A comparative study on microstructures and mechanical properties of Sn-۰.۸Cu and Sn-۸Cr lead-free solders

European Union's (EU), Restriction of Hazardous Substances (RoHS) Environmental, andProtection Agency (EPA) announced Lead and its compositions as poisonous chemicalmaterial and following that its usage was eliminated from microelectronic industries. The Sn-Cu solder was one of the first substitutions. According to its moderate mechanical properties, theimprovement of mechanical properties could be achieved by adding alloying elements like Cr.There are two challenges in the field of Sn-Cu and Sn-Cu-Cr solders, the disagreement betweenresearchers over the composition of eutectic Sn-Cu alloy (Sn-۰.۷Cu and Sn-۰.۹Cu) and theformation of Sn-Cr intermetallic compounds (IMCs). This study is about Sn-۰.۸Cu and Sn-۸Cr tofound the behavior of Cu and Cr in the Sn matrix separately. It was confirmed that the microstructureof Sn-Cu solder can be nearer to the eutectic point and despite no stable IMCs in the Sn-Cr phasediagram, the stable IMCs were observed. The presence of Cr can also improve density andmicrohardness compare to Sn-Cu solder.

کلیدواژه ها:

Lead-free solder ، microstructure ، density ، microhardness ، intermetallic compound (IMC) ، chromium