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Electroplating and characterization of Cr–Al2O3 nanocomposite film from a trivalent chromium bath

Mohsen Salehi Doolabi (Department of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran)
Sayed Khatiboleslam Sadrnezhaad (Department of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran)
Davood Salehi Doolabi (Department of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran)

Anti-Corrosion Methods and Materials

ISSN: 0003-5599

Article publication date: 27 May 2014

Abstract

Purpose

The main aim of this study was to improve current efficiency and to obtain thicker coatings via aluminum oxide (Al2O3) addition to the chromium (Cr) (III) bath.

Design/methodology/approach

Pure Cr and nanocomposite Cr–Al2O3 coatings were electrodeposited from Cr (III) bath onto cathode copper substrates by conventional method. Dependence of current efficiency to current density, Al2O3 content and particle size were investigated.

Findings

Current efficiency increased with Al2O3 amount and decreased with Al2O3 particle size. Maximum current efficiency was achieved at 25 A/dm2 for pure Cr and 30 A/dm2 for composite coatings. Al2O3 bath content, current density and stirring rate increased the coating Al2O3 weight per cent significantly. Addition of Al3+ bath composition inhibited nanoparticle agglomeration, increasing film homogeneity. Cr–Al2O3 nanocomposites showed higher microhardness and better corrosion resistance than pure Cr layer.

Originality/value

Cr (III) is not as toxic and as carcinogenic as Cr (VI) which is widely used for Cr electroplating these days. Low current efficiency and poor product quality are, however, major drawbacks of the former. This paper describes significant improvements obtainable by addition of Al2O3 nanoparticles to the Cr (III) bath for increasing the microhardness, the corrosion resistance and the current efficiency of the deposition.

Keywords

Acknowledgements

Financial support of Vice President of research of Sharif University of Technology under Quality Program No. 7100.14592 is appreciated.

Citation

Salehi Doolabi, M., Khatiboleslam Sadrnezhaad, S. and Salehi Doolabi, D. (2014), "Electroplating and characterization of Cr–Al2O3 nanocomposite film from a trivalent chromium bath", Anti-Corrosion Methods and Materials, Vol. 61 No. 4, pp. 205-214. https://doi.org/10.1108/ACMM-12-2012-1227

Publisher

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Emerald Group Publishing Limited

Copyright © 2014, Emerald Group Publishing Limited