The role of physico-chemical properties of liquid solder in reactive wetting: the Cu/SnZnIn system

Pstruś, J.

doi:10.2298/jmmb170728037p

Cited by 5 publications

(1 citation statement)

References 21 publications

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“…• The process implies two things: the change of wetting system from liquid solder/Cu-substrate into liquid solder/IMC-substrate resulting in worsening of wetting (increase of wetting angle) and the change of mass transport mechanism from the dissolution of copper substrate and liquid state processes into diffusion mechanisms in the solid state. • Model The earliest stage of wetting the copper substrate by liquid solder Sn-Zn included: adsorption and surface diffusion of Zn atoms, dissolution of the copper pad and diffusion of Cu atoms into the liquid, nucleation and create clusters of the epsilon phase, clusters coagulated, sedimentation and solidification [57,58].…”

Section: Discussionmentioning

confidence: 99%

Early stages of wetting of copper by Sn–Zn eutectic alloy

Pstruś

2018

J Mater Sci: Mater Electron

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The manuscript presents studies of the interaction of Sn-Zn eutectic solder alloy with a solid copper substrate, in the early times of the wetting process. The wetting tests were performed using the sessile drop method, with flux, in air, at 230 °C, 250 °C and 280 °C and reflow time of 2 s, 5 s, 10 s, 20 s, 40 s, 90 s and 180 s. The wetting time was measured from the moment of contact of the liquid solder with copper. It was noted, that during the reaction of copper with the liquid solder, an IMC (intermetallic compound) layer formed in the interface. Solidified solder/substrate couples were studied using scanning electron microscopy (SEM) and synchrotron measurements. The intermetallic phases of Cu-Zn system that formed at the solder/substrate interface were identified as epsilon and gamma. The kinetics of the formation and growth of the intermetallic layer were determined. The model describing the sequence of events in the early time of wetting was proposed. The earliest stage of wetting the copper substrate by liquid solder Sn-Zn included: adsorption of Zn atoms on the Cu surface, surface diffusion of Zn atoms on the copper surface, dissolution of the copper pad by the liquid solder and diffusion of Cu atoms into the liquid. In the liquid solder, the copper atoms combined with zinc atoms to create clusters of the epsilon phase. Those clusters coagulated and a short-range ordered (SRO) Cu-Zn structure formed in the liquid. After short heating and cooling, the liquid solidified and the CuZn 5 border-layer appeared in the interface. Further heating caused the saturation of the reaction zone with Cu atoms and the crystallization of two intermetallic phases Cu 5 Zn 8 from the solid support side and CuZn 4 one from the solder side occurred.

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Section: Discussionmentioning

confidence: 99%

Early stages of wetting of copper by Sn–Zn eutectic alloy

Pstruś

2018

J Mater Sci: Mater Electron

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Role of Solid–Solid Interfacial Energy Anisotropy in the Formation of Broken Lamellar Structures in Eutectic Systems

Khanna

Aramanda

Choudhury

2020

Metall Mater Trans A

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Eutectic solidification gives rise to a wide range of microstructures. A commonly observed morphology is the periodic arrangement of lamellar plates with well-defined orientations of the solid-solid interface in a given eutectic grain. It is typically believed that this form of morphology develops due to the presence of solid-solid interfacial energy anisotropy. In this paper, we provide evidence using phase-field simulations where our focus is on alloys where the minority phase fraction is low. Our aim is to establish the role of solid-solid interfacial energy anisotropy in the stabilization of broken lamellar structures in such systems in contrast to the formation of a rod microstructure. In this regard, we conduct phase-field simulations for different strengths of anisotropy in both constrained and extended settings, using which we clarify the mechanisms by which a lamellar arrangement gets stabilized in the presence of anisotropy in the solid-solid interfacial energy.

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