Michael D Sacks

US Patent:

61877050, Feb 13, 2001

Filed:

Nov 23, 1999

Appl. No.:

9/447609

Inventors:

Michael D. Sacks - Gainesville FL

International Classification:

C04B 35565

US Classification:

501 951

Abstract:

A high strength, high creep resistant, boron-doped, silicon carbon fiber having no boron nitride coating, originally formed by sintering, is produced by exposing the fiber to a nitrogen atmosphere at a temperature equal to or preferably elevated above the sintering temperature and also exposing the fiber to a carbon monoxide-containing atmosphere at a temperature sufficient to remove boron and boron nitride. The nitrogen atmosphere step may be performed before or after the carbon monoxide-containing atmosphere step. The resulting, uncoated SiC fibers have tensile strengths greater than approximately 2. 0 GPa and Morscher-DiCarlo BSR test creep resistance M values greater than approximately 0. 75 at 1400 degrees C for one hour in argon. The method is applicable to non-sintered fibers as well, in which case the nitrogen exposure is carried out at between approximately 1750 to 2250 degrees C and the carbon monoxide exposure is carried out at between approximately 1600 to 2200 degrees C.

US Patent:

60228202, Feb 8, 2000

Filed:

May 21, 1998

Appl. No.:

9/082945

Inventors:

Michael D. Sacks - Gainesville FL

Assignee:

University of Florida - Gainesville FL

International Classification:

C04B 35565
C04B 3552

US Classification:

501 951

Abstract:

Silicon carbide (SiC) fibers, or SiC bodies such as coatings, thin films, substrates or bulk objects, which have been sintered with boron containing additives to promote densification and pore removal, are further treated to remove a substantial amount of the residual boron from the SiC fibers. The SiC fibers, subsequent to the sintering steps and either before or after cooling, are exposed to a carbon monoxide (CO) containing atmosphere at elevated temperatures from approximately 1600-2200. degree. C. , but more preferably from approximately 1700-2000. degree. C. , with treatment times ranging from seconds to hours to days depending on the chosen treatment temperature. The resulting SiC fibers show a significant reduction of residual boron content, a reduction of greater than 90% in some cases, while retaining high tensile strength. Fibers with less than 0. 1 wt % residual boron have been obtained.

US Patent:

50098225, Apr 23, 1991

Filed:

Jul 17, 1989

Appl. No.:

7/380285

Inventors:

Michael D. Sacks - Gainesville FL

Assignee:

University of Florida - Gainesville FL

International Classification:

C04B 3334

US Classification:

264 23

Abstract:

A SiC whisker-reinforced ceramic article produced by subjecting the SiC whiskers to acid- and/or base-washing; subjecting ceramic particles and SiC whiskers to fluid classification; forming a suspension of the powdered ceramic and SiC whiskers; consolidating the suspension to form a green compact; optionally infiltrating the green compact with an aluminum compound which is a precursor to Al. sub. 2 O. sub. 3, and pressureless sintering the green compact to produce an SiC whisker-reinforced composite having high relative density at high SiC whisker loading.

US Patent:

60691026, May 30, 2000

Filed:

May 21, 1998

Appl. No.:

9/082868

Inventors:

Michael D. Sacks - Gainesville FL

Assignee:

University of Florida - Gainesville FL

International Classification:

C04B 35565

US Classification:

501 951

Abstract:

A high strength, high creep resistant, boron-doped, silicon carbon fiber having no boron nitride coating, originally formed by sintering, is produced by exposing the fiber to a nitrogen atmosphere at a temperature equal to or preferably elevated above the sintering temperature and also exposing the fiber to a carbon monoxide-containing atmosphere at a temperature sufficient to remove boron and boron nitride. The nitrogen atmosphere step may be performed before or after the carbon monoxide-containing atmosphere step. The resulting, uncoated SiC fibers have tensile strengths greater than approximately 2. 0 GPa and Morscher-DiCarlo BSR test creep resistance M values greater than approximately 0. 75 at 1400 degrees C. for one hour in argon.

US Patent:

62039040, Mar 20, 2001

Filed:

Nov 23, 1999

Appl. No.:

9/444615

Inventors:

Michael D. Sacks - Gainesville FL

International Classification:

B32B 900

US Classification:

428368

Abstract:

A process for forming a uniform, boron nitride coating on a boron-doped, refractory carbide body, and in particular on a sintered, boron-doped, silicon carbide fiber, where the body is exposed to a nitrogen-containing atmosphere at a temperature equal to or greater than the densification or sintering temperature. The coated fibers exhibit no loss in strength properties and show improved creep resistance.

US Patent:

60400080, Mar 21, 2000

Filed:

May 21, 1998

Appl. No.:

9/082869

Inventors:

Michael D. Sacks - Gainesville FL

Assignee:

University of Florida - Gainesville FL

International Classification:

B05D 302
B05D 304

US Classification:

427226

Abstract:

A process for forming a uniform, boron nitride coating on a boron-doped, refractory carbide body, and in particular on a sintered, boron-doped, silicon carbide fiber, where the body is exposed to a nitrogen-containing atmosphere at a temperature equal to or greater than the densification or sintering temperature. The coated fibers exhibit no loss in strength properties and show improved creep resistance.

US Patent:

57924163, Aug 11, 1998

Filed:

Jul 18, 1996

Appl. No.:

8/683475

Inventors:

Michael D. Sacks - Gainesville FL
William Toreki - Gainesville FL
Christopher D. Batich - Gainesville FL
Guang J. Choi - Seoul, KR

Assignee:

University of Florida - Gainesville FL

International Classification:

C04B 35565

US Classification:

264625

Abstract:

A method of preparing polymer derived silicon fibers comprising the steps of providing a spin dope solution comprising a silicon carbide forming organosilicon polymer, preferably polycarbosilane, a solvent, a soluble boron precursor, preferably solid boron hydride, and a nitrogen containing precursor, preferably polyvinylsilazane; spinning the solution to form high strength green fibers; and heat treating the green fibers to produce high strength, homogeneously doped, boron containing fibers. The fibers produced are high strength, homogeneously boron doped silicon carbide fibers with average tensile strength in the range of from about 2. 0 to 4. 0 GPa at room temperature.

US Patent:

58519424, Dec 22, 1998

Filed:

Aug 20, 1997

Appl. No.:

8/915181

Inventors:

Michael D. Sacks - Gainesville FL
William Toreki - Gainesville FL
Christopher D. Batich - Gainesville FL
Guang J. Choi - Seoul, KR

Assignee:

University of Florida - Gainesville FL

International Classification:

C04B 35565
C04B 3552

US Classification:

501 951

Abstract:

A method of preparing polymer derived silicon fibers comprising the steps of providing a spin dope solution comprising a silicon carbide forming organosilicon polymer, preferably polycarbosilane, a solvent, a soluble boron precursor, preferably solid boron hydride, and a nitrogen containing precursor, preferably polyvinylsilazane; spinning the solution to form high strength green fibers; and heat treating the green fibers to produce high strength, homogeneously doped, boron containing fibers. The fibers produced are high strength, homogeneously boron doped silicon carbide fibers with average tensile strength in the range of from about 2. 0 to 4. 0 GPa at room temperature.