The Effects Of High Magnetic Field On The Growth Of Intermetallic Compounds

With the development of super conducting materials, new-style equipments that can generate D.C static magnetic fields have been gradually and successfully manufactured and have been applied in various fields of science. As a result, many new academic intercross fields of science, which have very good potential for future development, have come into being. The new field of High Magnetic Field-related Materials Science and Engineering has also formed under this background.The high magnetic field not only can control the process of physical or chemic reaction but also can apply heavy intensity magnetization energy to mass on the scale of atom or molecule, change its arrange, match, migration and diffusion behavior. Therefore, during aging, the reaction between dissimilar substance and atomic diffusion behaviors of constitute elements with high magnetic field will be different from that without high magnetic field. This paper studies the growth behaviors of intermetallic compounds and diffusion phenomenon of atoms under different high magnetic field conditions. The result are shown as follows:1. The IMC layer thicknesses of Sn-3Ag-0.5Cu/Cu solder joints with OT; 3T and 8T positive high magnetic fields all increase with the increase of aging time. And the growthkinetic of IMC layer during aging with different high magnetic fields all obeys x=(Dt)^1/2. The growth rates of IMC layer gained from the slope of the curve of growth kinetics increase with the enhancement of the intensity of magnetic field. By calculation, the activation energies values for the growth of IMC with and without high magnetic fields are 27.693kJ/moland 59.123kJ/mol, respectively.2. The IMC layer thicknesses of Sn-3.5Ag/Ni solder joints under 8T adverse high magnetic condition versus the square root of aging time shows a linear dependence. And the slope of the beeline increases with the aging temperatures. Under the condition of 8T reverse high magnetic field, the growth rates obtained from growth kinetics also increase with the hoist of aging temperatures. Compared to that without high magnetic field, the growth rate of IMC layer with 8T adverse high magnetic field is enhanced. By calculation, the growth activation energies of Sn-3.5Ag/Ni solder joints with 8T adverse high magnetic field and no magnetic fields are 29.51kJ/mol and 48.22kJ/mol, respectively.3. During aging of 190°C, the growth rates of Sn-3Ag-0.5Cu/Cu; Sn-3.5Ag/Ni and Sn-0.7Cu/Ni solder joints under the condition of 8T positive and reverse high magnetic fiels show obviously different. The growth rates under the condition of 8T positive high magnetic field are always larger than that under the condition of 8T reverse high magnetic field. The EDX analysises for the IMC of Sn-3Ag-0.5Cu/Cu and Sn-0.7Cu/Ni solder joints indicate that different magnetic field directions have different effects on the atomic diffusion of different constitute elements.