Availableonlineatwww.sciencedirect.com Materials ScienceDirect Research Bulletin ELSEVIER Materials Research Bulletin 43(2008)1814-1828 Optimization of electrophoretic deposition of alumina onto steel substrates from its suspension in iso-propanol using statistical design of experiments Gauray mohanty a, Laxmidhar Besra., * Sarama Bhattacharjee b, Bimal P. Singh b Colloids and Materials Chemistry Research Group, Regional Research Laboratory(CSIR), Bhubaneswar 751013, Orissa, India Received 12 February 2007; received in revised form 17 June 2007: accepted 3 July 2007 Available online 17 July 2007 Abstract .n Statistical design of experiments was used to investigate the effect the process parameters on electrophoretic deposition(EPD)of alumina onto steel substrates from its suspension in iso-propanol. The process parameters considered were() concentration of particles in the suspension(solid loading), (ii)electrode separation, (iii)applied potential, and (iv)deposition time on the quantity ceramic particles electrophoretically deposited. A 2" full factorial matrix, with four repetitions of the center point, was used to develop the predictive regression equation for deposition of alumina per unit area of the electrode in the design space. The results show that particle concentration has the most dominant effect with more than 50%o contribution to the deposited amount. A good correlation was obtained between predicted and experimental values suggesting that the model can predict data accurately in the experimental matrix. C 2007 Elsevier Ltd. All rights reserved. Keywords: A. Ceramics: A. Composites; A. Multilayers; A. Thin films 1. Introduction lectrophoretic deposition(EPD), a colloidal deposition technique in ceramic processing has recently gaine ncreased application in a variety of field including preparation of thick film of silica [1], nano-size zeolite membrane [2], hydroxyapatite coating on metal substrate for biomedical applications [3, 41, luminescent materials[5-7 high-Tc superconducting films [8,9], gas diffusion electrodes and sensors [10,11], multi-layer composites [12], glass and ceramic matrix composites by infiltration of ceramic particles onto fibre fabrics [13], oxide nano-rods[ 14], carbon nanotube film [15], functionally graded ceramics [16, 17], layered ceramics [18], superconductors [19, 2( piezoelectric materials [21],etc. In EPD process, charged powder particles, dispersed stably in a liquid medium are attracted and deposited onto a substrate of opposite charge on application of a dc electric field. The advantages of EPD include simplicity, low cost equipment, good control of deposition thickness, short formation time, little restriction on the shape of the substrate, suitability for mass production, and no requirement for binder burnout as the green coating contains fewer or no Corresponding author E-mail address: ldbesra@rrlbhu res in (L. Besra). D025-5408/S- see front matter C 2007 Elsevier Ltd. All rights reserved doi: 10. 1016/j. materresbull 2007.07 014Optimization of electrophoretic deposition of alumina onto steel substrates from its suspension in iso-propanol using statistical design of experiments Gaurav Mohanty a , Laxmidhar Besra b, *, Sarama Bhattacharjee b , Bimal P. Singh b a Department of Metallurgy and Materials Engineering, National Institute of Technology Karnataka, Surathkal 575025, Karnataka, India bColloids and Materials Chemistry Research Group, Regional Research Laboratory (CSIR), Bhubaneswar 751013, Orissa, India Received 12 February 2007; received in revised form 17 June 2007; accepted 3 July 2007 Available online 17 July 2007 Abstract Statistical design of experiments was used to investigate the effect the process parameters on electrophoretic deposition (EPD) of alumina onto steel substrates from its suspension in iso-propanol. The process parameters considered were (i) concentration of particles in the suspension (solid loading), (ii) electrode separation, (iii) applied potential, and (iv) deposition time on the quantity of ceramic particles electrophoretically deposited. A 24 full factorial matrix, with four repetitions of the center point, was used to develop the predictive regression equation for deposition of alumina per unit area of the electrode in the design space. The results show that particle concentration has the most dominant effect with more than 50% contribution to the deposited amount. A good correlation was obtained between predicted and experimental values suggesting that the model can predict data accurately in the experimental matrix. # 2007 Elsevier Ltd. All rights reserved. Keywords: A. Ceramics; A. Composites; A. Multilayers; A. Thin films 1. Introduction Electrophoretic deposition (EPD), a colloidal deposition technique in ceramic processing has recently gained increased application in a variety of field including preparation of thick film of silica [1], nano-size zeolite membrane [2], hydroxyapatite coating on metal substrate for biomedical applications [3,4], luminescent materials [5–7], high-Tc superconducting films [8,9], gas diffusion electrodes and sensors [10,11], multi-layer composites [12], glass and ceramic matrix composites by infiltration of ceramic particles onto fibre fabrics [13], oxide nano-rods [14], carbon nanotube film [15], functionally graded ceramics [16,17], layered ceramics [18], superconductors [19,20], piezoelectric materials [21], etc. In EPD process, charged powder particles, dispersed stably in a liquid medium are attracted and deposited onto a substrate of opposite charge on application of a dc electric field. The advantages of EPD include simplicity, low cost equipment, good control of deposition thickness, short formation time, little restriction on the shape of the substrate, suitability for mass production, and no requirement for binder burnout as the green coating contains fewer or no www.elsevier.com/locate/matresbu Materials Research Bulletin 43 (2008) 1814–1828 * Corresponding author. E-mail address: ldbesra@rrlbhu.res.in (L. Besra). 0025-5408/$ – see front matter # 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.materresbull.2007.07.014