| 摘要 |
PURPOSE:To eliminate noises after recording by using an Mn-Zn ferrite having an average crystal grain size of <=30mum for a recording and reproducing head and holding the ferrite at a holding temp. above the distortion point of glass, then subjecting the ferrite to annealing by cooling. CONSTITUTION:The average crystal grain size of the core material is specified to 30mum and the material is held at the temp. above the softening point (also the distortion point or above) of the glass 5 used for glass welding and is subjected to annealing by cooling for 50 deg.C/hour down to the distortion point, by which the magnetic head free from generation of the noises after recording is produced. The cooling rate from the holding temp. down to the distortion point is set at 50 deg.C/hour, by which the generation of cracking of the glass is prevented. |
