Claims
- 1. A method of forming a composite product having a major phase of low exothermic potential product (LEPP) and a minor phase of high exothermic potential product (HEPP) and having a preselected LEPP rich LEPP/HEPP mole ratio, comprising:
- forming a powder compact of low exothermic potential (LEP) and high exothermic potential (HEP) reactants in ratios which produce the desired LEPP/HEPP mole ratio;
- preheating the powder compact to a preignition temperature determined by the desired LEPP/HEPP mole ratio;
- producing a self-propagating combustion wave in the preheated powder compact to form a composite product of the desired LEPP rich LEPP/HEPP mole ratio.
- 2. The method of claim 1 wherein the LEPP and HEPP are selected from the group consisting of: Al.sub.4 C.sub.3 (1200), B.sub.4 C (1000), Be.sub.2 C (1900), CaC.sub.2 (1100), CdS (2000), CeS (3000), CrB.sub.2 (2470), Cr.sub.3 Si (1500), Cr.sub.5 Si.sub.3 (1700), CrSi.sub.2 (1800), FeB (1700), HfC (3900), HfB.sub.2 (3520), Ir.sub.2 S.sub.3 (1700), LaB.sub.6 (2800), MnS (3000), MnSi (1550), Mo.sub.2 B (1500), MoB (1800), MoB.sub.2 (1500), Mo.sub.2 C (1000), Mo.sub.3 C.sub.2 (800), MoS.sub.2 (2900), Mo.sub.3 Si (1200), Mo.sub.5 Si.sub.3, MoSi.sub.2 (1900), NbB.sub.2 (2400), Nb.sub.2 C (2600), NbC (2800), NbSi.sub.2 (1900), NiB (2000), SiC (1800), TaB.sub. 2 (2700), Ta.sub.2 C (2600), TaC (2700), TaSi.sub.2 (1800), ThC.sub.2 (2930), TiB (3350), TiB.sub.2 (3190), TiC (3210), Ti.sub.5 (2500), Si.sub.3 TiSi (2000), TiSi.sub.2 (1800), UC.sub.2 (1000), US (3000), V.sub.3 B.sub.2 (2340), VB (2520), VB.sub.2 (2670), VC (2400), W.sub.2 B (1400), WB (1700), W.sub.2 B.sub.5 (1300), W.sub.2 C (800), WC (1000), W.sub.5 Si.sub.3 (1200), WSi.sub.2 (1500) ZrB.sub.2 (3310), ZrC (3400), Zr.sub.2 Si (2600), Zr.sub.5 Si.sub.3 (2800), ZrSi (2700), ZrSi.sub.2 (2100),
- wherein the temperature is the adiabatic temperature (K) and the HEPP has a higher adiabatic temperature than the LEPP.
- 3. The method of claim 2 further comprising selecting a HEPP with a minimum adiabatic temperature and a LEPP with a maximum adiabatic temperature of about 2000 .+-.200K.
- 4. The method of claim 1 further comprising selecting the LEPP and HEPP with one element in common.
- 5. The method of claim 1 further comprising infiltrating the LEPP/HEPP composite with molten metal to form a substantially fully dense ceramic metal composite.
- 6. The method of claim 5 comprising infiltrating the LEPP/HEPP composite with a metal phase selected from aluminum, nickel, titanium, zirconium or alloys thereof.
- 7. The method of claim 1 comprising forming the powder compact of:
- (a) Nb, Al and C; or
- (b) Nb, Ge and C.
- 8. The method of claim 1 comprising selecting the HEPP from a metal aluminide.
- 9. The method of claim 8 comprising selecting the metal aluminide from the aluminides of nickel, copper and titanium.
- 10. The method of claim 1 wherein the self-propagating combustion wave is initialed by igniting the powder compact
- 11. The method of claim 1 comprising increasing the preignition temperature to increase the LEPP/HEPP mole ratio.
- 12. The method of claim 2 further comprising infiltrating the LEPP/HEPP composite with molten metal to form a substantially fully dense ceramic-metal composite
- 13. The method of claim 12 comprising infiltrating the LEPP/HEPP composite with aluminum, nickel, titanium, zirconium or alloys thereof
- 14. A LEPP rich combustion synthesis product formed by the process of claim 1.
- 15. A LEPP rich combustion synthesis product formed by the process of claim 2.
- 16. A substantially fully dense metal infiltrated LEPP rich combustion synthesis product formed by the process of claim 5.
- 17. A substantially fully dense metal infiltrated LEPP rich combustion synthesis product formed by the process of claim 12.
- 18. A LEPP rich combustion synthesis product formed by the process of claim 7.
- 19. A LEPP rich combustion synthesis product formed by the process of claim 9.
- 20. A substantially fully dense metal infiltrated LEPP rich combustion synthesis product formed by the process of claim 6.
RELATED APPLICATIONS
This application is a continuation-in-part (CIP) of Ser. No. 225,413, filed July 28, 1988, now U.S. Pat. No. 4,879,262.
US Referenced Citations (11)
Non-Patent Literature Citations (1)
Entry |
Crider, Joey F., "Self-Propagating High Temperature Synthesis--A Soviet Method for Producing Ceramic Materials", Ceramic Engineering & Science Proceedings, Sep.-Oct. 1982, vol. 3, pp. 519-528. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
225413 |
Jul 1988 |
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