| ‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘ KAWASAKI STEEL TECHNICAL REPORT No.23 ( October 1990 ) R&D of High-Technology Research Laboratories, Commemorating the 20th Anniversary of the Technical Research Division ‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘‘ |
| Magnetic Properties of Amorphous Fe-B-Si Alloy with Surface Films Nobuyuki Morito, Chizuko Maeda, Yohko Kitano |
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Synopsis : Surface coatings on Fe79.5B12Si8.5 (mol%) amorphous alloy ribbons have been studied to obtain high insulating resistance and high corrosion resistance. (1) A surface coating of lithium silicate with a molecular ratio SiO2/Li2O=3.5 has been found to induce compressive stress in the ribbons. It achieves constant permeability to an extent of approximately 2000 A/m and an increase in the iron loss of the amorphous alloy. (2) A surface coating of lithium silicate with SiO2/Li2O=7.5 has no mechanical interactions with the ribbons and does not deteriorate magnetic properties. This surface coating is available for Fe-based amorphous alloy ribbons to be used for transformer core materials. (3) Although alumina sol surface coating has no mechanical interaction with the ribbons, water vapor evaporated from alumina sol during annealing in N2 atmosphere causes surface crystallization and an increase in the iron loss of the ribbons. The surface crystallization and deterioration of magnetic properties have not been observed when the ribbons are annealed either in vacuum or in air. |
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