Coating Method and Apparatus, a Permanent Magnet, and Manufacturing Method Thereof

摘要

A film is formed at a high rate on the surface of an iron-boron-rare-earth-metal magnet having a given shape, while effectively using dysprosium or terbium as a film-forming material. Thus, productivity is improved and a permanent magnet can be produced at low cost. A permanent magnet is produced through a film formation step in which a film of dysprosium is formed on the surface of an iron-boron-rare-earth-metal magnet of a given shape and a diffusion step in which the magnet coated is subjected to a heat treatment at a given temperature to cause the dysprosium deposited on the surface to diffuse into the grain boundary phase of the magnet. The film formation step comprises: a first step in which a treating chamber where this film formation is performed is heated to vaporize dysprosium which has been disposed in this treating chamber and thereby form a dysprosium vapor atmosphere having a given vapor pressure in the treating chamber; and a second step in which a magnet kept at a temperature lower than the internal temperature of the treating chamber is introduced into this treating chamber and the dysprosium is selectively deposited on the magnet surface based on a temperature difference between the treating chamber and the magnet until the magnet temperature reaches a given value.