.Sc. and M.Sc. degrees from the University of Madras with specialisation in inorganic and analytical chemistry. He obtained his doctoral degree in industrial chemistry from Alagappa University, Karaikudi. He has been working as a scientist in Central Electrochemical Research Institute, Karaikudi since 1964. He has long experience in the field of anodizing and metal finishing, and has 15 patents and published more than 50 research papers in reputable national and international journals. He has developed improved technologies to Indian industries in the field of anodizing.