摘要化学镀作为近年来表面处理工艺的一个热门技术，其用途越来越广泛。化学镀是 指镍盐与还原剂在溶液中发生自催化氧化还原反应，在基材表面获得镍沉积层。化学 镀可以明显提高工件表面耐蚀性和耐磨性，镀层均匀光洁，无需热处理以外的进一步 处理，且操作简便，成本低廉。79867

本文整理了化学镀镍沉积层机理并研究了化学镀镍的工艺。测量 Q235 钢在不同 浓度络合剂、加速剂、和温度下镀镍的镀速，利用扫描电子显微镜（SEM）、X 射线 衍射仪（XRD）和能谱仪（EDS）对镀层表面微观形貌、结构和成分进行分析。络合 剂含量的降低和温度的升高会一定程度上提高镀速，但是超过一定范围会导致镀液不 稳定，从而导致镀层表面粗糙无光泽。一定浓度的加速剂具有加快镀速作用。用研究 后确定的配方施镀得到含磷 12%左右的镍磷合金镀层，硬度在 300HV 左右，镀层光 洁。

本文进一步对铜基镀镍磷和 Q235 钢镀 Ni-Cu-P 进行了探究，对铜镀镍时需对其 进行引镀。镀镍可以显著提高 Q235 钢的耐蚀性和表面硬度。为了进一步提高镀层的 硬度，本次研究又对 Q235 钢镀的镍镀层及两种不同铜含量的 Ni-Cu-P 镀层进行热处 理，发现这三种镀层不同温度下处理一小时后，其硬度均在 400℃时达到最高。未镀 镍的 Q235 钢表面硬度较低，通过热处理镍镀层的硬度提高较明显，达到了 400~500HV。 这是由于镀层中析出的 Ni3P 弥散强化的结果，硬度随 Ni3P 的弥散程度而变化。

毕业论文关键词：化学镀镍；沉积机理；热处理；镀速；硬度

Abstract Electroless plating is widely used in recent years as a popular technology of surface treatment。 Electroless nickel-plating is refers to the nickel salt and reducing agent autocatalytic REDOX reaction in aqueous solution, which can form nickel deposit on the base material surface。 Electroless nickel-plating 。Electroless plating can significantly improve the surface corrosion resistance and wear resistance, coating is uniform and clean, without further processing, except heat treatment。 What’s more , it’s cheap。

This paper studied the mechanism of electroless nickel-plating and analyzed it’s process。 The plating rate was measured in different concentration of complexing agent, accelerant agent and different temperature。 SEM, XRD and EDS was used to analyzed the microstructure of the coating surface, composition and whether it is crystalline or not。 Decrease concentration of complexing agent or increase of temperature can increase the plating rate, however, more than a certain range will lead to instability of the  bath, resulting in coating surface rough and lusterless。 A certain concentration of Accelerating agent can prove the plating rate。 The Ni-P plating made by bath determined by study show a phosphorus concentration of 12%, of which is uniform and have a beautiful luster。 The average hardness is 300HV。

A further study of electroless nickel-plating on copper and Q235 steel had been made, plating on copper need to be lead by Fe。 Nickel-plating can improve the  corrosion resistance and hardness of Q235 steel。 In order to improve the coating hardness value more, some heat treatment of plating on Q235 steel was made, in which contain nickel-plating and two different Ni-Cu-P plating with different copper concentration。 Heat treatment of the three plating in three temperature all suggested that the maximum hardness appeared at

400℃。 Surface hardness value of Q235 steel without plating is low, the surface hardness

can be obviously improved by heat treatment, which achieve to 400~500HV。 A certain concentration of Accelerating agent can prove the plating rate。 The Ni-P plating made by bath determined by study show a phosphorus concentration of 12%, of which is uniform and have a beautiful luster。 The average hardness is 300HV。