Claims
- 1. In a method for producing magnetic particles for use in making magnetic inks comprising the steps of
- (a) placing substantially pure iron in a refractory support in a chamber that has been evacuated to a pressure of 10.sup.-6 mm.,
- (b) backfilling said chamber with argon,
- (c) heating said iron to its evaporation temperature and retaining it at such temperature until all or a portion of said iron has been evaporated,
- (d) collecting said evaporated particles on a magnetized surface lying in a straight line from said refractory support, and
- (e) oxidizing said collected particles at normal room temperatures and pressures.
- 2. The method of claim 1 wherein said argon is backfilled to a pressure of approximately one millimeter.
- 3. The method of claim 2 wherein said iron has a purity of 99.999%.
- 4. The method of claim 1 wherein said refractory support is AL.sub.2 O.sub.3.
- 5. The method of claim 1 wherein the oxidization of said collected iron particles takes place at approximately 70.degree. F. in ordinary atmosphere immediately upon removal from said chamber.
- 6. The method of claim 1 wherein the backfilled argon pressure can vary from 0.1 mm. to 1.0 mm.
- 7. In a method for producing magnetic particles for use in making magnetic inks comprising the steps of:
- (a) placing substantially pure iron in a refractory support in a chamber that has been evacuated to a pressure of 10.sup.-6 mm.,
- (b) backfilling said chamber with argon,
- (c) heating said iron to its evaporation temperature and retaining it at such temperature until all or a portion of said iron has been evaporated, and
- (d) collecting said evaporated particles on a magnetized surface lying in a straight line from said refractory support.
Parent Case Info
This application is a continuation of application Ser. No. 460,842 filed Apr. 15, 1974 now abandoned.
US Referenced Citations (8)
Foreign Referenced Citations (3)
Number |
Date |
Country |
4831,166 |
Apr 1973 |
JP |
930,402 |
Jul 1963 |
GB |
972,146 |
Oct 1964 |
GB |
Non-Patent Literature Citations (1)
Entry |
Rosensweig, R. E., "Magnetic Fluids", International Science and Technology, Jul. 1966. |
Continuations (1)
|
Number |
Date |
Country |
Parent |
460842 |
Apr 1974 |
|