径向锻机锤头磨损修复工艺研究

本文从径向锻机锤头的材料组成形式,分析了锤头磨损的不同方式。针对其磨损方式提出了不同铣削要求,使锤头表面工作层UDIMET520和中间过渡层E23-250形成了不同的焊接修复工艺,从而得到了具体的锤头修复工艺方法,提高锤头使用寿命。     

一种用于20Cr2Ni4A钢表面渗碳层的复合刷镀修复工艺

为解决20Cr2Ni4A钢表面渗碳层磨损后修复的难题,提出一种n-SiC/Ni-W复合刷镀修复工艺,并详细介绍了工艺流程、工艺参数及操作中的注意事项。通过测试修复层的耐磨性、硬度、结合力,结果表明,修复层具有很高的耐磨损性能,利用该复合电刷镀技术修复20Cr2Ni4A钢渗碳层的磨损表面完全满足使用要求。     

飞机铝合金结构件腐蚀的原位修复工艺研究

采用化学氧化层-底漆-密封胶三层防腐修复工艺,原位修复飞机铝合金结构件表面腐蚀.试验了修复层的防腐蚀性能.该工艺防腐蚀效果好,施工简单,成本低,有较强的实用性.     

热作模具修复层表面滚压加工研究进展

热作模具因工作环境恶劣,在服役过程中易出现失效,造成资源浪费和成本升高。热作模具修复工艺可以延长其使用寿命、提高生产效率,修复层需经加工才能在表面质量和尺寸精度上满足使用要求。滚压加工是一种经济高效的光整强化工艺,通过滚压工艺可以提高热作模具修复层力学性能和使用性能,对热作模具修复层滚压加工的研究逐渐成为当前的研究热点。介绍了热作模具常见的失效形式和性能要求,从修复预处理、修复方法、修复后处理三方面概述了热作模具修复工艺研究现状,综述了修复层滚压加工研究现状,分析了传统滚压存在的问题,对滚压工艺的发展和热作模具超声滚压研究进展进行了介绍。在此基础上,对热作模具修复层的超声滚压加工研究进行了展望。     

飞机高合金钢零件的电刷镀修复工艺

应用电刷镀技术修复飞机30CrMnSiA钢件，介绍了修复工艺的流程及条件，测定了修复层的性能，取得了满意的效果。     

浅谈国内外埋地管线外防护层修复的材料选择及应用

国外经较长时间的开发和应用,对旧管线修复的防护层材料选用,修复工艺等均有一些基本规定,近几年我国在此方面也开展了不少研究和应用。本文重点介绍目前国内外对埋地管道外防护层修复材料的选择原则,部分修复材料特性及相关修复工艺的研究和应用。     

电火花沉积修复铝合金组织与可降解性能

目的 采用电火花沉积技术修复铝合金铸造缺陷。方法 采用两种电极（ER5356电极和自制电极）,在优化电火花沉积工艺条件下,修复铝合金表面气孔,系统研究电火花沉积工艺、电极材料、沉积气氛对修复层的影响。采用扫描电子显微镜（SEM）结合能谱仪（EDS）对修复层界面组织和成分进行表征;用显微硬度计测试修复层的硬度;用电化学工作站测试修复层的Tafel曲线,在水浴中测试修复层的降解速率,从热力学与动力学两方面对修复层的降解性能进行全面评价。结果 在氩气气氛中的最佳修复工艺参数为：频率5000 Hz,电容150 μF,沉积角度45°,此时的热输入为0.480 J。在氩气气氛中的修复层组织致密,且元素均匀分布,减小了成分偏析。由于消除了枝晶,修复层的硬度相对于基体的硬度略有提高。自制电极修复层的自腐蚀电位（–1.493 V）低于基体的自腐蚀电位（–1.421 V）,ER5356电极修复层不溶于水,自制电极修复层降解速率稍快于基体。结论 使用电火花沉积技术,可对3.5英寸压裂球表面缺陷进行修复,经测试,硬度和降解性能达到工程指标。     

铜电解低位槽的修复

一直以来,由于砼基础层连带破坏及时间短等因素影响,铜电解槽旧设备防腐蚀层损坏修复一直是一个较难处理的问题。本文介绍了一个案例的具体的修复方法,既经济又适用。     

烟机涡轮盘和叶片的损伤分析与激光随形熔铸重建

讨论了我国烟机轮盘与叶片冲蚀损伤的多种形态和修复的可行性 ,研究了激光修复的工艺方法、修复用材料、修复层的结构、组织与性能等特性。研究发展的控制激光熔铸随形定向生长和高能微弧冷焊沉积技术可实现高质量、高性能修复     

堆焊技术在冷冲模修复中的应用

阐明了堆焊工艺在冷冲模修复中的重要作用.叙述了堆焊制造工艺、工作条件、性能要求及其优点.文末介绍了具体的举例应用.     

Metal-carbon layers for industrial application in the automotive industry

Physical vapour deposition (PVD) coatings have been well established in the cutting tool industry for many years. In the near future the high wear resistance and low friction coefficient of PVD coatings will be of interest for applications in constructional elements. Today the deposition process and the quality control of coated parts are accompanied by several problems: during the deposition process the temperature of the constructional elements must not exceed 200 °C; the composition of the deposited layers has to be reproducible; methods for the quality control of coated parts need to be integrated in series control. These problems will be discussed for reactively sputtered metal-carbon layers (W-C:H). Methods of quality control such as Rockwell C indentation and glow discharge optical spectrometry will be illustrated. First applications of W-C layers in the automotive industry are presented.     

A method for the determination of the plastic deformation resistance of filler wires in electric resistance surfacing

The article presents the characteristics of the remanufacturing process, as well as the economic conditions and technical applications of these methods of regeneration of parts. It also describes the application of welding methods for creating repair coatings.     

Suspension Plasma Spraying: Process Characteristics and Applications

Suspension plasma spraying (SPS) offers the manufacture of unique microstructures which are not possible with conventional powdery feedstock. Due to the considerably smaller size of the droplets and also the further fragmentation of these in the plasma jet, the attainable microstructural features like splat and pore sizes can be downsized to the nanometer range. Our present understanding of the deposition process including injection, suspension plasma plume interaction, and deposition will be outlined. The drawn conclusions are based on analysis of the coating microstructures in combination with particle temperature and velocity measurements as well as enthalpy probe investigations. The last measurements with the water cooled stagnation probe gives valuable information on the interaction of the carrier fluid with the plasma plume. Meanwhile, different areas of application of SPS coatings are known. In this paper, the focus will be on coatings for energy systems. Thermal barrier coatings (TBCs) for modern gas turbines are one important application field. SPS coatings offer the manufacture of strain-tolerant, segmented TBCs with low thermal conductivity. In addition, highly reflective coatings, which reduce the thermal load of the parts from radiation, can be produced. Further applications of SPS coatings as cathode layers in solid oxide fuel cells (SOFC) and for photovoltaic (PV) applications will be presented.     

Plasma Electrolytic Oxidation of Arc-Sprayed Aluminum Coatings

Different posttreatment methods, such as heat treatment, mechanical processing, sealing, etc., are known to be capable to improve microstructure and exploitation properties of thermal spray coatings. In this work, a plasma electrolytic oxidation of aluminum coatings obtained by arc spraying on aluminum and carbon steel substrates is carried out. Microstructure and properties of oxidized layers formed on sprayed coating as well as on bulk material are investigated. Oxidation is performed in electrolyte containing KOH and liquid glass under different process parameters. It is shown that thick uniform oxidized layers can be formed on arc-sprayed aluminum coatings as well as on solid material. Distribution of alloying elements and phase composition of obtained layers are investigated. A significant improvement of wear resistance of treated layers in two types of abrasive wear conditions is observed. This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain Montavon, Ed., ASM International, Materials Park, OH, 2007.     

Research activities of biomedical magnesium alloys in China

The potential application of Mg alloys as bioabsorable/biodegradable implants have attracted much recent attention in China. Advances in the design and biocompatibility evaluation of bio-Mg alloys in China are reviewed in this paper. Bio-Mg alloys have been developed by alloying with the trace elements existing in human body, such as Mg-Ca, Mg-Zn and Mg-Si based systems. Additionally, novel structured Mg alloys such as porous, composited, nanocrystalline and bulk metallic glass alloys were tried. To control the biocorrosion rate of bio-Mg implant to match the self-healing/regeneration rate of the surrounding tissue in vivo, surface modification layers were coated with physical and chemical methods.     

Vacuum- Plasma- Sprayed titanium- manganese electrode layers for MnO2 deposition

Vacuum-plasma-sprayed titanium-manganese alloy electrode layers are intended to improve the economy and efficiency of the synthesis of electrolytic manganese dioxide, which is commercially used as cathodic material in primary batteries. Titanium anodes with a high content of manganese offer high electrochemical activity and corrosion resistance, but poor mechanical stability. Therefore, dense and well-bonded coatings of this brittle alloy were vacuum plasma sprayed onto ductile substrates using commercially pure titanium and manganese powder mixtures as well as mechanically alloyed powders. The mechanically alloyed powders, fabricated in a planetary ball mill, are suitable for the plasma spray process. The microstructure and electrochemical properties of the anode coatings produced by these two methods are discussed. Results are compared to commercially pure titanium anodes.     

镁合金表面加弧辉光离子渗镀Ti的腐蚀性能研究

加弧辉光离子渗镀技术将辉光放电与弧光放电有机地结合起来,利用辉光放电空心阴极效应使工件迅速升温,同时在真空容器壁上设置一个或多个金属阴极电弧靶源,利用真空电弧放电而不断地发射出高能量、高电流密度、高离化率的欲渗金属离子流,依靠扩散和离子轰击作用快速渗入工件表面层,在工件表面可以形成渗层、镀层、渗镀结合层.在实验条件下对镁合金AZ91表面渗镀了Ti,采用极化曲线测试和盐雾实验分析了处理后材料的腐蚀行为,用扫描电镜（SEM）分析了Ti镀膜的表面形貌,用电子衍射光谱（EDS）和辉光放电光谱仪（GDS）分析了表面化学成分分布.结果表明渗镀Ti显著提高了AZ91的耐腐蚀性.     

等离子熔覆技术的研究现状及展望

等离子熔覆技术是一种高效且应用广泛的表面处理技术,具有与基体结合良好、设备成本低、工作环境无污染及操作简单等优点。从等离子熔覆工艺参数研究、等离子熔覆合金涂层、等离子熔覆颗粒增强金属基复合涂层、等离子熔覆层质量调控方法、等离子熔覆技术应用等五个方面,介绍了等离子熔覆技术当前的发展概况。其中,关于等离子熔覆工艺参数研究方面,阐述了熔覆电流、离子气体流量、送粉气体流量、粉末送粉量、焊枪摆动幅度、焊接速度、喷嘴与工件之间的高度及多道搭接时搭接率等参数对涂层组织性能的影响;在等离子熔覆合金涂层方面,介绍了等离子熔覆用合金粉末及其引入方式的研究进展;在等离子熔覆颗粒增强金属基复合涂层方面,叙述了增强颗粒及其添加方式的最新研究成果;在等离子熔覆层质量调控方法部分,阐述了预热缓冷、热处理、外加磁场、机械振动、超声波辅助、加入变质剂及添加稀土元素等手段对熔覆层的质量调控作用;在等离子熔覆技术应用方面,介绍了等离子熔覆技术在矿山机械、汽车零部件再制造以及阀门修复等领域的应用。最后对等离子熔覆技术的应用前景及发展趋势做出了展望。     

Progress in theory and practice of thermochemical treatment of steels

Abstract

Recent developments in the thermochemical treatment of steels at MADI, Moscow are presented. These technologies combine nitriding with other methods of surface modification, e.g. thermal diffusion and laser alloying, plasma treatment, galvanic and slurry metallisation, and oxidation. By regulating the parameters of each process, it is possible to control the structure of the surface at the micro- and nanoscales, to form coatings and/or surface layers on various carbon and alloyed steels with tailored properties (hardness, wear and corrosion resistance, etc.) for machine parts used in various working conditions.     

Nanoparticle incorporation in plasma-electrolytic oxidation

One remaining problem of thicker PEO based topcoats on light metal substrates is the enhanced porosity with increasing layer thickness. While modern deposition techniques such as pulsed anodisation counteract this phenomenon, a simple current signal based approach cannot completely eliminate this problem. In the process described in this paper the pulse anodised PEO layers are modified by the incorporation of functional nanoparticles and the effects of such embedded nanoparticles on the resulting microstructure of the layer are studied. The examination of the layer properties was performed using scanning electron microscopy, electrochemical techniques and X-ray diffraction methods. The dependency of corrosion resistance on the presence of nanoparticles in the layer as well as the alloy composition of the substrate and the applied current signal is shown.