Electrophoretic deposition of thin alumina films from water suspension K. Simovic, V.B. Miskovic-Stankovic*, D. Kicevic, P. Jovanic Physicochemical and Engineering Aspects 209 (2002) 47–55 Advisor : Prof. S.C.Wang Advisee : Jyun-Jia Huang 1

outline Introduction Experimental Results and discussion Conclusions Future work 9

Introduction 近年來，電泳沉積常被使用在複合層、薄層、絲、有機陶瓷和生物陶 瓷上。 在這篇報告中，主要是製備出最佳的氧化鋁水懸浮液參數，獲取孔隙 率最低的薄膜 ( zeta 電位、低黏度、施加電壓、沉積時間 and 懸浮液濃度 ) Zeta 電位、 黏度計、 OM and SEM. 9

Experimental DI water Dolapix ET wt.% alumina A16SG 10 、 20 、 30 wt.% ball mill for 2 h without balls for 1 h EPD dried at room temperature SEMOM 9 polyvinyl alcohol 1.0 wt.% pH 4 by 65% nitric acid EPD 參數 D.C = V cathode ： steel (5X5 mm) ， anode ： Pt distance ： 18 mm deposition time = 2 、 5 、 10 min δ ＝ G(ρS) -1 δ ： thickness of alumina films G ： w 2 -w 1 ρ ： 3.96 g cm -3 (powder density) S ： surface area of the steel 分散劑凝聚劑

Results and discussion 9 分散劑 ξ (mV) Treated suspensionUntreated suspension Dolapix PC Dolapix ET Table 1 The values of zeta potential, ξ, of alumina suspension ( treated and untreated in the ultrasonic bath) for different type of deflocculant X-ray diffraction pattern of alumina poweder AlcoaA-16 SG

3 The viscosity of the alumina suspension versus deflocculant content. 分散劑濃度 (wt.%) ξ (mV) Table 2 The values of zeta potential, ξ, of alumina suspension for different content of deflocculant Dolapix ET 85 過多的分散劑會破壞懸浮液的穩定性

4 Alumina film thickness as a function of applied deposition voltage (range V) for concentration of: (a) 10 wt.%, (b) 20 wt.% and (c) 30 wt.% alumina suspension, and different deposition time.

6 Alumina film thicknes as a function of applied deposition voltage (range V) for concentration of: (a) 10 wt.%, (b) 20 wt.% and (c) 30 wt.% alumina suspension, and different deposition time.

5 The percentage of alumina film surface covered by pores versus applied deposition voltage for different content of alumina powder in suspension (deposition time: 10 min). The pore number vs. applied deposition voltage in the range of: (a) V and (b) V, for 20 wt.% alumina suspension and different deposition time. 30V

7 The percentage of alumina film surface covered by pores vs. applied deposition voltage in the of: (a) V and (b) V, for 20 wt.% alumina suspension and different time. Dependence of mean pore diameter on aplied deposition voltage in the range of: (a) V and (b) V, for 20 wt.% alumina suspension and different deposition time

8 Fig. 9. The microphotographs of alumina film surface electrodeposited from 20 wt.% alumina suspension at 30 V and for deposition time of 10 min: (a) optical microscope view and (b) scanning electron microscope view.

Conclusions 為了在不繡鋼上沉積氧化鋁薄膜，氧化鋁水懸浮液必須 要高 zeta 電位和低黏度。 最佳的氧化鋁薄膜參數為施加電壓 :30V 、懸浮液濃度 為 20wt.% 和沉積時間 10min 。 9

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