• Title/Summary/Keyword: Ni trends

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Interdiffusion Studies of βNiAl Bond Coats: Understanding the Zr, Pt, and Al Migration Trends and Their Beneficial Effects

  • Chandio, Ali Dad;Haque, Nafisul;Shaikh, Asif Ahmed
    • Korean Journal of Materials Research
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    • v.31 no.8
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    • pp.439-444
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    • 2021
  • The oxidation resistance of the diffusion aluminide bond coat (BC) is compromised largely by interdiffusion (ID) effects on coated turbine blades of aeroengines. The present study is designed to understand the influence of ID on βNiAl coatings or BC. In this regard, nickel substrate and CMSX-4 superalloy are deposited. In total, four sets of BCs are developed, i.e. pure βNiAl (on Ni substrate), simple βNiAl (on CMSX-4 substrate), Zr-βNiAl (on CMSX-4 substrate) and Pt-βNiAl (on CMSX-4 substrate). The main aim of this study is to understand the interdiffusion of Al, Zr and Pt during preparation and oxidation. In addition, the beneficial effects of both Zr and platinum are assessed. Pure βNiAl and simple βNiAl show Ni-out-diffusion, whereas for platinum inward diffusion to the substrate is noticed under vacuum treatment. Interestingly, Zr-βNiAl shows the least ID in all BCs and exhibit stability under both vacuum and oxidation treatments. However, its spallation resistance is slightly lower than that of Pt-βNiAl BC. All BCs show similar oxide growth trends, except for Zr-βNiAl, which exhibits two-stage oxidations, i.e. transient and steady-state. Moreover, it is suggested that the localized spallation in all BCs is caused by βNiAl - γ'-Ni3Al transformation.

Geochemical Dispersion and Enrichment of Fluvial Sediments Depending on the Particla Size Distribution (입도분포에 따른 하상퇴적물의 지구화학적 분산 및 부화)

  • 이현구
    • Economic and Environmental Geology
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    • v.32 no.3
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    • pp.247-260
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    • 1999
  • Geochermical characteristics of the fluvial sediments deprnding on particle size distribution size were investigated in the respect of majir, minor and rare eath element chemisitry. Ratios of $Al_{2}O_{3}/Na_{2}O$ and $K_{2}O/Na_{2}O$ of the sediments show the homogeneous valus, and partly positive correlation with $SiO_{2}/Al_{2}O_{3}$, respecively. Characteristics of minor element ratios (V/Ni, Cr/V, Ni/Co and Zr/Hf)are within the lower and narrow range. Thesesuggested that sediment sources may be acidic to intermediate granitic rock, and may be explained by simple weathering and sedimentation. With increasing SiO2 contents, concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, CaO and MgO decreased, but those of $K_{2}O$ and $Na_{2}O$ increased, Concentrations of Ba, Be, Cs, Cu, Li, Ni, Sr, V and Zr show comparatively normal negative and some positive trends. Compared with the mean composition of granite, concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, MnO, CaO and MgO in the sediments of the study area were highly enriced. Among some minor and rare earth elements, concentrations of As, Cd, Cu, and V were enriched, but those of Be, Ce, Rb, Sc, Sr and Zn were depleted when compared with average composition of granite. By decreasing of particle size fractions, SiO2, Rb and Sr conterts decreased, but concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, CaO, MgO, $TiO_{2}$, MgO, $P_{2}O_{5}$, Be, Cu, Hf, Pb, V and Zr increased. From the correlations between particle size fractions and element concenreations, some elements of $Fe_{2}O_{3}$, CaO, MgO, $P_{2}O_{5}$, Cu, Ni, Zn and Zr showed typical trends in the secondary contramination sediments. These trends are typically shown under 100 mesh fractions. It indicates that the fraction of minus 100 mesh is the optimum size fraction for geochemical and environmental survey.

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Development Trend of Ni-less Surface Treatment Technology for Semiconductor Packaging Substrates (반도체 패키지 기판용 Ni-less 표면처리 기술 개발동향)

  • Min-Kyo Cho;Jin-Ki Cho;Kyoung-Min Kim;Sung Yong Kim;Deok-Gon Han;Tae-Hyun Sung
    • Journal of the Microelectronics and Packaging Society
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    • v.30 no.1
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    • pp.49-54
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    • 2023
  • Recently, System in Packaging(SIP) technology needs to meet high frequency (5G and more) communication technology and fine pitch surface treatment. The conventional Electroless Ni/Immersion Au plating(ENIG) is not suitable for high frequency range because of magnetic properties are increasing the transmission loss. Without nickel plating layer, the pattern and pad reliability level must be meet the condition. In this review paper, we investigated research trends on Ni-less surface treatment technology for high-frequency communication and frequency characteristics according to materials.

Accumulation of Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn in urban soil and their mobility characteristics

  • Bhattacharyya, Krishna G.;Mahanta, Mayur J.
    • Advances in environmental research
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    • v.3 no.4
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    • pp.321-335
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    • 2014
  • Eight trace metals, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn, were measured in the urban soil of Guwahati City, Assam, India from 31 sites representing five different types of land use, residential, commercial, industrial, public utilities, and roadside. Cd and Co occurred in very low concentrations (Cd << Co) in all types of land use without any significant variation from one type of land use to another. Ni concentrations were more than those of Co, and the concentrations depended on land use pattern. Average Cr and Cu concentrations were ${\geq}100mg/kg$, but Cr had a significantly higher presence in industrial land use. Pb concentrations showed similar trends. The two metals, Mn and Zn, were present in much larger amounts compared to the others with values ${\geq}300mg/kg$. Industrial and roadside soil contained much more Mn while commercial soil was enriched with Zn. Toxicity Characteristic Leaching Procedure (TCLP) was used for elucidating the mobility characteristics of the eight heavy metals. Mn suffered the highest leaching from commercial land (9.9 mg/kg on average) and also from other types of land. Co, Cu and Pb showed higher leachability from commercial soils but the leached concentrations were less than those of Mn. The two metals, Zn and Ni, were leached from residential land in considerable amounts. The TCLP showed Mn to be the most leachable metal and Cr the least.

Reliability of Sn-Ag-Cu Solder Joint on ENEPIG Surface Finish: 1. Effects of thickness and roughness of electroless Ni-P deposit (ENEPIG 표면처리에서의 Sn-Ag-Cu 솔더조인트 신뢰성: 1. 무전해 Ni-P도금의 두께와 표면거칠기의 영향)

  • Huh, Seok-Hwan;Lee, Ji-Hye;Ham, Suk-Jin
    • Journal of the Microelectronics and Packaging Society
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    • v.21 no.3
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    • pp.43-50
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    • 2014
  • By the trends of electronic package to be smaller, thinner and more integrative, the reliability of interconnection between Si chip and printed circuit board is required. This paper reports on a study of high speed shear energy of Sn-4.0wt%Ag-0.5wt%Cu (SAC405) solder joints with different the thicknesses of electroless Ni-P deposit. A high speed shear testing of solder joints was conducted to find a relationship between the thickness of Ni-P deposit and the brittle fracture in electroless Ni-P deposit/SAC405 solder. A focused ion beam (FIB) was used to polish the cross sections to reveal details of the microstructure of the fractured pad surface with and without $HNO_3$ vapor treatment. The high speed shear energy of SAC405 solder joint with $1{\mu}m$ Ni-P deposit was found to be lower without $HNO_3$ vapor, compared to those of over $3{\mu}m$ Ni-P deposit. This could be due to the edge of solder resist in $1{\mu}m$ Ni-P deposit, which provides a fracture location for the weakened shear energy of solder joints and brittle fracture in high speed shear test. With $HNO_3$ vapor, the brittle fracture mode in high speed shear test decreased with increasing the thickness of Ni-P deposit. Then the roughness (Ra) of Ni-P deposits decreased with increasing its thickness. Thus, this gives the evidence that the decrease in roughness of Ni-P deposit for Eelectroless Ni/ Electroless Pd/ Immersion Au (ENEPIG) surface play a critical role for improving the robustness of SAC405 solder joint.

Design of Advanced Weathering Steel with High Corrosion Resistance for Structural Applications

  • Choi, B.K.;Jung, H.G.;Yoo, J.Y.;Kim, K.Y.
    • Corrosion Science and Technology
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    • v.4 no.4
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    • pp.121-129
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    • 2005
  • Basic design concept of the future steel structure requires environmental compatibility and maintenance free capability to minimize economic burdens. Recent trends in alloy design for advanced weathering steel include addition of various alloying elements which can enhance formation of stable and protective rust layer even in polluted urban and/or high $Cl^{-}$ environment. The effects of Ca, Ni, W, and Mo addition on the corrosion property of Ca-modified weathering steel were evaluated through a series of electrochemical tests (pH measurement and electrochemical impedance spectroscopy: EIS) and structural analysis on rust layer formed on the steel surface. Ca-containing inclusions of Ca-Al-Mn-O-S compound are formed if the amount of Ca addition is over 25 ppm. Steels with higher Ca content results in higher pH value for condensed water film formed on the steel surface, however, addition of Ni, W, and Mo does not affect pH value of the thin water film. The steels containing a high amount of Ca, Ni, W and Mo showed a dense and compact rust layer with enhanced amount of ${\alpha}-FeOOH$. Addition of Ni, W and Mo in Ca-modified weathering steel shows anion-selectivity and contributes to lower the permeability of $Cl^{-}$ ions. Effect of each alloying element on the formation of protective rust layer will be discussed in detail with respect to corrosion resistance.

CHARACTERIZATION AND ANALYSIS OF SHEAR TEST WITH TESTING CONDITIONS ON BGA PACKAGE

  • Koo, Ja-Myeong;Kim, Dae-Up;Jung, Seung-Boo
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.463-468
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    • 2002
  • This study investigates the variations of shear force, displacement, and fracture surface with the shear speed and the number of reflows. The experimental data of shear tests indicate that the shear force increases as increasing the number of reflows and the shear speed due to the formation of a kind of intermetallic compound, Ni$_3$Sn$_4$, on Au/Ni/Cu pad, and the work-hardening. However, general trends show that the shear force decreases due to increasing the thickness of the intermetallic compound over 4x reflow. It is observed that the intermetallic compound which is formed between solder and pad increases according to increasing the number of reflows, and the growth rate of the intermetallic compound at central region on the interface is faster than one at edge part. The general tendencies of shear force and displacement with different shear speeds are almost identical as an increase of the number of reflows.

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Recent Trends in Ferrous PM Materials in Japan

  • Takajo, Shigeaki
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 1993.11a
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    • pp.4-4
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    • 1993
  • Ferrous powder metallurgy in Japan has developed in the last four decades, where every decade is featured by certain breakthroughs in materials. The progress in PM materials is closely related to newly developed powders. Low alloy steel powders for high strength PM components are grouped into three types: Ni and/or Mo containing completely alloyed powders, Ni containing partially alloyed powders, and Cr containing completely alloyed powders. Every type has its special characteristics. The tensile strength of PM materials is improved up to 2 GPa. The hardness is also increased to exceed 500 HV with normal hardening methods, and 700 HV with novel surface treatment techniques. The present maximum of fatigue strength is 550 MPa, and that of impact energy is 100 J. Novel PM materials with improved properties are applied to a variety of automobile and other components: power steering pumps, rocker anns, valve guides and inserts, bearings, torque sensors, etc. The future outlook for the ferrous PM is Quite positive, and the industry is expected to show renewed growth by applying many types of alloy steel powders and new ferrous PM materials.

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Self-Sensing and Interfacial Evaluation of Ni Nanowire/Polymer Composites Using Electro-Macromechanical Technique (전기적 미세역학적 시험법을 이용한 Ni nanowire강화 고분자 복합재료의 자체 감지능 및 계면 물성평가)

  • Kim, Sung-Ju;Yoon, Dong-Jin;Hansen George;DeVries K. Lawrence;Park, Joung-Man
    • Composites Research
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    • v.19 no.5
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    • pp.20-27
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    • 2006
  • Self-sensing and interfacial evaluation of Ni nanowire/polymer composites were investigated using electro-macromechanical technique, which can be used fur a feasible sensing measurement on tensile and compressive loading/consequent unloading, temperature, and humidity. Mechanical properties of Ni nanowire with different aspect ratio and adding contents in either epoxy or silicone composites were measured indirectly using electro-pullout test under uniform and non-uniform cyclic loadings. Comparing apparent modulus with the conventional mechanical tensile modulus of Ni nanowire/epoxy composites, the trends were consistent with each other. Ni nanowire/epoxy composites showed the sensing response on humidity and temperature. Self-sensing on applied tensile and compressive loading/unloading was also responded for Ni nanowire/silicone composites via electrical contact resistivity showing the opposite trend between tension and compression. It can be due to the different electrically-interconnecting mechanisms of dispersed Ni nanowires embedded in silicone matrix.

Trend of Researches for Human Effects of Electromagnetic Fields (전자파 인체영향 연구동향)

  • Kwon, J.H.
    • Electronics and Telecommunications Trends
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    • v.31 no.3
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    • pp.42-49
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    • 2016
  • 전자파 인체영향 관련 다양한 연구들이 유럽은 물론 미국, 일본, 중국 등 기술 선진국을 중심으로 전세계적으로 진행되고 있다. 특히, 유럽에서는 FP7 RTD 프로젝트의 일환으로 국가 간 혹은 관련 산업 간 컨소시엄을 구성하여 1990년대부터 전자파에 의한 인체영향과 관련된 다양한 프로젝트가 수행되었으며 현재도 다양한 주제의 프로젝트들이 수행 중이다. 본고에서는 유럽을 중심으로 진행 중인 전자파 인체영향 관련 프로젝트, 즉 휴대전화 전자파와 인체영향에 대해 연구를 수행하는 Interphone Study, Mobi-Kids Study, 그리고 Mobi-Kids 연구결과 및 프로토콜을 기반으로 일반인에 대해 누적되고 종합적인 전자파 영향 연구를 수행하는 GERoNiMO 프로젝트, 그리고 노출량 저감 관련 LEXNET 프로젝트에 대해 소개하였다.

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