Method of consolidating FeNdB magnets

In the method of treating a preform consisting of metallic alloy particles subject to rapid oxidation, the steps that includes:

• (a) removing O.sub.2 from the preform and applying an O.sub.2 resistant coating to the preform surface,
• (b) heating the coated preform to elevated temperature and in a non-oxidizing atmosphere, to facilitate subsequent bonding of the particles during their consolidation,
• (c) providing a consolidation zone containing a grain bed and transferring the heated and coated preform to said zone to be embedded in the grain bed,
• (d) applying pressure to the grain bed sufficient to be transferred via the bed to the heated preform, thereby to consolidate the preform, said application of pressure to the grain bed carried out to increase to a dwell level at a rate that minimizes fracturing of the consolidated preform, said application of pressure held at said dwell level for at least several seconds and subsequently increased to a second dwell level.

In the method of treating a preform consisting of alloy particles, the steps that include:

• (a) applying a vitreous coating to the preform surface,
• (b) heating the coated preform to facilitate subsequent bonding of the particles during their consolidation,
• (c) providing a consolidation zone containing a grain bed and transferring the heated and coated preform to said zone to be embedded in the grain bed,
• (d) applying pressure to the grain bed sufficient to be transferred via the bed and coating to the heated preform, thereby to consolidate the preform, said application of pressure to the grain bed carried out to increase to a dwell level at a rate that minimizes fracturing of the consolidated preform, said application of pressure held at said dwell level for at least several seconds and subsequently increased to a second dwell level.

In the method of treating a preform consisting essentially of FeNdB alloy particles to produce a magnet having superior magnetic properties, the steps that include:

• (a) maintaining an O.sub.2 -free environment at the preform,
• (b) heating the preform to elevated temperature and in a non-oxidizing atmosphere, to facilitate subsequent bonding of the particles during their consolidation,
• (c) providing a consolidation zone containing a grain bed and transferring the heated preform to said zone to be embedded in the grain bed,
• (d) applying pressure to the grain bed sufficient to be transferred via the bed and to the heated preform, thereby to consolidate the preform, said application of pressure to the grain bed carried out to increase to a dwell level at a rate that minimizes fracturing of the consolidated preform, said application of pressure held at said dwell level for at least several seconds and subsequently increased to a second dwell level.

In the method of treating a preform consisting of metallic alloy particles subject to rapid oxidation, the steps that include:

• (a) maintaining an O.sub.2 free environment at the preform,
• (b) heating the preform to elevated temperature and in a non-oxidizing atmosphere, to facilitate subsequent bonding of the particles during their consolidation,
• (c) providing a consolidation zone containing a grain bed and transferring the heated preform to said zone to be embedded in the grain bed,
• (d) applying pressure to the grain bed sufficient to be transferred via the bed to the heated preform, thereby to consolidate the preform, said application of pressure to the grain bed carried out to increase to a dwell level at a rate that minimizes fracturing of the consolidated preform, said application of pressure held at said dwell level for at least several seconds and subsequently increased to a second dwell level.