【作者】 王楠；

【导师】 荆天辅；

【作者基本信息】 燕山大学 ， 材料学， 2006， 硕士

【摘要】 本文采用电解液喷射电沉积法制备了纳米晶钴镍合金。利用扫描电子显微镜（SEM）、能谱分析（EDS）、透射电子显微镜（TEM）、X射线衍射仪（XRD）、差热分析仪（DSC）、恒电位仪和显微硬度仪等方法研究了电解液温度、电解液Co²⁺离子浓度、电流密度与添加剂（邻磺酰苯酰亚胺）对喷射电沉积阴极极化行为、沉积层微观组织结构和显微硬度等方面的影响;利用差热分析法对沉积层的热稳定性进行了研究。实验结果表明:喷射电沉积阴极极化主要受电化学反应步骤控制。电解液温度的升高导致阴极极化减弱,沉积层晶粒尺寸增大;电解液Co²⁺浓度增加,Co-Ni合金沉积层中Co含量明显增加;添加剂（邻磺酰苯酰亚胺）使阴极极化增大,沉积层晶粒尺寸明显减小,但对沉积层Co含量影响很小;电流密度增加,阴极过电位增大,沉积速率提高,晶粒尺寸下降,显微硬度提高,但对沉积层Co含量影响很小。平均晶粒尺寸5.1 nm的Co₇₈Ni₂₂合金镀层,晶粒尺寸长大分为三个阶段:孕育阶段（小于370℃）,晶粒急剧长大阶段（370-400℃）和晶粒正常长大阶段（大于400℃）;差热分析得出,加热速度10℃·min^-1时,晶粒长大峰温度范围368-419℃,峰值温度389℃,平均放热焓变14.05±0.33 J·g^-1。JMA法求出晶粒长大激活能为4.57 kJ·g^-1。Co₇₈Ni₂₂合金镀层晶粒尺寸在5.1-34.4 nm之间,显微硬度符合Hall-Petch关系。更多还原

【Abstract】 Nanocrystalline Co-Ni alloys deposits prepared by Jet-electrodepositionwere studied. The influence of temperature, Co²⁺ content, current density,additive on cathodic polarization, grain size, microstructure and microhardnessof deposits were investigated by potentiostatic apparatus, transition electronmicroscope （TEM）, X-ray diffraction （XRD）, scanning electron microscope（SEM） and microhardness tests. The thermal stability of nanocrystallineCo₇₈Ni₂₂ alloys deposits were investigated in situ by synchrotron X-raydiffraction and differential scanning calorimetry （DSC）. The experimentalresults show that:Cathodic polarization in Jet-electrodeposition is mostly controlled byelectrochemical interaction. Increasing the temperature of the bath could lowerthe cathodic overpotential and increased the grain size of deposits. The changeof Co²⁺ content had little influence on cathodic polarization, but had deeplyinfluenced on Co content of Co-Ni alloys deposits. Additive （saccharin） couldaugment the cathodic polarization and refined the grain size obviously, but hadlittle influence on Co content of deposits and current efficiency;Increasing thecurrent density could decreased the cathodic potential, increased the depositingspeed, refined the grain size and enhanced the microhardness, but had no effecton Co content of deposits and current efficiency.The growth of grain include three steps: the first step is incubation at thetemperature under 370℃, the second step is grow evidently step at 370℃ to400℃, the final step is grow normally at the temperature exceed 400℃. Atheating rate 10℃·min^-1, the temperature of grain growth extension is 368℃ to419℃, the peak temperature of heating is 389℃, the average heat enthalpy is14.05±0.33 J·g^-1. Activation energy values of grain growth are 4.57 kJ·g^-1 byJMA equation. The grain size of nanocrystalline Co78Ni22 alloys at 5.1-34.4 nm,the microhardness accord with the Hall-Petch relationship.更多还原