Cu-Cr合金触头材料制备技术的研究进展

Cu-Cr合金是新一代中压大功率真空开关触头材料之一,有着广泛的应用前景。本文综合述评了Cu-Cr合金的几种传统制备方法,粉末烧结法、熔渗法和电弧熔炼法,以及制备新技术真空感应熔炼法、自蔓延熔铸法、机械合金化法等工艺方法,分析了它们的优缺点及研究现状,并指出了Cu-Cr合金发展趋势。     

几种Cu-Cr合金的晶体生长特点

介绍了在电弧熔炼、水冷铜模工艺条件下,几种不同含Cr量Cu-Cr合金的晶体生长特点.分析了其微观组织的形成原因.在较大的富Cr粒子的心部有一暗色的区域,在其周围有一亮色圆环,这是一种罕见的显微组织.随着Cu-Cr合金中含Cr量的增加,合金组织变的越来越差,富Cr相的分布越来越不均匀.该工艺方法可以用于制作Cr含量≤10 %的Cu-Cr合金,但无法保证Cr含量≥15 %的触头材料具有良好的性能.     

Cu-Cr复合材料的燃烧合成-熔铸过程的研究

提出了制备大功率真空断路器中Cu-Cr触头复合材料的燃烧合成-熔铸工艺.通过对CuO-Cr2O3-Al反应体系的热力学计算,分析了该体系发生燃烧合成反应并形成Cu-Cr合金熔体的可行性,研究了熔体的凝固过程和最终获得材料的显微组织.结果表明,以廉价的CuO、Cr2O3、和Al粉为原料,利用燃烧合成-熔铸工艺可以制备晶粒细小的Cu-Cr复合材料.     

挤压对燃烧合成Cu-Cr复合材料组织和性能的影响

研究了冷挤压致密化处理对燃烧合成-熔铸CuCr30触头材料组织及其电导率、密度、硬度等性能的影响。结果表明，冷挤压致密化处理不仅可细化材料的晶粒尺寸，而且可提高材料的致密性、硬度、电导率。因此，对燃烧合成-熔铸的Cu-Cr合金进一步进行冷挤压致密化处理，可获得组织和性能更好的Cu—Cr触头复合材料。     

添加剂对自蔓延法制备Cu-Cr合金的影响

以CuO、Cr2O3、Al为原料,采用自蔓延法制备Cu-Cr合金,考察了不同添加剂对Cu-Cr合金结构和纯度的影响。结果表明,合金由Cu、Cr相以及少量的Cr23C6相组成,熔渣由Al2O3相和Na3AlF6相以及少量的Cr相组成,熔渣中存在Cr相表明渣分离效果不理想。随着Na3AlF6配料量的增加,合金中氧化物夹杂得到有效去除,合金的微观结构变得致密均匀。随着铝粉配料量的增加,合金中氧含量降低,但铝残留量增加,合金的纯度大于97.0%。     

热型连铸Cu-Cr合金铸态下的组织与性能

用热型连铸法制备过共晶Cu-Cr合金线．探讨了其在铸态下的微观组织形态、力学性能和导电性能。结果表明：随着含Cr量的增加，Cu-Cr合金的抗拉强度增加，拉铸速度增加，Cu-Cr合金的导电性增加。     

工频感应电炉生产QCr0.5铸锭生产工艺

通过对Cr的特性进行分析，探讨了工频有芯感应电炉条件下生产QCr0.5铸锭合理的生产工艺，包括Cr的加工形式，Cu-Cr中间合金的制备，覆盖剂的选择，减少Cr熔损的措施以及Cr配料比的确定等。     

Cu-Cr合金电滑动摩擦磨损性能研究

对制备的Cu-Cr析出强化型铜合金在电磨损试验机上进行磨损试验,并用扫描电子显微镜观察材料的磨损表面形貌,用能谱仪对其磨损表面主要元素进行分析,然后探讨其磨损机制.结果表明,Cu-Cr合金的磨损率随滑行距离的增加而增加;磨损率随Cr含量的增加而减小,其中Cu-0.65Cr、Cu-0.76Cr合金的磨损率是Cu-0.86Cr合金磨损率的2～3倍;Cu-Cr合金的磨损机制以粘着磨损为主.     

第三组元对Al-Bi偏晶合金凝固组织的影响

采用控制铸造技术制备了减摩轴瓦材料Ａｌ－Ｂｉ偏晶合金,并通过活加第三组元的方法,研究了Ｓｉ,Ｓｎ、Ｐｂ对Ａｌ－Ｂｉ合金凝固组织的影响,合金加热至１０００℃后采用控制铸造技术制蜊均匀铸锭,金相分析结果显示,第三组元Ｐｂ、Ｓｎ对偏晶合金中Ｂｉ粒子的尺寸及形有很大的影响。     

CuCr25合金的形变与组织细化

研究了熔铸法制备的CuCr2 5合金的形变和热处理过程及在不同的冷轧与热处理制度下合金显微组织的特点。试验结果表明 ,熔铸法制备的CuCr合金具有良好的塑性变形能力 ,冷轧形变量可达 95 %以上。当冷轧形变量达到 70 %以上时 ,合金中第二相Cr开始产生形变 ;形变量达 95 %以上时 ,Cr粒子产生大量形变 ,并呈纤维状分布。形变合金在 10 73K退火 1h后 ,纤维状Cr相发生显著细化和球化 ,平均半径小于 10 μm。因而 ,采用合适的形变与热处理方法可以细化合金中的第二相Cr粒子     

STUDY ON MORPHOLOGY OF CHROMIUM IN CHILLED Cu-0.14%-2.0%Cr ALLOYS

The morphology of chromium in chilled Cu-Cr alloys with 0.14%-2.0% Cr has been studied. The results showed that eutectic Cr phase takes a fibrous shape, and pre-eutectic Cr is dendritic in the studied chilled Cu-Cr alloy. During solute treatment of the eutectic and super-eutectic Cu-Cr alloys, only part of chromium particles dissolved in copper phase,some fiber and dendritic chromium still remained. Forging before solute treatment can reduce the size of primary Cr particles, which benefits the aging structure.     

Liquid phase separation of Cu-Cr alloys during rapid cooling

1 Introduction Cu-Cr alloys containing 20%- 50%Cr have been widely investigated because they are the most important contact materials used in high voltage vacuum switches. It has been well known that the smaller the Cr particles in Cu-Cr alloys are, the b…     

Microstructural effects on the high temperature oxidation of two-phase Cu-Cr alloys in 1 atm O2

The oxidation of a Cu-Cr alloy containing about 60 wt% Cr and of two Cu-Cr alloys containing about 40 wt% Cr was studied at 700 and 800 °C in 1 atm O₂. The 60 wt% Cr alloy was prepared by powder metallurgy (PM) and had a phase particle size of 50-150 μm. One of the two alloys containing about 40 wt% Cr was prepared by mechanical alloying (MA) and had a phase grain size ranging from 10-50 nm to 200-300 nm, depending on the location, while the other was prepared by magnetron sputtering (MS) and had a phase grain size around 5-10 nm. The most important difference between the oxidation behavior of the three alloys is the formation of an exclusive chromia scale on the surface of the Cu-40 wt% Cr alloy prepared by magnetron sputtering and of a continuous chromia layer beneath an outermost layer of copper oxides on the corresponding alloy prepared by mechanical alloying, while the Cu-60 wt% Cr alloy prepared by powder metallurgy formed complex scales composed mostly of CuO, Cu₂O with some Cu₂Cr₂O₄ and Cr₂O₃. Thus, the microstructure of two-phase binary alloys has a strong effect of their oxidation behavior. In particular, a decrease of the alloy grain size favors the exclusive external oxidation of the most reactive component, reducing the corresponding critical content in the alloy. This effect is attributed to the presence of larger concentrations of rapid diffusion paths for the migration of the components in the alloy as well as to a faster dissolution of the particles of the Cr-rich phase in the copper matrix.     

大功率真空开关铜铬触头材料

综述了大功率真空开关铜铬触头材料最近的进展,主要内容包括：铜铬合金的发明及技术上的优点,铜络合金二元相图上的特点及常规铸造工艺上的困难。铜铬合金的主要制备工艺包括粉末烧结法,粉末烧结－熔渗法以及自耦电极法等,铜铬合金中杂质的影响,包括残余气体的影响,残余碳的影响及第二组元的影响等。对铜铬合金及其材料的显微组织对真空电触头的基本电性能（分析电流能力,抗电弧烧蚀能力,截断电流等）的影响进行了简要的概述,最后对铜铬合金进一步发展方向（如铬粒子细化,材料回收及准快速凝固工艺,喷射成型等）进行了简要的讨论。     

Cu-Cr合金强化机制研究及其对导电性能的影响

采用真空铸造-固溶处理-冷轧-时效处理工艺制备了Cu-0．8％Cr合金。利用金相显微镜、透射电镜、选取电子衍射、硬度和电导率测试等手段考察了合金在不同处理状态下的组织和性能，定量分析了不同强化方式对合金硬度及导电性能的影响。结果表明：与固溶强化相比，析出强化方法更能有效强化合金，对导电性能影响也更小；形变强化能显著提高合金硬度，但对导电性能几乎无影响；大预变形、短时时效是合金获得较高综合性能的有效手段。     

Dechromisation of Cu-Cr alloy in acid solutions containing Cl~-

1　INTRODUCTIONItisveryimportanttoexploitanewkindofCualloyswithexcellentanti corrosion performancebe causeCualloy ,asakindofanti corrosionmaterialsappliedforalongtime ,oftenundertakesleakageandseriouscorrosionintheearlystageduringitsser vice[1] .Cu Cralloyhashighstrengthandexcellentelectricconductivityandheatconductivity ,anditisappliedwidelytopreparefunctionaldevicesinhighstrength ,highconductivityfields .Althoughmanyattentionwas paidtotheCu Cralloyandalargenumberofworkshadbeendone[2 12…     

Effects of extrusion on chromium precipitation in Cu-Cr alloy

1　INTRODUCTIONChromiummaycrystallizeasashortbarorden driteduringsolidificationofCu Cralloy[13] .AllkindsofCrparticlesmaydissolveintocoppermatrixduringsolutiontreatmentat 980℃ .Duringthesub sequentaging ,thechromiumdissolvedincopperma trixwillprecipitate[4 6 ] .Theprecipitatedchromiumparticleshavegreateffectsonmechanicalandelectri calpropertiesofCu Cralloyaccordingtotheirsize ,shapeanddistribution[79] .Someworksfocusedoneffectofalloyingadditionsonthesizeofchromiumparticleandpropertyof…     

Sintering mechanisms of Cu-Cr metallic composites

Sintered Cu-Cr composites are widely used as electrical contacts for medium voltage circuit breakers. These materials take advantage of the high thermal and electrical conductivity of Cu and of the refractory and oxygen getter properties of reinforcing Cr particles. Although uniaxial compaction followed by free sintering is a cost-effective route for the net-shape manufacturing of Cu-Cr contacts, the sintering mechanisms of these composites are not well documented. This work analyses the solid-state sintering mechanisms of Cu-Cr powder mixtures using dilatometric and thermogravimetric analyses, completed with microstructural observations. Comparison of pure Cu and of Cu-Cr sintering evidences two main effects of Cr on the sintering of the Cu matrix: i) Cr prevents swelling by fixing in the solid phase the gas compounds produced by reaction of the powder with the atmosphere; ii) Cr limits densification through constrained sintering of the Cu matrix. These effects can balance each other. The role of Cr content and atmosphere is analyzed and discussed to the purpose of optimizing the densification of the composites.     

磁控溅射Cu-Cr合金薄膜与Sn-Ag-Cu焊料在时效处理时的界面反应

采用磁控溅射的方式沉积不同Cr含量的Cu-Cr合金薄膜,通过与Sn-Ag-Cu(SAC)焊料在240 ℃下回焊形成焊点结构,然后将试样置于180 ℃下进行真空时效处理。研究Cu-Cr合金作为凸点下金属化(UBM)层时与SAC形成焊点的焊接可靠性。使用配备能量色散X射线光谱仪的场发射扫描电镜和多功能推力测试仪等分析界面金属间化合物(IMC)的形貌及焊点的剪切强度。结果表明,SAC/Cu-Cr焊点结构在回焊后形成了不同于传统的SAC/Cu焊点扇贝状IMC的针状IMC。在时效处理后,Cr在晶界处的偏析形成了富铬层,其作为扩散阻挡层阻碍Cu扩散到IMC中,使得Cu₃Sn和柯肯达尔空洞的生长受到抑制。剪切强度测试结果表明,回焊后SAC/Cu-Cr试样比SAC/Cu试样具有更高的剪切强度。Cr靶电流为1.5 A的Cu-Cr合金UBM层形成的焊点结构具有较小的IMC厚度,且拥有最高的焊点剪切强度。证实了Cu-Cr 合金UBM层有利于提高焊接可靠性。