| 摘要 |
PURPOSE:To obtain single-crystalline ferrite nearly free from pores and grown over a long range by joining polycrystalline ferrite to single-crystalline ferrite as a seed, heating them and growing the single-crystalline ferrite by a solid phase reaction. CONSTITUTION:A prescribed ferrite sintered body is successively subjected to primary firing by treatment at 1,100-1,280 deg.C in vacuum, calcining in an He atmosphere or an He atmosphere contg. <=3% oxygen and cooling in N2 or by the treatment and cooling and to secondary calcining by hot isostatic pressing at 1,150-1,350 deg.C above the primary calcining temp. under >=60kg/cm<2> pressure to obtain polycrystalline ferrite. This ferrite is joined to single-crystalline ferrite as a seed and they are heated at 1,300-1,560 deg.C in nitrogen or a nitrogen atmosphere contg. <=3% oxygen to produce single-crystalline ferrite by a solid phase reaction. |
