| 摘要 |
PROBLEM TO BE SOLVED: To improve surface cleanliness by setting the ratio of the number of ferromagnetic particles to the total number of contamination particles adhered on the surface of rare earth magnet plated with Ni a specific value or below. SOLUTION: Works and media after electrolytic Ni plating are separated in a cleaning solution. Then, a series of cleaning processes are performed by arranging the works not to contact each other. In this manner, scratches on the Ni plates surface of a rare earth magnet by electrolytic plating are suppressed and adhesion of ferromagnetic contamination particles is suppressed to be extremely small in number. At this time, the ratio of the number of ferromagnetic particles to the total number of contamination particles adhered on the surface of the rare earth magnet plated with Ni is set to be approximately 10% or below. The average number of scratches on the surface of the rare earth magnet is set approximately 10 scratches/cm<2> or less. Thus the surface cleanliness is remarkably improved, and a possibility of causing recording/ reproducing error is significantly lowered. |
