الفهرس 
chapter 1Only 14 pages are availabe for public view
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Abstract
Mechanical, electrical, and thermal properties, as well as microstructural conditions, are important factors to consider when studying nanoparticle-containing materials. Phase identification and morphology of the (SAC355)100-x(ZnO)x (x= 0.1, 0.3, 0.5, 0.7 and 1wt. % ) solder alloys were studied using X-ray diffraction (XRD), and scanning electron microscopy (SEM). Microstructural analysis revealed that ZnO NPs were distributed uniformly throughout the Sn matrix. Furthermore, the addition of 0.1, 0.3, and 0.7 wt.% of ZnO NPs to the eutectic (SAC355) prevented crystallite size reduction, which increased the strength of the solder alloy. Mechanic parameters such as Young’s modulus improved significantly at 0.1, 0.3, and 0.7 wt.% of ZnO NPs contents compared to ZnO-free soldering. The Vickers hardness value (Hv) increased to its maximum value as the ZnO NPs content increased to 0.5. A stress exponent value (n) of approximately 2 in most composite solder alloys suggests us to believe that grain boundary sliding is the dominant mechanism in this system. The electrical resistance () increased its maximum value at 0.5 wt.% of ZnO NPs contents. The addition of ZnO NPs to plain (SAC355) solder alloys increased the melting temperature (Tm) by a few degrees. Microstructure investigations revealed that the addition of TiO2 NPs particles to eutectic (SAC355) inhibited reducing and refining 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 due to the existence of an 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 has an effective method to enhance new solder joints. Phase identification and morphology features of the (SAC355)100-x(Al2O3)x NPs where (x = 0.1, 0.3, 0.5, 0.7, and 1 wt. %) solder were systematically studied and investigated. Microstructure studies revealed that adding a trace amount of Al2O3 NPs to the eutectic (SAC355) system refine the crystallite size of both rhombohedral β-Sn, orthorhombic Cu6Sn5, and Ag3Sn IMCs. The modification of microstructure led to a strong adsorption effect and high surface-free energy of Al2O3 NPs. The elastic modulus (E) and Vickers microhardness (Hv) were improved. This can be attributed to the interstitial dispersion of Al2O3 NPs at grain boundaries, which makes snail-like Ag3Sn particles more uniformly distributed within β-Sn matrix that could obstruct the dislocation slipping. The results showed that creep resistance (n) decreases from dislocation climb value at 0.1 wt.% to grain boundary sliding value at 1 wt.% Al2O3 NPs content. Electrical resistance (), Fermi energy (Ef), and Fermi velocity (Vf ) increased with Al2O3 NPs content, while electron concentration (N) decreased due to increased charge carrier scattering centers. However, increasing the doping content of Al2O3 NPs led to an increase in the melting temperature (Tm), compared with plain solder. All results showed that Al2O3 NPs addition has an effective method to enhance new lead-free solder joints.