Kyushu University · Engineering
Professor Xin Fu Tan's research lab specializes in the microstructural evolution and interfacial reactions in advanced solder materials and intermetallic compounds, with a focus on understanding dynamic processes at the nanoscale during solidification, reflow, and electrochemical cycling. The lab employs advanced in-situ characterization techniques—particularly high-voltage transmission electron microscopy (HV-TEM) and in-situ SEM—to investigate phase transformations, diffusion mechanisms, and microstructural stability in Sn-based solders (e.g., Sn-Bi, SAC305) and intermetallic anodes (e.g., Cu6Sn5) for electronics and energy storage applications. A key research direction involves optimizing solder joint reliability and battery anode performance through fundamental insights into diffusion kinetics, phase separation, and microstructural design.
Figures are computed from collected data and may differ slightly.
Intermetallics such as Cu6Sn5, NiSi2, and CuGa2 etc., are promising candidate materials to replace carbon-based lithium-ion battery anodes. However, the lithiation reactions of these anodes often involve the separation of the inactive phases, a slow process that retards the lithiation kinetics and deactivates their role as a stress buffer. This research visualizes the separated Cu in a lithiated Cu6Sn5 anode by advanced transmission electron microscopy techniques. Cu nanospheres of 3–4 nm are fo
Alloys based on the Sn-Bi system are widely considered as the most promising candidates for low temperature solders (LTS) in the electronics industry due to their low liquidus temperature, non-toxicity and relatively low cost. However, implementation of LTS is complicated as they exhibit different characteristics from conventional Pb-free solders. While the solid solubility of alloying additions in Sn is typically <1 wt% in the current generation of Pb-free solders, the solubility of Bi in Sn ra
Abstract Cu 6 Sn 5 is the most common intermetallic compound (IMC) in lead-free solder joints, and is also a promising anode material for advanced lithium-ion batteries. It has been reported that the growth rates of (Cu,Ni) 6 Sn 5 in Sn-based solder alloy/Cu-xNi substrate couples are greatly accelerated compared to the intermetallic layers that form on a pure Cu substrate. Due to the faster growth rates, solidification can progress through a transient-liquid-phase reaction in commercially releva
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
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