Compositions: ceramic – Ceramic compositions – Carbide or oxycarbide containing
Reexamination Certificate
2006-02-07
2006-02-07
Group, Karl (Department: 1755)
Compositions: ceramic
Ceramic compositions
Carbide or oxycarbide containing
C501S089000, C501S091000, C501S092000, C089S036020, C109S049500
Reexamination Certificate
active
06995103
ABSTRACT:
A silicon-containing composite body that would otherwise be brittle can be engineered to exhibit enhanced fracture toughness. Specifically, a silicon-ceramic composite body is produced, preferably by a reactive infiltration technique. The ceramic is selected such that it has a higher coefficient of thermal expansion (CTE) than does the silicon phase. At least at some point during processing, the silicon phase is at a temperature above its normal ductile/brittle transition temperature of about 500° C., and preferably above its melting point. The formed composite body containing the silicon phase is then cooled below its ductile/brittle transition. During cooling, the ceramic phase shrinks more than does the silicon phase, thereby placing the latter in a state of compressive stress. By the time the composite body has cooled to substantially ambient temperature, the induced compressive stress in the silicon phase is sufficient as to impart a measurable degree of semi-ductile character to the silicon phase. This pseudo-ductility manifests itself in the composite body as a significant increase in the fracture toughness of the body. For example, when the ceramic reinforcement was boron carbide particulate instead of silicon carbide (which has a CTE similar to that of silicon), fracture toughness increased by almost 30 percent.
REFERENCES:
patent: 3205043 (1965-09-01), Taylor
patent: 3275722 (1966-09-01), Popper
patent: 3495939 (1970-02-01), Forrest
patent: 3725015 (1973-04-01), Weaver
patent: 3796564 (1974-03-01), Taylor et al.
patent: 3857744 (1974-12-01), Moss
patent: 3859399 (1975-01-01), Bailey et al.
patent: 4944904 (1990-07-01), Singh et al.
patent: 5436208 (1995-07-01), Johnson
patent: 5840221 (1998-11-01), Lau et al.
patent: 5962103 (1999-10-01), Luthra et al.
patent: 6347446 (2002-02-01), Luthra et al.
patent: 6398991 (2002-06-01), Brazil et al.
patent: 6609452 (2003-08-01), McCormick et al.
patent: 2004/0065868 (2004-04-01), Aghajanian et al.
patent: 0 798 281 (1997-10-01), None
patent: WO 00 62007 (2000-10-01), None
M.T. Lin and Marvin L. Cohen, “Microscopic Theory of the Phase Transformation and Lattice Dynamics of Si”,Phys. Rev. Letters, (45) 12, Sep. 22, 1980, pp. 1004-1007.
T.K. Gupta and C.A. Andersson, “Transformation-Toughened Bulk Tetragonal Zirconia: I, Overview of Development and Properties”,Cer. Engr.&Sci. Proc., (7) 9-10, Sep.-Oct. 1986, pp. 1150-1157.
C.A. Andersson and T.K. Gupta, “Transformation-Toughened Bulk Tetragonal Zirconia: II, Mechanical Properties Dependence on Composition, Grain Size, and Temperature”,Cer. Engr.&Sci. Proc., (7) 9-10, Sep.-Oct. 1986, pp. 1158-1168.
J. Samuels, S.G. Roberts, and P.B. Hirsch, “The Brittle-to-Ductile Transition in Silicon,”Materials Science and Engineering, A105/106 39-46 (1988).
P.D. Warren, “The Brittle-Ductile Transition in Silicon: The Influence of Pre-Existing Dislocation Arrangements,”Scripta Met., 23 637-42 (1989).
K. Sumino, “Dislocations and Mechanical Properties of Silicon,”Materials Science and Engineering, B4 335-41 (1989).
“Reaction-Bonded Silicon Carbide”,Ceramics and Glasses Handbook, American Society for Materials, p. 293, 1990.
P. Haasen, “Brittle-to-Ductile Transition in Silicon as a Model for Intermetallics”,Materials Science and Engineering, A137 105-10 (1991).
Stewart J. Clark, “Pressure Effects in Semiconductors”, (a portion of his thesis posted to the Internet at http://cmt.dur.ac.uk/sjc/thesis/thesis
ode4.html on Oct. 31, 1996.).
“Crystal Lattice Structures: The Beta-Tin (A5) Structure”, posted on the Internet at http://cst-www.nrl.navy.mil/lattice/struk/a5.html. Reference date: Jul. 1, 1997.
Murli H. Manghnani, Yuchang Wang, Fengying Li, Pavel Zinin and William Rafaniello, “Elastic and Vibrational Properties of B4C to 21 GPa,”Science and Technology of High Pressure, Proceedings of AIRAPT-17, M.H. Manghnani, W.J. Nellis and M.F. Nicol, eds., Universities Press, Hyderabad, India, pp. 945-948 (2000).
Vladislav Domnich, Yury Gogotsi and Michael Trenary, “Identification of Pressure-Induced Phase Transformations Using Nanoindentation,”Mat. Res. Soc. Symp. 649 Q8.9.1-Q8.9.6 (2001).
Vladislav Domnich, Yury Gogatsi, Michael Trenary and Takaho Tanaka, “Nanoindentation and Raman spectroscopy studies of boron carbide single crystals,”Appl. Phys. Letters, 81 Nov. 11, 2002.
In Sub Han, Kee Sung Lee, Doo Won Seo, and Sang Kuk Woo, “Improvement of mechanical properties in RBSC by boron carbide addition”,J. Mat. Sci. Letters, Chapman and Hall Ltd., London, GR, vol. 21, No. 9, May 1, 2002, pp. 703-706.
Group Karl
M Cubed Technologies, Inc.
Ramberg Jeffrey R.
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