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This work describes the use of polymer dextran to enhance the corrosion protection of epoxy coating applied on 6061 Al-15% (v) SiC (p) composite material (Al-CM). Initially, conditions were established to obtain optimum inhibition efficiency of dextran. Electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy were adopted for the corrosion rate measurements. Later, the same techniques were employed to study the corrosion rate of the epoxy resin coated composite material (EC-CM) before and after the addition of environmentally benign dextran polymer. Detailed investigation of the surface morphology of the coated Al-CM was carried out using scanning electron microscopy, energy dispersion X-ray analysis, and atomic force microscopy techniques. The work which is done with dual purpose, establishes not only the anticorrosive property of dextran, but also proves its ability to improve the coating characteristics of epoxy resin on Al-CM.

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Corrosion resistance properties of Ti/TiN and TiAl/TiAlN nanolayered multilayered coatings deposited on Ti6Al4V alloy substrates by unbalanced magnetron sputtering were investigated. The coatings contain a bi-layer thickness of Ti/TiN or TiAl/TiAlN ~3.5/4 nm and the total thickness of the coating is ~ 9 µm. Corrosion properties of the coatings were investigated using electrochemical impedance spectroscopy (EIS) for 30 days while immersed in 3.5 wt.% NaCl solution. EIS investigation of the coatings showed that the corrosion occurred due to the penetration of electrolyte and oxygen through the micro/nano pores present in the coatings. It was found that the TiAl/TIAlN coating offered corrosion protection superior to that of the Ti/TiN coating during the immersion study. Potentiodynamic polarization studies revealed that both coatings showed passive behaviour. Formation of a passive film on the coated surface during polarization enhanced the barrier properties of the coatings and provided anodic protection to the underlying alloy.