Characterization and microhardness of electrodeposited Ni-W coatings obtained from gluconate bath

Bera, Parthasarathi and Dinesh Kumar, M and Anandan, C and Shivakumara, C (2015) Characterization and microhardness of electrodeposited Ni-W coatings obtained from gluconate bath. Surface Review and Letters, 22 (1). ISSN 1793-6667

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Abstract

Ni-W alloy coatings were electrodeposited with direct and pulse current using gluconate bath at pH5. The effects of direct current (DC) and pulse current (PC) on the structural characteristics of the alloys were investigated by EDXS, XRD, FESEM, AFM, DSC and XPS. EDXS shows that W contents are 14.9 and 13.4 at.% in DC and PC Ni-W coatings, respectively. FESEM analysis exhibits the homogeneous coarse nodular morphology for DC plated deposits. The phase transformation behavior of the Ni-W coatings studied using DSC indicates that NiW alloys are thermally stable up to 400 C. XPS studies demonstrate that DC plated alloy has significant amount of Ni and W in elemental form along with their respective oxidized species. In contrast, mainly oxidized metals are present in the as-deposited coatings prepared with PC plating. The microhardness of pulse current (100:400 ratio) deposited Ni-W alloy coating is about 750 HK that is much higher than DC plated coating (635 HK). Heat treatment of the deposits carried out at different temperatures show a significant increase in microhardness which could be comparable with hard chromium coatings.

Item Type:	Article
Additional Information:	Copyright to this article belongs to M/s. World Scientific
Uncontrolled Keywords:	Ni-W coating;Electrodeposition;Gluconate bath;XPS; Microhardness
Subjects:	AERONAUTICS > Aeronautics (General)
Depositing User:	Ms. Alphones Mary
Date Deposited:	25 Jun 2015 10:51
Last Modified:	18 May 2016 08:26
URI:	http://nal-ir.nal.res.in/id/eprint/12132

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