Characterization and corrosion behavior of Co and Co–P coatings electrodeposited from chloride bath

Ezhil Selvi, V and Seenivasan, H and Bera, Parthasarathi and Anandan, C (2014) Characterization and corrosion behavior of Co and Co–P coatings electrodeposited from chloride bath. RSC Advances, 4 . 46293-46304 .

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    Abstract

    Low and high phosphorous Co-P coatings are electrodeposited using direct current (DC) and pulse current (PC) methods from cobalt chloride baths. Low phosphorous coatings from DC and PC methods are crystalline and displayed predominantly fcc structure while the high P coatings are amorphous. Electrochemical corrosion studies show an increase in corrosion resistance with increase in phosphorous in both DC and PC plated coatings. PC coatings show higher polarization resistance (Rp) and lower corrosion current density (icorr) suggesting better corrosion resistance of these coatings. Compositional analysis shows a slight or no increase in P content after corrosion in PC coatings with high P exhibiting better corrosion resistance. Comparisons of surface morphologies before and after corrosion illustrate that PC plated coatings are less affected compared to their DC counterparts. Higher amount of oxidized cobalt in PC electrodeposited coatings is deduced from X-ray photoelectron spectroscopy (XPS) while mainly metallic Co species is found in DC plated coatings. This study demonstrates that the overall corrosion resistance for the PC deposited coatings is better than the DC deposited coatings owing to reasons like high P content, amorphous structure, smooth morphology and higher metal oxide content in the deposits.

    Item Type: Journal Article
    Additional Information: Copyright to this article belongs to M/s. Royal Society of Chemistry
    Uncontrolled Keywords: Co–P eletrodepostion;Corrosion;XPS;Hard chromium replacement
    Subjects: CHEMISTRY AND MATERIALS > Chemistry and Materials (General)
    Division/Department: Surface Engineering Division, Surface Engineering Division, Surface Engineering Division, Surface Engineering Division
    Depositing User: Ms. Alphones Mary
    Date Deposited: 09 Oct 2015 11:43
    Last Modified: 09 Oct 2015 11:43
    URI: http://nal-ir.nal.res.in/id/eprint/12374

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