Manufacture of magnetic particles by reacting iron,cobalt,or nickel salts with oxalic acid salts in dialkyl sulfoxide
Abstract
Abstract THIS INVENTION RELATES TO THE PREPARATION OF HIGH COERCIVITY, FINELY DIVIDED ACICULAR MAGNETIC METAL, ALLOY, OR OXIDE PARTICLES BY PRECIPITATION OF OXALATES OF IRON, NICKEL, COBALT, OR MIXTURES OF THESE METAL OXALATES FROM A BATH CONTAINING DIALKYL SULFOXIDE, PREFERABLY DIMETHYL SULFOXIDE. OXALIC ACID OR A SOLUBLE SALT OF OXALIC CID WHICH PROVIDES OXALATE IONS IN SOLUTION IS REACTED WITH A SOLUBLE METAL SALT OF IRON, NICKEL, OR COBALT DISSOLVED IN THE BATH. PRECIPITATION IS CAUSED BY THE ADDITION OF WATER TO THE DIALKYL SULFOXIDE BATH. AFTER SEPARATING AND DRYING, THE PRECIPITATE IS DECOMPOSED, EITHER BY HEAT ALONE OR BY REDUCTION WITH A REDUCING GAS AT ELEVATED TEMPERATURES TO PRODUCE METAL PARTICLES WHICH ARE OBLONG IN SHAPE AND WHICH VARY IN SIZE FROM ABOUT 0.1 MICRON TO 1.0 MICRON.
Inventors
- 👤 Robert S Haines
Bibliographic Details
Claims Analysis
Total Claims: 0References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-12 | 1974-10-12 | 1975-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-12 | 1978-10-12 | 1979-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-12 | 1982-10-12 | 1983-04-13 | $7700.00 | Window Closed / Lapsed |