文摘辑要

新型金配合物巯基乙酸亚金铵的合成及其理化性质和在镀金中的应用为了减少和避免镀金过程中剧毒物质氰、腈的使用,以巯基乙酸为配体合成了一种新型亚金配合物巯基乙酸亚金铵：采用试金法和元素分析法分析了其成分,利用红外光谱、紫外光谱、热失重分析和导电性测量等研究了其基本理化性质,并将其用于电镀金,     

半胱氨酸亚金钠的理化性质及化镍金工艺研究

目的合成一种新型水溶性亚金配合物,并分析其应用于无氰镀金的可行性。方法以氯金酸为金液、半胱氨酸为配体,在弱碱性条件下合成半胱氨酸亚金钠,通过元素分析仪、红外光谱仪、紫外可见光谱仪、热重分析仪、电导率仪研究其理化性质。以温度、p H值和金质量浓度为变量,通过单因素试验分析它们对镀金的影响,通过正交试验获得适宜的镀金工艺条件。结果该产物的分子式为Na Au(Cys)2。该配合物的结构中,半胱氨酸里巯基和亚金进行配位并形成了很强的配位键,该配合物的特征吸收波长范围在205~210 nm。差热曲线和电导率值测定结果显示,该配合物在170℃以前的热稳定性较好,是典型的离子化合物。最佳的镀金工艺参数为:p H=2,金质量浓度2 g/L,温度45℃。在该条件下,镀层的结合力好,镀速可控,镀金效果良好。结论合成了新型水溶性亚金配合物,其理化性质稳定,有望用于无氰镀金工业领域。     

一种新的PCB无氰化学沉金工艺

介绍了一种新的不含游离氛的无氰化学沉金工艺,并从工艺特.s、沉金效果、产品品质和环保处理等方面将该无氰沉金工艺与传统的有氛化学沉金工艺进行了对比分析,分析表明:该无氰沉金工艺的金缸溶液寿命更长,沉积均匀性更好,沉积速率可控,有利于控制金厚和降低镀金的材料成本;产品的品质有保障,过程更环保,可望替代传统的有氰工艺.     

简单一步法合成Co9S8氧还原反应电催化剂

采用低温回流技术,以Co₄(CO)₁₂和S粉为原料,在1, 6-己二醇溶剂中一步合成了钴硫化物催化剂。用X射线衍射仪和扫描电子显微镜对合成的化合物进行了表征。XRD分析表明合成样品为立方结构的Co₉S₈化合物,其SEM图片显示了花椰菜状的表面形貌。Co₉S₈化合物表现出良好的氧还原催化活性,开路电位为0.75 V(vs. NHE)。在电荷转移控制电位区,电极反应传递系数和塔菲尔斜率分别为0.50和119 mV。同时,将催化剂的催化活性和电化学稳定性与商业铂催化剂进行了比较。     

纳米晶NiAl的机械合金化合成机理研究

采用机械合金化方法,以元素粉末为原料,对四种成分的NixA1100-x(x=25,30,40.50)进行不同球磨时间和球磨转速的机械合金化合成,制备纳米晶NiA1金属间化合物粉末.利用X射线衍射技术对球磨产物进行了物相分析,并对NiA1机械合金化合成机理进行了探讨.研究表明:NixAl100-x四种成分的元素粉末采用机械合金化方法均可以制备出纳米晶NiA1金属间化合物粉末;NiA1金属间化合物的机械合金化合成机理为燃烧合成反应.     

金渠矿石无氰法选矿回收金试验研究

对金渠矿石选矿生产实践研究分析,结合小秦岭矿石性质特点,提出"重-氰-浮"和"重-浮-氰"2种选浸工艺方案。通过试验研究,金回收率相应提高3%~6%,效果显著。使用LJ环保低毒药剂代替氰化钠浸出提金,有效地减少了环境污染,对同类型黄金矿山具有较好的推广应用价值。     

还原镀金研究进展

金在电子产品和装饰性产品中的应用十分广泛,其稳定的化学性质不仅能够对基底起到良好的保护作用,金黄的色泽还具有装饰效果.虽然电镀金和置换镀金均能够沉积金层,但是金层的质量还存在不可控的难题,诸如基底形状会影响镀层的均匀性、"黑盘"现象的产生以及镀层厚度有限等.近年来,随着电子产品的快速发展,许多行业对电路板的整体质量提出了越来越高的要求,金层对保证电子器件的可靠性起着非常重要的作用.还原镀金是克服上述缺陷的一个重要研究领域,特别是环境友好的无氰镀金技术已成为研究热点.对氰化物体系和无氰体系镀金液常用还原剂(包括亚硫酸盐、二甲基胺硼烷、次磷酸盐、联氨、抗坏血酸、硼氢化钠、硫脲和其他还原剂)及促进剂的研究和作用基本原理进行了总结,重点阐述了镍和金对这些还原剂的催化活性.大部分还原剂仅受镍和金其中一种金属的催化,在沉积初始阶段和后期阶段,两种或多种还原剂的复配是实现反应速率保持较高的一种可行方案.沉积厚金依赖于可被金催化氧化的还原剂.最后展望了无氰还原镀金的发展方向.     

氨氰浸金原理及研究进展

氨氰浸出技术自从发明以来就被认为是从含铜难处枞金矿资源中恒择性回收金的一种有效方法。系统总结了目前国内外氨氰浸金的研究进展,主要包括氨氰浸金的基本原枞、浸出动力学研究、溶液化学研究、氨氰浸金实验室实验及工业应用研究现状,对氨氰浸金过程中存在的问题及其未来的发展趋势做了评价。     

U-Cu金属间化合物制备与表征的研究

为了提高核工程系统中核材料的相容性和安全性,贫铀金属间化合物的物理化学行为是技术上值得十分关注的问题。这是因为,有时这些金属间化合物以夹杂形式存在于材料中;有时核材料不可避免的与包壳材料如钢、锆、铝和铜等接触并形成化合物。因而U金属间化合物特性研究及其相容性预测需要制备并表征这些金属间化合物。本项目拟采用材料基因工程研究方法,制备了U-Cu等金属间化合物,利用纳米压痕、SEM、能谱仪等表征了化合物的形貌、成份和力学性质如弹性模量、硬度等。结果显示在一定压力和温度作用下,在金属U和Cu界面获得了一定厚度的金属间化合物。扩散层成份为Cu和U,Cu/U比例约为78:22。对界面化合物进行了微区纳米压痕测试,结果显示U-Cu化合物弹性模量为121 GPa,压入硬度为5.2 GPa,热膨胀系数为7.3×10_-5K_-1。U-Cu化合物的应变硬化效应比金属U明显。金属U应变率效应比U-Cu化合物明显。     

负载纳米Au-Pd合金催化剂对苄胺氧化偶联合成亚胺的研究

采用浸渍还原法制备了Au/γ-Al₂O₃, Pd/γ-Al₂O₃和Au-Pd/γ-Al₂O₃系列纳米催化剂,考察了催化剂对无碱条件下苄胺自身氧化偶联合成亚胺的反应性能。研究结果显示3wt% Au-Pd/γ-Al₂O₃催化剂对伯苄胺自身氧化偶联合成亚胺的反应表现出较好的催化活性,在70℃、常压条件下,不加氧化剂和碱时,亚胺收率可达93%。催化剂能够回收利用,使用循环5次后的催化剂,产物亚胺的收率降到44%。     

Oxygen-free precursor for chemical vapor deposition of gold films: thermal properties and decomposition mechanism

Thermal properties of oxygen-, phosphorus-, and halogen-free dimethylgold(III) diethyldithiocarbamate complex (CH₃)₂AuS₂CN(C₂H₅)₂ (gold, dimethyl(diethylcarbamodithioato -S,S′)-) having excellent storage stability and the mechanism of its decomposition to elemental gold were studied. Saturated vapor pressure was found to be ~10⁻³–10⁻¹ Torr at 50–90°C. Decomposition of the vapor on the surface starts at T = 210°C. The temperature dependence of gas phase composition was studied using the original mass spectrometric technique, it was established that the decomposition of the compound on the surface in vacuum follows three main pathways. Two of them result in the formation of elemental gold, saturated C2–C4 alkanes and (1) protonated ligand or (2) methylated ligand. The third one results in elemental gold and gaseous products: C2–C3 alkylmercaptanes and CH₃SCN(C₂H₅)₂. The formation of gold as a sole solid product within the temperature range 210–240°C was confirmed by X-ray photoelectron spectroscopy analysis. It was shown that the compound exhibits the best combination of volatility, thermal, and storage stability among volatile organogold complexes and thus it may be a promising precursor for obtaining gold films by chemical vapor deposition.     

Effect of sintering temperature on the structural, electrical and magnetic properties of Li0.5Al1.0Fe2O4 ferrite prepared by combustion method

Al³⁺ substituted lithium ferrite of S-type having chemical formula Li_0.5Fe_1.5Al_1.0O₄ was successfully synthesized by the combustion method. The ferrite was then divided into two parts and sintered at two different temperatures, respectively to study the effect on its properties. It was found that at lower sintering temperature the particle size of product was reduced. This was clearly indicated by the broadening of major peaks of X-ray diffraction pattern. Corresponding increase in activation energy and decrease in coercivity and retentivity were also observed during electrical and magnetic studies. The part of compound sintered at lower temperature was judged as admixture of single domain and superparamagnetic particles. The micrographs of the compound supported this judgment.     

半导体用高纯金制备技术及应用研究进展

综述了目前制备高纯金的各种方法的原理及工艺,并对其优缺点进行了分析。化学还原分离法效率高、周期短,但酸耗大、污染严重;熔融氯化法对原料适应范围广,但存在氯化过程复杂、工艺难于精准控制和产品质量不稳定等不足;溶剂萃取法效率高、产品质量稳定,但试剂消耗大、有机污染严重和易燃易爆;电解法具有成本低、除杂效果好、产品纯度稳定性强及环境污染小的优点,但原料适应性相对较差、生产周期相对较长且会积压金。高纯金具体应用形式为键合用金丝、溅射靶材及高纯度金基合金,涉及电子、半导体及航空航天等领域。     

丝蛋白多肽原位制备金纳米粒子的研究

用来自丝素蛋白的GAGAGAGY序列多肽原位还原氯金酸制备了粒径小于12 nm的球形金纳米粒子,用紫外-可见吸收光谱和透射电子显微镜对反应过程和产物进行了表征分析,探索制备条件对产物的影响。结果表明,多肽可发挥稳定剂的作用,使合成的金纳米溶液具有较好的稳定性;多肽和氯金酸的摩尔比为10:4时合成的粒子粒径大小合适且分布均匀;溶液碱性越强,还原反应速度越慢但金纳米粒径不受影响;反应温度升高,反应速率变快,紫外吸收峰蓝移。     

陈化胶体金的简便合成与光谱特性

文章描述了通过只添加氢氧化钠到氯金酸和十六烷基三甲基溴化铵混合液中合成陈化纳米金胶体,并研究了该胶体的光谱特性。基于傅里叶红外光谱对纳米金的形成机理进行了分析并以紫外可见光谱和扫描电子显微镜表征了添加不同量的氢氧化钠而获得的陈化三个月的胶体金。同时文章获得了吸附于陈化了三个月的胶体金表面上的亚甲基蓝的表面增强拉曼光谱。结果表明,陈化三个月的胶体金其紫外可见光谱具有宽的等离子吸收峰,这种宽化改变在文章对中进行了解释分析。其透射电子显微镜图片表明了在纳米金合成阶段,添加不同量的氢氧化钠可影响纳米金大小,同时不同量的氢氧化钠影响着胶体金的陈化过程并产生出形状依赖的陈化胶体金。表面增强拉曼光谱的增强特性不同证明了所形成的陈化胶体金的大小/形状依赖特征。因此,我们期望着这种陈化胶体金能够在生化分析领域被得到开发应用。     

Zinc-zinc chloride composite electrodeposited steel sheet

The corrosion product layer found on zinc attains to a stable state in natural environment after exposure of several months. To accelerate the formation of the protective corrosion product layer, a zinc-zinc chloride composite layer was electrodeposited on steel in 3 M ZnCl₂ bath, in which colloids of 4Zn(OH)₂·ZnCl₂ were suspended, 4Zn(OH)₂·ZnCl₂ is a stable compound in chloride environment. The amount of deposited colloids increased with bath temperature, whereas the uniformities of deposited zinc in crystal grain size and distribution were lost under the bath condition of high temperature and current density. The plating condition with low temperature and current density of bath maximized the uniformity of zinc-zinc chloride composite layer and enhanced the corrosion resistance of the composite layer by accelerating the formation of stable corrosion product layer.     

SHS synthesis of Si-SiC composite powders using Mg and reactants from industrial waste

Si-SiC composite powders were synthesized by self-propagating high-temperature synthesis (SHS) using reactants of fly ash-based silica, sawdust-based activated carbon, and magnesium. Fly ash-based silica and sawdust-based activated carbon were prepared from coal mining fly ash and Para rubber-wood sawdust, respectively. The work investigated the effects of the synthesis atmosphere (air and Ar) on the phase and morphology of the SHS products. The SHS product was leached by a two-step acid leaching processes, to obtain the Si-SiC composite powder. The SHS product and SHS product after leaching were characterized by X-ray diffractometry, scanning electron microscopy and energy dispersive X-ray spectrometry. The results indicated that the SHS product synthesized in air consisted of Si, SiC, MgO, and intermediate phases (SiO₂, Mg, Mg₂SiO₄, Mg₂Si), whereas the SHS product synthesized in Ar consisted of Si, SiC, MgO and a little Mg₂SiO₄. The SiC content in the leached-SHS product was higher when Ar was used as the synthesis atmosphere. As well as affecting the purity, the synthesis atmospheres also affected the average crystalline sizes of the products. The crystalline size of the product synthesized in Ar was smaller than that of the product synthesized in air. All of the results showed that fly ash and sawdust could be effective waste-material reactants for the synthesis of Si-SiC composite powders.     

A comparative study on Ti1 − xAlxN coatings reactively sputtered from compound and from mosaic targets

The aim of this work is to illuminate the influence of two widely applied target types, i.e. TiAl compound targets produced by powder metallurgy and mosaic TiAl targets, on the sputter deposition process as well as on the structure and properties of the obtained coatings. After development of a sputter process for the compound targets by optimization of cathode power and nitrogen partial pressure, this process was compared to the commercially applied mosaic target process by taking into account the sputter yields of Ti and Al and the respective deposition rates. The deposition rate achieved with the compound targets was ~ 44% higher than that obtained for the mosaic targets. The Al content in the coatings deposited from the compound targets was slightly higher and the domain size of the formed cubic Ti_1 − xAl_xN solid solution considerably larger than for the coatings deposited from the mosaic targets. The coatings grown from the compound targets showed, in contrast to those synthesized from the mosaic targets, tensile stresses. While the hardness of the coatings sputtered from the compound targets was slightly below that of the coatings synthesized from the mosaic targets, both their friction and wear behavior were slightly improved. In summary, it could be shown that using compound TiAl targets manufactured by powder metallurgy, Ti_1 − xAl_xN coatings with mechanical and tribological properties comparable to those grown from commercially applied mosaic targets can be deposited at significantly higher growth rates.     

Fabrication of modified-poly(divinylbenzene)/Au core–shell structure

A novel PDVB/Au core–shell structure was prepared by the chemical reduction of a gold–phenanthroline complex on the surface of a poly(divinylbenzene) (PDVB) cores (2–4 μm). The PDVB cores were synthesized by precipitation polymerization, and the surface was modified by introducing thiol and sulfonic acid groups. The modified surface structure was examined by FT-IR, XPS and EDS and the degree of sulfonation was measured according to its ion exchange capacity (IEC, 5.72 meq/g). The modified PDVB cores were immersed in a solution of a gold–phenanthroline complex and subsequently reduced to form gold nanoseeds. These were further grown in a solution of HAuCl₄ and NH₂OH to form gold nanoshells. The effects of the functional groups on the PDVB cores on fabrication of the core–shell structure were carefully examined. SEM and XPS were used to characterize the gold nanoshells. The presence of the functional groups could be of great assistance for the gold shell formation.