ORCID Profile
0000-0002-0721-6600
Current Organisation
University of Qeensland
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Publisher: Trans Tech Publications, Ltd.
Date: 04-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.273.20
Abstract: This paper investigated the effect of trace addition of Al and Mg on the grain refinements of Cu 6 Sn 5 in Sn-3wt%Ag-5wt%Cu high temperature solder alloys. Furthermore, the effect of Al and Mg addition on the Sn/Ag 3 Sn eutectic were also investigated. It was found that the addition of both Al and Mg successfully refined the Cu 6 Sn 5 in Sn-3wt%Ag-5wt%Cu solder alloy. In addition, Al suppresses the formation of Ag 3 Sn in the Sn/Ag 3 Sn eutectic while Mg promotes the formation of fine Sn/Ag 3 Sn eutectic microstructure. The refinement of Cu 6 Sn 5 is believed to be due to heterogeneous nucleation by Al and Mg rich intermetallic particles respectively. Effect of Al and Mg addition on the undercooling of the Sn/Ag 3 Sn eutectic was found to be similar, both reducing undercooling effectively at a low addition rate of 0.025wt%. The addition of Al and Mg have mixed effect on the nucleation temperature of Cu 6 Sn 5 . It is found that the nucleation temperature of Cu 6 Sn 5 is increased with 0.025wt% Al and 0.1wt% Mg addition to the unmodified alloy, while the nucleation temperature slowly decreases again as the trace element addition rate increases.
Publisher: Springer Science and Business Media LLC
Date: 28-05-2020
Publisher: Elsevier BV
Date: 12-1995
Publisher: Japan Institute of Light Metals
Date: 2004
DOI: 10.2464/JILM.54.440
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 10-2015
Publisher: Japan Institute of Metals
Date: 2008
Publisher: Springer Science and Business Media LLC
Date: 28-09-2013
Publisher: Elsevier BV
Date: 07-2012
Publisher: Elsevier BV
Date: 04-2018
Publisher: Springer Science and Business Media LLC
Date: 03-01-2021
Publisher: Elsevier BV
Date: 12-2013
Publisher: MDPI AG
Date: 31-01-2023
DOI: 10.3390/MA16031211
Abstract: Dross in a Zn-55wt%Al-1.6wt%Si metal coating bath is a mixture of bath metal and the quaternary intermetallic phase τ5c-Al20Fe5Si2(+Zn). Understanding the properties and formation of dross in a hot-dip Al-Zn galvanizing bath at the processing temperature (~600 °C) is critical for improving the production quality of steel sheet coating. However, dross analysis is usually conducted at room temperature with dross s les taken from the hot-dip bath and it is not known how representative these s les are of the phase(s) existing at high temperature. Using in-situ synchrotron X-ray diffraction (XRD), the crystal lattice and the coefficient of thermal expansion (CTE) of the intermetallic phase have been determined in the temperature range of 30 °C to 660 °C. Phase formation and phase stability of the intermetallic phase in the dross powder have been determined, providing fundamental knowledge for optimizing the production and quality of steel sheet coating.
Publisher: Elsevier BV
Date: 06-2005
Publisher: Elsevier BV
Date: 09-2006
Publisher: Elsevier BV
Date: 11-2016
Publisher: Wiley
Date: 10-11-2015
Publisher: Springer Science and Business Media LLC
Date: 19-01-2021
Publisher: American Chemical Society (ACS)
Date: 18-12-2019
Publisher: Springer Science and Business Media LLC
Date: 11-09-2012
Publisher: Elsevier BV
Date: 09-2021
Publisher: Trans Tech Publications, Ltd.
Date: 04-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.273.14
Abstract: This paper presents the use of the transient liquid phase concept to grow the high temperature Cu 6 Sn 5 intermetallic compound between Cu 3 Sn-rich powdered alloys and molten Sn. In this study, high temperature powdered alloys containing high fractions of Cu 3 Sn were fabricated from a chill-cast Sn-60 wt.%Cu alloy. A ternary alloy with composition of Sn-59 wt.%Cu-1 wt.%Ni was also prepared to investigate the effect of Ni. The reaction products were obtained at 250°C over a period of 30 minutes. The results provide new insight into the mechanism of the interfacial reaction between liquid Sn and solid Cu 3 Sn-rich alloy with and without Ni additions.
Publisher: Trans Tech Publications, Ltd.
Date: 04-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.273.95
Abstract: Cu 6 Sn 5 is an important intermetallic compound in soldering and electronic packaging. It is formed at the interface between molten solder and substrate during the soldering process, and the evolution of microstructure and properties also occurs in service. Previous studies revealed that Au and Ni are stabilization alloying elements for hexagonal η - Cu 6 Sn 5 intermetallic. For better understanding of stabilization mechanisms at atomic resolution level, in this work, we made an attempt atomic structure analysis on a stoichiometric (Cu, Au, Ni) 6 Sn 5 intermetallic prepared by direct alloying. High-angle annular dark-field (HAADF) imaging and atomic-resolution chemical mapping were taken by the aberration-corrected (Cs-corrected) scanning transmission electron microscopy (STEM). It is found that Au and Ni doped Cu 6 Sn 5 has hexagonal structure. The atom sites of Cu1 and Sn can be distinguished in atomic-resolution images after being observed from orientation [2110], which is also confirmed by atomic-resolution chemical mapping analysis. Importantly, atomic-resolution about distribution of alloying Au atom was directly observed, and Au atoms occupy the Cu1 sites in η - Cu 6 Sn 5 .
Publisher: Elsevier BV
Date: 06-1994
Publisher: Springer Science and Business Media LLC
Date: 12-04-2019
Publisher: Elsevier BV
Date: 12-2020
Publisher: Springer Science and Business Media LLC
Date: 07-04-2016
DOI: 10.1557/JMR.2016.123
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.2446
Abstract: The intermetallics of Cu6Sn5 that are formed at the Sn-based solder/ Cu substrate interface play a significant role in solder joint reliability. The characterization of the mechanical properties of the interface Cu6Sn5 is essential to understand the mechanical performance and structural integrity of the solder joints. In this study, the interface Cu6Sn5 and (Cu,Ni)6Sn5 formed in Sn-Cu and Sn-Cu-Ni ball grid array (BGA) joints were investigated using nanoindentation. The results demonstrated that the strain rate sensitivity and the activation volume of these intermetallics were affected by the reflow times and load conditions. The strain rate sensitivity of Cu6Sn5 and (Cu,Ni)6Sn5 were estimated from 0.023 to 0.105, and the activation volume of Cu6Sn5 and (Cu,Ni)6Sn5 were estimated from 0.128 b3 to 0.624 b3 (b=4.2062x10-9 m) for 1, 2 and 4-reflowed Sn-Cu (-Ni) s les.
Publisher: Elsevier BV
Date: 2010
Publisher: Elsevier BV
Date: 2020
Publisher: AIP Publishing
Date: 08-02-2010
DOI: 10.1063/1.3310019
Abstract: We investigate how 5 at. % Ni influences the relative stability of η and η′ Cu6Sn5. Synchrotron x-ray diffraction shows that, while Cu6Sn5 exists as η′ at 25 and 150 °C and transforms to η on heating to 200 °C, Cu5.5Ni0.5Sn5 is best fit to η throughout 25–200 °C. Our first principles calculations predict that η′ is stable at T=0 K in both Cu6Sn5 and Cu5.5Ni0.5Sn5, but that the energy difference is substantially reduced from 1.21 to 0.90 eV per 22 atom cell by the Ni addition. This effect is attributed to Ni developing distinct bonding to both Cu and Sn in the η phase.
Publisher: Elsevier BV
Date: 05-2019
Publisher: MDPI AG
Date: 13-06-2023
DOI: 10.3390/MA16124360
Abstract: The growth and formation of primary intermetallics formed in Sn-3.5Ag soldered on copper organic solderability preservative (Cu-OSP) and electroless nickel immersion gold (ENIG) surface finish after multiple reflows were systematically investigated. Real-time synchrotron imaging was used to investigate the microstructure, focusing on the in situ growth behavior of primary intermetallics during the solid–liquid–solid interactions. The high-speed shear test was conducted to observe the correlation of microstructure formation to the solder joint strength. Subsequently, the experimental results were correlated with the numerical Finite Element (FE) modeling using ANSYS software to investigate the effects of primary intermetallics on the reliability of solder joints. In the Sn-3.5Ag/Cu-OSP solder joint, the well-known Cu6Sn5 interfacial intermetallic compounds (IMCs) layer was observed in each reflow, where the thickness of the IMC layer increases with an increasing number of reflows due to the Cu diffusion from the substrate. Meanwhile, for the Sn-3.5Ag/ENIG solder joints, the Ni3Sn4 interfacial IMC layer was formed first, followed by the (Cu, Ni)6Sn5 IMC layer, where the formation was detected after five cycles of reflow. The results obtained from real-time imaging prove that the Ni layer from the ENIG surface finish possessed an effective barrier to suppress and control the Cu dissolution from the substrates, as there is no sizeable primary phase observed up to four cycles of reflow. Thus, this resulted in a thinner IMC layer and smaller primary intermetallics, producing a stronger solder joint for Sn-3.5Ag/ENIG even after the repeated reflow process relative to the Sn-3.5Ag/Cu-OSP joints.
Publisher: Elsevier BV
Date: 02-2003
Publisher: American Society for Microbiology
Date: 09-2014
DOI: 10.1128/AAC.02727-13
Abstract: Renewed global efforts toward malaria eradication have highlighted the need for novel antimalarial agents with activity against multiple stages of the parasite life cycle. We have previously reported the discovery of a novel class of antimalarial compounds in the imidazolopiperazine series that have activity in the prevention and treatment of blood stage infection in a mouse model of malaria. Consistent with the previously reported activity profile of this series, the clinical candidate KAF156 shows blood schizonticidal activity with 50% inhibitory concentrations of 6 to 17.4 nM against P. falciparum drug-sensitive and drug-resistant strains, as well as potent therapeutic activity in a mouse models of malaria with 50, 90, and 99% effective doses of 0.6, 0.9, and 1.4 mg/kg, respectively. When administered prophylactically in a sporozoite challenge mouse model, KAF156 is completely protective as a single oral dose of 10 mg/kg. Finally, KAF156 displays potent Plasmodium transmission blocking activities both in vitro and in vivo . Collectively, our data suggest that KAF156, currently under evaluation in clinical trials, has the potential to treat, prevent, and block the transmission of malaria.
Publisher: Elsevier BV
Date: 08-1999
Publisher: Elsevier BV
Date: 06-2011
Publisher: Springer Science and Business Media LLC
Date: 13-11-2010
Publisher: MDPI AG
Date: 10-01-2022
DOI: 10.3390/MA15020510
Abstract: The complex reaction between liquid solder alloys and solid substrates has been studied ex-situ in a few studies, utilizing creative setups to “freeze” the reactions at different stages during the reflow soldering process. However, full understanding of the dynamics of the process is difficult due to the lack of direct observation at micro- and nano-meter resolutions. In this study, high voltage transmission electron microscopy (HV-TEM) is employed to observe the morphological changes that occur in Cu6Sn5 between a Sn-3.0 wt%Ag-0.5 wt%Cu (SAC305) solder alloy and a Cu substrate in situ at temperatures above the solidus of the alloy. This enables the continuous surveillance of rapid grain boundary movements of Cu6Sn5 during soldering and increases the fundamental understanding of reaction mechanisms in solder solid/liquid interfaces.
Publisher: Springer Science and Business Media LLC
Date: 19-09-2008
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 12-1997
Publisher: Elsevier BV
Date: 11-2011
Publisher: Springer Science and Business Media LLC
Date: 13-02-2015
DOI: 10.1038/SREP08450
Abstract: Hydrogen has the potential to power much of the modern world with only water as a by-product, but storing hydrogen safely and efficiently in solid form such as magnesium hydride remains a major obstacle. A significant challenge has been the difficulty of proving the hydriding/dehydriding mechanisms and, therefore, the mechanisms have long been the subject of debate. Here we use in situ ultra-high voltage transmission electron microscopy (TEM) to directly verify the mechanisms of the hydride decomposition of bulk MgH 2 in Mg-Ni alloys. We find that the hydrogen release mechanism from bulk (2 μm) MgH 2 particles is based on the growth of multiple pre-existing Mg crystallites within the MgH 2 matrix, present due to the difficulty of fully transforming all Mg during a hydrogenation cycle whereas, in thin s les analogous to nano-powders, dehydriding occurs by a ‘shrinking core’ mechanism.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 03-2011
Publisher: Elsevier BV
Date: 02-2022
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.2450
Abstract: High-temperature lead-free solders are important materials for electrical and electronic devices due to increasing legislative requirements that aim at reducing the use of traditional lead-based solders. For the successful use of lead-free solders, a comprehensive understanding of the formation and mechanical properties of Intermetallic Compounds (IMCs) that form in the vicinity of the solder-substrate interface is essential. In this work, the effect of nickel addition on the formation and mechanical properties of Cu6Sn5 IMCs in Sn-Cu high-temperature lead-free solder joints was investigated using Scanning Electron Microscopy (SEM) and nanoindentation. It was found that the nickel addition increased the elastic modulus and hardness of the (Cu, Ni)6Sn5. The relationship between the nickel content and the mechanical properties of the IMCs was also established.
Publisher: Elsevier BV
Date: 03-2013
Publisher: Oxford University Press (OUP)
Date: 08-2004
Abstract: Aluminium phosphide (AlP) particles are often suggested to be the nucleation site for eutectic silicon in Al-Si alloys, since both the crystal structure and lattice parameter of AlP (crystal structure: cubic F43m lattice parameter: 5.421 A) are close to that of silicon (cubic Fd3m, 5.431 A), and the melting point is higher than the Al-Si eutectic temperature. However, the crystallographic relationships between AlP particles and the surrounding eutectic silicon are seldom reported due to the difficulty in analysing the AlP particles, which react with water during s le preparation for polishing. In this study, the orientation relationships between AlP and Si are analysed by transmission electron microscopy using focused ion-beam milling for s le preparation to investigate the nucleation mechanism of eutectic silicon on AlP. The results show a clear and direct lattice relationship between centrally located AlP particles and the surrounding silicon in the hypoeutectic Al-Si alloy.
Publisher: Elsevier BV
Date: 10-2018
Publisher: Elsevier BV
Date: 02-2017
Publisher: Springer International Publishing
Date: 2018
Publisher: Wiley
Date: 30-03-2017
DOI: 10.1111/RESP.13034
Abstract: Coal workers' pneumoconiosis (CWP), as part of the spectrum of coal mine dust lung disease (CMDLD), is a preventable but incurable lung disease that can be complicated by respiratory failure and death. Recent increases in coal production from the financial incentive of economic growth lead to higher respirable coal and quartz dust levels, often associated with mechanization of longwall coal mining. In Australia, the observed increase in the number of new CWP diagnoses since the year 2000 has necessitated a review of recommended respirable dust exposure limits, where exposure limits and monitoring protocols should ideally be standardized. Evidence that considers the regulation of engineering dust controls in the mines is lacking even in high-income countries, despite this being the primary preventative measure. Also, it is a global public health priority for at-risk miners to be systemically screened to detect early changes of CWP and to include confirmed patients within a central registry a task limited by financial constraints in less developed countries. Characteristic X-ray changes are usually categorized using the International Labour Office classification, although future evaluation by low-dose HRCT) chest scanning may allow for CWP detection and thus avoidance of further exposure, at an earlier stage. Preclinical animal and human organoid-based models are required to explore potential re-purposing of anti-fibrotic and related agents with potential efficacy. Epidemiological patterns and the assessment of molecular and genetic biomarkers may further enhance our capacity to identify susceptible in iduals to the inhalation of coal dust in the modern era.
Publisher: MDPI AG
Date: 09-11-2018
DOI: 10.3390/MA11112229
Abstract: In-situ observations of the polymorphic transformation in a single targeted Cu6Sn5 grain constrained between Sn-0.7 wt % Cu solder and Cu-Cu3Sn phases and the associated structural evolution during a solid-state thermal cycle were achieved via a high-voltage transmission electron microscope (HV-TEM) technique. Here, we show that the monoclinic η′-Cu6Sn5 superlattice reflections appear in the hexagonal η-Cu6Sn5 diffraction pattern upon cooling to isothermal 140 °C from 210 °C. The in-situ real space imaging shows that the η′-Cu6Sn5 contrast pattern is initiated at the grain boundary. This method demonstrates a new approach for further understanding the polymorphic transformation behavior on a real solder joint.
Publisher: Informa UK Limited
Date: 07-2004
Publisher: Elsevier BV
Date: 08-2021
Publisher: Elsevier BV
Date: 09-2009
Publisher: Elsevier BV
Date: 05-2014
Publisher: Elsevier BV
Date: 08-2023
Publisher: Elsevier BV
Date: 2001
Publisher: Japan Institute of Metals
Date: 2004
Publisher: Springer Science and Business Media LLC
Date: 04-2001
Publisher: Elsevier BV
Date: 09-1997
Publisher: Springer Science and Business Media LLC
Date: 31-07-2012
DOI: 10.1557/JMR.2012.247
Publisher: Elsevier BV
Date: 11-2001
Publisher: Elsevier BV
Date: 04-2001
Publisher: IEEE
Date: 04-2017
Publisher: Elsevier BV
Date: 09-2008
Publisher: American Chemical Society (ACS)
Date: 14-08-2019
Abstract: Ga and Ga-based alloys have received significant attention for applications in the liquid state and also for their potential as a bonding material in microelectronic assemblies. This study investigates the phase stability of the CuGa
Publisher: Springer Science and Business Media LLC
Date: 11-01-2007
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 06-2020
Publisher: Informa UK Limited
Date: 09-1993
Publisher: IEEE
Date: 04-2014
Publisher: Elsevier BV
Date: 07-2015
Publisher: MDPI AG
Date: 16-01-2021
DOI: 10.3390/MAGNETOCHEMISTRY7010014
Abstract: Ag/TiO2 thin films were prepared using the sol-gel spin coating method. The microstructural growth behaviors of the prepared Ag/TiO2 thin films were elucidated using real-time synchrotron radiation imaging, its structure was determined using grazing incidence X-ray diffraction (GIXRD), its morphology was imaged using the field emission scanning electron microscopy (FESEM), and its surface topography was examined using the atomic force microscope (AFM) in contact mode. The cubical shape was detected and identified as Ag, while the anatase, TiO2 thin film resembled a porous ring-like structure. It was found that each ring that coalesced and formed channels occurred at a low annealing temperature of 280 °C. The energy dispersive X-ray (EDX) result revealed a small amount of Ag presence in the Ag/TiO2 thin films. From the in-situ synchrotron radiation imaging, it was observed that as the annealing time increased, the growth of Ag/TiO2 also increased in terms of area and the number of junctions. The growth rate of Ag/TiO2 at 600 s was 47.26 µm2/s, and after 1200 s it decreased to 11.50 µm2/s and 11.55 µm2/s at 1800 s. Prolonged annealing will further decrease the growth rate to 5.94 µm2/s, 4.12 µm2/s and 4.86 µm2/s at 2400 s, 3000 s and 3600 s, respectively.
Publisher: Elsevier BV
Date: 11-2021
Publisher: Springer Science and Business Media LLC
Date: 21-09-2008
Publisher: Springer Science and Business Media LLC
Date: 12-01-2017
DOI: 10.1038/SREP40010
Abstract: The development of microstructure during melting, reactive wetting and solidification of solder pastes on Cu-plated printed circuit boards has been studied by synchrotron radiography. Using Sn-3.0Ag-0.5Cu/Cu and Sn-0.7Cu/Cu as ex les, we show that the interfacial Cu 6 Sn 5 layer is present within 0.05 s of wetting, and explore the kinetics of flux void formation at the interface between the liquid and the Cu 6 Sn 5 layer. Quantification of the nucleation locations and anisotropic growth kinetics of primary Cu 6 Sn 5 crystals reveals a competition between the nucleation of Cu 6 Sn 5 in the liquid versus growth of Cu 6 Sn 5 from the existing Cu 6 Sn 5 layer. Direct imaging confirms that the β-Sn nucleates at/near the Cu 6 Sn 5 layer in Sn-3.0Ag-0.5Cu/Cu joints.
Publisher: Elsevier BV
Date: 08-2019
Publisher: Elsevier BV
Date: 08-2022
Publisher: Elsevier BV
Date: 07-2010
Publisher: American Physical Society (APS)
Date: 17-06-2020
Publisher: Springer Science and Business Media LLC
Date: 05-09-2012
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 06-1992
Publisher: MDPI AG
Date: 23-11-2022
DOI: 10.3390/MA15238321
Abstract: This research evaluates the mechanical properties of a variety of binary In-Sn alloys as potential candidates for low temperature electronic joints. The tensile and hardness tests of as-cast In-5Sn, In-12.5Sn, In-25Sn, In-30Sn, In-35Sn, In-40Sn, In-50Sn, In-60Sn, In-80Sn (wt.%) were assessed at room temperature and compared to those of pure In and Sn. The ultimate tensile strength (UTS) increased from 4.2 MPa to 37.8 MPa with increasing tin content in the alloys under the testing condition of 18 mm/min and the results showed little difference under a lower strain rate (1.8 mm/min). Most compositions showed good ductility in tensile testing with an average of 40% elongation. A melting point range of 119.3 °C to 194.9 °C for tested alloys was measured using differential scanning calorimetry (DSC). The microstructure investigated by scanning electron microscopy (SEM) was discussed with respect to the mechanical properties and it has been found that the presence of the Sn-rich γ-InSn4 phase in the microstructure has a significant impact on mechanical properties. The fundamental data from this study can be used for the development of new low temperature In-Sn alloys.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 05-1998
Publisher: Springer Science and Business Media LLC
Date: 02-01-2019
Publisher: Elsevier BV
Date: 07-2008
Publisher: Informa UK Limited
Date: 20-11-2013
Publisher: Elsevier BV
Date: 11-2012
Publisher: Trans Tech Publications, Ltd.
Date: 04-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.273.66
Abstract: Sn-0.7Cu-0.05Ni is a widely used Pb-free solder that solidifies into a near-eutectic microstructure and a small fraction of primary Cu 6 Sn 5 . This paper overviews in-situ time-resolved imaging experiments on the solidification of Sn-0.7Cu-0.05Ni solder under three conditions: (i) directional solidification, (ii) continuous cooling in a near-uniform thermal field, and (iii) solder joint solidification on a Cu substrate. Primary Cu 6 Sn 5 grow as rods along [0001] in each case but can also grow as X-shaped crystals in (iii). There are significant differences in eutectic growth due to nucleation difficulties for tin in conditions (ii) and (iii).
Publisher: IEEE
Date: 12-2009
Publisher: Elsevier BV
Date: 11-2006
Publisher: Maney Publishing
Date: 03-2004
Publisher: Japan Institute of Metals
Date: 2001
Publisher: Elsevier BV
Date: 2015
Publisher: Japan Institute of Metals
Date: 2003
Publisher: Elsevier BV
Date: 04-2017
Publisher: Informa UK Limited
Date: 09-1994
Publisher: Springer Science and Business Media LLC
Date: 20-09-2011
DOI: 10.1557/JMR.2011.293
Publisher: Elsevier BV
Date: 11-1993
Publisher: Informa UK Limited
Date: 07-1997
Publisher: Elsevier BV
Date: 08-1996
Publisher: Elsevier BV
Date: 11-2011
Publisher: Elsevier BV
Date: 11-2014
Publisher: IEEE
Date: 04-2018
Publisher: Trans Tech Publications, Ltd.
Date: 05-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.857.49
Abstract: Phosphorus (P) is often added to wave-solder baths as an anti-oxidation agent for older generation eutectic Sn-37wt%Pb solders. For Pb-free solder alloys trace amounts of germanium (Ge) have been added successfully in Sn-0.7wt%Cu-0.05wt%Ni for anti-oxidation purposes during the wave soldering process. Despite this practice, there is little information on how P and Ge distribute in solder alloys and dross in this alloy system. In this paper, the effects of combinations of trace levels of Ge ( 100ppm) and P ( 100ppm) in Sn-Cu-Ni solder alloys and their dross has been investigated by XRD and SEM/EDS. It was found that the weight fraction of tin oxides in the dross is increased with an addition of less than 100ppm P. The dross consists on SnO oxide with Sn in s les containing Ge and no P, while SnO and SnO 2 oxide are both present when P and Ge additions are made. In s les containing P, (Cu,Ni) 6 Sn 5 and Ni-P and/or Ni-Sn-P intermetallics particles were found.
Publisher: Elsevier BV
Date: 03-2019
Publisher: Springer International Publishing
Date: 2017
Publisher: Elsevier BV
Date: 05-2018
Publisher: MDPI AG
Date: 08-04-2022
DOI: 10.3390/MA15082758
Abstract: Solder interconnection in three-dimensional (3D) electronic packaging is required to undergo multiple reflow cycles of the soldering process. This paper elucidates the effects of multiple reflow cycles on the solder joints of Sn-3.0Ag-0.5Cu (SAC305) lead (Pb)-free solder with the addition of 1.0 wt.% kaolin geopolymer ceramics (KGC). The s les were fabricated using powder metallurgy with the hybrid microwave sintering method. Apart from using conventional cross-sectioned microstructure imaging, advanced synchrotron real-time in situ imaging was used to observe primary IMC formation in SAC305-KGC solder joints subjected to multiple reflow soldering. The addition of KGC particles in SAC305 suppressed the Cu6Sn5 IMC’s growth as primary and interfacial layers, improving the shear strength after multiple reflow soldering. The growth rate constant for the interfacial Cu6Sn5 IMC was also calculated in this study. The average growth rate of the primary Cu6Sn5 IMCs decreased from 49 µm/s in SAC305 to 38 µm/s with the addition of KGC particles. As a result, the average solidified length in the SAC305-KGC is shorter than SAC305 for multiple reflow soldering. It was also observed that with KGC additions, the growth direction of the primary Cu6Sn5 IMC in SAC305 changed from one growth to two growth directions. The observed results can be attributed to the presence of KGC particles both at grains of interfacial Cu6Sn5 IMCs and at the surface of primary Cu6Sn5 IMC.
Publisher: Elsevier BV
Date: 10-2016
Publisher: Elsevier BV
Date: 08-2009
Publisher: Springer Science and Business Media LLC
Date: 20-12-2018
DOI: 10.1007/S11663-018-1456-8
Abstract: The rapid increase of scrapped electrical products disposed in landfill sites is significantly influencing the environment because of the composition of the associated components. This situation has been the stimulus for the international community to issue a directive to prohibit the use of Pb-containing solders in electronic devices and effectively ban such products on the market. The Sn-Cu-Ni has become increasingly significant as it is used in several solder alloys and more generally both Cu and Ni are common substrates that interact with Sn-based solders in microelectronic applications. However, there is currently an insufficient understanding of the phase equilibria and the associated phase diagrams of many Sn alloys. The present work implemented an experimental methodology to obtain high accuracy results for the phase equilibria between one liquid and one or two intermetallic compounds. The Sn-Cu-Ni and the associated Sn-Cu and Sn-Ni binary systems have been re-evaluated and compared with the literature. The liquidus and the invariant lines were determined for the Sn-Cu-Ni ternary at the temperatures ranges of between 240 °C and 270 °C. The result will contribute to filling phase equilibria data gaps in the Sn-rich corner of the Sn-Cu-Ni alloy system.
Publisher: Elsevier BV
Date: 11-2014
Publisher: Trans Tech Publications, Ltd.
Date: 12-2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.626.200
Abstract: This paper demonstrates how recent progress for real-time solidification observation at SPring-8 synchrotron has contributed to the development of Sn-7wt%Cu-0.05wt%Ni high temperature lead-free solder alloys. Lead-free solder alloys in the composition range Sn-0.7 to 7.6wt%Cu that consist of primary Cu 6 Sn 5 in a eutectic Sn-Cu 6 Sn 5 matrix have been proposed as solders for application at temperatures up to 400°C for the assembly high current semiconductors. It is shown that trace levels of Al have a marked effect on the solder microstructure and refine the size of the primary Cu 6 Sn 5 . The solidification pathway that leads to the refinement was observed in real-time using X-ray synchrotron observations.
Publisher: Trans Tech Publications, Ltd.
Date: 04-2009
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.618-619.391
Abstract: The potential for Mg and Mg-Ni alloys to be used as hydrogen storage alloys has been known for some time. Although the maximum storage capacity in these alloys is high (7.6wt%H2 for Mg and 3.4wt%H2 for Mg2Ni), they have, until recently, been disregarded for practical applications due to their slow kinetics and high reaction temperatures. This paper discusses the recent discovery that the non-faceted/faceted hypo-eutectic Mg-Mg2Ni system can, similar to Al-Si eutectic alloys, be modified by trace additions and that this results in improved hydrogen storage properties. The hydrogen storage properties depend on the composition, including trace levels of modifying elements, and processing conditions. In alloys of optimal composition it has been shown that the reversible storage of 6.5-7wt% H2 is possible at a rate of reaction that is far better than that previously documented. In addition, the alloy can be satisfactorily processed in air, as opposed to controlled atmospheric conditions. This paper discusses the mechanism of improved hydrogen absorption/desorption kinetics when eutectic Mg-Ni hypo-eutectic alloys are modified. This discussion is based on atomic scale analysis using electron microscopy and examination with synchrotron radiation.
Publisher: Elsevier BV
Date: 12-2013
Publisher: Elsevier BV
Date: 08-2004
Publisher: Trans Tech Publications, Ltd.
Date: 07-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.700.161
Abstract: This paper investigates the effect of 1 wt% TiO 2 on the formation of primary and interfacial Cu 6 Sn 5 in Sn-0.7wt%Cu and Sn-0.7wt%Cu-0.05wt%Ni solder pastes soldered on a Cu substrate using a real-time synchrotron imaging technique. It was found that TiO 2 had altered the nucleation time of the primary Cu 6 Sn 5 intermetallics and increased the number of particles observed. In addition, a more planar Cu 6 Sn 5 interfacial layer had formed in joints made with TiO 2 reinforced solders. This indicated that TiO 2 promotes nucleation of primary Cu 6 Sn 5 intermetallics in the early stages of soldering while being a barrier for further growth of interfacial Cu 6 Sn 5 intermetallics. The synchrotron imaging technique provides direct evidence of the sequence of events in the soldering reaction and how these are influenced by TiO 2 reinforcement.
Publisher: Trans Tech Publications, Ltd.
Date: 05-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.857.44
Abstract: The solidification of Sn-3Ag-0.5Cu and Sn-0.7Cu-0.05Ni are overviewed and compared. In joints on Cu substrates, both solders begin solidification with primary Cu 6 Sn 5 growing in the bulk liquid prior to tin nucleation. In freestanding balls and joints, SAC305 generally solidifies with a single tin nucleation event and exhibits a mutually-twinned tin grain structure. In contrast, SN100C BGA balls and joints exhibit multiple independent tin grains that grow as a columnar array in joints.
Publisher: Elsevier BV
Date: 04-2016
Publisher: Elsevier BV
Date: 03-2005
Publisher: IEEE
Date: 04-2015
Publisher: IEEE
Date: 04-2014
Publisher: Japan Institute of Metals
Date: 2003
Publisher: Elsevier BV
Date: 03-2017
Publisher: Elsevier BV
Date: 11-2012
Publisher: Elsevier BV
Date: 12-2020
Publisher: Trans Tech Publications, Ltd.
Date: 04-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.273.101
Abstract: Liquid metal structure of Sn-Cu alloys studied by synchrotron high energy X-ray diffraction have been performed to investigate the effect of the trace elements Ni and Al. It has been demonstrated that trace Ni and Al additions are able to alter the liquid Sn-4wt%Cu structure. The refinement of the primary Cu 6 Sn 5 phase after trace Al additions is proposed to be caused by the consumption of Cu atoms involved in a AlCu chemical ordering and an associated change in the undercooling for Cu 6 Sn 5 nucleation.
Publisher: Elsevier BV
Date: 11-2001
Publisher: Springer International Publishing
Date: 2020
Publisher: Elsevier BV
Date: 02-2000
Publisher: Japan Institute of Metals
Date: 2001
Publisher: Elsevier BV
Date: 2019
Publisher: IEEE
Date: 04-2018
Publisher: Elsevier BV
Date: 03-2022
Publisher: Trans Tech Publications, Ltd.
Date: 05-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.857.53
Abstract: This research examines the relationship between Cu and Ni concentration and the formation of primary Cu 3 Sn in high Cu containing Sn-Cu solder alloys. Through thermal analysis and optical microscopy, it was determined that Ni additions still have a significant effect in minimising or eliminating Cu 3 Sn for Cu concentrations as high as 30wt%. In addition, it is clear that a relationship exists between Cu concentration and the effect of Ni addition and the volume fraction of Cu 3 Sn increases as the Cu content increases. It is likely that the Ni addition has a significant effect on the interdiffusional coefficients of the diffusing species of Cu 3 Sn and Cu 6 Sn 5 , slowing the growth of Cu 3 Sn and encouraging primary Cu 6 Sn 5 nucleation.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 04-2015
Publisher: Trans Tech Publications, Ltd.
Date: 05-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.857.58
Abstract: Extending the use of the Sn-Cu system to high-temperature solders poses additional challenges as the necessary high Cu content is in a region of the binary phase diagram which is dominated by the peritectic reaction and has the intermetallic compound (IMC) Cu 3 Sn as the primary phase, which is known to have negative effects on soldering properties. Minor additions of nickel (Ni) have been reported to suppress the formation of Cu 3 Sn in low Cu content Sn-Cu solder alloys though higher Cu content alloys have not been investigated. As such, the objective of this paper was to investigate the effect of more significant concentrations of Ni on the microstructure of a Sn-30wt%Cu alloy. An initial addition of 2wt%Ni greatly reduced the volume fractions of Cu 3 Sn and the amount of eutectic present whilst significantly increasing the volume fraction of Cu 6 Sn 5 however, further additions of Ni had a less pronounced affect. The Sn-30wt%Cu morphology was changed from a plate-like structure to a dendritic structure by adding Ni, which would improve solder performance by decreasing the possible crack plane length.
Publisher: Japan Institute of Metals
Date: 2004
Publisher: American Chemical Society (ACS)
Date: 09-04-2020
Publisher: Elsevier BV
Date: 2010
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.654-656.2851
Abstract: Alloys of the hypo-eutectic Mg-Mg2Ni system can be modified by trace elemental additions which change the microstructure and the functional properties. The modified microstructure results in improvements to the hydrogen storage properties. In alloys of optimal composition, it has been shown that the reversible storage of 6.5-7wt% H2 is possible at a rate of reaction that is realistic for industrial applications. This paper discusses the mechanism of hydrogen release in air at atmospheric pressure with in-situ crystallographic phase transformation analysis obtained by synchrotron radiation X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS).
Publisher: Elsevier BV
Date: 12-2017
Publisher: Elsevier BV
Date: 07-2011
Publisher: Springer Science and Business Media LLC
Date: 08-2006
DOI: 10.1007/BF02586230
Publisher: Elsevier BV
Date: 08-2018
Publisher: Elsevier BV
Date: 12-2005
Publisher: Elsevier BV
Date: 12-2009
Publisher: Springer Science and Business Media LLC
Date: 06-2009
Publisher: Elsevier BV
Date: 11-2018
Publisher: IEEE
Date: 04-2016
Publisher: Springer Science and Business Media LLC
Date: 11-2004
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 2001
Publisher: Springer Science and Business Media LLC
Date: 23-11-2022
Publisher: IOP Publishing
Date: 11-06-2015
Publisher: Trans Tech Publications, Ltd.
Date: 04-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.273.3
Abstract: Ga and Ga-based alloys appear to be promising materials for low temperature soldering in microelectronics. This research involved an analysis of the joint interfaces that resulted from reactions between a eutectic Ga-Sn alloy and Au coated Cu substrates at both room temperature and 100°C. At both temperatures the intermetallic CuGa 2 accounted for the majority of the interfacial microstructure. This study has shown the possibility of using eutectic Ga-Sn alloys in low temperature soldering applications, as well as the advantages of Synchrotron XFM techniques in characterising trace element distributions in solder joints.
Publisher: Elsevier BV
Date: 08-2018
Publisher: Elsevier BV
Date: 04-2013
Publisher: Elsevier BV
Date: 05-2006
Publisher: Elsevier BV
Date: 03-2020
Publisher: Trans Tech Publications, Ltd.
Date: 05-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.857.63
Abstract: A sessile drop experiment involving slow heating and cooling of lead-free solder alloys under inert gas revealed segregation of trace elements to the s le surface. Addition of germanium or gallium to Sn-0.7Cu-0.05Ni alloys promoted a metallic lustre in s les, in contrast with the blue urple colour of the parent alloy. Alloys with Ge or Ga additions showed oxidation resistance. Depth profiling of surfaces of s le alloys with Ge or Ga showed a significant concentration of these elements within the oxide film, which may be responsible for oxidation resistance of these alloys.
Publisher: Trans Tech Publications, Ltd.
Date: 04-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.273.9
Abstract: Additions of trace elements such as Phosphorus (P) and Germanium (Ge) are common practice to improve the oxidation resistance in Tin-Copper (Sn-Cu) wave solder systems, however, little insights are available regarding their combined role. In this article, the effect of trace P ( ppm), in the presence of Ge ( ppm), on the phase composition and microstructure of Sn-Cu-Ni wave solder dross is studied using various techniques including Synchrotron XRPD, SEM, FIB and TEM. We find that P additions, in the presence of Ge, result in the formations of SnO, SnO 2 and Ni 2 SnP intermetallic in the dross whereas only SnO is present in the P-free equivalent. The crystal structure of Ni 2 SnP is identified as orthorhombic with the space group Pnma. Based on the findings, it is evident that P not only influences the oxidation state of tin oxides but also reduces the concentration of effective Ni in the alloys via the formation of Ni 2 SnP intermetallic.
Publisher: Elsevier BV
Date: 06-2002
Publisher: Japan Institute of Metals
Date: 2001
Publisher: No publisher found
Date: 2015
Abstract: P2-type Na(2/3)Ni(1/3)Mn(2/3)O2 was synthesized by a controlled co-precipitation method followed by a high-temperature solid-state reaction and was used as a cathode material for a sodium-ion battery (SIB). The electrochemical behavior of this layered material was studied and an initial discharge capacity of 151.8 mA h g(-1) was achieved in the voltage range of 1.5-3.75 V versus Na(+)/Na. The retained discharge capacity was found to be 123.5 mA h g(-1) after charging/discharging 50 cycles, approximately 81.4% of the initial discharge capacity. In situ X-ray diffraction analysis was used to investigate the sodium insertion and extraction mechanism and clearly revealed the reversible structural changes of the P2-Na(2/3)Ni(1/3)Mn(2/3)O2 and no emergence of the O2-Ni(1/3)Mn(2/3)O2 phase during the cycling test, which is important for designing stable and high-performance SIB cathode materials.
Publisher: Japan Institute of Metals
Date: 2906
Publisher: Trans Tech Publications, Ltd.
Date: 11-09-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.421.260
Abstract: To increase the solder joint robustness, researches and studies on composite solder carried out by many researchers in an effort to develop viable lead-free solders which can replace the conventional lead-based solders.This paper reviews the fabrication processes of the lead-free composite solder and its non-metal reinforcing effects to the suppression of intermetallic formation. Most researchers using different solder fabrication methods have found that byadditions of non-metal reinforcement from micron up to nanoparticle size had suppressed the intermetallic compound formations of lead-free composite solders.
Publisher: Elsevier BV
Date: 11-2015
Publisher: Elsevier BV
Date: 11-2019
Publisher: MDPI AG
Date: 16-03-2021
DOI: 10.3390/RS13061128
Abstract: Hyperspectral imaging (HSI) is an emerging rapid and non-destructive technology that has promising application within feed mills and processing plants in poultry and other intensive animal industries. HSI may be advantageous over near infrared spectroscopy (NIRS) as it scans entire s les, which enables compositional gradients and s le heterogenicity to be visualised and analysed. This study was a preliminary investigation to compare the performance of HSI with that of NIRS for quality measurements of ground s les of Australian wheat and to identify the most important spectral regions for predicting carbon (C) and nitrogen (N) concentrations. In total, 69 s les were scanned using an NIRS (400–2500 nm), and two HSI cameras operated in 400–1000 nm (VNIR) and 1000–2500 nm (SWIR) spectral regions. Partial least square regression (PLSR) models were used to correlate C and N concentrations of 63 calibration s les with their spectral reflectance, with 6 additional s les used for testing the models. The accuracy of the HSI predictions (full spectra) were similar or slightly higher than those of NIRS (NIRS Rc2 for C = 0.90 and N = 0.96 vs. HSI Rc2 for C (VNIR) = 0.97 and N (SWIR) = 0.97). The most important spectral region for C prediction identified using HSI reflectance was 400–550 nm with R2 of 0.93 and RMSE of 0.17% in the calibration set and R2 of 0.86, RMSE of 0.21% and ratio of performance to deviation (RPD) of 2.03 in the test set. The most important spectral regions for predicting N concentrations in the feed s les included 1451–1600 nm, 1901–2050 nm and 2051–2200 nm, providing prediction with R2 ranging from 0.91 to 0.93, RMSE ranging from 0.06% to 0.07% in the calibration sets, R2 from 0.96 to 0.99, RMSE of 0.06% and RPD from 3.47 to 3.92 in the test sets. The prediction accuracy of HSI and NIRS were comparable possibly due to the larger statistical population (larger number of pixels) that HSI provided, despite the fact that HSI had smaller spectral range compared with that of NIRS. In addition, HSI enabled visualising the variability of C and N in the s les. Therefore, HSI is advantageous compared to NIRS as it is a multifunctional tool that poses many potential applications in data collection and quality assurance within feed mills and poultry processing plants. The ability to more accurately measure and visualise the properties of feed ingredients has potential economic benefits and therefore additional investigation and development of HSI in this application is warranted.
Publisher: Elsevier BV
Date: 03-2017
Publisher: Elsevier BV
Date: 11-2001
Publisher: Japan Institute of Metals
Date: 2005
Publisher: American Chemical Society (ACS)
Date: 03-11-2015
Publisher: Elsevier BV
Date: 07-2012
Publisher: Springer Science and Business Media LLC
Date: 13-07-2016
Publisher: Springer Science and Business Media LLC
Date: 10-10-2020
Publisher: Trans Tech Publications, Ltd.
Date: 04-2018
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.273.27
Abstract: The effect of bismuth (Bi) micro-alloying additions on wettability and mechanical properties of Sn-0.7Cu lead-free solder were explored. This paper also investigates the influences of various Bi percentages on the suppression of intermetallic compound formation. Scanning electron microscope (SEM) was used to observe the microstructure evolution of solder joint including the thickness of interfacial intermetallic layers. Overall, with the addition of Bi to Sn-0.7Cu solder, the size of primary Cu 6 Sn 5 become smaller and suppresses the thickness of interfacial intermetallic compound between solder and the Cu substrate. Microhardness value and wetting properties also increased with Bi addition which resulted in smaller size of β-Sn and Cu 6 Sn 5 .
Publisher: Informa UK Limited
Date: 11-06-2004
Publisher: Elsevier BV
Date: 04-2022
Publisher: Springer Science and Business Media LLC
Date: 07-04-2017
DOI: 10.1038/SREP43720
Abstract: In a comment on our Article “Evidence of the hydrogen release mechanism in bulk MgH 2 ”, Surrey et al . assert that the MgH 2 s le we studied was not MgH 2 at any time but rather MgO and that the transformation we observed was the formation of Kirkendall voids due to the outward diffusion of Mg. We address these issues in this reply.
Publisher: Springer Science and Business Media LLC
Date: 28-08-2021
Publisher: IEEE
Date: 04-2017
Publisher: Springer Science and Business Media LLC
Date: 15-06-2017
No related grants have been discovered for Kazuhiro Nogita.