Investigations of precipitates in heat treated AgPd30/CuSn6 layers

The subject of the investigations are precipitation zones, which grew as a result of chemical diffusion in AgPd30/CuSn6 bimetals. These precipitation zones have been characterized by metallography, electron probe microanalysis and x-ray diffraction. The growth of precipitation zones in the plating layer and in the substrate layer in dependence on time have been determined. The use of x-ray diffraction alone for the identification of the precipitates could not supply satisfying results in every case. This problem was solved by the application of electron probe microanalysis using a correction method, which allows the estimation of the chemical composition of small particles.Dedicated to Professor Dr. rer. nat. Dr. h. c. Hubertus Nickel on the occasion of his 65th birthday     

纳米核壳式铜-锡双金属粉的制备及性能研究

A kind of novel core-shell Cu-Sn bimetallic nanoparticles has been prepared by a new method (displacement method), in which Sn was made to cover on the surface of Cu nano-core. The preparation method and reaction mechanism have been discussed. This reaction happened under the existence of coordinate agent-(NH₂)₂CS and protective agent PVP. The nanoparticles prepared were with a core-shell structure, granule diameter between 50～100 nm and good dispersing capability. The Cu-Sn nanoparticles proposed has better oxidation-resistant ability than Cu nanoparticles with corresponding granule diameter and can be applied as lubricant additives as well as antibacterial agent. When the additive amount is very low (0.1wt‰～0.5wt‰), it can improve the P_B of the lubricant by 92%～106%, and also enhance its antiwear characteristics and friction-reducing properties. At the concentration of 1 000 ppm, it can reach an antibacterial ratio of 99.99%.     

硬质合金-45钢双金属复合耐磨材料冲击韧性研究

采用镶铸工艺制备了硬质合金-45钢双金属复合耐磨材料。用光学金相显微镜和冲击试验研究了双金属材料的显微组织和冲击韧性。结果表明：硬质合金-45钢双金属复合耐磨材料结合层硬度过渡均匀，冲击韧性是普通硬质合金的5-6倍。     

MnWO4/生物质衍生碳纳米复合催化剂的制备及催化性能

通过共沉淀法合成了双金属氧化物MnWO₄镶嵌生物质衍生碳（MnWO₄/BC）纳米复合催化剂,并将其作为对电极（counter electrode,CE）催化剂组装了染料敏化太阳能电池（dye-sensitized solar cell,DSSC）,探究了MnWO₄/BC在非碘体系中的催化性能和光伏性能。结果表明：在铜氧化还原（Cu²⁺/Cu⁺）电对DSSC中获得的光电能量转换效率（power conversion efficiency,PCE）为3.57%（D35）和1.59%（Y123）,高于Pt电极的PCE（3.12%,1.16%）;50次连续循环伏安测试表明,MnWO₄/BC催化剂具有较好的电化学稳定性。     

双金属纳米材料与催化

双金属纳米材料作为工业上少见的一类催化剂材料,在合成过程中可通过对其组成、结构晶粒大小尺寸的调控,实现其催化性能的合理调控,因此,近年来备受催化材料化学领域科技工作者的广泛关注.随着纳米材料调控合成方面的技术进步,具有均一小尺寸可控结构的纳米材料对于制备高效催化剂材料和研究催化反应机理具有重要的意义.结合纳米技术探索开发设计新型的双金属纳米催化剂材料颇具挑战性.本文围绕双金属纳米催化剂的合成、结构及其相关催化性能,从不同的双金属纳米催化剂出发,对催化剂的性能提高、催化机理研究的若干问题和分析手段及方法在催化研究中的进展发表一点初浅认识.     

Pt/Au双金属纳米粒子的制备及表征

Poly (N-vinyl-2-pyrrolidone)-protected Pt/Au bimetallic nanoparticles were obtained by reducing the mixture of HAuCl4 and H2PtCl6 with sodium borohydride. UV-vis spectra, transmission electronic microscopy and X-my diffraction reveal that the prepared bimetallic nanoparticles are of alloy structure.     

载荷对双金属复合带锯条锯切寿命及断口特征的影响

研究了不同载荷条件对双金属复合带锯条的锯切寿命及断口特征的影响，结果表明：低载荷条件下，锯切寿命取决于背部材料疲劳性能，裂纹扩展初期呈沿晶开裂形貌特征；高载荷条件下，锯切寿命取决于齿部材料的耐磨性能，裂纹扩展初期呈穿晶准解理开裂形貌特征，这些现象均与氢脆有关。     

双金属固相复合异步轧制新工艺

在φ90/φ200×200 mm 可逆的四辊轧机上进行异步轧制复合新工艺的研究,并与常规轧制的特性比较;研究了轧制工艺参数对复合过程的影响。结果表明,异步轧制对双金属固相复合有特殊的优越性,充分显示出降低轧制压力的特点。采用此工艺可以在一般的四辊轧机上轧出宽板带复合双金属。此工艺可以应用于双金属固相复合的工业生产中。     

横拼电阻型热双金属电子束焊接

研究了电子束焊接工艺对FeNi36／Cu／Cu／Mn72Cu18Ni10横拼电阻型热双金属焊缝质量与性能的影响．结果表明在电子束焊接参数V，IL，v一定时，随着IB增加，焊缝的饱满性、抗拉强度以及抗弯强度不断提高，电阻率ρ也相应增加．以实施双面焊接工艺的焊缝具有较佳的综合性能．     

Nitrite Oxidation with Copper–Cobalt Nanoparticles on Carbon Nanotubes Doped Conducting Polymer PEDOT Composite

Copper–cobalt bimetal nanoparticles (Cu?Co) have been electrochemically prepared on glassy carbon electrodes (GCEs), which were electrodeposited with conducting polymer nanocomposites of poly(3,4‐ethylenedioxythiophene) (PEDOT) doped with carbon nanotubes (CNTs). Owing to their good conductivity, high mechanical strength, and large surface area, the PEDOT/CNTs composites offered excellent substrates for the electrochemical deposition of Cu?Co nanoparticles. As a result of their nanostructure and the synergic effect between Cu and Co, the Cu?Co/PEDOT/CNTs composites exhibited significantly enhanced catalytic activity towards the electrochemical oxidation of nitrite. Under optimized conditions, the nanocomposite‐modified electrodes had a fast response time within 2 s and a linear range from 0.5 to 430 μm for the detection of nitrite, with a detection limit of 60 nm . Moreover, the Cu?Co/PEDOT/CNTs composites were highly stable, and the prepared nitrite sensors could retain more than 96 % of their initial response after 30 days.