磁场作用对化学复合镀Ni-P-金刚石影响机理研究

发布时间：2018-04-05 10:55

本文选题：化学复合镀　切入点：匀强磁场　出处：《青岛科技大学》2015年硕士论文

【摘要】：本文采用化学复合镀技术,在磁场影响的环境下通过向传统的Ni-P化学镀液中加入亚微米金刚石颗粒,制备了Ni-P-金刚石化学复合镀层。作为对比,同时使用传统化学复合镀工艺制备了无磁场影响的Ni-P-金刚石复合镀层。本文使用的金刚石颗粒尺寸在0.01-0.5μm之间,其平均尺寸为0.251μm。利用金相显微镜、涂层附着力测试仪、带能谱的扫描电子显微镜(SEM/EDS)、摩擦磨损试验机等技术和设备,研究了磁场强度对镀层中金刚石浓度、形态、尺寸的影响；利用特斯拉计对通电螺线管内的磁场场强分部进行计算和测试并构建匀强磁场、梯度磁场环境,结合磁化学理论、吸附理论对磁场影响化学复合镀的机理进行了分析。结果显示,在匀强磁场环境下,复合镀层中金刚石颗粒的含量、尺寸、分散状态明显受到磁场强度的影响,复合镀层的沉积速率、显微硬度、镀层与基体的结合强度等随着磁场强度的增强表现出先增大后减小的趋势,Ni-P-金刚石复合镀层的孔隙率、摩擦系数随着磁场强度的增大而增加；镀液中金刚石浓度为4g/L,磁场强度为10.60mT时,化学复合镀层的摩擦系数最小；化学复合镀层中各元素的质量分数也随着磁场强度的变化而变化。梯度磁场环境下,复合镀层的显微硬度、镀层与基体的结合强度随场强梯度变化明显。结合磁化学理论、吸附理论分析认为：(1)磁场作用可以加快镍离子、活化氢原子自由基对从三重简并态向单重简并态转化,造成镍离子沉积速度增加；(2)镍离子沉积速度增加促使了复合镀液中的次亚磷酸根离子氧化速率增加,次亚磷酸根离子氧化产生的活化氢原子浓度增大；(3)过多的氢原子以氢气的形式逸出反应界面,对反应界面附近的化学复合镀液起到微搅拌作用,从而影响化学复合镀层中金刚石颗粒的团聚尺寸；(4)强磁场下产生的大量气泡会破坏基材表面的活化位点,并“冲刷”掉吸附的金刚石颗粒和基体吸附的活化氢原子,造成化学复合镀层中金刚石含量降低,镀层表面粗糙度增加。对梯度磁场环境下,对化学复合镀层的显微硬度、结合力分析表明,磁场对化学复合镀的影响符合磁化学理论分析结果。
[Abstract]:In this paper, Ni-P- diamond electroless composite coating was prepared by adding submicron diamond particles into the traditional Ni-P electroless plating bath under the influence of magnetic field.As a contrast, Ni-P- diamond composite coatings without magnetic field effect were prepared by traditional electroless composite plating process.The size of diamond particles used in this paper is between 0.01-0.5 渭 m and the average size is 0.251 渭 m.The effects of magnetic field strength on the concentration, morphology and size of diamond in the coating were studied by means of metallographic microscope, coating adhesion tester, scanning electron microscope (SEM) with energy spectrum and friction and wear tester.The magnetic field field in solenoid was calculated and measured by Tesla meter, and the uniform magnetic field and gradient magnetic field environment were constructed. The mechanism of the effect of magnetic field on electroless composite plating was analyzed by combining magnetization theory and adsorption theory.The results show that the content, size and dispersion of diamond particles in the composite coating are obviously affected by the magnetic field intensity, the deposition rate and the microhardness of the composite coating under uniform magnetic field.With the increase of the magnetic field intensity, the bonding strength of the coating and the substrate shows a tendency of increasing at first and then decreasing the porosity of Ni-P- diamond composite coating, and the friction coefficient increases with the increase of the magnetic field intensity.When diamond concentration is 4 g / L and magnetic field intensity is 10.60mT, the friction coefficient of the electroless composite coating is the smallest, and the mass fraction of each element in the electroless composite coating changes with the change of the magnetic field intensity.The microhardness of the composite coating and the bonding strength between the coating and the substrate changed obviously with the field intensity gradient under the gradient magnetic field environment.Based on magnetization theory and adsorption theory, it is concluded that the magnetic field action can accelerate the conversion of nickel ion and hydrogen atom radical from triplex state to simple state.The higher the deposition rate of nickel ion, the higher the oxidation rate of phosphite ion in the composite bath.The active hydrogen atoms produced by the oxidation of hypophosphite ions increase the concentration of activated hydrogen atoms.) too many hydrogen atoms escape the reaction interface in the form of hydrogen, which plays a microstirring role in the electroless composite plating bath near the reaction interface.Thus, a large number of bubbles produced under the strong magnetic field will destroy the activation sites on the substrate surface and "scour" the adsorbed diamond particles and the activated hydrogen atoms adsorbed by the matrix, which affect the agglomeration size of diamond particles in the electroless composite coating.The diamond content in the electroless composite coating decreased and the surface roughness increased.The effect of magnetic field on the microhardness and adhesion of the electroless composite coating under the gradient magnetic field environment is in accordance with the results of magnetization theory.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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