Assessment of alternatives alloys for Laser soldering of electronics microcomponents
Solidification; Sn-Ag-Cu alloys; microstructure; Laser; Thermal Treatment.
The study, selection and viability of non-toxic alloys for the soldering of electronic microcomponents is an urgent and necessary demand in a context of technological advancement in industry 4.0. Alternative lead-free alloys such as the Sn-Ag-Cu (SAC) alloys have highlighted for this application, as they show good wettability, interfacial properties superior and high creep resistance. The addition of nickel (Ni) in SAC alloys can inhibit the growth of intermetallics and the presence of microvoids in the reaction interface, in addition to improving the mechanical properties. Moreover, Laser surface treatments and heat treatments can result in significant microstructural changes. In this sense, the present work aims to understand the microstructural features and hardness of the Sn-2wt.% Ag-0.5wt.% Cu (SAC205) and SAC205-0.2wt.% Ni alloys in three different states: i. as-cast conditions via transient directional solidification; ii. Laser Treated and iii. Heat treated. The effect of Ni addition in the SAC205 alloy will also be evaluated. Microstructural growth and Hall-Petch laws will be discussed considering each microstructural arrangement and Ni content. Microstructural characterization will be performed by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and x-ray flourescence (XRF).