微量Al-RE对Zn-2%Ni合金的组织细化研究

研究了RE，Al及Al-RE合金对Zn-2％（质量分数，下同）Ni合金组织中Zn-Ni合金相粒子的细化作用，利用扫描电镜（SEM）及能谱分析（EDS）等方法分析了合金凝固组织特点。结果表明：在Zn-2％Ni合金中，加入0．02％～1％RE会产生新的Zn—RE—Ni合金相粒子，对Zn-Ni合金相粒子没有明显的细化作用；加入0．02％～1％Al，虽然对Zn-Ni合金粒子有细化作用，但此合金组织不适宜在热镀锌中运用。在铝浓度较低（〈0．1％）时。凝固组织中的合金相粒子尺寸不均匀；当铝浓度较高（〉0．2％）时，高熔点、低密度β-NiAl相核心长大，合金相粒子易上浮，出现比重偏析；加入0．02％～0．2％Al-RE时，能形成细小弥散而均匀分布的异质晶核β-NiAl相，促进了γ-Ni2Zn5相的生成，获得细小且均匀分布的γ-Ni2Zn5相。Al-RE合金细化效果明显优于RE和Al，其最佳加入浓度为0．05％～0．1％。     

悬浮进样阻抑火焰原子吸收光谱法测定甘薯粉条中的微量铝

本文利用铝对钙吸收的阻抑效应,建立了悬浮进样-火焰原子吸收光谱法快速测定甘薯粉条中微量铝的方法。结果表明,当底液中的钙为20.0μg/mL时,测定铝的线性范围是0.5~8.0μg/mL,检出限为0.25μg/mL。本法用于三种不同粉条中铝的测定,相对标准偏差为0.7%~1.9%,加标回收率为95%~104%。     

微波等离子体化学气相沉积法低温制备直纳米碳管膜

Among the three main methods for the synthesis of carbon nanotubes (CNTs)， chemical vapor deposition (CVD) has received a great deal of attention since CNTs can be synthesized at significantly low temperature. Plasma chemical vapor deposition methods can synthesize CNTs at lower temperature than thermal CVD. But in the usual catalytic growth of CNTs by CVD， CNTs are often tangled together and have some defects. These will limit the property research and potential applications. How to synthesize the straight CNTs at low temperature becomes a challenging issue. In this letter， straight carbon nanotube (CNT) films were achieved by microwave plasma chemical vapor deposition (MWPCVD) catalyzed by round Fe-Co-Ni alloy particles on Ni substrate at 610℃. It was found that， in our experimental condition， the uniform growth rate along the circumference of round alloy particles plays a very important role in the growth of straight CNT films. And because the substrate is conducting， the straight CNT films grown at low temperature may have the benefit for property research and offer the possibility to use them in the future applications.     

改善GdSiGe室温磁致冷材料磁热性能的途径

GdSiGe合金是最优良的室温磁致冷材料之一。介绍了改善GdsiGe合金磁热性能的各种途径，涉及该材料的合金化、熔炼、凝固、热处理、纳米化、复合化等方面的工作研究。     

A new simple preparation of platinum-nickel alloy nanoparticles and their characterization as an electrocatalyst for methanol oxidation

Pt-Ni alloy nanoparticles were produced by casting 2 or 10 mM H₂PtCl₆ solutions on a Ni column. The apparent particle size for the resultant Pt-Ni alloys increased with the concentration of the H₂PtCl₆ solution, while the content of Pt in the alloy decreased. The potential sweeps of 5 cycles in an H₂SO₄ aqueous solution for Pt-Ni (2 mM)/Ni and Pt-Ni (10 mM)/Ni electrodes led to electrochemical behavior similar to a polycrystalline Pt electrode, suggesting the formation of a few thin Pt layers on each Pt-Ni alloy surface. In electrochemical measurements, both Pt-Ni/Ni electrodes showed more negative onset potential of methanol oxidation and slower degradation of oxidation current of methanol than the polycrystalline Pt electrode. X-ray photoelectron spectroscopy of both Pt-Ni/Ni electrodes showed the shift of Pt4f peaks to a higher binding energy, suggesting that the increase in the d vacancy in the balance band 5d orbital of Pt contributed to the improved electrocatalytic activity and durability of the Pt-Ni/Ni electrodes.     

原子吸收光谱法测定铅中微量元素铜钙铝

铅中微量元素直接影响铅蓄电池使用寿命,本文采用原子吸收光谱法测定铅中的微量元素Cu、Ca、Al.用HNO_3(1 3)溶解样品,用HCl沉淀铅排除铅基干扰,在不过滤的情况下,直接测定上层清液,方法快速简便.通过试样分析及方法检验,结果满意.加标回收率93%～100%,相对标准偏差(n=8)2.4%～8.4%.     

多晶Fe60Ni40合金阳极钝化膜的XPS研究

过渡金属Fe、Ni或其合金由于它们具有磁性和在工业上被用作催化剂等，它们与氧化腐蚀性气体02、C12等的作用已被广泛研究［‘－3］．含Ni的不锈钢和含Ni50％的FeNi基合金在酸性溶液中表现出比铁更好的耐腐蚀性并增强了氧化钝化层的附着力，放它们在溶液的腐蚀与钝性研究已引起广泛的兴趣，甚至包括对F6Ni基非晶合全玻璃的腐蚀与钝性研究【4一刊，用不同的方法研究溶液状态下的自然氧化膜或阳极钝化膜，得出的结果不同，对腐蚀与钝性解释也很不一致，硼酸一础砂或磷酸一磷酸盐缓冲液在工业上被广泛用作清洗剂、缓蚀剂或成膜剂等·因此，…     

Ethanol reforming processes over ZnO-supported palladium catalysts: Effect of alloy formation

ZnO- and SiO₂-supported palladium catalysts were evaluated in the ethanol steam-reforming and oxidative ethanol steam-reforming reactions in the temperature range 548–723 K. The catalysts were characterized before and after reaction by X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and infrared spectroscopy using CO as a probe molecule. On silica-supported Pd catalyst, ethanol decomposes into H₂, CO and CH₄ in both steam-reforming and oxidative steam-reforming reactions. In contrast, ZnO-supported catalysts containing the PdZn phase exhibit a better catalytic performance for hydrogen production through dehydrogenation of ethanol into acetaldehyde and ulterior reforming.     

稀土元素对Cu-6%Ag及Cu-24%Ag合金微观组织的影响

制备了Cu-6％Ag及Cu-24％Ag合金铸锭并进行了均匀化处理。通过在合金中添加0．1％混合稀土的方法，研究了稀土元素对高Ag含量和低Ag含量两种合金原始组织的影响。稀土元素可在一定程度上使共晶体数量增加，细化低Ag含量合金的铸态α基体晶粒，降低高Ag含量合金中被连续网状共晶组织包围的枝晶轴问距。在均匀化退火过程中，稀土元素可明显细化在α基体中析出的次生相，并使共晶组织更趋于分散和向离异共晶形态发展。