河北石湖金矿床含金、银矿物特征研究

通过河北石湖金矿野外产出的地质现象及矿脉间的穿插关系,结合显微镜和电子探针进行综合分析.本矿区主要为两个矿化阶段,即石英-黄铁矿阶段和石英-多金属硫化物阶段：石英-黄铁矿阶段主要产出矿物：石英、黄铁矿、银金矿和金银矿等;石英-多金属硫化物阶段主要产出矿物：石英、黄铁矿、闪锌矿、方铅矿、黄铜矿、银金矿、金银矿、硫碲银矿、辉银矿和自然银等.本文着重对这两个阶段产出的含Au、Ag矿物特征进行了探讨性研究.其中两个矿化阶段中都产出银金矿与金银矿,随着温度的下降Au的含量呈下降趋势Ag含量呈上升趋势,Au与Ag呈负相关性,类质同象替代.本区产出的硫碲银矿是前人研究中未见有报道的矿物,产出于晚期多金属脉中并与闪锌矿、黄铁矿和黄铜矿共生.Ag含量与Te含量成弱负相关性.     

电子探针在冀东峪耳崖金矿载金矿物研究中的应用

利用电子探针对矿相显微镜下难以分辨的矿物颗粒进行了微区图像及成分分析。峪耳崖金矿中的载金矿物为黄铁矿、碲铋矿。碲铋矿为本次工作中重点研究的载金矿物。根据矿物组合及矿物形成温度把碲铋矿分为早晚两期。碲铋矿多呈他形粒状,从早期到晚期碲铋矿中Fe元素含量降低而Te、Bi、Ag元素含量升高。利用背散射电子像可清晰地看到碲铋矿中包裹银金矿。通过比较碲铋矿中金的含量与黄铁矿中金的含量,看出碲铋矿中金的含量略高于黄铁矿中金的含量,可将碲铋矿作为找矿标志之一。     

陕西省陈耳金矿含金银矿物赋存状态研究

在野外地质调查的基础上,本文着重利用电子探针分析手段,对陈耳金矿床中产出的含金银矿物的赋存状态及成分进行了研究。研究发现,在早期形成的银金矿中,由核部到边缘,金的含量逐渐减少,而银的含量逐渐增加。碲银矿、硫银铋矿为本次研究工作中新发现的矿物,未见前人研究工作中有关于碲银矿、硫银铋矿的报道。碲银矿被包裹在硫银铋矿颗粒中产出,鉴于碲、铋和金相近的地球化学特征和密切关系,可将碲银矿和硫银铋矿作为找矿标志。     

陕西岚皋浦家沟铜矿床中硒矿物的赋存状态研究

笔者在对陕西省岚皋县浦家沟铜矿床进行矿物学研究的过程中,发现该矿床中存在硒铜银矿、硒铅矿等2种硒的独立矿物.利用电子探针分析结果计算得:硒铜银矿化学分子式为(Ag0.95~1.00 Cu0.95~1.00 Fe0.02~0.03)1.97~1.99(Se0.72~0.76 S0.22~0.27 Te0.01)1,硒铅矿化学分子式为(Pb0.96~0.98 Fe0.01~0.03 Cu0.01~0.03)1.00~1.01(Se0.86~0.93 S0.07~0.14)1.其中硒铜银矿分布于表生辉铜矿内部或边缘,与之关系密切;硒铅矿则主要分布于黄铁矿与黄铜矿的接触部位或黄铁矿内部,与方铅矿、闪锌矿等共生.硒铅矿作为一种中低温热液矿物,它的出现暗示浦家沟铜矿经历过中低温热液阶段;硒铜银矿由后期含Ag+、Cu+溶液与次生辉铜矿反应形成的,它的存在暗示该矿床经历过后期成矿作用的叠加改造.     

青海陆日格矿床中铋碲赋存形式的电子探针研究

本文主要利用电子探针对陆日格斑岩铜钼矿床中的Bi、Te矿物进行X射线元素图像分析及定量分析,明确了Bi、Te的赋存状态、分布形态及元素成分组合。研究结果表明,陆日格斑岩铜钼矿床中Bi、Te主要以两种形式赋存于矿石中。一种以类质同象的形式存在于黄铁矿中;另一种以独立矿物的形式存在于黄铁矿包体或裂隙中。独立矿物主要为自然铋、因硫铋碲矿、辉硫铋碲矿及硫铋铅矿等。矿床勘探开发需考虑Bi、Te等分散元素的综合利用,以提高矿区的经济价值。     

电子探针在黑龙江省三矿沟铁铜矿床含金、银矿物研究中的应用

通过对三矿沟铁铜矿床野外产出的地质特征及矿脉间的穿插关系、矿物共生组合特征的观察,结合光学显微镜观察和电子探针分析,研究了三矿沟铁铜矿床的含金、银矿物.将矿床的成矿期次划分为矽卡岩期、石英-硫化物期和表生氧化期3个成矿期5个成矿阶段.从物理化学性质上的变化,探讨了含金、银矿物的特征.碲银矿的发现在前人研究资料中未见有报...     

罗山金矿不同产状金矿物电子探针分析

本文在地质研究的基础上,详细研究了罗山金矿不同主成矿阶段、不同产状金矿物的成分特征。所获取的早阶段金矿物成色高于晚阶段,包裹金的成色高于裂隙金,同一金矿物组成成分在不同部位是有变化的。这些结论对确定该矿床的成因和指导找矿预测具有重要意义。矿床地质特征罗山金矿床位于胶东西北部著名的招掖金矿带的东端,属于玲珑金矿田的欧家界矿段。罗山金矿的金矿围岩为玲珑黑云母花岗岩,控矿构造以北东,北北东向断裂构造为主,矿体呈脉状、透镜状或不规则状产于矿脉内。矿石组成有石英、黄铁矿、黄铜矿、银金矿、自然金、自然银等。矿石构…     

电子组装用高温无铅钎料的研制

Bi-Ag合金是一种替代高铅钎料的芯片封装无铅焊料。研制了Bi-2.5Ag、Bi-2.5Ag-0.1RE、Bi-5Ag-0.1RE、Bi-7.5Ag-0.1RE、Bi-10Ag、Bi-10Ag-0.1RE钎料。结果表明,该合金系钎料的熔化温度范围随Ag含量的增加而增大,而且其润湿性能良好,润湿角都处于30o～40o。不同Ag含量的Bi-Ag/Cu接头在界面处发生断裂,剪切强度差别不大,都略大于30MPa。Bi-Ag/Cu界面没有金属间化合物形成,结合强度较弱。     

Effect of mechanical deformation on the mass density of Ag-clad (Bi,Pb)2Sr2Ca2Cu3O10 wire and tape

The mass densities of Ag-clad (Bi,Pb)₂Sr₂Ca₂Cu₃O₁₀ wire and tape varies during the mechanical deformation process, which is one of the steps of the oxide-powder-in-tube technique used to fabricate the composite superconductor. Results show that the rolling has a more significant effect on densifying the tape core, whereas the drawing process can only densify the core to about 75% of the theoretical density. SEM observations of the rolled samples also reveal very dense morphology, consistent with the mass density calculations. SEM observation also shows that with increasing the deformation extent, the average grain size is reduced. It is proposed that although the rolling densifies the tape core significantly, it also destroys the crystallinity of the superconducting phases and results in the formation of an amorphous phase. Since the textured Bi-2223 phase forms by the epitaxial growth on the textured Bi-2212 seed crystals, the deformation induced texture is critical. Appropriate deformation extent is necessary, since too high an extent of deformation may change the well-aligned grains into amorphous phase. The formation of the amorphous phase is harmful to the texturing formation of the Bi-2223 phase, which finally leads to critical current degrading.     

Effects of Ce Addition on the Microstructure and Mechanical Properties of Sn-58Bi Solder Joints

The effects of a rare-earth element on the microstructure, mechanical properties, and whisker growth of Sn-58Bi alloys and solder joints in ball grid array (BGA) packages with Ag/Cu pads have been investigated. Mechanical testing indicated that the elongation of Sn-58Bi alloys doped with Ce increased significantly, and the tensile strength decreased slightly, in compar- ison with undoped Sn-58Bi. In addition, the growth of both fiber- and hillock-shaped tin whiskers on the surface of Sn-58Bi-0.5Ce was retarded in the case of Sn-3Ag-0.5Cu-0.5Ce alloys. The growth of interfacial intermetallic compounds (IMC) in Sn-58Bi-0.5Ce solder joints was slower than that in Sn-58Bi because the activity of Ce atoms at the interface of the Cu₆Sn₅ IMC/solder was reduced. The reflowed Sn-58Bi and Sn-58Bi-0.5Ce BGA packages with Ag/Cu pads had a ball shear strength of 7.91 N and 7.64 N, which decreased to about 7.13 N and 6.87 N after aging at 100°C for 1000 h, respectively. The reflowed and aged solder joints fractured across the solder balls with ductile characteristics after ball shear tests.     

Interfacial reaction and solder joint reliability of Pb-free solders in lead frame chip scale packages (LF-CSP)

Chip scale packages (CSP) have essential solder joint quality problems, and a board level reliability is a key issue in design and development of the CSP type packages. There has been an effort to eliminate Pb from solder due to its toxicology. To evaluate the various solder balls in CSP package applications, Pb-free Sn-Ag-X (X=In, Cu, Bi) and Sn-9Zn-1Bi-5In solder balls were characterized by melting behavior, phases, interfacial reaction, and solder joint reliability. For studying joint strength between solders and under bump metallurgy (UBM) systems, various UBMs were prepared by electroplating and electroless plating. After T/C (temperature cycle) test, Sn3.5Ag8.5In solder was partially corroded and its shape was distorted. This phenomenon was observed in a Sn3Ag10In 1Cu solder system, too. Their fractured surface, microstructure of solder joint interface, and of bulk solder ball were examined and analyzed by optical microscopy, SEM and EDX. To simulate the real surface mounting condition and evaluate the solder joint reliability on board level, Daisy chain test samples using LF-CSP packages were prepared with various Pb-free solders, then a temperature cycle test (−65∼ 150°C) was performed. All tested Pb-free solders showed better board level solder joint reliability than Sn-36Pb-2Ag. Sn-3.5Ag-0.7Cu and Sn-9Zn-1Bi-5In solders showed 35%, 100% superior solder joint reliability than Sn-36Pb-2Ag solder ball, respectively.     

Superconducting magnet system containing Bi-2212/Ag Coil Generates 21.8 T at 1.8K

We fabricated a Bi-2212/Ag double stacked pancake coil of 13 mmØ) in inner bore and of 46.5 mmØ in outer diameter, by using Bi-2212/Ag tapes prepared by the combination of continuous dip-coating process and melt-solidification technique. This small superconducting magnet was used as an insert magnet of a conventional superconducting magnet system and tested at saturated superfluid helium temperature (～ 1.8K) in various bias fields. The generated field of Bi2212/Ag coil was 0.9 T, with I_c of 310 A(criterion 10^-13Ω·m), in the bias field of 20.9 T. Thus, this superconducting magnet system achieved generation of magnetic field of 21.8 T in the full superconducting state.     

A comparative study of the kinetics of interfacial reaction between eutectic solders and Cu/Ni/Pd metallization

A comparative study of the kinetics of interfacial reaction between the eutectic solders (Sn-3.5Ag, Sn-57Bi, and Sn-38Pb) and electroplated Ni/Pd on Cu substrate (Cu/Ni/NiPd/Ni/Pd) was performed. The interfacial microstructure was characterized by imaging and energy dispersive x-ray analysis in scanning electron microscope (SEM). For a Pd-layer thickness of less than 75 nm, the presence or the absence of Pd-bearing intermetallic was found to be dependent on the reaction temperature. In the case of Sn-3.5Ag solder, we did not observe any Pd-bearing intermetallic after reaction even at 230°C. In the case of Sn-57Bi solder the PdSn₄ intermetallic was observed after reaction at 150°C and 180°C, while in the case of Sn-38Pb solder the PdSn₄ intermetallic was observed after reaction only at 200°C. The PdSn₄ grains were always dispersed in the bulk solder within about 10 μm from the solder/substrate interface. At higher reaction temperatures, there was no Pd-bearing intermetallic due to increased solubility in the liquid solder. The presence or absence of Pd-bearing intermetallic was correlated with the diffusion path in the calculated Pd-Sn-X (X=Ag, Bi, Pb) isothermal sections. In the presence of unconsumed Ni, only Ni₃Sn₄ intermetallic was observed at the solder-substrate interface by SEM. The presence of Ni₃Sn₄ intermetallic was consistent with the expected diffusion path based on the calculated Ni-Sn-X (X=Ag, Bi, Pb) isothermal sections. Selective etching of solders revealed that Ni₃Sn₄ had a faceted scallop morphology. Both the radial growth and the thickening kinetics of Ni₃Sn₄ intermetallic were studied. In the thickness regime of 0.14 μm to 1.2 μm, the growth kinetics always yielded a time exponent n >3 for liquid-state reaction. The temporal law for coarsening also yielded time exponent m >3. The apparent activation energies for thickening were: 16936J/mol for the Sn-3.5Ag solder, 17804 J/mol for the Sn-57Bi solder, and 25749 J/mol for the Sn-38Pb solder during liquid-state reaction. The corresponding activation energies for coarsening were very similar. However, an apparent activation energy of 37599 J/mol was obtained for the growth of Ni₃Sn₄ intermetallic layer during solid-state aging of the Sn-57Bi/substrate diffusion couples. The kinetic parameters associated with thickening and radial growth were discussed in terms of current theories.