Compositions: ceramic – Ceramic compositions – Refractory
Reexamination Certificate
2000-08-25
2002-10-01
Elve, M. Alexandra (Department: 1725)
Compositions: ceramic
Ceramic compositions
Refractory
C501S095200, C501S127000, C264S279000
Reexamination Certificate
active
06458733
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to refractory products and more particularly it relates to an improved reinforced refractory having improved resistance to cracking at elevated temperatures.
Reinforcement such as fiber reinforcement has been used to improve the strength of refractory products. This concept is disclosed in U.S. Pat. No. 4,366,255. This patent discloses the use of stainless steel and carbon steel fibers. However, stainless steel fiber and carbon steel fibers have the problem that they initiate cracks in the refractory, particularly in elevated temperature applications. This exposes the metal fibers and results in further cracking of the refractory body. If, for example, the refractory body is in contact with molten aluminum, the exposed steel fibers are dissolved resulting in catastrophic failure of the refractory body. Varying the amount of metal fibers or employing different release agents still resulted in cracking of the refractory body.
Thus, it will be seen that there is a great need for a reinforced refractory which is not subject to cracking, particularly at elevated temperatures. The subject invention provides such an improved body.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an improved refractory body.
It is another object of this invention to provide an improved metal reinforced refractory body highly resistant to cracking at elevated temperatures.
It is a further object of this invention to provide an improved metal reinforced refractory body wherein the body is reinforced with metal fibers comprised of nickel based alloys.
It is a further object of the invention to provide an improved refractory body reinforced with a metal material having a coefficient of thermal expansion of less than 10×10
−6
in/in/° F. and preferably less than 5×10
−6
in/in/° F.
And yet it is a further object of the invention to provide a metal reinforced refractory body wherein the refractory is controlled to have a coefficient of thermal expansion of less than 10×10
−6
in/in/° F. and preferably 5×10
−6
in/in/° F.
These and other objects will become apparent from a reading of the specification and claims appended hereto.
In accordance with these objects, there is provided a method for preparing a metal reinforced refractory body comprising the steps of providing a mold for containing a slurry of refractory material. A body of metal fibers is inserted into the mold, the metal fibers having a coefficient of thermal expansion of less than 10×10
−6
in/in/° F. The slurry of refractory material is introduced to the mold to provide the slurry in intimate contact with the metal fibers, the refractory material in the hardened condition having a coefficient of thermal expansion of less than 10×10
−6
in/in/° F. The refractory material is hardened to provide a metal reinforced composite refractory body comprised of a reinforcing component and a refractory component having a coefficient of thermal expansion of less than 10×10
−6
in/in/° F. to minimize cracking of the refractory body.
This method provides a metal reinforced refractory body comprised of a metal component having a coefficient of thermal expansion of less than 10×10
−6
in/in/° F. and a refractory component having a coefficient of thermal expansion of less than 10×10
−6
in/in/° F., the body being highly resistant to cracking at elevated temperatures.
REFERENCES:
patent: 4366255 (1982-12-01), Lankard
patent: 4764488 (1988-08-01), Saito et al.
patent: 5290737 (1994-03-01), Andersson et al.
patent: 5308572 (1994-05-01), Hackman
patent: 5459114 (1995-10-01), Kaya et al.
patent: 5571628 (1996-11-01), Hackman
patent: 6210786 (2001-04-01), Atmur et al.
patent: 2805808 (2001-09-01), None
patent: 2173185 (1986-10-01), None
patent: 63288161 (1988-11-01), None
patent: WO 01/53068 (2001-07-01), None
Alexander Andrew
Cooke Colleen P.
Elve M. Alexandra
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