Coated hardmetal body

Claim 2

A coated hardmetal body, comprising a hardmetal core and at least one binder metal free hard substance layer, wherein the hardmetal core comprises cobalt and tungsten carbide and the binder metal free hard substance layer consists of one or more hard oxides, a mixture of one or more hard oxides and one or more hard nitrides, or mixed crystals of one or more hard oxides and one or more hard nitrides; characterized in that the hardmetal core has a zone at its surface which is 0.2 to 20 microns thick and consists essentially of, in addition to the components of the hardmetal core, a CoWB phase, which CoWB phase is present as particles of CoWB embedded in the surface zone of the hardmetal core, wherein the binder metal free hard substance layer contacts the components of the hardmetal core including cobalt and tungsten carbide and particles of the CoWB phase at the surface of the hardmetal core.

Claim 3

The coated hardmetal body as defined in claim 1, wherein the hard substance layer has a thickness of 0.2 to 20 microns and consists of one or more hard substances selected from the group consisting of aluminum oxide, zirconium oxide and aluminum oxynitride, wherein the nitrogen content of the aluminum oxynitride is from 0.1 to 10 atomic percent.

Claim 4

The coated hardmetal body as defined in claim 1, wherein at least one additional binder metal free hard substance layer of one or more hard substances selected from the group consisting of carbides, nitrides, borides and oxides of one or more elements selected from the group consisting of aluminum, silicon, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten and yttrium, is applied to the binder metal free hard substance layer, and wherein the thickness of the hard substance layers combined is from 0.5 to 30 microns.

Claim 5

The coated hardmetal body as defined in claim 1 comprising a cutting bit for machining metallic materials.

Claim 6

The coated hardmetal body as defined in claim 2 comprising a cutting bit for machining metallic materials.

Claim 7

The coated hardmetal body as defined in claim 3 comprising a cutting bit for machining metallic materials.

Claim 8

A coated hardmetal body, comprising a hardmetal core and at least one binder-metal-free hard substance layer, wherein the hardmetal core comprises cobalt and tungsten carbide and the binder-metal-free hard substance layer consists of one or more hard oxides, a mixture of one or more hard oxides and one or more hard nitrides, or mixed crystals of one or more hard oxides and one or more hard nitrides; characterized in that the hardmetal core has a zone at its surface which is 0.2 to 20 microns thick and consists essentially of, in addition to the components of the hardmetal core, a CoWB phase, which CoWB phase is present as particles of CoWB embedded in the surface zone of the hardmetal core, wherein the binder metal free hard substance layer contacts the components of the hardmetal core including cobalt and tungsten carbide and particles of the CoWB phase at the surface of the hardmetal core, and wherein the coated hardmetal body is produced by a process comprising: treating the hardmetal core with a gas mixture of boron trichloride and hydrogen for from 3 to 60 minutes, at a temperature ranging from 800° to 1200° C., and at a pressure ranging from 5,000 to 100,000 Pascal to form the CoWB phase, wherein the partial pressure of the boron trichloride ranges from 1 to 10% of the total pressure; and precipitating thereafter at least one binder-metal-free hard substance layer from a vapor phase.

Claim 9

A coated hardmetal body, comprising a hardmetal core and at least one binder-metal-free hard substance layer, wherein the hardmetal core comprises cobalt and tungsten carbide and the binder-metal-free hard substance layer consists of one or more hard oxides, a mixture of one or more hard oxides and one or more hard nitrides, or mixed crystals of one or more hard oxides and one or more hard nitrides; characterized in that the hardmetal core has a zone at its surface which is 0.2 to 20 microns thick and consists essentially of, in addition to the components of the hardmetal core, a CoWB phase, which CoWB phase is present as particles of CoWB embedded in the surface zone of the hardmetal core, wherein the binder metal free hard substance layer contacts the components of the hardmetal core including cobalt and tungsten carbide and particles of the CoWB phase at the surface of the hardmetal core, and wherein the coated hardmetal body is produced by a process comprising: treating the hardmetal core with a gas mixture of boron trichloride and hydrogen for from 3 to 60 minutes, at a temperature ranging from 800° to 1200° C., and at a pressure ranging from 5,000 to 100,000 Pascal to form the CoWB phase, wherein the partial pressure of the boron trichloride ranges from 1 to 10% of the total pressure; and precipitating thereafter at least one binder-metal-free hard substance layer from a vapor phase.

Claim 10

The coated hardmetal body according to claim 7, wherein the hardmetal core is treated with the gas mixture of boron trichloride and hydrogen at a temperature ranging from 950° C. to 1050° C.

Claim 11

The coated hardmetal body according to claim 7, wherein the zone containing the CoWB phase has a thickness ranging from 0.2 to 20 microns.

Claim 12

The coated hardmetal body according to claim 7, wherein a single layer of hard substances is precipitated which has a thickness ranging from 0.2 to 20 microns.

Claim 13

The coated hardmetal body according to claim 7, wherein each said at least one binder-metal-free hard substance layer consists of one or more hard substance selected from the group consisting of hard carbides, nitrides, borides and oxides of one or more elements selected from the group consisting of aluminum, silicon, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten and yttrium.

Claim 14

The coated hardmetal body according to claim 11, wherein the total thickness of all hard substance layers ranges from 0.5 to 30 microns.

Claim 15

A process for producing a coated hardmetal body comprising a hardmetal core comprised of cobalt and tungsten carbide and having a CoWB phase in the surface zone thereof coated with at least one binder metal free hard substance layer, comprising; treating the hard metal core with a gas mixture of boron trichloride and hydrogen for 3 to 60 minutes at a temperature of from 800° to 1200° C., and at a pressure from 5,000 to 100,000 Pascal to form a CoWB containing zone at the surface of the hardmetal core; wherein the partial pressure of the boron trichloride is 1 to 10% of the total pressure, and thereafter precipitating at least one binder metal free hard substance layer from a vapor phase.

Claim 16

A process for producing a coated hardmetal body comprising a hardmetal core comprised of cobalt and tungsten carbide and having a CoWB phase in the surface zone thereof coated with at least one binder metal free hard substance layer, comprising; treating the hard metal core with a gas mixture of boron trichloride and hydrogen for 3 to 60 minutes at a temperature of from 800° to 1200° C., and at a pressure from 5,000 to 100,000 Pascal to form a CoWB containing zone at the surface of the hardmetal core; wherein the partial pressure of the boron trichloride is 1 to 10% of the total pressure, and thereafter precipitating at least one binder metal free hard substance layer from a vapor phase.

Claim 17

The process of claim 13, wherein the hardmetal core is treated with the gas mixture of boron trichloride and hydrogen at a temperature of from 950° C. to 1050° C.

Claim 18

The process of claim 13, wherein the CoWB containing zone has a thickness of from 0.2 to 20 microns.

Claim 19

The process of claim 13, wherein the binder metal free hard substance layer consists of one or more hard substances selected from the group consisting of hard oxides, a mixture of hard oxides and hard nitrides, and mixed crystals of hard oxides and hard nitrides.

Claim 20

The process of claim 16, wherein a single layer of hard substances is precipitated which has a thickness of from 0.2 to 20 microns.

Claim 21

The process of claim 16, wherein one or more additional binder metal free hard substance layers is precipitated onto the coated hardmetal core, said layer consisting of one or more hard substances selected from the group consisting of hard carbides, nitrides, borides and oxides of one or more elements selected from the group consisting of aluminum, silicon, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten and yttrium.

Claim 22

The process of claim 18, wherein the thickness of all hard substance layers is from 0.5 to 30 microns.