An alternative thermal approach to evaluate the wettability of solder alloys

Autor(es)

Santos, Washington L. R. ; Silva, Bismarck L. ; Bertelli, Felipe ; Spinelli, Jose E. ; Cheung, Noe ; Garcia, Amauri

• Tipo de documento: Artigo Científico
• Fonte: APPLIED THERMAL ENGINEERING; v. 107, p. 431-440, AUG 25 2016.
• Citações Web of Science: 6

Resumo

The aim of the work is to propose an alternative method to qualitatively evaluate the wettability of different alloys of a particular alloy system. The technique is based on a thermal approach supported by experimental/theoretical methodologies involving a directional solidification procedure and numerical simulations based on the solution of the inverse heat conduction problem (IHCP). The wettability strongly affects the heat ability to flow across the alloy/substrate interface during solidification, which is construed as a heat transfer coefficient (h(g)). Particularly, for the alloys used in soldering processes, the wettability plays an important role in the integrity of solder junctions, being a fundamental parameter for selecting the most appropriate solder composition. The experiments were carried out with high temperature Zn-Sn solder alloys (10, 20, 30 and 40 wt%Sn) in a solidification device in which heat is extracted only through a water-cooled steel bottom. Experimental thermal profiles collected during solidification are used as input data to solve the IHCP and determine expressions hg vs. time for each alloy examined, permitting a tendency of wettability to be established. In order to validate the wetting behavior indicated by the hg values, alloy/substrate contact angles (theta) were measured on a steel substrate using a goniometer. It is shown that both hg and theta indicate improvements in wettability with the decrease in the alloy Sn content. (C) 2016 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 15/11863-5 - Parâmetros da microestrutura de solidificação de ligas multicomponentes Al-Si-Cu, Sn-Bi-Sb e Zn-Sn-Cu e propriedades mecânicas decorrentes
• Beneficiário: José Eduardo Spinelli
• Modalidade de apoio: Auxílio à Pesquisa - Regular