Non-oxide sintered ceramic fibers

• US 4,908,340 A
• Filed: 07/16/1987
• Issued: 03/13/1990
• Est. Priority Date: 07/16/1987
• Status: Expired due to Term

• Current Assignee: Stemcor Corporation
• Original Assignee: Standard Oil Company (BP PLC)
• Inventors: Kasprzyk, Martin R., McMurtry, Carl H., Boecker, Wolfgang D. G., Frechette, Francis J.
• Primary Examiner(s): Dixon, Jr., William R.
• Assistant Examiner(s): Green, Anthony J.
• Application Number:
  US07/074,080
• Time in Patent Office: 971 Days
• Field of Search: 501/95, 501/96, 501/88, 501/97, 264/DIG. 19, 428/614
• US Class Current: 501/95.2
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3232 Titanium oxides or titanates, e.g. rutile or anatase
• CPC Class Codes: C04B 2235/3813 Refractory metal borides
• CPC Class Codes: C04B 2235/3821 Boron carbides
• CPC Class Codes: C04B 2235/3826 Silicon carbides
• CPC Class Codes: C04B 2235/383 Alpha silicon carbide
• CPC Class Codes: C04B 2235/3834 Beta silicon carbide
• CPC Class Codes: C04B 2235/3865 Aluminium nitrides
• CPC Class Codes: C04B 2235/524 Non-oxidic, e.g. borides, carbides, silicides or nitrides
• CPC Class Codes: C04B 2235/5244 Silicon carbide
• CPC Class Codes: C04B 2235/526 characterised by the length of the fibers
• CPC Class Codes: C04B 2235/5264 characterised by the diameter of the fibers
• CPC Class Codes: C04B 2235/5409 expressed by specific surface values
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/6021 Extrusion moulding
• CPC Class Codes: C04B 2235/604 Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/6562 Heating rate
• CPC Class Codes: C04B 2235/6567 Treatment time
• CPC Class Codes: C04B 2235/77 : Density
• CPC Class Codes: C04B 35/117 : Composites
• CPC Class Codes: C04B 35/62272 : based on non-oxide ceramics carbon nanotubes C01B32/15; carbon fibers D01F9/12
• CPC Class Codes: C04B 35/62277 : Fibres based on carbides
• CPC Class Codes: C04B 35/62281 : based on silicon carbide C04B35/571 takes precedence
• CPC Class Codes: C04B 35/62286 : Fibres based on nitrides
• CPC Class Codes: C04B 35/62635 : Mixing details
• CPC Class Codes: C04B 35/6264 : Mixing media, e.g. organic solvents
• CPC Class Codes: C04B 35/632 : Organic additives
• CPC Class Codes: C04B 35/63408 : Polyalkenes
• CPC Class Codes: C04B 35/6342 : Polyvinylacetals, e.g. polyvinylbutyral [PVB]
• CPC Class Codes: C04B 35/63476 : Phenol-formaldehyde condensation polymers
• CPC Class Codes: C04B 35/63488 : Polyethers, e.g. alkylphenol polyglycolether, polyethylene glycol [PEG], polyethylene oxide [PEO]
• CPC Class Codes: C04B 35/645 : Pressure sintering
• CPC Class Codes: C04B 35/80 : Fibres, filaments, whiskers, platelets, or the like
• CPC Class Codes: Y10S 264/19 : Inorganic fiber

Abstract

A high temperature, preferably polycrystalline, ceramic fiber having a selectable diameter of between 1 and 200 microns. The fiber is stable in an inert atmosphere at a temperature above about 1700° C. and is often stable even in air at a temperature above 1500° C. The fiber comprises a sintered ceramic powder having a maximum particle size less than the diameter of the fiber and an average particle size less than 0.2 times the diameter of the fiber. The ceramic powder is also stable in an inert atmosphere at a temperature above about 1700° C. At least 90% of the ceramic is selected from borides, nitrides, carbides, and silicides. The fiber is characterized by a smooth surface and is preferably out of round.

The invention further comprises a textilable sinterable filament, comprising a flexible polymer matrix containing high temperature sinterable ceramic powder particles. The ceramic powder particles are selected from ceramic borides, nitrides, carbides, and silicides. The diameter of the filament is from 2 to 300 microns. The invention also comprises the method for making textilable filament by fiberizing a mixture of a polymer and a sinterable non-oxide fiber and the method wherein the high temperature ceramic fiber is prepared by sintering the textilable sinterable filament as previously described. The invention also includes composites containing such filaments.

Claims

1. A high temperature polycrystalline ceramic fiber consisting essentially of non-oxide ceramic materials, said fiber having a diameter of between 1 and 200 microns, said fiber being stable in an inert atmosphere at a temperature above about 1700°

C., said fiber comprised of a sintered ceramic powder having a maximum particle size less than the diameter of the fiber, said ceramic powder also being stable in an inert atmosphere at a temperature above about 1700°

C., at least 90% of said ceramic material in said fiber consisting of non-oxide borides, nitrides, carbides and silicides of aluminum, boron, chromium, hafnium, molybdenum, niobium, silicon, tantalum, titanium, tungsten, vanadium and zirconium, said fiber having a smooth surface, said fiber having a roundness of greater than 1.15.

2. The fiber of claim 1 wherein the fiber has a cross sectional average aspect ratio of at least 1.3:

1.

3. The fiber of claim 1 wherein the fiber has a roundness of greater than 1.5.

4. The ceramic fiber of claim 1 wherein the ceramic powder is selected from ceramic powders of the group consisting of B₄ C, HfC, NbC, SiC, TaC, VC, WC, ZrC, CrB₂, HfB₂, NbB₂, TaB₂, TiB₂, VB, WB, ZrB₂, AlN, HfN, NbN, Si₃ N₄, TaN, TiN, VN, ZrN, Mo₅ Si₃, MoSi₂ and ZrSi and mixtures thereof.

5. The ceramic fiber of claim 1 wherein the ceramic powder is titanium diboride, silicon carbide, boron carbide or mixtures thereof.

6. The ceramic fiber of claim 2 wherein the ceramic powder is titanium diboride, silicon carbide, boron carbide or mixtures thereof.

7. The ceramic fiber of claim 1 wherein the ceramic powder is silicon carbide powder.

8. The ceramic fiber of claim 6 wherein the ceramic powder is silicon carbide powder.

9. The high temperature ceramic fiber of claim 1 wherein the ceramic powder is stable in an inert atmosphere at a temperature above 2000°

C.

10. The ceramic fiber of claim 1 wherein the fiber has a tensile strength in excess of about 100,000 psi (689 MPa).

11. The ceramic fiber of claim 1 wherein the ceramic fiber has a tensile strength in excess of about 175,000 psi (1,200 MPa).

12. The ceramic fiber of claim 1 wherein the fiber diameter is between 10 and 150 microns.

13. The ceramic fiber of claim 7 wherein the fiber diameter is between 10 and 150 microns.

14. The fiber of claim 1 wherein the fiber has a modulus of elasticity in excess of 25 million psi (172 GPa).

15. The fiber of claim 1 wherein the fiber has a modulus of elasticity in excess of 50 million psi (345 GPa).

16. The fiber of claim 7 wherein the fiber has a modulus of elasticity in excess of 25 million psi (172 GPa).

17. The fiber of claim 7 wherein the fiber has a modulus of elasticity in excess of 50 million psi (345 GPa).

18. A structural material reinforced with the fiber of claim 1 wherein the structural material is a metal, ceramic, glass, glass ceramic or polymer.

19. A ceramic product reinforced with the fiber of claim 1.

20. A ceramic product reinforced with the fiber of claim 2.

21. A structural material reinforced with the fiber of claim 5 wherein the structural material is a metal, ceramic, glass, glass ceramic or polymer.

22. A ceramic product reinforced with the fiber of claim 5.

23. A structural material reinforced with the fiber of claim 7 wherein the structural material is a metal, ceramic, glass, glass ceramic or polymer.

24. A ceramic product reinforced with the fiber of claim 7.

25. A ceramic product reinforced with the fiber of claim 14.

26. A ceramic product reinforced with the fiber of claim 15.

27. A ceramic product reinforced with the fiber of claim 17.

28. The fiber of claim 1 wherein the ceramic powder has an average particle size less than 1 micron.

29. The ceramic fiber of claim 2 wherein the powder has an average particle size of less than 1 micron.

30. The ceramic fiber of claim 7 wherein the silicon carbide powder has an average particle size of less than 1 micron.