Optimising sulfuric acid hard coat anodising for an Al-Mg-Si wrought aluminium alloy

Open access


This research evaluates the effects of sulfuric acid hard coat anodising parameters, such as acid concentration, electrolyte temperature, current density and time, on the hardness and thickness of the resultant anodised layers. A small scale anodising facility was designed and set up to enable experimental investigation of the anodising parameters. An experimental design using the Taguchi method to optimise the parameters within an established operating window was performed. Qualitative and quantitative methods of characterisation of the resultant anodised layers were carried out. The anodised layer’s thickness, and morphology were determined using a light optical microscope (LOM) and field emission gun scanning electron microscope (FEG-SEM). Hardness measurements were carried out using a nano hardness tester. Correlations between the various anodising parameters and their effect on the hardness and thickness of the anodised layers were established. Careful evaluation of these effects enabled optimum parameters to be determined using the Taguchi method, which were verified experimentally. Anodised layers having hardness varying between 2.4–5.2 GPa and a thickness of between 20–80 μm were produced. The Taguchi method was shown to be applicable to anodising. This finding could facilitate on-going and future research and development of anodising, which is attracting remarkable academic and industrial interest.

[1] Miller W.S., Zhuang L., Bottema J., Wittebrood A.J., De Smet P., Haszler A., Vieregge A., Mat. Sci. Eng. A-Struct., 280 (2000), 37. http://dx.doi.org/10.1016/S0921-5093(99)00653-X

[2] European Aluminium Association, Aluminium in Cars, 9 (2008), http://www.alueurope.eu/pdf/Aluminium_in_cars_Sept2008.pdf.

[3] Hirsch J., Mater. Forum., 28 (2004), 15.

[4] Yerokhin A., Khan R.H.U., Anodising of Light Alloys, in: DONG H. (Ed.), Surface Engineering of Light Alloys: Aluminium, Magnesium and Titanium Alloys, Woodhead Publishing Ltd., Cambridge, 2010, p. 83. http://dx.doi.org/10.1533/9781845699451.2.83

[5] Ghazali M.J., Jurnal Kejuruteraan, 18 (2006), 49.

[6] Skoneczny W., Mater. Sci.+, 46 (2010), 276. http://dx.doi.org/10.1007/s11003-010-9285-1

[7] Velterop L., ATB Metallurgie, 43 (2003), 284.

[8] Runge J.M., Pomis A.J., Plat. Surf. Finish., 90 (2003), 60.

[9] Henley V.F., Anodic Oxidation of Aluminium and its Alloys, Pergamon Press, London, 1982.

[10] Sadeler R., J. Mater. Sci., 41 (2006), 5803. http://dx.doi.org/10.1007/s10853-006-0725-0

[11] Probert R.H., Aluminum How To: The Chromatizing, Anodizing, Hard Coating Handbook, Raleigh, NC: Tailored Text, 2005.

[12] Fang T.-H., Wang T.H., Kang S.-H., Chuang C.-H., Curr. Appl. Phys., 9 (2009), 880–883. http://dx.doi.org/10.1016/j.cap.2008.08.034

[13] Aerts T., Dimogerontakis Th., De Graeve I., Fransaer J., Terryn H., Surf. Coat. Tech., 201 (2007), 7310. http://dx.doi.org/10.1016/j.surfcoat.2007.01.044

[14] Runge J., Pomis A., 2006 EBRATS — Brazilian Surface Treatment Meeting and II Latin-American Interfinish, Sao Paulo, May 10, 2006.

[15] Critchlow G.W., Yendall K.A., Bahrani D., Quinn A., Andrews F., Int. J. Adhes. Adhes., 26 (2006), 419. http://dx.doi.org/10.1016/j.ijadhadh.2005.07.001

Journal Information

IMPACT FACTOR 2017: 0.854
5-year IMPACT FACTOR: 0.794

CiteScore 2017: 0.90

SCImago Journal Rank (SJR) 2017: 0.275
Source Normalized Impact per Paper (SNIP) 2017: 0.471


All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 53 53 15
PDF Downloads 10 10 6