Sialon cutting tool composition
AssigneeKennametal Inc.
InventorPankaj K. Mehrotra
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Abstract
A sialon ceramic material comprising a ceramic core selected from alpha-prime-sialon, beta-prime-sialon, and an intergranular phase and, optionally substantially substantially inert refractory phases. The sialon ceramic material has an alloyed surface layer with a substantially increased aluminum and oxygen content.
Claims52
A sialon ceramic material comprising a ceramic core containing beta-prime-sialon phase, and an intergranular phase and, said sialon ceramic material having a beta-prime-sialon alloyed surface layer phase comprising an alloy of the beta prime sialon phase in said ceramic core with a substantially increased aluminum and oxygen content compared to the beta-prime-sialon in said ceramic core and wherein said alloyed surface layer has a thickness of 2 to 10 microns and bonded directly on said alloyed surface layer is a coating of alumina.
A method of alloying the surface of sialon material to increase the Z value of the beta-prime-sialons near the surface comprising the steps of:
- (a) preparing a sialon core composition,
- (b) applying a coating of alumina to the surface of the core composition in a thickness of about 1 to 10 microns by chemical vapor deposition, and
- (c) heat treating the coated composition at temperatures up to 1750 degrees Centigrade and for times until at least a portion of the oxygen and aluminum of the alumina coating diffuses into the surface of the core composition.
A cutting tool insert comprising a ceramic core consisting essentially of alpha-prime-sialon, beta-prime-sialon, an intergranular phase, and said ceramic core having an alloyed surface layer having beta-prime-sialon with a substantially increased aluminum and oxygen content and alpha-prime-sialon, wherein said alloyed surface layer has a thickness of 2 to 10 microns, and bonded over and directly to said alloyed surface layer is a coating of alumina.
A cutting tool insert comprising a ceramic core consisting essentially of beta-prime-sialon, an intergranular phase and, said sialon ceramic material having an alloyed surface layer having a composition similar to the said ceramic core but with a substantially increased aluminum and oxygen content, wherein said alloyed surface layer has a thickness of 2 to 10 microns, and bonded over and directly to said alloyed surface layer is a coating of alumina.
A sialon ceramic material comprising a ceramic core containing beta-prime-sialon phase, and an intergranular phase and, said sialon ceramic material having a beta-prime-sialon alloyed surface layer phase comprising an alloy of the beta prime sialon phase in said ceramic core with a substantially increased aluminum and oxygen content compared to the beta-prime-sialon in said ceramic core.
A cutting tool insert comprising a ceramic core consisting essentially of alpha-prime-sialon, beta-prime-sialon, an intergranular phase, and said ceramic core having an alloyed surface layer having beta-prime-sialon with a substantially increased aluminum and oxygen content and alpha-prime-sialon.
A cutting tool insert comprising a ceramic core consisting essentially of beta-prime-sialon, an intergranular phase and, said sialon ceramic material having an alloyed surface layer having a composition similar to the said ceramic core but with a substantially increased aluminum and oxygen content.
Dependencies are inferred from the claim text.