Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
192 words
A surface-coated cemented carbide article wherein the cemented carbon substrate initially containing free carbon in an amount of 0.01 to 0.50% by weight up to a depth of at least 50 microns from the surface and having at least one layer coated thereupon, which coating layer consists of at least one material selected from the group consisting of oxides, carbides, nitrides, carbonitrides and mixtures or compounds thereof, wherein the most interior coated layer, closest to the surface of the cemented carbide substrate, consists of at least one material selected from carbides and carbonitrides of Group IVa, Va and VIa elements, said article having being free of a decarburized layer called an η phase located between the cemented carbide substrate and the most interior coating layer or containing such η phase having a thickness of at most 0.5 micron in the case where the curvature of the interface is zero and the lattice constant of binder metal in the cemented carbide, as a mean value of from the interface to 50 microns, is not more than that of the iron group metal solid solution in the cemented carbide by at least 0.005 A.
Claim 2
Dependent Claim
192 words
A surface-coated cemented carbide article wherein the cemented carbon substrate initially containing free carbon in an amount of 0.01 to 0.50% by weight up to a depth of at least 50 microns from the surface and having at least one layer coated thereupon, which coating layer consists of at least one material selected from the group consisting of oxides, carbides, nitrides, carbonitrides and mixtures or compounds thereof, wherein the most interior coated layer, closest to the surface of the cemented carbide substrate, consists of at least one material selected from carbides and carbonitrides of Group IVa, Va and VIa elements, said article having being free of a decarburized layer called an η phase located between the cemented carbide substrate and the most interior coating layer or containing such η phase having a thickness of at most 0.5 micron in the case where the curvature of the interface is zero and the lattice constant of binder metal in the cemented carbide, as a mean value of from the interface to 50 microns, is not more than that of the iron group metal solid solution in the cemented carbide by at least 0.005 A.
Claim 3
Dependent Claim
24 words
The surface-coated cemented carbide article as claimed in claim 1, wherein the cemented carbide substrate contains 0.05 to 0.35% by weight of free carbon.
Claim 4
Dependent Claim
42 words
The surface-coated cemented carbide article as claimed in claim 1, wherein the binder metal is cobalt and wherein the X-ray lattice constant of the cobalt phase as a binder phase up to a depth of 100 microns is at most 3.550 A.
Claim 5
Dependent Claim
23 words
The surface-coated cemented carbide article as claimed in claim 1, wherein at least one intermediate layer is sandwiched in between the coating layers.
Claim 6
Dependent Claim
24 words
The surface-coated cemented carbide article as claimed in claim 1, wherein at least one layer consists of oxides of Group III to VI elements.
Claim 7
Dependent Claim
77 words
A process for producing the coated cemented carbide article of claim 1, which comprises coating a cemented carbide substrate with at least one layer of a material selected from the group consisting of oxides, carbides, nitrides carbonitrides and mixtures of compounds thereof by chemical vapor deposition, characterized in that the cemented carbide substrate contains free carbon in amounts of 0.01 to 0.50% by weight and up to a depth of at least 50 microns from the surface.
Claim 8
Dependent Claim
42 words
A process for the production of the surface-coated cemented carbide article as claimed in claim 6, characterized by subjecting the surface-coated cemented carbide article after coating to a diffusion treatment of carbon at 950° to 1100° C. for 0.5 to 10 hours.