甲基磺酸盐体系Pb-Sn-Cu合金镀液性能的研究

测定了甲基磺酸盐体系Pb-Sn-Cu合金镀液的参数,测试了镀液的分散能力、深镀能力以及镀液的稳定性.试验表明:镀液的电导率随游离甲基磺酸浓度的增加而增大;电流效率随着电流密度的增大而降低;在镀液中加入添加剂,可以增大阴极极化及增加镀液的稳定性.     

电化学工作站在电路板表面镀锡研究中的应用

在电化学工作站上采用电偶电流测试的方法,研究以硫脲作为电位调整剂,在印刷电路板表面浸镀锡(I-Sn)的过程.采用FE-SEM观察锡镀层的显微形貌.结果证明,这种方法用来研究电路板上的浸镀金属过程是切实可行的,可以确定镀覆工艺的终了点.此方法所确定的浸镀锡工艺,可以获得致密、晶粒细小而均匀的镀层.     

添加微量稀土对提高电工用铜母线性能的作用

在纯铜熔体中以 Al-RE 中间合金形式加入富 Ce 混合稀土,探讨了 RE 加入量对电工用铜母线铸态组织、力学性能和导电性的影响规律.结果表明:纯铜基体的纯净度随RE加入量的增加而明显提高,当w(RE)=0.02%时,结晶组织最为细小,力学性能得到改善;添加RE可显著改善纯铜的导电性,其影响作用取决于稀土化合物的分布状态及基体的纯净度,当w(RE)》0.02%后,导电率略为降低.当w(RE)=0.05%,可使纯铜获得较理想的综合性能,基本满足高强高韧高导铜母线的生产要求.     

Experimental study on the interfacial delamination in a thermal barrier coating system at elevated temperatures

The failure mode and adhesion of thermal barrier coating (TBC) 8YSZ (ZrO2+8% (w/w) Y2O3) deposited on NiCoCrAlTaY bond coat by atmospheric plasma spraying were investigated. A grooved modified three-point bending specimen that can generate a single interface crack to facilitate the control of crack growth was adopted for testing, which was conducted at the ambient temperature of 100 °C. The morphology and composition of fractured surfaces were examined by means of a scanning electron microscopy (SEM) and an energy disperse spectroscopy (EDS). Images and spectrum show that cracks are initiated and propagated exclusively within YSZ layer adjacent to top/bond coat interface. The load-displacement curves obtained exhibit similar shapes that indicate two distinct stages in crack initiation and stable crack growth. Finite element analyses were performed to extract the adhesion strength of the TBCs. The delamination toughness of the plasma-sprayed 8YSZ coatings at 100 °C, in terms of critical strain energy release rate Gc, can be reliably obtained from an analytical solution.     

Comparison of the effects of copper and lead on soil microbial biomass carbon and nitrogen in red soil

A laboratory incubation experiment was conducted to study the effect of copper as cupric sulfate (CuSO₄.5H₂O), and lead as lead acetate (Pb (OAc)₂) on the size of the microbial biomass in red soil. The metals were applied, separately at six different levels: Cu at 50, 100, 200, 300, 400, and 600 μg·g⁻¹ soil and Pb at 100, 200, 400, 600, 800, and 1000 μg·g⁻¹ soil. In comparison to uncontaminated soil, the microbial biomass carbon (C_mic) and biomass nitrogen (N_mic) decreased sharply in soils contaminated with Cu and Pb. The microbial biomass C:N ratio in the metal contaminated soil was observed to be considerably higher than that in untreated control. Between the two tested metals, Cu displayed greater biocidal effect on microbial biomass carbon and nitrogen than Pb, showing their relative toxicity in the order: Cu≫Pb. Project (No. 49671050) supported by National Natural Science Foundation of China. Wa’el Mohamad—Former Ph. D. Student of Zhejiang University and is working in Ministry Of Agriculture (P. O. box. 2099), Amman, Jordan.     

结构钢中残余镍、铬、铜的联合测定分析方法研究

试样用盐—硝混酸溶解,在盐酸（１％）介质中加氯化铵溶液抑制铁对铬的干扰,在同一份试样中分别测定镍、铬、铜．     

PEG600-PVP-(NH_4)_2-H_2O双水相体系萃取Cu~(2+)

研究了聚乙二醇600-聚乙烯吡咯烷酮(K30)组合表面活性剂水溶液在(NH4)2SO4存在下形成双水相体系的条件,初步探讨了5-Br-PADAP与Cu2+螯合物在该体系中两相间的分配行为,在一定实验条件下可实现的Cu2+萃取.