Effect of TiO2 nanoparticles on the microstructure, mechanical and thermal properties of rapid quenching SAC355 lead-free solder alloy

Abstract

PurposeThis study aims to investigate the effect of a small amount of TiO2 NPs addition on the microstructure, thermal, mechanical and electrical properties of environmentally friendly eutectic (SAC355)100-x(TiO2)x (x = 0.1, 0.3, 0.5, 0.7 and 1 wt.%) solder alloys.Design/methodology/approachMechanical, thermal and electrical properties and microstructure conditions are taken into major consideration in any study of materials containing nanoparticles. Dynamic resonance technique, X-ray diffraction and scanning electron microscopy were carried out to study stiffness, identification of the phases and the morphology features of the solder. Structure and microstructure analysis indicated that the presence of rhombohedral β–Sn phase in addition to orthorhombic intermetallic compound (IMC) Ag3Sn and Cu3Sn phase dispersed in Sn matrix. In addition, the results showed that TiO2 NPs addition at a small trace amount into SAC355 system reduces and improves the particle size of both rhombohedral β–Sn and orthorhombic IMC Ag3Sn and Cu3Sn. The interstitial dispersion of TiO2 NPs at grain boundaries resulted in Ag3Sn being more uniform needle-like, which is distributed in the β–Sn matrix. The fine and uniform microstructure leads to improvement of mechanical strength.FindingsSome important conclusions are summarized as follows: microstructure investigations revealed that the addition of TiO2 NPs particles to eutectic SAC355 inhibited in reducing and refines the crystallite size as well as the Ag3Sn IMC, which reinforced the strength of plain solder alloy. The mechanical properties values such as Young’s modulus and Vickers microhardness of SAC355 solder alloy can be significantly improved by adding a trace amount of TiO2 NPs compared with plain solder because of the existence of appropriate volume fraction of Ag3Sn IMC. The results show that the best creep resistance is obtained when the addition of 0.3 wt.% of TiO2 NPs is compared to plain solder. TiO2 NPs addition could increase the melting temperature, compared with plain solder. All results showed that TiO2 NPs addition is an effective method to enhance new solder joints.Practical implicationsNew solder alloys.Originality/valueDevelopment of TiO2 NPs-doped eutectic SAC355 lead-free solder for electronic packaging.