Wettability is defined as the tendency of a liquid metal to spread on a solid surface. The solder/substrate thermal conductance represented by a heat transfer coefficient, hi, states the heat ability to flow across the solder/substrate interface during solidification, being affected by the...

Wettability is defined as the tendency of a liquid metal to spread on a solid surface. The solder/substrate thermal conductance represented by a heat transfer coefficient, hi, states the heat ability to flow across the solder/substrate interface during solidification, being affected by the wettability. This letter aims to investigate the wetting behavior of Sn–0.7 wt%Cu–(Ni) lead-free solders by measuring the contact angles (θ) on a copper substrate as a function of the alloy Ni content. Furthermore, time-dependent hi profiles are determined from thermal readings during directional solidification (DS) of Sn–0.7 wt%Cu–(xNi) alloys. It is shown that a smaller initial contact angle (θi=32.7) characterizes the Sn–0.7 wt%Cu–0.05 wt%Ni associated with the highest hi value of 11,500t−0.03 W/m2 K (t: time)

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP

2013/08259-3; 2013/13030-5

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