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Magnetic property in Alnico V type permanent magnet is improved by adding special elemets, heat treatment in magnetic field and producing columnar structres. This experiment is a part of an investigation into methods of producing columnar structure in Fe-Ni-Al alloy of high Co content, with consequent improvement in their magnetic properties. Alnico V type alloys are coarse grained and columnar growth is readily induced by casting into suitably chilled molds. As increasing amounts of Ti are added to this type of alloy, the grain size becomes progressively smaller, and the production of columnar castings more difficult. Consequently, high coercivity alloys with the composition 14.5% Ni, 28∼35% Co, 4.5% Cu, 7% Al and 5% Ti are extremly fine grained and, when chill cast, form only very small columnar crystals near the chilled face. The occurrence of fine equi-axed crystals in Fe-Ni-Co-Cu-Al-Ti alloys is a function of Al and Ti contents and not Ti contents alone.

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Surface diffusion was studied by means of grain boundary grooving technique. The surface selfdiffusion coefficient of copper(D_s) has been measured between 847˚and 1,069℃ for six different orientations. These were the (111), (110), (100) and three higher index surfaces. The activation energy for D_s (designated Q_s) was found to be about 49 kcal per mole for all six surfaces, and Do about 2×10⁴sq cm per sec. At any temperature D_s varied by no more than a factor of three over these orientations. It is shown that, if the free energy of a surface atom is uniquely determined by its number of nearest neighbors, it follows from the principle of microscopic reversibility that Q_s should have the same value for all surface orientations, and D_s should vary little with orientation. This model also suggests that for clean fee metals Q_s=2/3 Hv(heat of vaporization). This is true for copper. These results will be supported by the results of radio isotope technique on copper surfaces performed by author at high temperatures.

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