Claims
- 1. 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) 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 to 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 to the heated preform, thereby to consolidate the preform, said application of pressure to the grain bed carried out to increase to at least one level and at rate that minimizes fracturing of the consolidated preform, said application of pressure held at said dwell level for at least several seconds and at a level of at least about 10 TSI.
- 2. The method of claim 1 including the initial step of forming said preform by pressurizing a mass of the particles.
- 3. The method of claim 2 wherein said pressurizing of the particles is carried out by locating said mass of the particles within another grain bed and pressurizing said other bed.
- 4. The method of claim 2 wherein said pressurizing of the particles is carried out by providing a die having a cavity, locating said mass of the particles in said cavity, and providing a plunger and displacing the plunger to pressurize said mass of particles.
- 5. The method of claim 2 including the step of initially displacing the particles to align them in generally the same direction.
- 6. The method of claim 5 wherein said displacing of the particles is effected by vibrating them.
- 7. The method of claim 1 wherein said coating consists of glass.
- 8. The method of claim 1 wherein said coating consists of glass frit in a liquid carrier vehicle, and including the step of removing the liquid carrier vehicle from the coating by vacuum application.
- 9. The method of claim 8 wherein said heating of the glass coated preform is carried out at a temperature of between about 700.degree. C. and 800.degree. C.
- 10. The method of claim 9 wherein said heating is contained for between about 6 to 10 minutes.
- 11. The method of one of claims 9 wherein said heating is effected by magnetic induction.
- 12. The method of claim 1 wherein said transfer of the heated and coated preform is carried out rapidly to pass through an air environment.
- 13. The method of claim 1 wherein said grain bed consists essentially of carbonaceous grain particles.
- 14. The method of claim 13 wherein said carbonaceous particles are resiliently compressible.
- 15. The method of claim 13 wherein said carbonaceous particles consist of graphite.
- 16. The method of claim 13 wherein said carbonaceous particles are fissured.
- 17. The method of claim 1 wherein said rate is between 0.1 and 0.7 TSI/sec.
- 18. The method of claim 1 wherein the bed consists essentially of ceramic grain particles.
- 19. The method of claim 1 wherein the bed consists of both ceramic and carbonaceous grain particles.
- 20. The method of claim 1 wherein application of pressure is held at a first dwell level up to 120 seconds.
- 21. The method of claim 1 including:
- (i) reducing said pressure application, at the end of a dwell interval at said dwell level,
- (ii) and again performing (a'), (b'), (c') and (d') steps corresponding to said (a), (b), (c) and (d) steps, upon the same preform.
- 22. 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 graphite 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 swell level for at least several seconds and at a level of at least about 10 TSI.
- 23. 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 graphite grain bed and transferring the heated and coated preform to said zone to 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 at a level of at least about 10 TSI.
- 24. The method of claim 23 wherein said coating consists of glass frit in a liquid carrier vehicle.
- 25. 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 or levels 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 at different pressures exceeding about 10 TSI.
- 26. 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 or levels 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 at different pressures exceeding about 10 TSI.
Parent Case Info
This is a continuation of application Ser. No. 099,321 filed Sept. 25, 1987, now U.S. Pat. No. 4,808,224.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
4808224 |
Anderson et al. |
Feb 1989 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
99321 |
Sep 1987 |
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