Ni-Al₂O₃快速复合镀工艺的研究

【作者】 王红星；

【导师】 林萍华； 董寅生；

【作者基本信息】 东南大学 ， 材料加工工程， 2004， 硕士

【摘要】 采用正八棱柱体形状的阴极,在普通的瓦特型镀液中加入氧化铝颗粒制备复合镀层,研究了阴极电流密度、搅拌速度和颗粒在镀液中的浓度等因素对复合镀层厚度和镀层内粒子含量与阴极不同方向之间的关系。实验结果表明,阴极电流密度、搅拌速度和镀液中Al2O3含量都对镀层中复合粒子的含量有明显的影响,总体趋势是与阳极距离近的方向,镀层厚、粒子含量多,且各个位向之间的厚度和含量随工艺条件的不同而变化。采用使镀液垂直于阴极表面和平行于阴极表面两种方向的定向流动进行复合镀,以减小阴极表面扩散层的厚度,从而提高阴极电流密度,加速Al2O3与基质金属镍的共沉积速度,增加颗粒在镀层中的沉积量。初步研究结果表明,通过采取使镀液定向流动的途径,能够提高复合镀层的沉积速率,但对提高颗粒在镀层内的沉积量不很明显,其内在规律,还有待进一步深入研究。在一定的电流密度,适当的搅拌速度和颗粒浓度条件下,通过旋转阴极,使镀层在确定的时间内,按一定的规律分别位于不同的位向,就可能得到粒子含量随镀层厚度变化的梯度镀层,为制备复合材料提供了一种新的方法。更多还原

【Abstract】 An octangonal cathode was designed and used and the Ni-Al2O3 composite coating was produced in watt’ solution with Al2O3 particles in the dissertation. The relationship of the coating thickness and the mount of particles in the composite coatings with the current density, stirring rate and the particle content in electrolyte were studied. Result show that the current density, the speed of the rotation and Al2O3 content in electrolyte influence the content of particles of the composite coatings obviously. The whole tendency is that the more thickness and particle content in the composite coatings, the nearer distance from the anode to the plated layer, the coatings thickness and it’s particle content vary with the technological parameters. When the current density was 10 A/dm2 and stirring rate 350r/min, the most amount of particle contents of different coatings gained too as the particle concentration was 80 g/L in the electrolyte.The co-deposition was performed using the directional flowing of the electrolyte with two directions of the perpendicularity and the horizon in order to reduce the thickness of the diffusion layer close to the cathode, enhance the current density, and accelerate the rate of the co-deposition Al2O3 and nickel. Result showed that the rate of co-deposition was increased by means of making the electrolyte flow along the surface of the cathode in certain direction, while it is not obvious how to increase the content of particle in the coating. The inherent principle was needed further study in the future experiments.Under certain current density, stirring rate and Al2O3 particle concentration in the plating solutions, the functional gradient coating with particle continuously distributed in the direction of thickness was prepared by roatating the cathode according to a decided regularity, which provide a new technique for fabrication of functional gradient materials.更多还原