Phase equilibria in Sn rich corner of Cu–Ni–Sn system

Snugovsky, L.; Snugovsky, Polina; Perović, D. D.; Rutter, J. W.

doi:10.1179/174328406x109249

Cited by 28 publications

(29 citation statements)

References 2 publications

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“…Previous research by the authors 5,14) has shown that, as the Ni content in Sn-0.7Cu-xNi decreases from 0.05 mass%, the volume fraction of primary Sn dendrites in the microstructure increases. This result was shown to be consistent with the phase equilibria of the Sn-Cu-Ni system, 15) where Sn-0.7Cu-0.05Ni is closer to a eutectic valley than Sn-0.7Cu. 4,5) However, the increased volume fraction of Sn-dendrites with increasing P content in Figs.…”

Section: Compositionsupporting

confidence: 78%

Effects of Phosphorus on Microstructure and Fluidity of Sn-0.7Cu-0.05Ni Lead-Free Solder

et al. 2008

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Phosphorus is often added to wave-solder baths as an anti-oxidation agent. Despite this practice, there is little information on how phosphorus influences the solidification and flow properties of new lead-free solders such as Sn-0.7Cu-0.05Ni. This paper investigates the effects of phosphorus content on microstructure and maximum fluidity length in Sn-0.7Cu-0.05Ni-xP alloys containing 0-0.08 mass% phosphorous. Ppm levels of phosphorous are found to cause Sn-xP, Ni-xP-(Sn) and Cu-xP-(Sn) intermetallic compounds to form in the liquid solder. The IMCs are less dense than liquid Sn and float towards the surface of the melt driven by buoyancy. It is shown that P-free Sn-0.7Cu-0.05Ni solidifies with a near-eutectic microstructure whereas, when P is added to this alloy, a significant volume fraction of primary Sn dendrites form once the P content exceeds $0:01 mass% P. It is further shown that P additions decrease the ability of Sn-0.7Cu-0.05Ni to flow as it solidifies.

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Section: Compositionsupporting

confidence: 78%

Effects of Phosphorus on Microstructure and Fluidity of Sn-0.7Cu-0.05Ni Lead-Free Solder

et al. 2008

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“…The ternary liquidus projections of Snugovsky et al 18 and Lin et al 19 suggest that Ni additions to Sn-0.7Cu move the composition in the direction of a monovariant valley or an invariant point, both of which would involve the formation of an additional intermetallic phase. Based on this, the compositions of intermetallics with different morphologies were examined to study whether coarse, fine, and coralzone intermetallics have different compositions.…”

Section: Microstructural Observationsmentioning

confidence: 99%

“…4c-h. However, further studies are required to confirm the phase equilibria in Sn-rich Sn-Cu-Ni alloys because Lin et al 19 propose a liquidus projection containing different phases to Snugovsky et al 18 and the two sets of researchers also propose different types of invariant reactions.…”

Section: Microstructural Observationsmentioning

confidence: 99%

“…4c-h. The ternary liquidus projection of Snugovsky et al 18 suggests that Ni additions in the range 0-1,000 ppm Ni are significant compared to the phase diagram. Furthermore, their projection suggests that Ni additions to Sn-0.7Cu move the ternary composition towards a monovariant valley, consistent with the decreasing volume fraction of primary b-Sn with increasing Ni content in Fig.…”

Section: Microstructural Observationsmentioning

confidence: 99%

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The Influence of 0–0.1 wt.% Ni on the Microstructure and Fluidity Length of Sn-0.7Cu-xNi

Ventura

Gourlay

Nogita

et al. 2007

Journal of Elec Materi

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Alloys based on the Sn-0.7Cu-xNi system are potential Pb-free solders. In this paper we report on the solidification characteristics and microstructures of Sn-0.7Cu alloys containing 0-1,000 ppm nickel. The microstructural observations show that increasing the nickel content reduces the volume fraction of primary Sn, thus generating a more-eutectic microstructure. In an attempt to better understand the changes in solderability with Ni additions, fluidity tests were carried out using the Ragone method for small incremental increases in nickel content. The maximum fluidity length was found to vary strongly with nickel content. Additionally, the distribution of nickel within samples was investigated using synchrotron micro X-ray fluorescence.

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“…15 Little research has been published on the phase equilibria, solidification, and microstructure formation of the very Sn-rich compositions relevant to Sn-Cu-Ni solders. 14,16 Now that Sn-Cu-Ni solders are in commercial use, there is a need to improve our understanding of the metallurgy of the Sn-Cu-Ni compositions that are liquid at soldering temperatures.…”

Section: Introductionmentioning

confidence: 99%

Intermetallic Formation and Fluidity in Sn-Rich Sn-Cu-Ni Alloys

Gourlay

Nogita

Read

et al. 2009

Journal of Elec Materi

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This paper investigates the phase equilibria and solidification behavior of Sn-Cu-Ni alloys with compositions in the range of 0 wt.% to 1.5 wt.% Cu and 0 wt.% to 0.3 wt.% Ni. The isothermal section at 268°C in the Sn-rich corner was determined. No evidence for a ternary phase was found, and the section is in good agreement with past experimental studies that report wide solubility ranges for (Cu,Ni) 6 Sn 5 and (Ni,Cu) 3 Sn 4 . The vacuum fluidity test was applied to compositions that are liquid at 268°C to map the variation in microstructure and flow behavior with composition in this system. Significant variations in fluidity length were measured among the Sn-Cu-Ni alloys, and the variations correlate with the microstructure that develops during solidification. The generated fluidity map enables the selection of Sn-Cu-Ni solder compositions that exhibit good fluidity behavior during solidification and form near-eutectic microstructures.

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Phase equilibria in Sn rich corner of Cu–Ni–Sn system

Cited by 28 publications

References 2 publications

Effects of Phosphorus on Microstructure and Fluidity of Sn-0.7Cu-0.05Ni Lead-Free Solder

Effects of Phosphorus on Microstructure and Fluidity of Sn-0.7Cu-0.05Ni Lead-Free Solder

The Influence of 0–0.1 wt.% Ni on the Microstructure and Fluidity Length of Sn-0.7Cu-xNi

Intermetallic Formation and Fluidity in Sn-Rich Sn-Cu-Ni Alloys

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