无氰镀镉替代氰化镀镉工艺研究

介绍了新配方无氰镀镉镀液成分、工艺流程和电镀参数。总结了镀液的配制和维护经验,分析对比了与传统氰化镀镉工艺的差异。结果表明,无氰镀镉工艺的氢脆性优于氰化镀镉;镀液的分散能力、深镀能力及镀层的结合力、耐蚀性及沉积速度等性能与氰化镀镉接近,能够完全替代氰化镀镉工艺用于飞机起落架碳钢和低合金钢零件的表面防护。     

电镀锌-镍合金替代镀镉、镀镉-钛工艺研究

介绍了一种镀层镍含量为12%～15%的碱性镀锌-镍合金工艺,并将经过三价铬钝化的锌-镍镀层与六价铬钝化的镀镉和镀镉-钛层的外观、结合力、耐蚀性及氢脆性等进行对比。结果表明:锌-镍合金镀层的耐蚀性能优于镀镉层和镀镉-钛层,氢脆性合格。且该工艺环保低污染,能够替代镀镉、镀镉-钛用于起落架钢零件的表面防护。     

橡胶制品在局部镀镉中的应用

我厂在八五年从国外引进一种新产品，按国外工艺要求，有一个零件需要大部磷化处理，局部镀镉处理。从国外引进的资料来看，他们的工艺方法是采用可剥性涂料做局部镀镉保护，由于国外未提供可剥性涂料的具体规格型号，也未供给样品，只是提供了几个镀镉零件样品。在这种情况下，我们只好采用了我国的可     

高强度钢低氢脆镀镉钛工艺的应用

按照镀镉钛工艺进行试镀,试镀后的试件进行结合力、耐蚀性、氢脆性、电流效率、镀层钛含量等一系列质量检测。实验结果均满足工艺质量控制要求。     

镉金属和镀镉层染色

该文阐述了镉金属和镀镉层染色原理;介绍了染色的染料、工艺流程、镀镉液、化学转化液、染色工艺、染色实例.     

低氢脆镀镉层与钢基体间结合力的改进

在氰化物低氢脆镀镉过程中,由于镀镉层的起皮造成零件的外观和结合力质量较差,不仅不能起到良好的腐蚀保护效果,同时也不能为喷漆涂层提供良好的结合力底层.通过严格控制零件的前处理除油效果和彻底去除零件表面的氧化层,以及合理的控制槽液中的杂质含量、槽液温度和电流密度,可以提高镀层的结合力.     

无氰镀镉在我厂的应用

叙述了应用氨三乙酸无氰镀镉的镀液成分，工艺条件和故障分析，实验证明这是一种理想的无氰镀镉工艺，适用于水兵兵器及航空航天产品的防护。     

达克罗技术的绿色特点及代镉镀层的研究

首先简介了达克罗技术涂层结构、发展及应用情况,然后从工艺过程少污染、涂层高性能长寿命和低六价铬溶出量三个方面阐述了达克罗技术的绿色特点,涂层高性能主要指优异的耐蚀性和无氢脆的特性,最后综述了以达克罗涂层取代镀镉层的对比性研究工作。     

喷砂对镀镉层防护性能的影响及分析

航空制造业钢制件防护通常采用电镀镉工艺,生产中经喷砂的工件电镀镉后在镀层表面往往出现黑色斑点,影响零件的外观质量及镀层的防护性能。通过中性盐雾试验研究了黑色斑点对零件耐蚀性的影响;采用光学数码显微镜、扫描电子显微镜及能谱分析等研究了黑色斑点出现的原因。结果表明,黑色斑点处首先发生腐蚀,黑色斑点处和刚玉砂表面形貌相似,都主要为铝和氧元素;由于刚玉砂砂残留处未能成功电镀沉积镀层,形成黑斑缺陷。     

降低钢铁零件在镀镉过程中的氢脆性

钢铁零件在镀镉过程中由于氢原子渗透到镉镀层内以及金属晶格间形成氢分子,电镀后如果除氢不彻底会造成零件表面出现起泡,空洞和麻点,并且在使用过程中可能产生氢脆断裂。特别是针对航空产品中的受力件,会严重影响使用寿命。通过对不同工艺的应用和实际操作过程中经验的总结以及缺口拉伸试验,寻找出了预防氢脆断裂的措施和方法,对钢铁零件的镀镉有着实际的指导意义。     

无氰电镀镉-钛合金对钢基体氢脆性能的影响

研究了无氰电镀镉-钛合金工艺对A100钢基体氢脆性能的影响,分别采用测氢仪法、氢含量测定法、恒载荷持久拉伸及慢拉伸的方法对A100钢基体电镀镉-钛合金氢脆性进行评价.结果表明:A100钢具有较低的氢脆敏感性,电镀镉-钛合金后氢大部分存在于镀层中,基体中氢含量较低;采用慢拉伸试验可以评价A100钢电镀镉-钛合金工艺的氢脆...     

Hydrogen embrittlement of Zn-, Zn–Ni-, and Cd-coated high strength steel

Sacrificial coatings, such as Zn and Cd, are used to protect steel against corrosion. During the electrodeposition of metals, hydrogen is evolved due to electrolysis. The evolved hydrogen may diffuse outward and become trapped in the substrate/coating interface or migrate inward into the steel lattice causing delayed embrittlement when the component is subjected to stress. This study reports two principal variables for Zn, Zn–Ni, and Cd coatings: (i) the quantity of hydrogen absorbed by the coating and substrate by vacuum thermal desorption and (ii) the permeability of the coating material to hydrogen by electrochemical permeation. The findings were analyzed in correlation with the microstructural characteristics of both the coating material and the coating/substrate interface. With Zn–Ni, both coating process and coating material combined to significantly reduce the risk of internal hydrogen embrittlement by (i) introducing the least amount of hydrogen during the electrodeposition process and (ii) by the ease with which hydrogen can be extracted by baking due to the presence of cracks in the coating.     

不锈钢表面阻氢涂层研究进展

不锈钢是高压氢系统的常用材料，在氢能储输技术中发挥重要作用，但高压氢环境引起的塑性降低、疲劳裂纹扩展速率加快等不锈钢氢脆问题，严重阻碍了氢能的产业化发展，在不锈钢材料表面制备阻氢涂层是解决不锈钢氢损伤问题的重要手段之一。本文首先综合介绍了典型涂层材料的应用特点及阻氢性能，探讨了制备工艺对涂层阻氢性能的影响、不同涂层材料的阻氢机理，并分析了涂层阻氢性能影响因素，之后总结了涂层阻氢性能评价方法及各种评价方法的优势与不足，并根据各种评价方法的技术特点，指出每种方法的适用范围。最后，基于阻氢涂层研究进展，文章提出以开发新型涂层结构为研究重点，同时加快新型涂层材料的探索，并重点关注涂层氢环境原位性能评价方法的研究。     

刷镀镍对1Cr15Ni4Mo3N钢性能的影响

研究了刷镀镍对1Cr15Ni4Mo3N钢疲劳、氢脆等性能的影响.测定了1Cr15Ni4Mo3N钢刷镀镍镀层的结合力和显微硬度等镀层性能.并采用功能考核疲劳试验评价了刷镀镍修复后的衬套零件.结果表明:1Cr15Ni4Mo3N钢刷镀镍后可通过200h氢脆试验,氢脆性能合格;刷镀镍后疲劳极限下降36%,但可通过衬套的功能考核疲劳试验;刷镀镍镀层与1Cr15Ni4Mo3N钢基体具有良好的结合力,镀层硬度与1Cr15Ni4Mo3N钢相近.刷镀镍工艺可用于1Cr15Ni4Mo3N钢零件的修复.     

高压氢环境奥氏体不锈钢焊件氢脆研究进展

奥氏体不锈钢焊件是高压氢系统中重要的承载结构,其长期服役在高压高纯氢气环境中会出现塑性损减、疲劳裂纹扩展速率加快等氢脆现象,导致高压氢系统存在安全隐患。因此,为保障高压氢系统的安全运行,研究高压氢环境奥氏体不锈钢焊件的氢脆具有重要意义。本文首先介绍奥氏体不锈钢焊件中氢的两种来源,随后讨论评价材料氢脆敏感性的静态实验方法和动态实验方法,其次概述当前主流的氢脆机理,然后着重分析内部因素及外部因素对奥氏体不锈钢焊件氢脆敏感性的影响,最后归纳并总结五种典型的奥氏体不锈钢焊接工艺对焊件微观组织的影响,并进一步探讨相应焊件的氢脆敏感性。基于上述分析,针对奥氏体不锈钢焊件氢脆性能研究现状及发展趋势提出了若干建议。     

Transition metal-based hydrogen electrodes in alkaline solution — electrocatalysis on nickel based binary alloy coatings

Nickel-molybdenum, nickel-zinc, nickel-cobalt, nickel-tungsten, nickel-iron and nickel chromium binary alloy codeposits, obtained through electrodeposition methods on mild steel strips, have been characterized with the objective of qualitatively comparing and assessing their electrocatalytic activities as hydrogen electrodes in alkaline solution. It has been concluded that their electrocatalytic effects for the hydrogen evolution reaction rank in the following order: Ni-Mo > Ni-Zn (after leaching Zn in KOH) > Ni-Co > Ni-W > Ni-Fe > Ni-Cr > Ni plated steel. Further investigations on the alloy electrocatalysts have revealed that the cathodic overpotential contribution to the electrolysis voltage can be brought down by 0.3 V when compared with conventional cathodes. The best and most stable hydrogen evolving cathode, based on nickel-molybdenum alloy, exhibited an overpotential of about 0.18 V for over 1500 h of continuous electrolysis in 6m KOH at 300 mA cm^–2 and 353 K. The salient features of the coatings, such as physical characteristics, chemical composition, crystal structure of the alloy phases and the varying effects of the catalytic activation method were analysed with a view to correlating the micro-structural characteristics of the coatings with the hydrogen adsorption process. The stability under open-circuit conditions, the tolerance to electrochemical corrosion and the long term stability of nickel-molybdenum alloy cathodes were very encouraging. An attempt to identify the pathway for the hydrogen evolution reaction on these alloy coatings was made, in view of the very low apparent activation energy values obtained experimentally.     

Hydrogen permeation during zinc-manganese alloy plating

Electrodeposition of metals from solution is usually accompanied by the simultaneous discharge of hydrogen ions or water molecules. When hydrogen is liberated at an iron/steel surface during electrodeposition, a portion of the hydrogen is absorbed by the metal surface and then diffuses into the interior. The diffused hydrogen produces some detrimental effects, such as reduction in ductility and loss in mechanical strength, leading to hydrogen embrittlement. The present paper reports investigations on hydrogen permeation measurements in zinc-manganese alloy deposition using a modified electrode clamp for easy removal and fixing of the electrode. Hydrogen permeation studies indicate that the porosity of the deposit increases in the following order:Zn-Mn(14.3%), Zn-Mn(2.4%), Zn-Mn(24.8%) and Zn-Mn(37.5%).This is in agreement with the corrosion data obtained which indicates that Zn-Mn alloy deposits with low manganese content show better performance than pure zinc deposits.     

电沉积Zn-Fe合金的渗氢行为研究

用双电解池测氢法研究氯化物镀液体系中电沉积Zn-Fe合金过程中的渗氢行为.结果表明:在所考察的工艺参数中,镀液pH值对渗氢电流的影响最大.用慢应变速率拉伸试验法(SSRT)考察了电镀Zn-Fe合金试样的氢脆特性,并用扫描电子显微镜(SEM)对断口的微观形貌进行了表征.所有Zn-Fe合金镀层的试样均显示出不同程度的氢脆敏感性.     

SA387Cr11CL2钢制变换炉工艺方案

SA387Cr11CL2铬钼合金钢在中温下(350℃～480℃)临氢环境中具有防止氢脆、氢腐蚀、氢剥离、硫化物腐蚀性能,应用于气体变换等过程中效果良好。用该材料制作变换炉设备的过程中,冷、热加工(卷板、封头成型、焊接及热处理等)都要采取相应的技术和工艺措施,以控制焊缝及母材不出现裂纹、脆断等问题,确保设备的制造质量。