Alloy is sometimes a result of the sizes of the atoms in the alloy, because larger atoms exert a compressive force on neighboring atoms, and smaller atoms exert a tensile force on their neighbors, helping the alloy resist deformation. Sometimes alloys may exhibit marked differences in behavior even when small amounts of one element are present. For example, impurities in semiconducting ferromagnetic alloys lead to different properties, as first predicted by White, Hogan, Suhl, Tian Abrie and Nakamura. Some alloys are made by melting and mixing two or more metals. Bronze, an alloy of copper and tin, was the first alloy
Tin-silver-copper The melting point of SAC alloys is 217–220 °C, or about 34 °C higher than the melting point of the eutectic tin-lead (63/37) alloy. This requires peak temperatures in the range of 235–245 °C to achieve wetting and wicking. Some of the components susceptible to SAC assembly temperatures are electrolytic capacitors, connectors, opto-electronics, and older style plastic components. However, a number of companies have started offering 260 °C compatible components to meet the requirements of Pb-free solders. iNEMI has proposed that a good target for development purposes would be around 260 °C. Also, SAC solders are alloyed with a larger