【作者】 韩东生；

【导师】 荆天辅；

【作者基本信息】 燕山大学 ， 材料学， 2004， 硕士

【摘要】 本文主要研究喷射电沉积法制备块体纳米晶镍的阴极极化及其机理，利用恒电位仪、透射电子显微镜、X射线衍射仪、扫描电镜、磁性能测定仪等工具研究了喷射速度、邻磺酰苯酰亚胺添加剂、电解液组成与温度对阴极极化行为、沉积层晶粒尺寸及其微观组织结构、沉积层磁学性能等方面的影响。并探索了喷射电沉积高电流密度范围内阴极出现高过电位的原因。结果表明： (1)喷射电沉积阴极极化受电子转移步骤和液相传质步骤联合控制，阴极出现高过电位是由水合镍离子电化学反应缓慢以及氢原子在阴极表面的吸附共同作用导致。(2)喷射速度由0.83 m/s增大到5.00 m/s时，阴极过电位由1.35 V增至6.30 V(200 A/dm2)，沉积层晶粒尺寸由22.6 nm减小到18.9 nm。电解液主盐浓度增加，阴极过电位降低。电解液温度由40℃升高到60℃时，阴极过电位由3.80 V降低到2.95 V(150 A/dm2)，极限电流密度增大。电解液中加入少量邻磺酰苯酰亚胺(糖精)，阴极极化增大，沉积层平均晶粒尺寸在8 nm左右。糖精浓度高于2.5 g/l，阴极过电位不再显著增大。(3)本文实验条件下，增大喷射速度，沉积层晶粒尺寸降低，沿(111)易磁化晶面方向优先生长，沉积层矫顽力减小而剩磁增大；增大电流密度，沉积层沿(111)易磁化晶面方向优先生长趋势减弱，矫顽力和剩磁均增大。更多还原

【Abstract】 Principle of cathodic polarization in jet electrodeposited bulk nano- crystalline Ni was studied in this paper. Influence of jet flow rate, bath composition, temperature, additive on cathodic polarization action, grain size, microstructure and magnetic performance of depositions were investigated by potentiostatic apparatus, transition electron microscope (TEM), X-ray diffraction(XRD), scanning electron microscope(SEM) and measure magnetism performance(VSM). The reason of high cathodic overpotential under high current density was probed synchronously. The experimental results show that:(1)Cathodic polarization in jet electrodeposition is controlled by electronic transfer step and liquid transmission step. High cathodic overpotential is caused by slow electrochemistry reaction of nickel ion and adsorption of hydrogen atom on cathodic surface together.(2)Cathodic overpotential increases from 1.35 V to 6.30 V(200 A/dm2) and grain size decreases from 22.6 nm to 18.9 nm when the electrolyte flow rate increases from 0.83 m/s to 5.00 m/s. With increasing Ni2+ concentration of electrolyte, cathodic overpotential decreases. Temperature increases from 40℃ to 60℃, cathodic overpotential decreases from 3.80 V to 2.95 V(150 A/dm2) and limited current density increases. Effect of additive on cathodic polarization is obvious. But this effect becomes more minute when concentration of additive exceeds 2.5 g/l. Grain size of deposits is about 8.0 nm.(3) Coercive force decreases and remanence increases when increasing jet flow rate because there is prone to (111) magnetization orientation. Coercive force and remanence increases while current density increases, because it become weaker at (111) magnetization orientation of deposits.更多还原