渗氮技术与渗氮钢应用综述

综述了包括气体渗氮、离子渗氮、洁净氮化、两段氮化和高频氮化等现有渗氮技术的应用现状,比较了它们的技术参数和优缺点。与渗碳相比较,简述了渗氮处理对零件表面强化的优点和实用性,并对渗氮钢的发展做了介绍。分析了各种合金元素和稀土元素对渗氮钢渗氮性能的影响。最后,展望了渗氮技术和渗氮钢的开发。     

偏压对活性屏离子渗氮工艺的影响

通过对40C钢进行活性屏离子渗氮处理,研究了在活性屏离子渗氮工艺过程中工件所加的偏压对渗氮层的影响.试验结果表明,在不加偏压或偏压较低的情况下,对距离活性屏较近的工件,其表面有一定厚度的渗氮层形成,硬度提高;而距离活性屏较远的工件,其表面几乎没有渗氮层的形成,但当增大偏压至400～450 V时,工件表面产生弱的辉光放电...     

铝合金离子渗氮层的组织结构研究

研究了离子氮化工艺参数对Ｌ２和ＬＹ１２二种铝合金渗氮层的组织和结构的影响。应用ＳＥＭ，Ｘ－射线衍射分析，ＸＰＳ和ＴＥＭ等方法对渗氮层的组织、相结构、渗氮层的化学成分与价态进行了分析。结果表明，渗氮层由Ａ１Ｎ和含Ｎ的α－Ａｌ固溶体及微量的Ａｌ２Ｏ３所组成。随着离子氮化温度和时间的提高，渗氮层的厚度随之增加。     

离子渗氮温度对W9Mo3Cr4V钢渗层组织及性能的影响

目前,国内外对搅拌头材料W9Mo3Cr4V钢离子渗氮表面改性研究不多。采用金相分析、显微硬度测量、X射线衍射仪(XRD)等研究了离子渗氮温度对W9Mo3Cr4V钢搅拌头显微组织和性能的影响,从而得出制备高硬度耐磨氮化层搅拌头的合适的离子渗氮温度。结果表明:经离子渗氮的W9Mo3Cr4V钢搅拌头表层获得了主要由ε相(Fe3N)和γ’相(Fe4N)组成的均匀渗氮层,且随着从表面到基体距离的增加,渗氮层的硬度呈现平缓的硬度梯度分布;480~560℃范围内,随离子渗氮温度升高,渗氮层厚度不断增加,渗氮层硬度也不断提高;ε相(Fe3N)衍射峰随离子渗氮温度升高而逐渐降低,γ’相(Fe_4N)衍射峰则呈逐渐升高的趋势。渗氮层厚度ζ与渗氮温度T的关系满足ζ=3.85×108e-9 141/T·τ。     

铝合金离了渗氮层的组织结构研究

研究了离子氮化工艺参数对Ｌ２和ＬＹ１２二种名合金渗氮层的组织和结构的影响。应用ＳＥＭ，Ｘ－射线衍射分析，ＸＰＳ和ＴＥＭ等方法对渗氮层的组织，相结合渗氮层的化学成分与价态进行了分析。     

不锈耐热钢制件渗氮层缺陷的原因分析及其改进的工艺方法

本文分析了4Cr14N114W2Mo钢制件经一般气体氮化的渗氮层产生裂纹和剥落等缺隔的形式和主要原因。试验论证了氨氮氮化和离子氮化等工艺方法在解决渗氮层常见缺陷方面所起到的作用和取得的效果。     

不锈耐热钢制件渗氮层缺陷分析

分析了4Cr14Ni14W2Mo钢制件经一般气体氮化后的渗氮层裂纹和剥落等失效形式和其产生原因。论证了氨氮氮化和离子氮化工艺可避免裂纹和剥落的产生。     

离子渗氮对耐磨性的影响

对四种离子渗氮工艺条件下的３８ＣｒＭｏＡｌ新渗氮钢进行了磨损试验研究。通过Ｘ射线衍射表面相结构分析以及测量表明硬度，截面硬度梯度，化合物层厚度和渗氮层深度等试验结果表明，离子渗氮前的原始组织对３０Ｃｒ２ＭｏＶ钢耐磨性影响较小，而对３８ＣｒＭｏＡｌ钢的耐磨性影响较大。离子渗氮工艺条件对这两种钢耐磨性具有一最佳值。     

氮化温度对24Cr2Ni4MoV钢离子氮化显微组织的影响

为了提高24Cr2Ni4MoV钢零件的表面硬度和耐磨性,对24Cr2Ni4MoV钢进行了离子氮化工艺试验研究,应用光学显微镜和扫描电子显微镜等仪器对520,550,570℃共3个温度离子氮化试样的显微组织、氮化层深度、表面硬度、表面渗氮层脆性、脉状组织等进行了检测分析,并应用能谱仪对渗氮层中氮化物成分进行了分析。结果表明:24Cr2Ni4MoV钢具有良好的氮化效果,其最佳离子氮化温度为550℃;试样在550℃氮化后,不仅氮化层的各项性能均满足标准技术要求,而且提高了渗氮速率,缩短了渗氮时间。     

阴极辉光放电电压对离子渗氮的影响

利用离子渗氮设备对38CrMoAl钢件进行离子渗氮处理,研究不同阴极辉光放电电压(500~800V)对渗氮层的组织和性能的影响。试验结果表明:外辅助加热式当阴极辉光放电电压低于600V时可以获得纯扩散层的渗氮层组织,超过600V后,渗氮层表面出现含有脉状组织的白亮化合物层,并且随阴极电压的升高,渗氮层中的脉状组织越来越严重。由此可以得出结论,离子渗氮的阴极辉光放电电压能改变炉内渗氮气氛的氮势。     

Mathematical Models and Computer Simulation of Nitrogen Concentration Profiles in Pulse Plasma Nitrided Layers

Two materials, pure Fe and pure Al, were nitrided in a pulse plasma nitriding facility. The nitrogen profiles in surface layers and the surface phase structures of specimens nitrided at 500℃ for 8 h for Fe and for 6 h for Al were measured using the glow     

Comparison of conventional and active screen plasma nitriding of hard chromium electroplated steel

This paper considers the nitriding behavior of hard chromium electroplated steel by conventional plasma nitriding (CPN) and active screen plasma nitriding (ASPN) methods. Indentation test along the cross-section of the treated samples reveals that duplex treatment performed by two methods exhibits almost the same hardnesses. Furthermore, an increase in the time of plasma nitriding from 5 h to 10 h restores 30% of the hardness decline. Morphological studies show that surface particles formed on active screen plasma nitrided samples have orderly formed geometrical shapes while in conventional plasma nitriding they are in cauliflower shape. The reason for reaction between chromium and nitrogen seems to be the difference between thermal expansion coefficient of chromium oxide, chromium and steel substrate which results in partial breakdown of the oxide film. Moreover, the reducing of chromium oxide by hydrogen promotes the process. It looks as if nitriding treatment changes the corrosion behavior of the chromium coating from severe localized to uniform corrosion. Also active screen plasma nitriding treatment lowers the anodic dissolution 50-100 orders of magnitude which would be the result of full closure of surface microcracks.     

常压等离子体渗氮主要工艺参数分析

利用介质阻挡放电，进行了常压非平衡等离子体渗氮，着重讨论了有关工艺参数的影响情况。正交试验结果表明，合理选择放电电压、放电间距和渗氮温度是获得良好渗氮层的关键。在本工艺条件下，适当减小放电间隙，增大电场强度，可以明显提高渗层的硬度和深度。     

等离子体源离子渗氮合成硼碳氮薄膜的研究

采用等离子体源离子渗氮,即低能,超大剂量氮离子注入－同步热扩散技术,在３００－５００℃处理碳化硼薄膜,合成了硼碳酸三元薄膜。俄歇电子能谱和漫反射富氏变换红外光谱分析表明,合成的硼碳氮薄膜是碳硼比固定,氮含量可控的非晶态薄膜。     

Fatigue life determination of plasma nitrided medical grade CoCrMo alloy

In this paper, the fatigue behaviour of plasma nitrided medical grade forged CoCrMo alloy was studied. Since metallic biomaterials are used for implant applications where high and/or cyclic stresses along with corrosive effects of human body are of concern, enhancing mechanical and surface properties of implant alloys is crucial. Plasma nitriding was implemented at three different temperatures as 600, 700 and 800 °C for time intervals of 1 and 4 h. S–N curves of untreated and nitrided specimens were obtained via axial tension compression fatigue tests. It was found that plasma nitriding treatment reduces the fatigue resistance of forged CoCrMo alloy by the ratios of 7–23% depending on the surface roughness, phase structure and hardness of the modified layer which are determined by the treatment parameters.     

Effects of various nitriding parameters on active screen plasma nitriding behavior of a low-alloy steel

Active screen plasma nitriding (ASPN) is a novel surface modification technique that has many capabilities over the conventional DC plasma nitriding (CPN). In this study, 30CrNiMo8 low-alloy steel was active screen plasma-nitrided under various nitriding parameters such as active screen set-up parameters (different screen hole sizes, mesh sheet and plate top lids) and treatment temperature (520, 550 and 580 °C), in the gas mixture of 75% N₂+25% H₂ and chamber pressure of 500 Pa for 5 h. The properties of the nitrided specimens have been assessed by evaluating composition of phases, surface hardness, compound layer thickness and case depth using X-ray diffraction (XRD), microhardness measurements and scanning electron microscopy (SEM). It was found that the screen hole size and top lid type (mesh or plate) play an important role in transition of active species (nitrogen ions and neutrals) toward the sample surface, which in turn can affect the nitrided layer hardness and thickness. Treatment at higher temperature with bigger screen hole size resulted in a thicker compound layer and higher layer hardness. The compound layers developed on the samples treated under different conditions were dual phase consisting of γ′-Fe₄N and ε-Fe_2-3N phases.     

ECR微波等离子体氮化铁基材料的参数研究

以纯铁和 38CrMoAl为例给出了用电子回旋共振微波等离子体氮化的实验结果 ,并给出了气体成分及配比、时间、温度、偏压等工艺参数对氮化结果的影响。指出在 0 1Pa的工作气压下 ,采用N2 H2混合气体 ,样品温度接近 50 0℃ ,微波功率 2 0 0～ 2 50W ,可在样品表面形成氮化层 ,使样品表面硬度显著提高。改变N2 和H2 比例将改变样品氮化层中ε相和γ′相的比例。样品施加合适的负偏压有利于氮化     

奥氏体不锈钢的高频离子氮化

本文介绍一种只用高频产生等离子体的氮化方法(简称高频离子氮化法)。找出比较合适的氮-氢气体比例及合适气压、温度的氮化工艺参数。获得高的表面硬度(HV 1575左右)和较厚的氮化层(85μm)。初步分析了影响氮化层性质的一些因素。     

Cathodic cage plasma nitriding (CCPN) of austenitic stainless steel (AISI 316): Influence of the different ratios of the (N2/H2) on the nitrided layers properties

In this study, we assess how the ratio (N₂/H₂) - working atmosphere gas mixture - influences the properties of the layers produced on austenitic stainless steel surface by Cathodic Cage Plasma Nitriding (CCPN). The nitriding atmospheres contained nitrogen and hydrogen in three proportions: 20% N₂ + 80% H₂, 50% N₂ + 50% H₂, and 80% N₂ + 20% H₂ delivered at a flow rate of 20 sccm. The effect of 100% N₂ was also examined. The morphology, microstructure and electrochemical properties of the layer produced were studied. The samples characteristics were determined by optical microscopy, x-ray diffraction, microhardness test and electrochemical potential curves.