电沉积铁镍铬合金工艺参数对镀层铬含量的影响

给出了电沉积铁镍铬合金镀层的镀液配方和操作条件：着重研究了配合剂浓度，电流密度三价铬离子浓度，温度和酸度对镀层Ｃｒ含量的影响；通过优化工艺参数，得到了铬含量１５％￣４０％合金镀层。     

马氏体不锈钢电镀硬铬工艺简介

1　不锈钢特性分析不锈钢是以铬为主要合金元素的Ｆｅ Ｃｒ Ｃ合金 ,从组成成分划分 ,有铬系不锈钢和铬镍系不锈钢 ;按金相组织划分 ,有铁素体不锈钢、奥氏体不锈钢和马氏体不锈钢 3大类。常用的马氏体不锈钢有 2Ｃｒ13、3Ｃｒ13、9Ｃｒ18、9Ｃｒ18ＭｏＶ、Ｃｒ17Ｎｉ2等。不锈钢材料的合金元素主要是含 12 %以上的Ｃｒ和易于钝化的Ｎｉ、Ｔｉ、Ｍｏ等。不锈钢材料电极电位较钢铁高出很多 ,其表面在自然状态下也能生成薄而透明且附着牢固、致密稳定的钝化膜层 ,有良好的抗腐蚀性能。该钝化膜表面受到破坏后 ,恢复能力很强 ,会很快重新生成完…     

V_(0.91-x-y)Ti_xM_yNi_0.09(M=Cr,Si,Zr)系贮氢合金的电化学性能

本文研究了Ｖ０．９１－ｘ－ｙＴｉｘＭｙＮｉ０．０９（Ｍ＝Ｃｒ，Ｓｉ，Ｚｒ，Ｚｒ＋Ｃｒ，ｘ＝０．１８～０．５５，ｙ＝０～０．０９）系贮氢合金的相组成和电化学性能。结果表明，Ｖ０．９１－ｘＴｉｘＮｉ０．０９（ｘ＝０．１８～０．５５）合金系在吸氢时形成二种氢化物即单氢化物及双氢化物，但在通常放电条件下（截止电位为－０．７Ｖ）只能双氢化物放电，如果通过提高放电截止电位强制单氢化物放电，则合金中的Ｖ容易发生氧化。这样做虽然初始容量很高，却导致电极的循环寿命下降。分别用９％的Ｚｒ，Ｃｒ，Ｓｉ部分替代Ｖ０．９１－ｘ－ｙＴｉｘＭｙＮｉ０．０９合金中的Ｖ，导致合金的循环寿命变差，同时也使容量下降，三种元素对容量影响的次序为Ｓｉ＞Ｃｒ＞Ｚｒ。但同时用Ｚｒ、Ｃｒ替代Ｖ却可提高合金的电化学容量，Ｖ０．６４Ｔｉ０．１８Ｚｒ０．０４５Ｃｒ０．０４５Ｎｉ０．０９容量达到４２０ｍＡｈ／ｇ。     

用透射和扫描电镜观察Ni—Cr—Al合金γ‘和Cr（α）析出相

Ｎｉ－Ｃｒ－３％Ａｌ－０．２％Ｃｅ合金０．３ｍｍ细丝经５００－６００℃时效处理，用透射和扫描电镜观察组织形貌，用化学定量提取法和测定微区成分的方法确定相Ｎｉ、Ｃｒ、Ａｌ的含量，用程控图像仪测定富Ｃｒ（α）相析出颗粒大小和分布，查明了γ相沿基体９１００）面共格析出并细小颗粒状，在γ相周围析出的过饱和富Ｃｒ（α）相弥散分布在合金基体中，据此认为该合金是由γ相和富Ｃｒ（α）相复合析出强化合金基体的。     

含碳Fe—Mn—Si—Cr—Ni合金形状记忆效尖的研究

研究了碳加入后对Ｆｅ－１４Ｍｎ－５Ｓｉ－８Ｃｒ－４Ｎｉ合金形状记忆效应（ＳＭＥ）的影响。结果表明，碳元素的适当加入，有助于合金的可恢复应变的提高。在３．７５￣７．５％变形量时，含碳量为０．１２％的合金的可恢复应变量可达２．５￣３％，高于超低碳合金（Ｃ〈０．０２％）。     

含碳Fe－Mn－Si－Cr－Ni合金形状记忆效应的研究

研究了碳加入后对Ｆｅ－１４Ｍｎ－５Ｓｉ－８Ｃｒ－４Ｎｉ合金形状记忆效应（ＳＭＥ）的影响。结果表明，碳元素的适当加入，有助于合金的可愎复应变的提高。在３．７５～７．５％变形量时，含碳量为０．１２％的合金的可恢复应变量可达２．５～３％，高于超低碳合金（Ｃ＜０．０２％）     

非晶态铬镀层表面的X光电子能谱研究

非晶态铬镀层具有优良的物理、化学和机械性能，根据非晶态铬镀层的特点用Ｘ－射线光电子能谱（ＸＰＳ）对于进行表面元素全分析和Ａｒ＾＋溅射浓度剖析，发现所获非晶态铬镀层由Ｃｒ、Ｏ和Ｃ等元素组成。Ｏ和Ｃ元素不仅存在于镀层表面，而且存在于整个镀层中。其中Ｏ是以－ＣＯＯＨ和吸附Ｈ２Ｏ及Ｃｒ的氧化物形式存在；Ｃ以－ＣＯＯＨ和石墨存在；在Ｃｒ则以Ｃｒ、Ｃｒ２Ｏ３、ＣｒＯ２及ＣｒＯＯＨ形式存在。     

电沉积非晶态铬—铁合金镀镀层研究

研究了从三价铬的硫酸盐体系中电沉积Ｃｒ－Ｆｅ合金镀层的工艺以及镀层的形貌、结构和性能。利用该工艺获得了厚度３０μｍ以上、铁含量（２０－３０）％的Ｃｒ－Ｆｅ合金镀层。实验结果表明，该镀层表面结瘤状，含有大量微裂纹，为非晶态结构，具有可热处理性。在６００℃下热处理１ｈ后硬度最高可达１４００ＨＶ以上，因此，可作为经济、耐磨性镀层使用。     

非晶态Cr-C合金镀层与晶态Cr镀层的耐蚀性比较

用电化学方法对同积法制备的非晶态Ｃｒ镀层在几种常见腐蚀介质中的耐蚀性进行了测定。结果表明,非晶态Ｃｒ－Ｃ合金镀层的耐蚀性均明显优于晶态Ｃｒ镀层,文化馆速率约为晶态Ｃｒ镀层的０．５％～２．５％,通过对镀层孔隙率和表面形貌的研究表明,非晶态Ｃｒ－Ｃ合金镀层表面细致、均匀、无微裂纹,抑制了腐蚀微电池的形成,耐蚀性明显提高。     

铁锰硅系形状记忆合金的成分设计

讨论合金成分与层错能的关系,结合合金成分对合金组织影响的组织状态图（Ｓｃｈａｅｆｆｌｅｒ图）,提出了较为合理的合金成分设计。加入铬、镍合金元素的同时,降低锰含量可以保证合金具有较低的合金层错能。硅含量为６％时,基层错能量低。如无特征要求,铬含量应控制在１０％以内。镍含量为Ｃｒ％／１．７,以避免σ相件出。Ｍｎ含量则以保证Ｍｓ点比室温略高来确定。合金的成分当量应满足下式：ＮｉＥＱ＝－２５／ＣｒＥＱ＋２     

金属的化学成份对金属／ZrO_2连接的影响

研究了４Ｊ３３、纯Ｎｉ和４０Ｃｒ钢与ＺｒＯ_２的钎焊连接。结果表明：对Ａｇ_（６６）Ｃｕ_（３０）Ｔｉ_４活性钎料，４Ｊ３３与ＺｒＯ_２在１１８３Ｋ时能形成连接，而在１１０３Ｋ与１１３３Ｋ时连接失败；纯Ｎｉ与ＺｒＯ_２在温度升至１２７３Ｋ仍不能形成连接。这是因为纯Ｎｉ和４Ｊ３３所含的Ｆｅ、Ｎｉ、Ｃｏ元素扩散到钎料中并与之发生反应形成化合物所致。４０Ｃｒ钢和ＺｒＯ_２的连接钎料中未形成化合物，它们在１１３３Ｋ就能形成连接。     

Cu-Cr-Zr合金时效后显微硬度和导电率的研究

研究了Cu 0 .3Cr 0 .15Zr 0 .0 5Mg合金时效温度、时效时间和时效前变形量对导电率和显微硬度的影响。结果表明 ,合金 92 0℃固溶后在 4 5 0℃时效可以获得较高的硬度 ,在 6 0 0℃时效可以获得较高的导电率 ;时效前冷变形可以加速第二相的析出 ,大幅度提高合金的导电率 ,合金固溶并 6 0 %形变后在 5 0 0℃时效 0 .5h导电率可达 72 .0 2 %IACS ,而固溶后直接时效仅为 5 1.79%IACS。     

Study of deformation and aging behaviors of a hot rolled–quenched Cu–Cr–Zr–Mg–Si alloy during thermomechanical treatments

The deformation and aging behaviors of a hot rolled–quenched Cu–Cr–Zr–Mg–Si alloy were investigated by microhardness and electrical resistivity measurements, and transmission electron microscopy observations. The resistivity of aged alloy increases almost linearly with increasing of the secondary cold deformation reductions, and a faster and larger increase in resistivity of the peak-aged alloy is found during the deformation process due to the occurrence of resolution phenomenon. Quantitative analysis shows that about 0.0385 wt.% solutes are re-dissolved into the peak-aged alloy after 70% cold deformation. Results of the following aging treatment show that the deterioration caused by resolution phenomenon in electrical properties can be eliminated by the secondary aging treatment. A good combination of high hardness and low resistivity can be achieved in the Cu–Cr–Zr–Mg–Si alloy after suitable thermomechanical treatments.     

新型含Cu高熵合金的微观组织及热处理过程相变

目的为优化CrMnFeCoNi高熵合金成分,消除富Cr脆性相的析出倾向。方法用Cu取代Cr元素,以四元MnFeNiCu高熵合金为研究对象,探究含Cu高熵合金的微观组织及其热处理过程中的相变特征。结果铸态MnFeNiCu合金中Cu元素具有较强的偏析倾向,其枝晶间存在大量颗粒状富Cu析出物,通过均匀化热处理能完全消除Cu元素偏析现象,得到单相FCC组织。结论 Cu与其他3种元素均表现为不同程度的不相容性,具有最大的偏析倾向,使其在凝固过程中于枝晶间富集,均匀化热处理过程中Cu元素发生溶质扩散,最终形成了单相固溶体组织。     

Precipitation and aging in high-conductivity Cu–Cr alloys with additions of zirconium and magnesium

Abstract

The precipitation reactions responsible for age hardening in a high-conductivity Cu–Cr–Zr–Mg alloy have been investigated by analytical transmission electron microscopy and compared briefly with the processes that occur in simpler Cu–Cr and Cu–Cr–Mg alloys. Aging at low temperatures (400°C) results in the formation of Guinier–Preston zones. Peak hardness, obtained by aging for 24 h at 450°C, is found to be a result of the fine scale precipitation of an ordered compound, possibly of the Heusler type, with the suggested composition CrCu₂(Zr, Mg). Overaging results in the formation of coarse precipitates of Cr and CU₄Zr. The intergranular precipitate which forms in the Cu–Cr–Zr–Mg alloy is Cu₄Zr. This phase precipitates both as discrete particles on the grain boundaries and as thin ( ~ 5 nm) continuous intergranular films.

MST/89     

Fabrication and Microstructure of C/Cu Composites

C/Cu composites were prepared by a melting infiltration technique in vacuum. In order to improve the wettability between Cu and carbon fibers, Ti (8 wt.‐%) and Cr (1 wt.‐%) were added to the Cu alloy. Microstructures of the composites and interface between C and Cu were investigated by XRD, SEM, EDS and HRTEM. The results show that the Ti and Cr improved the wettability between Cu and C? C preform and the infiltration ability of Cu into C? C preform greatly. The prepared C/Cu composites are characterized as having good interface bonding and high density. In the process of infiltration, Ti and Cr concentrate on the boundary of carbon fiber. Formation of TiC results from the reaction of Ti and C between Cu and carbon fiber.     

Phase and microstructure evolution in Cu-In-Cr alloys

Abstract

Cu-In-Cr ternary alloy specimens were prepared with a metal mould and analysed by OP, EPMA, SEM, etc. The results show that the phase composition of Cu-11In-10Cr (wt-%) ternary alloy in casting microstructure includes Cu solid solution, Cr solid solution and Cu₉In₄ (δ) phase. Cu solid solution has dendritic morphology while Cr solid solution is star or petal shaped and is dispersed. In solidification, the solid/liquid interfaces of Cu solid solution and Cr solid solution are nonfaceted and they form by continuous growth, Cu solid solution forms dendrites under the influence of constitutional supercooling, while Cr solid solution forms equiaxed dendrites owing to the restricted chromium content. Chromium content has an influence on the morphology of Cu solid solution dendrites and Cr solid solution.     

Study of rapidly solidified Cu–Cr–RE alloys

Electrical engineering materials of Cu–Cr–RE have been made using the technology of rapid solidification, composite green compacts, extrusion and so on. By means of the analysis of optical metallographs, electron microscopy, physical and mechanical properties as well as electrical properties, and the examining of the hardness, softening temperature, etc. the authors selected Cu–Cr–Y alloy, which has excellent comprehensive properties. The authors have also made a deep study of the chromium and yttrium elements, which affect the structure, the recrystallization temperature, the strength at room and high temperature, the resistivity and contact resistance, and have also compared the properties of the Cu–Cr and Cu–Cr–Y alloy. The results show that rapidly solidified technology and added rare–earth elements not only enhance the fine grain boundary strengthening, but also the second phase strengthening. Cu/Cu–Cr–Y composite material improves the thermal stability and thermal endurance, and also maintains a better electrical conductivity and thermal conductivity.     

Study of rapidly solidified Cu–Cr–RE alloys

Electrical engineering materials of Cu–Cr–RE have been made using the technology of rapid solidification, composite green compacts, extrusion and so on. By means of the analysis of optical metallographs, electron microscopy, physical and mechanical properties as well as electrical properties, and the examining of the hardness, softening temperature, etc. the authors selected Cu–Cr–Y alloy, which has excellent comprehensive properties. The authors have also made a deep study of the chromium and yttrium elements, which affect the structure, the recrystallization temperature, the strength at room and high temperature, the resistivity and contact resistance, and have also compared the properties of the Cu–Cr and Cu–Cr–Y alloy. The results show that rapidly solidified technology and added rare-earth elements not only enhance the fine grain boundary strengthening, but also the second phase strengthening. Cu/Cu–Cr–Y composite material improves the thermal stability and thermal endurance, and also maintains a better electrical conductivity and thermal conductivity.     

Microstructure and properties of sintered Cu–25Cr alloy

Abstract

Sintered and precipitation hardened Cu–25Cr (wt-%) contact alloys were prepared and their properties related to those of a precipitation and strain hardened reference alloy. The evolution of microstructure during sintering, solution heat treatment, and precipitation hardening was studied, in particular with respect to precipitate morphology and growth. The influence of microstructure on the hardness, strength, and electrical conductivity of Cu–25Cr alloys was evaluated. The relative importance of precipitation and strain hardening has been clarified, and it is shown that the contribution of the precipitation effect is dominant. The importance of monitoring the evolution of microstructure with respect to long term stability of Cu–Cr contact alloys is emphasised.

MST/999