Electron Probe Microanalysis Mapping Research Articles

A Way of Analyzing an Oxide Layer on Irradiated Plate-Type Atomized U-Mo Fuel Using an EPMA and X-Ray Image Mapping

The oxide layer of atomized U-Mo particle nuclear fuel was analyzed using the electron probe microanalyzer (EPMA) wavelength dispersive spectroscopy (WDS) image mapping function. The density of the used nuclear fuel was 2.6 gU/cm3 and the burnup was 16.4%. Typically, measurements of the oxide layer of most nuclear fuel specimens that have been irradiated for research and experimental purposes in the Korea Atomic Energy Research Institute HANARO research reactor have been performed using metallographic equipment. But an oxide layer was not observed in the nuclear fuel used in this study. Therefore, we conducted this study to confirm the presence and thickness of the oxide layer using EPMA WDS image mapping analysis. We were able to confirm the existence of the oxide layer, but there were many shortcomings in determining the exact thickness of the oxide layer using only the identified X-ray image mapping. In this paper, we present a way to accurately measure the oxide layer by recalling the derived original X-ray values as Excel data. To accurately analyze the oxide layer derived from the image, a preliminary study was performed using samples taken from an irradiated Zr-2.5Nb pressure tube from a CANDU pressurized heavy water reactor. In the preliminary study, the exact thickness of the oxide layer measured by metallography and the results obtained by measuring the thickness of the oxide layer with Excel data obtained by X-ray mapping were compared, inferred, and applied to this study. In this study, a method of accurately measuring the thickness of an oxide layer using Excel data obtained by EPMA WDS image mapping of the oxide layer of plate-type fuel, which was not confirmed using metallography equipment, is described in detail.

Petrochronology of polygenetic white micas (Naxos, Greece)

AbstractNaxos in the Greek Cyclades preserves a type example of polymetamorphism. The southern and northern parts of the island record different Tertiary P–T histories between Eocene and Miocene times, including a blueschist facies event, one or more amphibolite/greenschist facies overprint(s) and contact metamorphism. Age attributions for these events are inconsistent in the literature. Here, we propose a new approach that combines electron probe microanalyzer (EPMA) characterization of the white mica (WM) with 39Ar‐40Ar–Rb‐Sr multichronometry. Textural–petrographic–compositional observations reveal that the polygenetic WM consists of five different generations: pre‐Eocene relicts, paragonite, high‐Si phengite, low‐Si phengite and muscovite. EPMA mapping of four WM samples, previously analysed by Rb‐Sr, reveals major element compositions heterogeneous down to the μm scale. Each WM consists of chemically distinct generations, documenting submicron‐scale retrogression of high‐pressure (HP) phengite grains to muscovite. Four WM samples from a N‐S traverse across the island were analysed by 39Ar‐40Ar stepheating, comparing coarse and fine sieve size fractions to obtain overdetermined K‐Ar systematics. Fine sieve fractions are richer in Cl than coarse ones. Linear arrays in Cl/K‐age isotope correlation diagrams show two predominant WM generations (one Cl‐poor at ca. 38 Ma and one Cl‐rich at <20 Ma). A lower‐grade sample from southern Naxos was less pervasively recrystallized, provides older ages and preserves at least three WM generations, including a relict WM with a pre‐Palaeocene K‐Ar age, consistent with the high Ar retentivity of WM in the absence of complete recrystallization. The age of the Cl‐poor end‐member WM approximates the age of the HP event, 38 Ma. Ar inheritance in Cretaceous mica relicts is heterogeneous at the single‐grain scale. Comparing the degassing rates of the WM fractions rules out ‘multidomain’ diffusion. As no sample is monomineralic, the degassing rate of each polygenetic mica is instead controlled by the mass balanced sum of the unrelated rate constants of its constituent minerals. Given the commonness of zoned and composite micas, the approach detailed here is potentially useful for reconstructing polyphase metamorphic histories worldwide.

Preparation of amorphous carbon membranes synthesized via a glucose-solution hydrothermal method

Carbon-based membranes are in the limelight as novel and high-performance materials for various applications. In this study, microporous carbon membranes were synthesized on porous alumina via a hydrothermal method from aqueous glucose solutions. The operating time and temperature for the hydrothermal treatment by evaluating the surface microstructure of the as-prepared membranes using various techniques like scanning electron microscopy (SEM) and electron probe microanalyzer mapping (EPMA). The SEM micrographs and the EPMA results indicate that the membranes formed were also deposited in the interiors of the porous alumina. A carbon membrane with few pinholes was prepared via a hydrothermal treatment at 200 °C for 5 h. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) analyses suggest that the obtained membranes are composed of amorphous carbon, including hydroxy groups. The result of the gas transmission rate (GTR) measurement indicates that the pore size of the amorphous carbon membranes had pores with a diameter of ∼0.3 nm. The ideal gas selectivities for H2/N2, N2/CH4, and H2/SF6 were over Knudsen theoretical values, showing approximately 7.0, 9.5, and 13.5, respectively.

Influence of CTO additives on microstructure and electrical properties of CCTO ceramics

CaCu3Ti4O12/CaTiO3(CCTO/CTO) composite ceramics were prepared through in-situ reaction and solid-state sintered at 1040°C for 10 h. The phase composition, microstructure, morphology, valence, and electrical properties of ceramics are systematically studied by X-ray diffraction(XRD), Field emission scanning electron microscopy(FESEM), Electron probe micro-analysis (EPMA), X-ray photoelectron spectroscopy(XPS), and LCR instruments. It can be found that the FESEM image shows that the addition of CTO inhibits the growth of CCTO grains, and there are nanocrystals inside the grains. The EPMA mapping demonstrated which nanocrystals are composed of CCTO and a small amount of CTO. Impedance spectroscopy observed two semi-circular arcs, which correspond to the effects of micron-level grains and nano-level nanocrystals, respectively. These two mechanisms significantly affect the colossal dielectric response of CCTO/CTO composite ceramics.

A way Analyzing Oxide Layer on an Irradiated CANDU-PHWR Pressure Tube Using an EPMA and X-ray Image Mapping

The oxide layer in samples taken from an irradiated Zr-2.5Nb pressure tube from a CANDU-PHWR reactor was analyzed using electron probe microanalysis (EPMA). The examined tube had been exposed to temperatures ranging from 264 to 306 ℃ and a neutron fluence of 8.9 × 1021 n/㎠ (E > 1 MeV) for the maximum 10 effective full-power years in a nuclear power plant. Measuring oxide layer thickness generally employs optical microscopy. However, in this study, analysis of the oxide layer from the irradiated pressure tube components was undertaken through X-ray image mapping obtained using EPMA. The oxide layer characteristics were analyzed by X-ray image mapping with 256 × 256 pixels using EPMA. In addition, the slope of the oxide layer was measured for each location. A particular advantage of this study was that backscattered electrons and X-ray image mapping were obtained at a magnification of 9,000 when 20 kV volts and 30 uA of current were applied to radiation-shielded EPMA. The results of this study should usefully contribute to the study of the oxide layer properties of various types of metallic materials irradiated by high radiation in nuclear power plants.

Comparison of Quantitative Analysis of Radioactive Corrosion Products Using an EPMA and X-ray Image Mapping

Radioactive corrosion product specimens were analyzed using an electron probe microanalyzer (EPMA) and X-ray image mapping. It is difficult to analyze the composition of radioactive corrosion products using an EPMA due to the size and rough shape of the surfaces. It is particularly challenging to analyze the composition of radioactive corrosion products in the form of piled up, small grains. However, useful results can be derived by applying a semi-quantitative analysis method using an EPMA with X-ray images. A standard-less, semi-quantitative method for wavelength dispersive spectrometry. EPMA analysis was developed with the objective of simplifying the analytical procedure required. In this study, we verified the reasonable theory of semi-quantitative analysis and observed the semi-quantitative results using a sample with a good surface condition. Based on the validated results, we analyzed highly rough-surface radioactive corrosion products and assessed their composition. Finally, the usefulness of the semi-quantitative analysis was reviewed by verifying the results of the analysis of radioactive corrosion products collected from spent nuclear fuel rods.

Synthesis of Nanosheets Containing Uniformly Dispersed PdII Ions at an Aqueous/Aqueous Interface: Development of a Highly Active Nanosheet Catalyst for Mizoroki-Heck Reaction.

A method was developed to synthesize a nanosheet at the interface of an aqueous layer of PdII ions and an aqueous layer of hydrophilic polymer bearing a metal coordination unit (HPMC). The nanosheet was synthesized through generation of an interface by the addition of an aqueous solution of PdII ions with a low specific gravity (1.03 g/cm3) to a dispersed aqueous solution of HPMC with a high specific gravity (1.50 g/cm3), resulting in rapid cross-linking at the interface. An electron probe microanalysis mapping image showed that the PdII ions were uniformly dispersed in the nanosheet. The nanosheet showed a high catalyst activity for the Mizoroki–Heck cross-coupling reaction with a turnover number (TON) and turnover frequency (TOF) greater than 3,333,333 and 138,889 h–1, respectively. These are the greatest TON and TOF values reported for heterogeneous polymeric catalysts for the Mizoroki–Heck reaction.

Determination of Primary Mineral Content and Calcium Sources in Forest Soils using Electron Probe Microanalysis Mapping and Cluster Analysis

Although mineral dissolution is a fundamental soil forming process, primary mineral content of soils is rarely inventoried or quantified. Concerns about maintenance of forest soil nutrient stocks require better mineralogic data. In particular, to understand recovery from Ca losses induced by acid deposition and sustainability of intensive forest harvest, better inventory of primary Ca minerals is needed. We developed a method based on electron probe micro‐analysis to quantify primary mineral concentrations in soil. Samples analyzed from three sites in the glaciated northeastern United States spanned a bulk Ca concentration of 0.03 to 0.94%. Plagioclase was the dominant Ca‐bearing mineral at two sites while apatite was the only Ca‐bearing mineral found in all three samples and was the dominant calcium source at one site. A variety of other Ca silicate minerals were found in trace amounts. Electron probe microanalysis (EPMA) proved more sensitive in detecting minor and trace Ca bearing minerals than standard XRD procedures. The Ca‐bearing minerals detected by EPMA matched those expected based on the lithologic composition of the glacial till and were consistent with measured bulk soil Ca content by lithium‐borate fusion. Taking into account the Ca concentration in each mineral and each mineral's abundance in the sample, this inventory provided a complete accounting of Ca sources.

Strontium marking on otoliths of Paralichthys olivaceus based on immersion experiments

PDF HTML阅读 XML下载 导出引用 引用提醒 基于浸泡法的牙鲆耳石锶标记技术研究 DOI: 作者: 作者单位: 1. 中国水产科学研究院北戴河中心实验站, 河北 秦皇岛 066100;2. 河北科技师范学院, 河北 秦皇岛 066600;3. 中国水产科学研究院淡水渔业研究中心, 江苏 无锡 214081;4. 中国水产科学研究院黄海水产研究所, 山东 青岛 266071;5. 青岛海洋科学与技术国家实验室海洋生态与环境科学功能实验室, 山东 青岛 266200 作者简介: 司飞(1981-),男,硕士,工程师,主要从事渔业资源增殖与养护研究.E-mail:beyond702@163.com 通讯作者: 中图分类号: S937 基金项目: 现代农业产业技术体系国家海水鱼产业技术体系（CARS-47-Z03）；公益性行业（农业）科研专项经费项目（201303050）. Strontium marking on otoliths of Paralichthys olivaceus based on immersion experiments Author: Affiliation: 1. Beidaihe Central Experiment Station, Chinese Academy of Fishery Sciences, Qinhuangdao 066100, China;2. Hebei Normal University of Science and Technology, Qinhuangdao 066600, China;3. Freshwater Fisheries Research Center of Chinese Academy of Fishery Sciences, Wuxi 214081, China;4. Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China;5. Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了探究耳石微化学标记技术在牙鲆增殖放流中的应用，以全长（1.56±0.16） cm的牙鲆幼鱼为研究对象，在其养殖水中分别添加0.5 mg/L、2 mg/L、8 mg/L、32 mg/L SrCl2·6H2O，以无添加SrCl2·6H2O组为对照组，人为改变牙鲆幼鱼生存环境中Sr2+浓度72 h，研究不同浓度SrCl2·6H2O对牙鲆耳石锶标记效果。标记期间每24 h换水1次，换水量为50%，换水后补加SrCl2·6H2O至原始浓度，记录各浓度组标记期间及标记后的鱼苗死亡数量。利用X射线电子探针微区分析仪（EPMA）对耳石样本进行分析，定量线分析结果表明，0.5 mg/L、2 mg/L SrCl2·6H2O浸染不能形成牙鲆耳石锶标记。8 mg/L浓度组出现Sr峰区，Sr/Ca（Sr：Ca×1000） 均值为4.50~6.60，Sr峰值为5.49~8.49。32 mg/L浓度组Sr峰区均值为4.83~7.55，Sr峰值为5.62~11.04。这说明8 mg/L、32 mg/L SrCl2·6H2O可对牙鲆耳石进行锶标记。但8 mg/L浓度组出现未标记样本，且Sr峰区均值较32 mg/L浓度组低。32 mg/L浓度组Sr/Ca比值显著增高，即锶标记的Sr/Ca比值为6.61±0.86，与标记前和对照组Sr/Ca比值差异均显著（·6H2O浓度组开始，耳石出现红色“高锶标记环”，与耳石本底颜色对比明显，且随浓度升高，红色“高锶标记环”由浅变深，锶标记效果明显增强。单因素方差分析和Duncan多重比较结果显示，各浓度组全长、体重与对照组差异不显著（检验，各浓度组在浸泡标记期间死亡率及标记后养殖90 d的累积死亡率无显著性差异（O对牙鲆幼鱼死亡率无显著影响。因此，32 mg/L SrCl2·6H2O为最佳标记浓度。 Abstract:To explore the method of microchemistry marking on the otolith of Japanese flounder, , during the process of proliferation and release, the juveniles with a total length of (1.56±0.16) cm were immersed at four different concentrations (0.5, 2, 8, and 32 mg/L) of SrCl2·6H2O for 72 h to detect the Sr sedimentation effect. During the immersion period, half of the water was exchanged by fresh seawater daily, and SrCl2·6H2O were added to maintain constant concentration for each group. The exogenous Sr sedimentation in otoliths was detected by X-ray electron probe microanalyzer (EPMA). Results of line transect analysis showed that the strontium marking on otoliths could not be formed after the immersion of two concentrations (0.5 mg/L and 2 mg/L). The Sr high area appeared in the 8 mg/L concentration group with a 5.49-8.49 peak value, and the mean value of the Sr/Ca (Sr:Ca×1000) ratio was 4.50-6.60. Furthermore, in the 32 mg/L group, the mean value of the Sr/Ca ratio was 6.61±0.86, and the peak value of Sr was 5.62-11.04. This means that otoliths of can be marked with strontium by the method of SrCl2·6H2O immersion. However, in the 8 mg/L concentration group there were also unlabeled samples. and the mean value of Sr/Ca was lower than that of the 32 mg/L group. In the 32 mg/L group, the strontium marking rate was 100%, and the mean value of the Sr/Ca ratio was 6.61±0.86, which was significantly different ( < 0.05) compared with that of the control group. The EPMA mapping analysis showed that the red "high strontium marking ring" in the otolith appeared in the 8 mg/L group and 32 mg/L group, and the color of the "high strontium marking ring" was deepened with increasing of concentration. One-way analysis results showed that the total length and weight was not significantly different between the experimental groups and the control group (O immersion did not affect the growth of young fish. A Chi-square test ( > 0.05) showed there were no significant differences in mortality rate among the different concentration groups. Overall, 32 mg/L SrCl2·6H2O was the best marker concentration. 参考文献 相似文献 引证文献

Photodarkening-resistance improvement of Yb3+/Al3+ co-doped silica fibers fabricated via sol-gel method.

Yb3+/Al3+ co-doped silica fibers (YDFs) with almost identical core glass compositions were prepared using the sol-gel and modified chemical vapor deposition (MCVD) methods. The photodarkening (PD) and laser performance before and after the PD process were tested under 974 nm pumping. The doping homogeneity of Yb3+ ions and clusters of Yb3+ ions in preform slices of these two fibers were investigated via optical absorption spectroscopy, photoluminescence emission spectra, electron probe microanalysis (EPMA), and low-temperature (4 K) electron paramagnetic resonance (EPR). It is known that the PD resistance of YDFs prepared via the sol-gel method is significantly better than that of YDFs prepared via MCVD under the same test conditions. EPMA mapping reveals that the doping homogeneity of Yb3+ ions in the sol-gel fiber core glass is better than that in the MCVD fiber. The low-temperature (4 K) EPR and cooperative luminescence spectra of Yb3+ ions indicate that the clustering degree of Yb3+ ions in the sol-gel fiber is lower than that in the MCVD fiber. In the absorption and emission spectra, small amounts of Yb2+ ions are observed in the preform slice from the sol-gel method. A model of the color-center generation in the PD process was proposed to explain the mechanism of PD resistance improvement for the YDFs fabricated via the sol-gel method.

Exploring the interactions and binding sites between Cd and functional groups in soil using two-dimensional correlation spectroscopy and synchrotron radiation based spectromicroscopies

Understanding how heavy metals bind and interact in soils is essential for predicting their distributions, reactions and fates in the environment. Here we propose a novel strategy, i.e., combining two-dimensional correlation spectroscopy (2D COS) and synchrotron radiation based spectromicroscopies, for identifying heavy metal binding to functional groups in soils. The results showed that although long-term (23 yrs) organic fertilization treatment caused the accumulation of Cd (over 3 times) in soils when compared to no fertilization and chemical fertilization treatments, it significantly (p<0.05) reduced the Cd concentration in wheat grain. The 2D COS analyses demonstrated that soil functional groups controlling Cd binding were modified by fertilization treatments, providing implications for the reduced bioavailability of heavy metals in organic fertilized soils. Furthermore, correlative micro X-ray fluorescence spectromicroscopy, electron probe micro-analyzer mapping, and synchrotron-radiation-based FTIR spectromicroscopy analysis showed that Cd, minerals, and organic functional groups were heterogeneously distributed at the micro-scale in soil colloids. Only minerals, rather than organic groups, had a similar distribution pattern with Cd. Together, this strategy has a potential to explore the interactions and binding sites among heavy metals, minerals and organic components in soil.

Visualization of trace-element zoning in fluorapatite using BSE and CL imaging, and EPMA and μPIXE/μPIGE mapping

In this paper, zonation patterns of trace elements in fluorapatite are discussed that were visualized using four analytical techniques, namely back-scattered electrons (BSE) and cathodoluminescence (CL) imaging, electron probe micro-analysis (EPMA), and micro-proton-induced X-ray/gamma ray emission (μPIXE/μPIGE) mapping. Each method demonstrates the in-grain compositional variations in a slightly different way. Both BSE and CL provide qualitative data, and the internal textures are displayed in most detail. Additionally, CL points to specific elements enriched in certain growth zones. Qualitative EPMA maps show detailed zonation patterns for specific elements (with high spatial resolution), which are in general correspondence with the patterns observed in BSE and CL images. The μPIXE/μPIGE maps are fully quantitative and the detection limits are relatively low compared to EPMA mapping. In present spot measurements μPIXE demonstrates lower detection limits than EPMA, however, the latter could be considerably improved by extending the acquisition times. There is no significant overlap of REE (rare earth elements) peaks in the acquired μPIXE energy spectra, however, when multiple REEs are present with sufficiently high concentrations, peak deconvolution may pose some difficulties. Spatial resolution of μPIXE/μPIGE images is not sufficiently high to reflect minor textural features, which also result from the greater interaction depth of the proton beam. However, major growth zones are distinguishable. Even though each method has their advantages and limitations, when applied together, they provide an almost complete characterization of compositional variability in trace-element-bearing minerals.

Effect of strontium addition on silicon phase and mechanical properties of Zn–27Al–3Si alloy

The evolution of silicon phase and mechanical properties of Zn–27Al–3Si alloy with Sr addition were investigated. The results showed that primary Si crystals were gradually modified from polygonal, plate-like and star-like to larger nodular with increasing the addition contents of Sr. A bimodal distribution of eutectic Si crystals was found. One was the coarse eutectic (CE) Si nucleating and growing from the primary Si crystals, the other was the fine eutectic (FE) Si nucleating at other sites (not primary Si). The average size and aspect ratio of FE Si crystals significantly decreased and whose morphology was transformed from a coarser plate-like structure to a fine fibrous structure with more branches with increasing Sr content. Through electron probe microanalysis mapping (EPMA) and cooling curves, it was concluded that the nodular primary Si crystals nucleated and grew by producing a large undercooling (about 40°C) and preferential attachment of Sr to silicon phase. The mechanical properties were investigated by tensile test with various concentration of Sr. It was found that the ultimate tensile strength (UTS) and elongation (EI) increased by 62.6% and 162%, respectively. The improvements in UTS and EI were attributed to the morphology change of silicon phase as well as the improved feeding solidification shrinkage.

Quantitative analysis on the depletion rate of β-NiAl phases in MCrAlY coating

In this study, a disk-shaped thermal barrier coating system for a gas turbine blade was isothermally aged at 1100°C for various times up to 800 h. The microstructures of the bond coat were observed by using an optical microscope for each aging condition. Diffusion of primary elements consisting of the bond coat was characterized by using electron probe microanalyzer mapping. Semi-quantitative analysis by using scanning electron microscopy energy-dispersive X-ray was insufficient to sense variations in the Al content within the bond coat according to exposure time. An area fraction of β-NiAl phases within the bond coat was calculated by image analysis, and a reasonable approach to estimate time for complete depletion of the Al-rich β-NiAl phase within the bond coat was suggested.

Element distribution in lean duplex stainless steel welds

Segregation of alloying elements and nitrogen loss may have a negative effect on the corrosion resistance of autogenously welded duplex stainless steel. The lean duplex LDX 2101® (EN 1.4162, UNS S32101) has less metal element segregation and improved austenite formation compared to other duplex grades and addition of filler metal is not always necessary to achieve good corrosion properties. In gas tungsten arc welding, nitrogen additions to the shielding gas can counteract nitrogen loss and thereby contribute to achievement of the required phase balance. The element distribution in S32101 welds performed autogenously bead-on-plate with and without nitrogen additions to the shielding gas has been quantified and illustrated with electron probe microanalysis mapping. Local segregation and depletion along the fusion line have been elucidated and explained in terms of epitaxial growth and dendritic solidification behavior. The resulting variations in the corrosion resistance are demonstrated by the pitting resistance equivalent distribution and compared to previously known corrosion data.

Solution Heat Treatment Optimization of Fourth-Generation Single-Crystal Nickel-Base Superalloys

The optimization of the solution heat treatment (SHT) of fourth-generation single-crystal nickel-base superalloys LDSX-6B and LDSX-6C is presented. The methodological approach to optimizing the SHT process is particularly highlighted. Differential scanning calorimetry (DSC) measurements and electron-probe microanalysis (EPMA) mapping were carried out to investigate material properties in the as-cast condition and after SHT. The DSC equipment was also adopted as a vacuum furnace to evaluate the suitability of the SHT ramp profile and to check the safety margins with regard to incipient melting during SHT. SHT trials were carried out in a laboratory-scale vacuum furnace, after which the heat-treated samples were subjected to DSC experiments, microstructural analysis, and EPMA mapping to assess the effects of SHT peak temperatures and soak periods. From the DSC and EPMA results, as-cast LDSX-6B shows a lower degree of elemental microsegregation; hence, this alloy is relatively easier to homogenize in the SHT trials. In contrast, as-cast LDSX-6C was found to have a higher degree of elemental microsegregation; therefore, it is much more difficult to homogenize and is highly prone to incipient melting. The results of this study indicate that an increase in the SHT peak temperature and/or soak period will lead to an improved compositional homogeneity in the material as expected. After SHT, both alloys retained some residual elemental microsegregation and the LDSX-6C alloy showed precipitation of topologically close-packed (TCP) phase at the dendrite cores. The most appropriate and economic SHT process may be determined based on the methodological approach presented in this study and the requirements of the materials during service.

Low-Resistance Cu-Sn Electroplated–Evaporated Microbumps for 3D Chip Stacking

Low-resistance copper-tin (Cu-Sn) microbumps, with sizes varying from 5 μm × 5 μm to 20 μm × 20 μm and formed by electroplating–evaporation bumping (EEB) technology for three-dimensional integration of large-scale integrated chips, have been evaluated for their microstructure and electrical resistance. It was inferred from x-ray diffraction data that the formation of low-resistance Cu3Sn intermetallic compound (IMC) is facilitated at higher bonding temperature. Electron probe microanalysis mapping showed that, even before bonding, Cu-Sn IMCs were formed at the interface between Cu and Sn, whereas they were sandwiched between the Cu of the upper and lower microbumps after bonding. Electron backscatter diffraction analysis revealed that the crystal orientation of Sn grains was sharply localized in the (100) orientation for physical vapor deposited (PVD) sample, while electroplated Sn film exhibited a mixed crystal orientation in all (100), (110), and (001) axes. A resistance value of ~35 mΩ per bump was obtained for Cu-Sn microbumps with area of 400 μm2, which is several times lower than the resistance value reported for Cu-Sn microbumps fabricated by a pure electroplating method. The low resistance value obtained for EEB-formed Cu-Sn microbumps after bonding is explained by (i) the reduced surface roughness for evaporated Sn, (ii) the high degree of crystal grain orientation resulting from layer-by-layer growth in the PVD Sn, despite their smaller grain size, and (iii) the absence of impurity segregation at grain boundaries.

理科学的分析法による舞崎遺跡出土の古代鉄材の材質調査

Parts of iron plate materials excavated from the Maisaki site at Tsuruga city of Fukui prefecture were analyzed by scientific methods of the element analysis and the metallographic observation. In the element analysis, a combustion infrared absorption method for determination of carbon and sulfur in iron plates, and a neutron activation analysis (NAA) for determination of 37 trace elements were used. In the metallographic observation, the metal structures were investigated by an optical microscope and an electron probe micro analyzer (EPMA). Carbon concentration in iron samples were low carbon steel or medium carbon steel of about 0.1–0.5%. The existence of ferrite and pearlite structures and non-metallic inclusions were observed in the samples by the optical microscope. An existence of titanium being an index of the origin of Japanese iron sand was not confirmed in these non-metallic inclusions by the EPMA mapping images. As a ratio of arsenic (As) concentration to antimony (Sb) concentration, As/Sb value were less than 1.0, the origin of the samples were estimated, namely, it is concluded that the iron plate materials were brought in Japan from ancient Korea made from iron ore as a raw material.

EPMA mapping of small particles of α-AlFeSi and β-AlFeSi in AA6063 alloy billets

It is well known that the spatial distribution and the spatial density of the particles oα-AlFeSi and β-AlFeSi in the billets of Al-Mg-Si alloys, such as AA6063 alloys affect the quality of anodizing performance of their extrusions. For this reason it is very important to control the spatial distribution and the spatial density of both AlFeSi particles at extrusion plants. The X-ray diffraction method (XRD) has been used for discrimination between α-AlFeSi and β-ALFeSi particles. However it is not an appropriate method for determining the spatial distributions of particles in the alloys. As an alternative method an electron probe microanalyzer (EPMA) has been used for determining the spatial distributions of each element in the microstructures. However, unfortunately it is difficult to discriminate between the particles composed of the same elements like α-AlFeSi and β-AlFeSi particles. Thus, we tried to develop a convenient method to discriminate between α-AlFeSi and β-AlFeSi particles in the microstructure of AA6063 alloys and developed the EPMA mapping of α-AlFeSi and β-AlFeSi particles. First, in order to discriminate between the two particles, we tried to use the relative X-ray intensity ratio, the I Fe/I Si ratio instead of the Fe/Si mass ratio. Then, we calculated the value of the I Fe/I Si ratio from α-AlFeSi and β-AlFeSi by using Monte Carlo calculations and obtained the critical value of the I Fe/I Si ratio, to distinguish between α-AlFeSi and β-AlFeSi. After that, using the discrimination value, we developed the EPMA mapping program (EPMA method) to observe the distributions of α-AlFeSi and β-AlFeSi, and to calculate the areas (%) of α-AlFeSi and β-AlFeSi. Finally, we checked the correlation between the EPMA and the XRD methods. Consequently, the two methods were in good agreement. Today, this EPMA method instead of the XRD method is successfully used in the quality control of 6063 aluminum alloy billets after heat treatment at our aluminum extrusion works.

Microstructure of Cast Strip in 0.1 mass%C Steels Containing Phosphorus

Cast strips of 0.1 mass%C steels with phosphorus contents ranging from 0.01 to 0.2 mass% have been produced by using a twin drum type continuous casting machine, and their microstructures have been characterized. Fine dendrite structure in the strips provides a fine dispersion of the segregated phosphorus regime. Phosphorus addition changes the α grain structure dramatically and decreases the γ grain size. The EPMA (Electron Probe Micro Analyzer) mapping and the diffusion analysis of phosphorus in the γ phase indicate the presence of a retained δ phase in the austenite temperature. The pinning effect of the δ-ferrite on the γ-grain growth must be kept in the temperature range of the rapid γ grain growth. The balance of strength and ductility for the cast strip is improved as the phosphorus content increases.