Establishment of Net-shaping Process of Ceramics by Electrophoretic Deposition

研究了具有三种不同烷氧官能团（乙基、丁基和丁氧乙基）的磷酸酯（PE）制备的氧化铝乙醇悬浮液的稳定性及其对电泳沉积特性的影响。通过测定悬浮液的pH、电导率、ζ电位和沉积产率，在不同的实验条件下表征了颗粒的充电机理。用磷酸丁氧乙酸制备的悬浮液稳定性最高，但三种悬浮液的电位非常相似。这归因于烷氧基官能团的空间排斥力。磷酸酯使氧化铝颗粒带正电，从而使阴极沉积发生。zeta电位、沉积产量和绿密度是PE添加量的函数，zeta电位最高时绿密度最高，而PE添加量最低时沉积速率最低。PE的过量添加导致zeta电位和绿密度降低，但增加了沉积物与金属基体的附着力。过量添加的PE悬浮液获得了表面光滑的厚沉积物。将导电聚吡咯（Ppy）薄膜均匀涂覆在非导电陶瓷材料上，并在电泳沉积（EPD）工艺中作为衬底。在吡咯（Py）溶液中采用化学氧化法合成了吡咯吡啶。以Fe （III）离子为氧化剂，采用光刻技术对Ppy进行了线形加工。以Ppy薄膜为阴极，用EPD对氧化铝或氧化锆颗粒进行了直接成形或线条图案化。

The stability of alumina ethanol suspensions prepared with phosphate esters (PE) having three different alkoxy functional groups (ethyl, butyl and butoxyethyl and the corresponding effects on the electrophoretic deposition characteristics were investigated. The mechanism of particle charging was characterized by measuring the suspension pH, conductivity, zeta-potential and deposition yield under various experimental conditions. The highest stability was observed for the suspension prepared with the butoxyethyl acid phosphate though the zeta-potentials of the three suspensions were very similar. This was attributed to the steric repulsion of the alkoxy functional group. The phosphate esters made the alumina particles positively charged which allowed the cathodic deposition to occur. The zeta-potential, deposition yield and green density were functions of the PE addition amount The highest green density was obtained at the highest zeta-potential, however, the deposition rate for this PE amount was the lowest. The over-addition of PE caused decreases in the zeta potential and green density, but an increase in the adhesion of the deposit to a metal substrate. Thick deposits with smooth surfaces were obtained from the over-added PE suspension.The uniform coating and the line patterning of a conductive polypyrrole (Ppy) film on non-conductive ceramic materials was performed for use as substrates in the electrophoretic deposition (EPD) process. The Ppy was synthesized by chemical oxidation in the pyrrole (Py) solution. The line patterning of Ppy was conducted by a photo lithographic technique using Fe (III) ions as the oxidant. The direct shaping or the line pattering of alumina or zirconia particles by EPD was carried out using the Ppy films as cathodes.