共查询到20条相似文献,搜索用时 31 毫秒
1.
Tama Fouzder Qingqian Li Y. C. Chan Daniel K. Chan 《Journal of Materials Science: Materials in Electronics》2014,25(9):4012-4023
Sn–Ag–Cu composite solder has been prepared by adding Ni nanoparticles. Interfacial reactions, the morphology of the intermetallic compounds (IMC) that were formed, the hardness between the solder joints and the plain Cu/immersion Ag-plated Cu pads depending on the number of the reflow cycles and the aging time have all been investigated. A scallop-shaped Cu6Sn5 IMC layer that adhered to the substrate surface was formed at the interfaces of the plain Sn–Ag–Cu solder joints during the early reflow cycles. A very thin Cu3Sn IMC layer was found between the Cu6Sn5 IMC layer and the substrates after a lengthy reflow cycle and solid-state aging process. However, after adding Ni nanoparticles, a scallop-shaped (Cu, Ni)–Sn IMC layer was clearly observed at both of the substrate surfaces, without any Cu3Sn IMC layer formation. Needle-shaped Ag3Sn and sphere-shaped Cu6Sn5 IMC particles were clearly observed in the β-Sn matrix in the solder-ball region of the plain Sn–Ag–Cu solder joints. Additional fine (Cu, Ni)-Sn IMC particles were found to be homogeneously distributed in the β-Sn matrix of the solder joints containing the Ni nanoparticles. The Sn–Ag–Cu–0.5Ni composite solder joints consistently displayed higher hardness values than the plain Sn–Ag–Cu solder joints for any specific number of reflow cycles–on both substrates–due to their well-controlled, fine network-type microstructures and the homogeneous distribution of fine (Cu, Ni)–Sn IMC particles, which acted as second-phase strengthening mechanisms. The hardness values of Sn–Ag–Cu and Sn–Ag–Cu–0.5Ni on the Cu substrates after one reflow cycle were about 15.1 and 16.6 Hv, respectively–and about 12.2 and 14.4 Hv after sixteen reflow cycles, respectively. However, the hardness values of the plain Sn–Ag–Cu solder joint and solder joint containing 0.5 wt% Ni nanoparticles after one reflow cycle on the immersion Ag plated Cu substrates were about 17.7 and 18.7 Hv, respectively, and about 13.2 and 15.3 Hv after sixteen reflow cycles, respectively. 相似文献
2.
Satyanarayan K. N. Prabhu 《Journal of Materials Science: Materials in Electronics》2013,24(5):1714-1719
In the present work, wetting characteristics and morphology of intermetallic compounds (IMCs) formed between Sn–2.5Ag–0.5Cu lead-free solder on copper (Cu) and silver (Ag) coated copper substrates were compared. It was found that, Ag coated Cu substrate improved the wettability of solder alloy. The average values of contact angles of solder alloy solidified on Ag coated Cu substrate were reduced to about 50 % as compared to contact angles obtained on Cu substrates. Flow restrictivity for spreading of solder on Ag coated Cu was found to be lower as compared to Cu substrate. The spreading of solder alloy on Ag coated Cu exhibited halo zone. Coarse needle shaped Cu6Sn5 IMCs were observed at the solder/Cu substrate interface whereas at the solder/Ag coated Cu interface Cu6Sn5 IMCs showed scallop morphology. The formation of Cu3Sn IMC was observed for the spreading of solder alloy on both substrates. The solder/Ag coated Cu substrate interface exhibited more particulates of Ag3Sn precipitates as compared to solder/Cu substrate interface. The improved wettability of solder alloy on Ag coated Cu substrate is due to the formation of scallop IMCs at the interface. 相似文献
3.
Tama Fouzder Qingqian Li Y. C. Chan Daniel K. Chan 《Journal of Materials Science: Materials in Electronics》2014,25(6):2529-2539
In order to identify the effect on the properties and behavior of tin–zinc–bismuth (Sn-8 wt% Zn-3 wt% Bi or Sn-13.6 at.% Zn-1.6 at.% Bi) based solders produced by adding nickel (Ni) nano-particles, the interfacial microstructure between plain and composite solders with newly developed immersion silver (Ag) plated copper (Cu) substrates has been investigated as a function of reaction time, at various temperatures. For plain Sn–8Zn–3Bi solder joints, a scallop-shaped Cu–Zn–Ag intermetallic compound layer was found to adhere to the surface of the immersion Ag-plated Cu substrate. However, after addition of Ni nano-particles into the Sn–8Zn–3Bi solder, Cu–Zn–Ag (at the bottom) and (Cu, Ni)–Zn (at the top) intermetallic compound layers were observed at the interfaces. In addition, these intermetallic compound layer thicknesses increased substantially with increases in the temperature and reaction time. In the solder ball region, needle-shaped α-Zn rich phase and spherically-shaped Bi-particles appeared to be homogeneously distributed throughout a beta-tin (β-Sn) matrix. However, after the addition of Ni nano-particles, needle-shaped α-Zn rich phase appeared that exhibited a fine microstructure, due to the heterogeneous nucleation of the Ni nano-particles. The calculated activation energy for the Cu–Zn–Ag intermetallic compound layer for the plain Sn–8Zn–3Bi solder/immersion Ag-plated Cu system was 29.95 kJ/mol—while the activation energy for the total [Cu–Zn–Ag + (Cu, Ni)–Zn] intermetallic compound layers formed in the Sn–8Zn–3Bi–0.5Ni (Sn-13.6 at.% Zn-1.6 at.% Bi ~1 at.% Ni) composite solder/immersion Ag-plated Cu system was 27.95 kJ/mol. Addition of Ni nano-particles reduces the activation energy which enhanced the reaction rate as we know that lower the activation energy indicates faster the reaction rate. 相似文献
4.
O. Kozlova R. Voytovych P. Protsenko N. Eustathopoulos 《Journal of Materials Science》2010,45(8):2099-2105
The fundamental issues of equilibrium and non-equilibrium (dissolutive) wetting and spreading in the liquid Ag/solid Cu system are studied by the dispensed drop technique. To this end, wetting experiments of Cu, both mono- and poly-crystalline, with two types of Ag–Cu alloys, one non-saturated and the other saturated in copper, are performed at 900 °C in high vacuum by the dispensed drop technique. The results are compared with those given in the literature for the same or similar systems as well as with model predictions. 相似文献
5.
6.
AbstractThe effect of silver addition on the formation of secondary phases in squeeze cast Al–4.0Cu–1.5Mg and Al–4.0Cu–1.5Mg–0.7Ag (all wt-%) alloys has been investigated using optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffractometry, and transmission electron microscopy. The as cast microstructure of both alloys consists of primary dendritic α-Al and various types of secondary solidification phase, e.g. Al2Cu, Al2CuMg, Al(Cu,Ag)Mg, and icosahedral (I) and decagonal (D) quasicrystalline phases. However, the solidification path in the interdendritic region during squeeze casting is different for each alloy, i.e. L→ternary α-Al–Al2Cu–Al2CuMg eutectic in Al–4.0Cu–1.5Mg and L→L′+Al2Cu→α-Al–Al2Cu–Al(Cu0.75Ag0.25)Mg eutectic in Al–4.0Cu–1.5Mg–0.7Ag. This indicates that silver acts as an alloying element stabilising the formation of Al(Cu,Ag)Mg Laves phase. The remaining copper and iron rich liquid in the interdendritic region at the final stage of solidification solidifies into a mixed structure of α-Al, Al2Cu, and AlCuFe I (or D) phases. The composition of the I and D phases, measured by energy dispersive X-ray spectroscopy, is in the range Al–(27~28)Cu–(9~10)Fe and Al–(26~27)Cu–(7~9)Fe (all at.-%) respectively. 相似文献
7.
Sn–0.7 wt%Cu–1.0 wt%Ag and Sn–0.7 wt%Cu–2.0 wt%Ag alloys were directionally solidified under transient conditions undergoing cooling rates varying from 0.1 to 25 K/s. The microstructure was characterized along the castings lengths and the present experimental results include the secondary dendrite arm spacing (λ2) and its correlation with: the tip cooling rate () during solidification and microhardness (HV), yield tensile strength (σy), ultimate tensile strength (σu) and elongation to fracture (δ). The aim is to examine the effects of Ag content and tip cooling rate on both the microstructure and mechanical properties. The initiation of tertiary branches within the dendritic arrangement, as well as the distinct morphologies of the intermetallic compounds (IMC) related to the solidification cooling rate was also assessed for both examined alloys. While the Cu6Sn5 phase appeared as large faceted crystals along the entire casting length, very fine Ag3Sn spheroids prevailed at higher cooling rates (>7.5 K/s and > 4.0 K/s for 1.0 wt%Ag and 2.0 wt%Ag alloying, respectively) with a mixture of Ag3Sn coarser spheroids and fibers predominating at lower cooling rates. The Sn–0.7 wt%Cu–2.0 wt%Ag alloy exhibited smaller dendritic spacings and HV of about two times higher than the corresponding values of the Sn–0.7 wt%Cu–1.0 wt%Ag alloy. A single Hall–Petch equation is proposed relating δ to λ2 for both alloys, which means that the increase in Ag content from 1.0 to 2.0 wt% does not affect the elongation. It is shown that δ decreases with the increase in λ2. 相似文献
8.
Takafumi Maeda Norihisa Matsubara Yusuke Yasuda Toshiaki Morita 《Materials Science & Technology》2017,33(14):1618-1625
A metal–metal bonding technique is described that uses nanoparticles composed of silver and copper. Colloid solutions of nanoparticles with an Ag content of 0–100?mol% were prepared by simultaneous reduction of Ag+ and Cu2+ using hydrazine with polyvinylpyrrolidone and citric acid as stabilisers. The nanoparticles ranged in size from 34 to 149?nm depending on the Ag content. Copper discs were strongly bonded at 400°C for 5?min under 1.2?MPa pressure in hydrogen gas; the maximum shear strength was as high as 23.9?MPa. The dependence of shear strength on the Ag content was explained by a mismatch between the d-spacings of Cu metal and Ag metal. 相似文献
9.
《Materials Science & Technology》2013,29(8):628-634
AbstractElectron probe microanalysis showed that Al–7Mg–Cu alloys possess serious segregation tendencies. The addition of copper promoted the segregation of magnesium and led to the formation of non-equilibrium eutectic. With an increase in the copper content of the alloys, the severity of the solute segregation increased. Homogenisation reduced the solute segregation significantly. During homogenisation, the non-equilibrium eutectic compound AlxCuyMgz gradually dissolved. Its dissolution behaviour depended on its copper content. Precipitates of AlxCuyMgz with a comparatively low level of copper dissolved, while those with a high level of copper were less soluble and became divided into small blocks. The higher the copper content of the alloys, the larger and the greater in number the remaining AlxCuyMgz particles. In the undissolved AlxCuyMgz, the concentration of copper increased and that of magnesium decreased. Two step homogenisation reduced the solute segregation and dissolved the non-equilibrium eutectic further.MST/3194 相似文献
10.
Alongheng Baated Keun-Soo Kim Katsuaki Suganuma Sharon Huang Benjamin Jurcik Shigeyoshi Nozawa Minoru Ueshima 《Journal of Materials Science: Materials in Electronics》2010,21(10):1066-1075
We evaluated the Sn whisker growth behavior of Sn–Ag–Cu solder fillets on lead frames of quad flat packages (QFPs) upon OSP
printed circuit boards that were exposed to 85 °C/85% relative humidity (RH) exposure. Three different concentrations of halogen
flux for activated Sn-3.0wt%Ag–0.5wt%Cu were used to solder in air and in an inert N2 reflow atmosphere. The lead frames of the QFPs consisted of Sn plated Cu and Fe-42wt%Ni (alloy 42). Sn whiskers were observed
on the surface of the QFP solder fillet joints that were reflowed with halogen containing flux in an air atmosphere. A substantial
amount of Sn oxides were formed in those solder fillets while whisker growth and the amount of Sn oxides increased with the
halogen content. Sn oxide formation apparently enhanced whisker formation. The combination of air reflow atmosphere and high
halogen flux was the worst combination for solder fillet oxidation resulting in Sn whisker formation regardless of the electrode’s
lead frame composition of Cu or alloy 42. In contrast, an inert N2 reflow atmosphere obviously prevented Sn whisker formation on Sn–Ag–Cu solder fillets under all conditions used in this work. 相似文献
11.
Bhupal Reddy P. Bhattacharya Bawa Singh K. Chattopadhyay 《Journal of Materials Science》2009,44(9):2257-2263
Sn–Ag–Cu (SAC) solder alloys are the best Pb free alternative for electronic industry. Since their introduction, efforts are
made to improve their efficacies by tuning the processing and composition to achieve lower melting point and better wettability.
Nanostructured alloys with large boundary content are known to depress the melting points of metals and alloys. In this article
we explore this possibility by processing prealloyed SAC alloys close to SAC305 composition (Sn-3wt%Ag-0.5wt%Cu) by mechanical
milling which results in the formation of nanostructured alloys. Pulverisette ball mill (P7) and Vibratory ball mills are
used to carry out the milling of the powders at room temperature and at lower temperatures (−104 °C), respectively. We report
a relatively smaller depression of melting point ranging up to 5 °C with respect to original alloys. The minimum grain sizes
achieved and the depression of melting point are similar for both room temperature and low-temperature processed samples.
An attempt has been made to rationalize the observations in terms of the basic processes occurring during the milling. 相似文献
12.
《Materials Science & Technology》2013,29(10):1267-1271
AbstractThe effect of sulphur on the microstructure and properties of Ag45–Cu30–Zn25 brazing filler metal was investigated. Under the given experimental conditions, the sulphuration products mainly consisted of CuS, ZnS, Ag2S, Cu2S and Ag3CuS2. These sulphides not only distributed on the surface but also diffused into the interior of the filler metal and cut apart the matrix thereby significantly damaging the tensile strength of the filler metal from 658 to 283 MPa. The corresponding fracture characterisation turned from ductile fracture to brittle fracture. The sulphides existed as solid particles, which hinder the spreading of the liquid filler metal and the spreading area dramatically decreased from 317?09 to 18?55 mm2, which indicates that the filler metal rarely wets the base metal. 相似文献
13.
Dong-xue Luo Song-bai Xue Zai-qian Li 《Journal of Materials Science: Materials in Electronics》2014,25(8):3566-3571
The effects of rare element Ga on solderability, microstructure, and mechanical properties of Sn–0.5Ag–0.7Cu lead-free solder were investigated. The experimental results show that Ga plays a positive role in improving the wettability and the microstructure of the solder. When the content of Ga is at 0.5 wt%, the grain size of the solder is smaller and the shear force is enhanced greatly. It is also found that the thickness of the IMCs at the solder/Cu interface is reduced with proper addition of Ga. The increase of mechanical properties may be related to the refining of IMCs of the solder due to Ga addition. 相似文献
14.
The effects of solution treatment on the microstructure and mechanical properties of Al–Cu–Mg–Ag alloy were studied by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), differential scanning calorimeter (DSC), transmission electron microscopy (TEM) and tensile test, respectively. The results show that the mechanical property increases and then decreases with increasing the solution temperature. And the residual phases are dissolved into the matrix gradually, the number fraction of the precipitation and the size of recrystallized grains increase. Compared to the solution temperature, the solution holding time has less effect on the microstructure and the mechanical properties of Al–Cu–Mg–Ag alloy. The overburnt temperature of Al–Cu–Mg–Ag alloy is 525 °C. The yield strength and the elongation get the best when the alloy is solution treated at 515 °C for 1.5 h, is 504 MPa and 12.2% respectively. The fracture mechanism of the samples is ductile fracture. 相似文献
15.
AbstractNanocomposite lead-free solders are gaining prominence as replacements for conventional lead-free solders such as Sn–Ag–Cu solder in the electronic packaging industry. They are fabricated by adding nanoparticles such as metallic and ceramic particles into conventional lead-free solder. It is reported that the addition of such nanoparticles could strengthen the solder matrix, refine the intermetallic compounds (IMCs) formed and suppress the growth of IMCs when the joint is subjected to different thermal conditions such as thermal aging and thermal cycling. In this paper, we first review the fundamental studies on the formation and growth of IMCs in lead-free solder joints. Subsequently, we discuss the effect of the addition of nanoparticles on IMC formation and their growth under several thermal conditions. Finally, an outlook on the future growth of research in the fabrication of nanocomposite solder is provided. 相似文献
16.
Ultrafine Ag–Cu nanoparticles (NPs) have been synthesized by a rapid one-step reduction within only 10 min. Effects of temperature and dispersants on the phases and morphology of Ag–Cu NPs were investigated. Results showed that citric acid exhibited an advantageous nature to avoid the formation of Cu2O and form uniform morphology over PVP. The average particle size of the Ag–Cu NPs synthesized simply in ice-cubes bath could be controlled in 8.6 nm about a quarter of that synthesized at room temperature. The synthesized Ag–Cu NPs presented alloy states near the eutectic composition of 72:28. Due to the lower Ostwald ripening rate and citric acid protection, smaller Ag–Cu NPs were achieved in ice-cube bath. Results also showed that the ultrafine Ag–Cu NPs could be expected to sinter at about 330 °C which was much lower than the eutectic temperature (779 °C) of bulk Ag–Cu alloy. The ultrafine Ag–Cu NPs could be applied as potential die attach materials for SiC power devices. 相似文献
17.
Liang Zhang Song-bai Xue Li-li Gao Yan Chen Sheng-lin Yu Zhong Sheng Guang Zeng 《Journal of Materials Science: Materials in Electronics》2009,20(12):1193-1199
Ternary lead free solder alloys Sn–Ag–Cu were considered as the promising alternatives to conventional SnPb alloys comparing with other solders. In the present work, effects of trace amounts of rare earth Ce on the wettability, mechanical properties and microstructure of Sn–Ag–Cu solder have been investigated by means of scanning electron microscopy and energy dispersive X-ray analysis systematically. The results indicate that adding trace amount of rare earth Ce can remarkably improve the wettability, mechanical strength of Sn–Ag–Cu solder joint at different temperature, especially when the content of rare earth Ce is at about 0.03%, the tensile strength will be 110% times or more than that of the lead free solder joint without rare earth Ce addition. Moreover, it was observed that the trace amount of rare earth Ce in Sn–Ag–Cu solder may refine the joint matrix microstructure, modify the Cu6Sn5 intermetallic phase at the copper substrate/solder interface, and the intermetallic compound layer thickness was reduced significantly. In addition, since rare earth Ce possesses a higher affinity to Sn in the alloy, adding of rare earth Ce can also lead to the delayed formation and growth of the intermetallic compounds of Ag3Sn and Cu6Sn5 in the alloy. 相似文献
18.
Mingna Wang Jianqiu Wang Wei Ke 《Journal of Materials Science: Materials in Electronics》2014,25(12):5269-5276
In this paper, the effects of microstructure on the corrosion behavior of Sn–3.0Ag–0.5Cu (SAC305) lead-free solder were investigated by potentiodynamic polarization and atmospheric corrosion test. Scanning electron microscopy and X-ray diffraction were used to characterize the samples after the electrochemical and atmospheric corrosion tests. Results showed that commercial SAC305 solder exhibits better corrosion resistance than air-cooled and furnace-cooled SAC305 solders both in 3.5 wt% NaCl solution and at 60 °C/100 % relative humidity condition. 相似文献
19.
《Materials Science & Technology》2013,29(11):1686-1693
AbstractSoldering experiments of chip scale package devices were carried out by means of diode laser soldering system with Sn–Ag–Cu solders. In addition, pull tests and a scanning electron microscope were used to analyse the effect of processing parameters on mechanical strength of solder joints. Viscoplastic finite element simulation was utilised to predict solder joint reliability for different package geometry under accelerated temperature cycling conditions. The results indicate that under the conditions of laser continuous scanning mode as well as the fixed soldering time, an optimal power and package geometry exists, while the optimal mechanical properties of microjoints are gained. 相似文献
20.
Mingna Wang Jianqiu Wang Hao Feng Wei Ke 《Journal of Materials Science: Materials in Electronics》2012,23(1):148-155
The heterogeneous microstructure of solder could be obtained when cooling rate of the solder joint was not even, which would
affect the corrosion behavior of solder during service. The ambient temperature would also affect the corrosion behavior of
solder joint. In this paper, the effects of microstructure and temperature on the corrosion behavior of Sn–3.0Ag–0.5Cu (SAC305)
lead-free solder were investigated. The various microstructures of SAC305 lead-free solder were obtained by cooling specimens
in air and furnace. Compared to the fine-fibrous Ag3Sn phase inside the commercial SAC305 solder, platelet-like Ag3Sn formed as cooling speed decreasing. The polarization behavior of SAC305 solders in 3.5 wt.% NaCl solution was not significantly
affected by various microstructures, but sensitive to temperature. 相似文献