纳米氧化锌对NR胶料性能的影响

研究纳米氧化锌等量或减量替代间接法氧化锌对NR胶料性能的影响。结果表明 ,当纳米氧化锌等量或减量 3 0 %替代间接法氧化锌应用时 ,胶料的焦烧时间和正硫化时间延长 ,抗硫化返原性能提高 ,硫化胶的邵尔A型硬度、3 0 0 %定伸应力和拉伸强度增大 ;当纳米氧化锌减量 60 %～ 80 %使用时 ,胶料的抗硫化返原性能下降 ,硫化胶的拉断伸长率和撕裂强度增大     

异辛酸钴的制备和应用

采用硫酸钴沉淀法制备异辛酸钴,并在水相与有机相的分离过程中添加助剂的方法,可使分离后有机相不经水洗即可彻底除去SO_4~(2-)离子,简化了工艺流程。介绍了异辛酸钴催干剂在4种醇酸磁漆中的应用及其性能检测结果。检测结果表明,异辛酸钴用于醇酸磁漆的性能指标达到或超过规定标准,尤其光泽、硬度两项指标优于同类产品水平,町作为环烷酸钴等常用催干剂的更新换代产品。     

Tungsten Oxide Nanorods Array and Nanobundle Prepared by Using Chemical Vapor Deposition Technique

Tungsten oxide (WO₃) nanorods array prepared using chemical vapor deposition techniques was studied. The influence of oxygen gas concentration on the nanoscale tungsten oxide structure was observed; it was responsible for the stoichiometric and morphology variation from nanoscale particle to nanorods array. Experimental results also indicated that the deposition temperature was highly related to the morphology; the chemical structure, however, was stable. The evolution of the crystalline structure and surface morphology was analyzed by scanning electron microscopy, Raman spectra and X-ray diffraction approaches. The stoichiometric variation was indicated by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy.     

Effect of thermal insulation on microstructural homogeneity and onset temperature of flash sintered materials

The present work aimed to reduce the microstructure heterogeneity inherent to flash sintering by using alumina blankets as a thermal insulator around ZnO cylindrical samples during the sintering process, under different electric field conditions. Thermal insulation significantly reduced the flash onset temperature and the grain size heterogeneity. For higher electric fields, a temperature reduction as high as 480 °C was observed, which also led to lower densification. These findings were discussed in terms of changes in the heat loss dynamics coupled with the adsorbed water retention, both promoted by the applied thermal insulation. A model to estimate the temperature at stage III of flash sintering was proposed. The final temperature reached with thermal insulation did not differ significantly from the ones without it. Thus, thermal insulation could represent an alternative route to flash sinter materials with lower furnace temperatures with energy savings up to 78 % and a more homogeneous microstructure.     

Electrochemical and microstructural characterization of cyclic redox behaviour of SOFC anodes

The oxidation of Ni to NiO in solid oxide fuel cell (SOFC) anode will result in large bulk volume change, which may change the interfaces of the two phases in the anode cermet and thus may cause significant performance degradation. The reduction and oxidation (redox) of the Ni/YSZ cermet were studied at 800 ℃. Anodic polarization measurements were performed before and after redox cycles. The anode current density at an overpotential of 100 mV kept decreasing during the whole redox treatment. It decreased from 19.11 to 7.95 mA·cm-2 after two redox cycles. Anode supported unit cell was assembled for cell's discharge measurements. Cell performance declined after each redox cycle. The maximum power density decreased from 126.28 to 40.32 mW·cm-2 . The microstructural changes after redox cycling were recorded using scanning electron microscopy (SEM). The results reveal that after re-oxidation, the Ni gets coarse and has a higher porosity; the nickel network structure turns to be desultory.     

用含Pb、As、Sn地方生铁砂型铸造生产D型石墨铸铁的研究

基于Ph、As、Sn等元素有增大铁液过冷倾向的作用，利用含Ph、As、Sn的地方生铁，采用合金化和砂型铸造可以获得D型石墨铸铁，对其工艺方案进行了研究。用正交试验法设计试验方案，得到最佳工艺方案为：在亚共晶成分（WB％：3．2C，2．1si）的铁液中加入适量的铝（0．6％）和钛（0．8％），可以得到含有100％D型石墨的铸铁，其抗拉强度最高可达276MPa。     

Electrochemical properties of some cobalt antimonides as anode materi-als for lithium- ion batteries

Some cobalt antimonides have been prepared and studied as the candidate anode materials for lithium ion batter-ies. Reversible capacities of 424,423 and 546 mA·h·g-1 were measured at the first cycle for as-solidified CoSb2, CoSb3 and annealed CoSb3 respectively. A low lithium ions diffusion coefficient in the order of 10-16 m2·s-1 was estimated from the coulometric titration measurements in the annealed CoSb3 electrode. It was found that the electrochemical properties of fine powders are significantly better than coarse powders. However the SEM picture shows that the nano-sized CoSb3 powders gathered to larger granules, which worsens somewhat the capacity retention of the nano-sized materials, although the volume capacities of the annealed and ball milled CoSb3 remain near twice of that of graphite after 50 cycles.     

Self-organized porous TiO2 and ZrO2 produced by anodization

The present work investigates the electrochemical formation of self-organized high aspect ratio TiO₂ and ZrO₂ nanotube layers. The formation and growth of a self-organized porous layer can be achieved directly by anodization without any templates in fluoride containing electrolytes. The morphology of the porous layers is affected by the electrochemical conditions such as the electrolyte composition, the pH and the exact polarization treatment (such as the potential sweep rate from the open-circuit potential to the anodizing potential). For Ti, nanotube layers are formed with diameters varying from approx. 20 nm to 100 nm and lengths from approx. 0.25 μm to 2.5 μm depending on the electrolytes and pH. On the other hand, for Zr, tubes of 50 nm in diameter and up to approx. 17 μm in length can be grown—a key parameter in this case is the potential sweep rate. The large difference between Ti and Zr in the achievable thickness of nanotube layers indicates a difference in the growth mechanism which may be based on the different chemical dissolution rates of electrochemically formed oxides.     

大剂量Si-Mn复合孕育剂在铸铁中的应用

从例证和机理两方面来说明通过大剂量Si Mn复合孕育在铸铁中的应用 ,使Mn的作用得到充分发挥 ;Mn13是提高铸铁组织中珠光体量和性能的理想元素 ;通过调节大剂量Si Mn复合孕育剂中Mn的比例来稳定和提高基体组织中的珠光体量 ,达到稳定和提高铸铁性能的目的 ,它的可操作性比通过控制化学成分来稳定和提高铸铁的性能更好更容易 ,冲天炉熔炼效果更明显。     

离心铸造CrMoWVNb白口铸铁轧辊的研究

应用离心铸造方法：以Cr,Mo,V,Nb为主要合金元素，研制成功了CrMoWVNb白口铸铁轧辊，分析了合金元素在轧辊中的作用，指出在轧辊中加入适量稀土和钛可细化轧辊组织，改善轧辊性能，同时还分析了轧辊生产中裂纹产生的原因，提出了消除裂纹的措施，并应用于高速线材轧机预精轧机架，使用寿命达到高镍铬无限冷硬铁轧辊的4－5倍。