第一章文献综述.docVIP

脉冲电沉积Ni-SiC复合镀层及其性能的研究 陈丽 指导教师：杨武 (西北师范大学化学化工学院 兰州 730070) 摘要：本文将脉冲电流应用于复合电沉积过程中，与纳米粉材料有机结合，制备了含有SiC微粒的镍基复合镀层，研究了镀液SiC含量、脉冲峰值电流密度、脉冲占空比等因素对不锈钢(45#)表面Ni-SiC复合镀层的影响规律。利用扫描电子显微镜(SEM)分析了复合镀层的表面形貌，同时对镀层的显微硬度、表面粗糙度及耐磨性进行了分析研究。结果表明：(1)脉冲电流使所得镀层晶粒细化；(2)与纯镍镀层相比，由于SiC固体微粒的加入，复合镀层的晶体结构发生了明显的变化；(3)峰值电流密度增大，复合镀层的硬度上升，表面粗糙度下降；(4)在平均电流密度不变的情况下，占空比的大小直接反映了峰值电流密度的大小，占空比增大，复合镀层的硬度下降，磨损率上升。 关键词：脉冲、复合电沉积、Ni-SiC、复合镀层 A study of Pulse Electrodeposited Ni-SiC Composite Coating and it’s Properties Student: Chen Li Tutor: Yang Wu (College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070,Gansu,China) Abstract: A composite coating of Ni matrix containing nano-SiC powder is prepared by pulse current electrodeposition. The influence of technological condition, such as SiC content in bath, peak current density, pulse current on-off ratio, on the property of Ni-SiC composite coating on the 45# steel substrates were investigated in detail. The morphology of the composite coating were analyzed by using SEM. The microhardness, surface roughness and wear behavior of Ni-SiC composite coating were investigated. The result show:(1)The pulse current make the crystal size of Ni matrix smaller;(2)Compare with pure Ni coating, the crystallization of the Ni matrix change due to the SiC particles incorporation;(3)The microhardness of composite coating increase and the surface roughness decrease with the increase of pulse peak current density;(4)Under the condition of same average current density, the microhardness of composite coating decrease, and the rate of wear increase with the increase of on-off ratio Key words: Pulse, Composite electrodeposition, Ni-SiC, Composite coating 第一章 综 述 1.复合电镀 随着工业和高新技术的飞速发展，单一材料已难以满足特殊需要，因此各种有特定功能的复合镀层及复合电镀技术的研究日益增强，它在材料的表面保护、表面处理、表面改性及表面强化等方面越来越显示出不可取代的重要地位。 复合电镀(composite plating)是通过金属电沉积的方法，将一种或数种不溶性的固体微粒均匀地夹杂到金属镀层中，以获得具有特殊性能的复合镀层的工艺过程[1]。其镀层是在保持原有基质金属镀层性质的同时，强化了原有金属镀层的性质，并对原镀层进行了改性，这就使复合镀层的功能具有相当的自由度，可以获得耐磨、自润滑、耐蚀、装饰、电接触等功能性镀层。