无裂纹电镀硬铬基础试验研究

发布时间：2018-03-12 17:05

本文选题：无裂纹　切入点：电镀　出处：《南京航空航天大学》2015年硕士论文　论文类型：学位论文

【摘要】：镀铬能赋予金属材料优异的耐腐蚀、耐磨损性能及较低的摩擦系数。功能性镀铬更能使材料表面获得多种特殊的性能,使之成为新功能材料。因此,电镀铬作为一项表面处理工艺技术,已被广泛应用在航空航天关键机械零部件表面的防护。飞机起落架用材—300M高强度钢的耐磨性、耐腐蚀性较差,在使用过程中往往在其表面须电镀上一层硬铬层。然而,传统电镀铬层不可避免地存在贯穿性微裂纹,影响零件的耐腐性;电镀铬后零件表面呈现拉应力状态,影响材料的性能,因此,需要对其工艺进行改进。为了从根本上消除镀铬层的微裂纹,提高镀层的耐腐蚀性,本文基于摩擦辅助电镀工艺技术对电镀层性能的改善作用,开展脉冲电镀无裂纹硬铬基础试验研究。主要研究内容如下:1.搭建无裂纹电镀硬铬加工试验平台,并对电镀工艺系统进行改进和优化。为了使阴极表面获得均匀的电场,采用辅助阴极消除阴极端面电力线集中现象。利用COMSOL软件对辅助阴极的外形尺寸和阴极工艺倒角进行了仿真优化,研究了不同尺寸的辅助阴极和工艺倒角对阴极表面电场的作用规律。最后,通过试验对比仿真结果。2.在300M钢基体上进行电镀无裂纹硬铬试验,对比分析不同工艺参数对镀铬层的微观形貌、应力状态、耐腐蚀性、显微硬度及拉伸强度的影响规律,并进行归纳总结与评价。3.研制回转体无裂纹电镀硬铬机床,包括床身结构、传动系统、旋转密封结构、工件便携式装夹装置、压紧引电结构、电镀加工区与电镀液循环系统、电气控制系统等。
[Abstract]:Chromium plating can give metal material excellent corrosion resistance, wear resistance and low friction coefficient. Functional chromium plating can make the material surface obtain many special properties and make it a new functional material. As a surface treatment technology, chromium plating has been widely used in the protection of the surface of key mechanical parts in aerospace. The wear resistance and corrosion resistance of aircraft landing gear material -300M high strength steel are poor. In the process of application, a hard chromium layer is often plating on the surface of the chromium electroplating. However, there are inevitable microcracks in the traditional electroplated chromium layer, which affect the corrosion resistance of the parts, and the surface of the part after chromium electroplating is in a tensile stress state. In order to eliminate the micro-cracks of chromium coating and improve the corrosion resistance of the coating, this paper based on the friction assisted electroplating technology to improve the performance of the electroplating layer. In order to obtain uniform electric field on cathode surface, the basic experiment of pulse electroplating of hard chromium without crack was carried out. The main contents were as follows: 1. Setting up a processing test platform for hard chromium electroplating without cracks, and improving and optimizing the electroplating process system, in order to obtain a uniform electric field on the cathode surface, The auxiliary cathode is used to eliminate the power line concentration on the cathode end surface. The shape and size of the auxiliary cathode and the chamfering of the cathode process are simulated and optimized by using COMSOL software. The effect of different sizes of auxiliary cathode and process chamfer on the surface electric field of cathode was studied. Finally, the experiment was carried out on 300M steel substrate. The effects of different process parameters on the microstructure, stress state, corrosion resistance, microhardness and tensile strength of chromium plating layer were analyzed, and summarized and evaluated. Including bed structure, transmission system, rotating seal structure, workpiece portable clamping device, compaction electric structure, electroplating processing zone and electroplating liquid circulation system, electrical control system, etc.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ153.11

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