Authors: Akash Singh Somasundaram Murugesan P Parameswaran R Priya R Thirumurugessan N Muthukumar E Mohandas U Kamachi Mudali J Krishnamurthi
Publish Date: 2016/09/12
Volume: 25, Issue: 11, Pages: 4666-4679
Abstract
Zirconium coatings of different thicknesses have been deposited at 773 K on 9Cr1Mo steel substrate using pulsed DC magnetron sputtering These coatings were heat treated in vacuum at two different temperatures 1173 and 1273 K for one hour Xray diffraction XRD analysis of Zrcoated samples revealed the formation of αphase HCP structure of Zr XRD analysis of heattreated samples show the presence of Zr3Fe and Zr2Fe intermetallics The lattice parameter of these coatings was calculated and it matches with the bulk values when the thickness reached 2µm In order to understand this crystallite size and strain values of these coatings were calculated from XRD plots employing WilliamsonHall method In order to assess the performance of the coatings systematic corrosion tests were carried out The corrosion current density calculated from the polarization behavior showed that the corrosion current density of the uncoated 9Cr1Mo steel was higher than the coated sample before and after the heat treatment Studies using electrochemical impedance spectroscopy confirmed that the coated steel has higher impedance than the uncoated steel The corrosion resistance of 9Cr1Mo steel had improved after Zr coating However the corrosion resistance of the coating after heat treatment decreased when compared to the asdeposited coating The microstructure and composition of the surface oxide film influence the corrosion resistance of the Zrcoated 9Cr1Mo steelThe authors thank Smt MJyothi Foreman A MSSCD IGCAR for support during experimental stages of the current studies Further we thank Dr M Vijayalakshmi Associate Director PMG Dr A K Bhaduri Director MMG and Dr SAV Satya Murty Director IGCAR for their continuous support and encouragement
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