Method of increasing the coercivity of a sintered Nd—Fe—B permanent magnet

A method of increasing coercivity of a sintered Nd—Fe—B permanent magnet, the method including the steps of:

• providing an organic film including a pair of opposing surfaces and having a thickness of between 5 μm and 50 μm;
• depositing, under an inert gas environment, a powder containing at least one heavy rare earth elements on each of the opposing surfaces of the organic film thereby forming a diffusion source;
• providing a sintered Nd—Fe—B magnet block having a pair of block surfaces, opposite and spaced from of one another, extending perpendicular to a magnetization direction;
• depositing the diffusion source on at least one of the block surface of the sintered Nd—Fe—B magnet block with the powder being in abutment relationship with at least one of the block surfaces;
• pressing the sintered Nd—Fe—B magnet block containing the diffusion source allowing the powder of the diffusion source to be in close contact with the at least one of the block surfaces of the sintered Nd—Fe—B magnet block;
• diffusing the diffusion source into the sintered Nd—Fe—B magnet block under a vacuum environment or an inert gas environment to produce a diffused magnet block;
• and
• aging the diffused magnet block under the vacuum environment or the inert gas environment.

A method of increasing coercivity of a sintered Nd—Fe—B permanent magnet, the method including the steps of:

• providing an organic film including a pair of opposing surfaces and having a thickness of between 5 μm and 50 μm with the organic film being selected from at least one of a substrate-less double-sided tape, a one-sided Polyethylene terephthalate tape, a double-sided Polyethylene terephthalate tape, a one-sided Polyvinyl Chloride tape, or a double-sided Polyvinyl Chloride tape;
• depositing, under an inert gas environment, a powder containing at least one heavy rare earth elements on each of the opposing surfaces of the organic film thereby forming a diffusion source;
• providing a sintered Nd—Fe—B magnet block having a pair of block surfaces, opposite and spaced from of one another, extending perpendicular to a magnetization direction;
• depositing the diffusion source on at least one of the block surfaces of the sintered Nd—Fe—B magnet block with the powder being in abutment relationship with the at least one of the block surfaces;
• pressing the sintered Nd—Fe—B magnet block containing the diffusion source allowing the powder of the diffusion source to be in close contact with the at least one of the block surfaces of the sintered Nd—Fe—B magnet block;
• diffusing the diffusion source into the sintered Nd—Fe—B magnet block under a vacuum environment or an inert gas environment to produce a diffused magnet block;
• and
• aging the diffused magnet block under the vacuum environment or the inert gas environment.