Electrodeposition of Metal into Pores of Ceramic Materials and Their Mechanical and Electrical Properties.

本文报道了一种在室温下将金属离子电沉积到陶瓷材料的孔隙中制备金属/陶瓷复合材料的工艺。新工艺的特点总结如下：(1)金属/陶瓷复合材料的最终微观结构取决于陶瓷材料的初始孔隙结构；(2)溶解在水或非水溶液中的金属离子在低温下电化学沉淀在陶瓷材料的孔隙中，导致不控制加工气氛和不限制金属熔点的可能性；(3)在金属/陶瓷界面上没有或很少发生反应。(4)复合材料中金属的比例由加工过程中通过的电荷控制；(5)一旦电化学反应开始，沉积的金属本身就充当了后续电极，表明金属在陶瓷材料的开放空间中连续进行电化学沉积。基于ab…More over的概念，用多孔氧化铝压块和镍溶液进行了基本实验。在硝酸镍/尿素/乙二醇/硫酸铵的水溶液中，采用110 ~ 300ma的直电流、脉冲电流和锥形电流，通过Ni^<2+ b>离子的电化学反应，将镍渗透到理论密度为37 ~ 62%的多孔氧化铝压块中。沉积镍的重量与t^<0.22-0.64>成正比（t：沉积时间）。对于高孔隙率的氧化铝致密体，在直流电条件下Ni的沉积速率高于脉冲电流或锥形电流。使用脉冲或锥形电流似乎可以抑制Ni在多孔氧化铝中直流电的枝晶生长。在理论密度为93-94%的情况下，复合材料的维氏硬度从镍/氧化铝区域（样品外部）的17.5GPa提高到氧化铝基体内部的21.5GPa，表明形成了功能梯度复合材料。复合材料的位移与应力呈非线性关系，表明脆性陶瓷的加入改善了复合材料的力学性能。复合材料的电学性能正在研究中。少

We report a processing for preparation of metal/ceramic composites by electrical deposition of metal ions into pores of ceramic material at room temperature. The feature of the new processing is to be summarized as follows ; (1) The final microstructure of metal/ceramic composite depends upon a starting pore structure of ceramic material, (2) The metal ions dissolved in an aqueous or a nonaqueous solution are electrochemically precipitated in the pores of ceramic material at a low temprature, leading to possibilities of no control of processing atmosphere and no restriction of a melting point of metal, (3) No or little reaction at the interfaces of metal/ceramics, (4) the fraction of metal in the composite is controlled by the electric charge passed during the processing, (5) Once the electrochemical reaction starts, the deposited metal itself acts as a following electrode, indicating continuous electrochemical deposition of metal in the open spaces of ceramic material. Based on the ab … More ove concept, a basic experiment was performed with porous alumina compacts and a nickel solution.Nickel was infiltrated into porous alumina compacts of 37-62% of theoretical density by electrochemical reaction of Ni^<2+> ions with direct, pulsed and conical current of 110-300mA in an aqueous solution of nickel nitrate/urea/ethylene glycol/ammonium sulfate. The weight of Ni deposited was in proportion to t^<0.22-0.64> (t : deposition time). The deposition rate of Ni was higher for direct current than for pulsed or conical current, and for a higher-porosity alumina compact. Use of pulsed or conical current seemed to suppress the dendritic growth of Ni which was observed in a porous alumina with direct current. The Vickers hardness of composites with 93-94% of theoretical density increased from 17.5GPa in the nickel/alumina region (outside of sample) to 21.5GPa in the inside alumina matrix, indicating formation of a functionally gradient composite. The composite showed a non- linear relation between displacement and stress, indicating the improvement of mechanical properties associated with brittle ceramics. The electrical properties of composite is under investigation. Less