Claims
- 1. A method of producing a densified shape containing rare earth boride and alumina, said method comprising:
- (a) combining rare earth borate glass frit and aluminum to form a mixture;
- (b) compacting said mixture to form an unreacted shape;
- (c) heating said unreacted shape to a temperature adequate to cause said glass to flow but not adequate to cause reaction between said glass and said aluminum, thereby resulting in a modified unreacted shape of higher density than said unreacted shape of step (b);
- (d) further heating said modified shape, whereby said glass and aluminum react to form rare earth boride and alumina; and
- (e) densifying said reacted shape.
- 2. The method of claim 1 wherein pressure is applied to said shape during heating step (c) to facilitate said glass flow.
- 3. The method of claim 1 wherein said rare earth borate glass has the composition:
- La.sub.2 O.sub.3. 6 B.sub.2 O.sub.3.
- 4. The method of claim 3 wherein said reacting includes the reaction:
- La.sub.2 O.sub.3. 6 B.sub.2 O.sub.3 +14 Al .fwdarw.7 Al.sub.2 O.sub.3 +2 LaB.sub.6.
- 5. The method of claim 1 wherein said densifying step (e) is performed by hot pressing.
- 6. The method of claim 5 wherein said hot pressing is performed at a temperature of about 1650.degree.-1700.degree. C. and a pressure of about 1000-1500 psi.
- 7. The method of claim 2 wherein said temperature in heating step (c) is about 650.degree. C.
- 8. The method of claim 6 wherein said shape is densified to at least about 99% of theoretical density in step (e).
Government Interests
This invention was made with Government support under Contract N00014-87-C-0515 awarded by the Office of Naval Research, Dept. of the Navy. The Government has certain rights in the invention.
US Referenced Citations (4)