Hot Tin Essay

1256 Words 6 Pages
The above graph shows temperature of Sn0.3Ag0.7Cux In alloy as a function of indi-um weight percentage. Initially with no traces of Indium, the solidus temperature & liquidus temperature are 219.40̊C and 241.70̊C. It clearly shows that the temperature range goes wider as the concentration of indium is increased [6]. This is not a cost effective solution as indium is very costly.
Titanium oxide nano particles addition led to temperature changing from 217 to 217.64 degree Celsius [7]. Zinc oxide bearing SAC had temperature of about 222.16
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degree celsius when zinc was about 0.5% by weight [8]. From this it can be conclud-ed that there no major effect on melting temperature.
2.2.2 Wettability
It is the ability of
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They can grow upto several microns and have excellent electrical conductivity. Their growth can be re-tarded by adding 0.5% Zn, using reflowed tin or hot tin dip. Reflowed tin is a tech-nique that involves reheating a part above the melting temperature of tin after it has been electroplated with tin. Hot tin Dip is a process in which a part is dipped into a bath of molten tin above 450 F. This creates a thin layer at the interface of the base material & tin.
3.2 Voids
The voids can be removed by adding sintered silver foil that is already coated with chromium and gold. On reaction a uniform layer is formed between Ag/Sn & Sn/Au.
3.3 Reduction in Melting Point
Further reduction in melting point can be made by adding more of the rare earth ele-ments into Sn-Ag-Cu solder.
3.4 Calculation of melting Temperature
(Given)
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3.5 State of the Art
The trend is shifting towards lead free solders with different base materials hypo eu-tectic Bi-Ag alloys are preferred based on liquidus temperature in comparison to PbSn solders. Zn-Al eutectic systems alloyed with Mg, Ge ,Ga ,Sn, Sb, Bi may serve interesting topics for
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Kanlayasiri, M. Mongkolwongrojn, and T. Ariga, “Influence of indium addition on characteristics of Sn-0.3Ag-0.7Cu solder alloy,” Journal of Alloys & Compounds, vol. 485, no. 1-2, pp. 225–230, 2009.
[7] L.W. Lin, J.M. Song, Y. S. Lai, Y. T. Chiu,N.C.Lee, and J. Y. Uan, “Alloying modification of Sn-Ag-Cu solders by manganese and titanium,” Microelectronics Reliability, Vol.49,no.3, pp235-241,2009.
[8] A. Fawzy, S. A. Fayek, M. Sobhy, E. Nassr, M. M. Mousa, and G. Saad, “Tensil -Creep characteristics of Sn−3.5Ag−0.5Cu(SAC355) solder reinforced with nano-metric ZnO Particles”, Materials Science and Engineering A, vol. 603, pp. 1-10, 2014.
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[9] C. M. T. Law, C. M. L. Wu, D. Q. Yu, L. Wang, and J. K. L. Lai, “Microstructure, Solderability & growth of intermetallic compounds of Sn-Ag-Cu-RE lead-free solder alloys”, Journal of Electronic Materials, vol. 35, no. 1, pp. 89–93, 2006.
[10] L. Zhang, X. Y. Fan, Y. H. Guo, and C. W. He, “Properties enhancement of SnAgCu solders containing rare earth element Yb”, Materials & Design, Vol. 57, pp. 646–651, 2014.
[11] L. C. Tsao, S. Y. Chang, C. I. Lee, W. H. Sun, and C. H. Huang, “Effects of nano Al2O3 additions on microstructure development and hardness of Sn3.5Ag0.5Cu solder,” Materials and Design, vol. 31, no. 10, pp. 4831–4835, 2010.

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