镀Cu-Ni的碳纤维及其复合材料SCIEI

用连续电镀法在碳纤维表面镀Cu后再镀Ni,制备了镀覆Cu-Ni双镀层的碳纤维,研究了Cu-Ni双镀层与碳纤维的高温相容性。并用镀Cu-Ni的碳纤维制备了Cu基复合材料,测试其弯曲强度、线热膨胀系数和电阻率。结果表明,Cu-Ni双镀层在高温下转变为面心立方的Cu-Ni固溶体,克服了在高温下Cu镀层的球化缩聚行为和Ni镀层对碳纤维的催化石墨化作用,且不影响碳纤维的拉伸强度。由于在界面上形成了可溶解微量碳的Cu Ni固溶体而增加了碳纤维与基体的结合强度,复合材料的弯曲强度显著增加,断口上的碳纤维拔出长度大为减小,复合材料的界面属于溶解结合型界面。     

Diffusional bonds in laminated composites produced by ECAP

The microstructure, diffusional and mechanical bonding behavior and microhardness distribution of laminated composites fabricated by ECAP process were investigated. Al-Cu and Cu-Ni laminated composites were produced by ECAP process up to 4 passes at room temperature and high temperature (300 °C). The results of microstructure characterization by SEM and shear strength test revealed that the joints between the layers of 4-pass ECAPed samples were considerably stronger than those of 1-pass ECAPed samples due to tolerating higher values of plastic deformations during ECAP. Furthermore, shear strength data showed that increasing ECAP temperature caused a notable increase in shear strength of the specimens. The reason lies in the formation of diffusional joint between the interface of both Al/Cu and Cu/Ni layers at high temperature. The shear bonding strength of ECAPed Cu/Ni/Cu composite at high temperature was remarkably higher than that of ECAPed Cu/Al/Cu composite.     

Effect of Bonding Temperature on the Microstructures and Strengths of C/C Composite/GH3044 Alloy Joints by Partial Transient Liquid-Phase（PTLP） Bonding with Multiple Interlayers

With the use of Ti/Ni/Cu/Ni multiple foils as interlayer,carbon/carbon(C/C) composite was bonded to Nibased superalloy GH3044 by partial transient liquid-phase bonding technique.The effect of bonding temperature on the microstructures and strengths of the joints was investigated.The results showed that gradient structural multiple interlayers composed of ‘‘C–Ti reaction layer/Ti–Ni intermetallic compound layer/Ni–Cu sosoloid/residual Cu layer/Ni-GH3044 diffusion layer' were formed between C/C composite and GH3044.The shear strength of the C/C composite/GH3044 joint reached the highest value of 26.1 MPa when the bonding temperature was 1,030 °C.In addition,the fracture morphology showed that the fracture mode changed with the increase of bonding temperature.     

火焰喷涂热障陶瓷梯度涂层的制备工艺及性能

在优化热障梯度涂层和过渡层的成分设计及氧乙炔火焰法制备工艺的基础上，获得了组织致密，有良好冶金结合的Al2O3／Fe热障梯度涂层。结果表明，涂层中的Al2O3分布基本均匀，且在整个涂层中，从钢基体到涂层表面的化学成分呈梯度分布，涂层与钢基体及各涂层之间存在明显的冶金结合；所获得的Al2O3热障梯度涂层与普通纯Al2O3热障涂层和带底层（Ni）和过渡层（Cu）的热障涂层相比，与基体间的结合力显著提高，弯曲强度、耐热冲击性能大为增强，涂层热障效果随涂层的数量和Al2O3含量的增加也获得明显提高。     

电刷镀Ni-W过渡层与离子镀TiN复合涂层的结合力和磨损特性

研究了3Cr2W8V基体电刷镀Ni-W过渡层和离子镀TiN复合涂层的结合力及强化机理.利用XRD、SEM和TEM分析了涂层结构,用划痕法测定了涂层结合力,并测定和分析了涂层的磨损特性.结果表明由于TiN沉积过程中的温度效应,混合晶态的电刷镀Ni-W层发生晶化和析出强化,并形成界面扩散层和双层复合,从而使TiN复合涂层的结合力和硬度明显提高;Ni-W过渡层对TiN涂层起有力的支撑作用.Ni-W与TiN复合涂层的耐磨性优于TiN单层.     

C/SiC复合材料用莫来石/硅酸钇双层涂层的抗氧化性能研究

针对C/SiC复合材料的防氧化要求,在材料表面通过等离子喷涂法制备了莫来石/硅酸钇的双层涂层,对涂层的形貌、组成和结构及其与基底的结合强度进行了表征,开展了1500℃、1h静态空气氧化实验,对抗氧化涂层的结构演变进行了分析,并对C/SiC复合材料氧化实验前后的质量和力学性能变化进行了研究。结果表明,莫来石/硅酸钇双层涂层抗氧化作用较好,涂层C/SiC复合材料的强度保留率达95.3%。     

Durability of Titanium/Dicalcium Silicate Composite Coatings in Simulated Body Fluid

Titanium/dicalcium silicate composite coatings with different ratios (weight ratios as Ca₂SiO₄: Ti = 3:7, 5:5, 7:3) were prepared by plasma spraying. Effects of titanium addition on coating properties, such as bonding strength, flexural modulus, and dissolution in simulated physiological environment, were studied. Results showed that the bonding strength between coating and Ti-6Al-4V substrate increased with increase of titanium content in the composite coatings. It was explained by the narrowed dissimilarity of thermal expansion coefficients between the coatings and substrates. Degradation of mechanical properties after immersion in simulated body fluid was also studied. The dissolution of dicalcium silicate in the composite coatings resulted in the decrease of flexural strength and flexural modulus of the coatings in the simulated physiological environment. The higher titanium content in the composite coatings, the stabler are the composite coatings in the physiological environment.     

Effect of nickel coating on the shear strength of FSW lap joint between Ni–Cu alloy and steel

Cu–Ni alloy and low-carbon steel were joined by friction stir lap welding (FSLW) with the help of a nickel coating. The appropriate welding parameters were investigated and the lap joints were analyzed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and shear strength testing. The shear strength of joints with a nickel coating was about 2.9 times as high as that of the joints without Ni coating. According to the EDS analysis of the fractured surfaces under the shear strength test, the micro-voids occurred in the Cu–Ni/steel interface without Ni coating, thus reducing the shear strength. These micro-voids were reduced in size using a nickel coating due to the self-diffusion in the Ni/Ni interface at high interface temperature and high contact pressure. The strong bonding mechanism using a nickel coating could be explained by the iron and copper atoms diffusing into the coating through the interface at high interface temperature and holding time.     

Solid–liquid Interdiffusion Bonding of Cu/Sn/Ni Micro-joints with the Assistance of Temperature Gradient

A novel solid-liquid interdiffusion(SLID) bonding method with the assistance of temperature gradient(TG) was carried out to bonding Cu and Ni substrates with Sn as interlayer.The element distribution and grain morphology of interfacial intermetallic compound(IMC) in Cu/Sn/Ni micro-joints during both SLID and TG-SLID bonding and in the final Cu/(Cu,Ni)₆ Sn₅/Ni full IMC micro-joints were analyzed.Under the effect of Cu-Ni cross-interaction,interfacial(Cu,Ni)₆ Sn     

SiCP颗粒增强Al基复合材料的瞬间液相连接

采用Ni箔和Cu/Ni/Cu多层箔作中间层在923K进行了SiC颗粒增强铝基复合材料的瞬间液相连接。研究表明,无压连接时,接头强度随保温时间延长有所增高,但界面处会存在纯金属（无增强颗粒）区域和氧化物夹杂,是导致接头强度不高的主要原因。加压TLP连接则能有效改善界面组织和接头性能。采用Cu/Ni/Cu多层箔作中间层加压连接时接头强度可达189．6MPa,约为母材强度的85％。本文对压力的作用和复合材料TLP连接界面特性进行了讨论。     

电接触强化对Ni/Cu复合镀层组织与性能的影响

利用电刷镀在铸铁表面制备了厚度在1 mm左右的Ni/Cu复合镀层,并对镀层进行了电接触强化试验。利用场发射电镜(FESEM)、维氏硬度计分析了电接触强化对镀层组织性能的影响。试验结果表明,电接触强化改善了镀层表面和内部质量,减少了镀层内部裂纹、孔洞等缺陷。同时,电接触强化使镀层和基体之间产生了部分镶嵌熔融。电接触强化改变了Ni层与Cu层的组织结构,使镀层组织更加致密紧实,Cu层和Ni层之间发生了塑性变形,产生了一定的镶嵌。强化后镀层表面及截面硬度都有所提升。镀层与基体之间形成的硬化层硬度远大于基体硬度,电接触强化提高了镀层与基体之间的结合力。     

Effect of immersion Ni plating on interface microstructure and mechanical properties of Al/Cu bimetal

A nickel-based coating was deposited on the pure Al substrate by immersion plating, and the Al/Cu bimetals were prepared by diffusion bonding in the temperature range of 450–550 °C. The interface microstructure and fracture surface of Al/Cu joints were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanical properties of the Al/Cu bimetals were measured by tensile shear and microhardness tests. The results show that the Ni interlayer can effectively eliminate the formation of Al-Cu intermetallic compounds. The Al/Ni interface consists of the Al₃Ni and Al₃Ni₂ phases, while it is Ni-Cu solid solution at the Ni/Cu interface. The tensile shear strength of the joints is improved by the addition of Ni interlayer. The joint with Ni interlayer annealed at 500 °C exhibits a maximum value of tensile shear strength of 34.7 MPa.     

CuCrZr合金表面等离子喷涂Cr3C2-NiCr及NiAl/Cr3C2-NiCr涂层的结合性能

在CuCrZr合金表面等离子喷涂Cr3C2-NiCr涂层、NiAl/Cr3C2-NiCr复合涂层.测试涂层与基体间的结合强度及涂层的热震性能,结合SEM,EDS和XRD等分析涂层物相变化,探讨涂层的结合机理.结果表明,涂层的结合强度均较高;Ni-Al发生放热反应,生成Al4Ni3,Al3Ni2,AlNi3,剩余的铝与铜反应生成Cu3Al2,CuAl2,CuAl,局部区域形成微冶金结合;二种涂层均以机械锚合为主,在参数适合且基体相同的情况下,涂层结合强度取决于涂层材料的力学性能;相同试验条件下,NiAl/Cr3C2-NiCr复合涂层的热震性能优于Cr3C2-NiCr涂层.     

纯铜表面等离子喷焊 Ni 60 涂层组织及性能的研究

采用等离子喷焊工艺在纯铜基体表面成功制备了Ni60焊层,并对其微观形貌、元素成分、显微硬度及耐磨性能进行分析。分析表明:焊层与基体呈现良好的冶金结合,稀释率仅为5%左右,且其显微组织呈细小枝晶状,硬质相呈弥散分布,焊层显微硬度高达606HV,耐磨性能较Cu-Ni合金焊层提高了1倍。     

碳纤维表面SiO2涂层的制备及其在镁基复合材料中的应用

利用Sol-Gel方法,通过优化溶胶的配置、纤维提拉过程和干燥烧结等工艺过程,在碳纤维表面制备出均匀的、无裂纹的SiO2涂层.采用SEM、XPS和TEM表征了碳纤维表面SiO2涂层的结构、形貌、元素分布以及涂层碳纤维/镁基体的界面结构.结果表明,涂覆SiO2的碳纤维,抗氧化能力提高,拉伸性能略有降低,但与镁基体复合后其拉伸强度降低了20%.SiO2涂层改善了Mg对碳纤维的润湿能力,有效地促进了熔融Mg液对碳纤维的浸渗.     

碳纤维表面超声振荡辅助电镀镍涂层工艺及其参数的影响规律

碳纤维增强铝基复合材料具有诸多优良性能,在航空航天以及民用领域有广阔的应用前景。在碳纤维表面电镀镍涂层,可有效改善碳纤维与铝基体的润湿性,并抑制基体对纤维的损伤。镍涂层的质量与改善效果密切相关。通过预氧化处理并结合超声振荡辅助电镀的方法在纤维表面沉积镍涂层,解决碳纤维在电镀过程中因纤维束丝难以分散而出现的"黑心"问题。在此基础上,研究电镀工艺参数对涂层质量的影响规律,并对优化工艺参数后制备的镍涂层与碳纤维的结合强度进行评价。结果表明:使用添加剂可提高镍涂层与碳纤维之间的结合力,当电镀液pH值调整到3～4、电流密度大于0.3 A/dm²、电镀液温度控制在20～40℃时,所制备的镍涂层均匀致密。     

Mechanism of Zr in in situ-synthesized particle reinforced composite coatings by laser cladding

By adding mixture of ZrO_2 and carbon, a Zrenhanced composite coating was produced onto an AISI1045 substrate by laser cladding. The microstructure and phase formation, microhardness and wear resistance of the composite coating were studied. The experimental results indicate that the composite coating with metallurgical bonding to substrate consists of y-Ni, massive ceramic particles of ZrC,NiZr_2, Ni_7 Zr_2,(Fe,Ni)_(23)C_6 and Fe_3 C. The in situ-synthesized ZrC particles are uniformly dispersed in composite coating, which refines the microstructure of composite coating. With different Zr02 and carbon additions, the properties are improved differently. Finally, the fine in situ ZrC particles improve the microhardness of composite coating to HV_(0.2) 650, which is nearly 2.7 times that of Ni25 coating. Also, the composite coating has an advantage in wear resistance; it offers better wear resistance when more mixture of ZrO_2 and carbon was added in nickel alloys.     

低碳钢表面热喷涂镍基合金涂层工艺研究

采用热喷涂工艺在Q235低碳钢板表面喷涂了Ni60合金涂层,并进行了金相分析和硬度试验。结果表明,热喷涂层组织是由细小的扁平粒子堆积起来的片层结构,涂层晶粒粗大且分布不均,具有典型的快速凝固组织特征。涂层的硬度明显高于基体,其组织组成物为γ-固溶体,碳、硼化合物,氧化物以及金属间化合物。热喷涂层与基体之间为机械结合,结合强度并不高。     

LD31铝合金电刷镀SnPb钎料合金软钎焊

采用在LD31表面电刷镍阻挡层、铜改性层,将LD31铝合金的连接转化为铜的连接,在镀铜层的表面电刷镀SnPb钎料直接进行钎焊,通过开发低应力镀镍液和调整电刷镀工艺参数解决镍过渡层的裂纹问题,研究分析了镀层的显微结构及表面状态,焊缝的结构及元素分布,考察了焊接加热过程对镀层的影响。研究表明,通过在镀铜层表面直接刷镀SnPb钎料合金可以实现软钎焊连接,接头的抗剪强度可达20MPa,镀镍层、镀铜层钎焊后无裂纹、剥离等缺陷产生。     

6061铝合金激光熔覆铜基复合涂层组织及磨损性能

利用激光熔覆工艺在6061合金表面熔覆铜基复合涂层,分析熔覆涂层的微观组织及化学成分,考察熔覆合金成分变化对涂层质量、硬度以及磨损性能的影响.结果表明,熔覆层主要由(Cu,Ni)固溶体、Cu9Al4、AlFe0.23Ni0.77以及CoFe增强相等组成.优化成分条件下,Fe含量为7%,Co含量为9%,熔覆层硬质颗粒体积分数增大,大量硬质颗粒增强体弥散分布在熔覆层Cu-Ni固溶体合金基体组织中,大大增强了基体的抗磨损性能.激光熔覆后的熔覆层表面硬度比6061铝合金提高了4.5倍;磨损体积约为铝合金基线的30%,摩擦因数降至0.3002.