High toughness ceramic cutting tool

Claim 2

A high toughness ceramic composition consisting essentially of a dense, homogeneous sintered body consisting essentially of, on a volume percent basis, about 4 to about 20% zirconia, about 60 to about 90% alumina, and about 3 to about 30% of a refractory metal compound selected from the group consisting of: the carbides, nitrides and carbo-nitrides of the Group IVB and VB metals of the periodic table; the carbides of the Group VIB metals of the periodic table; and mixtures of any of the foregoing refractory metal compounds, said composition further characterized in containing less than 1% total of the iron group metals and mixtures thereof.

Claim 3

The composition as defined in claim 1 containing about 5 to about 14% zirconia.

Claim 4

The composition as defined in claim 1 containing about 8 to about 12% zirconia.

Claim 5

The composition as defined in claim 1 in which said refractory metal compound is present in an amount of about 4 to about 20%.

Claim 6

The composition as defined in claim 1 in which said refractory metal compound is present in an amount of about 5 to about 15%.

Claim 7

The composition as defined in claim 1 in which said refractory metal compound is present in an amount of about 6 to about 10%.

Claim 8

The composition as defined in claim 1 in which said iron group metals are present in an amount less than about 0.5%.

Claim 9

The composition as defined in claim 1 in which said iron group metals are present in an amount less than about 0.25%.

Claim 10

The composition as defined in claim 1 in which said refractory metal compound is chosen from the group consisting of titanium carbide, titanium nitride, tungsten carbide, a 60:40 mixture of hafnium carbide: niobium carbide and mixtures thereof.

Claim 11

The composition as defined in claim 1 containing about 78-86% alumina, about 8-12% zirconia and about 6-10% titanium carbide.

Claim 12

A high toughness ceramic cutting tool consisting essentially of a dense, homogeneous body of a composition consisting essentially of, on a volume percent basis, about 4 to about 20% zirconia, about 60 to about 90% alumina, and about 3 to about 30% of a refractory metal compound selected from the group consisting of: the carbides, nitrides and carbonitrides of the Group IVB and VB metals of the periodic table; the carbides of the Group VIB metals of the periodic table; and mixtures of any of the foregoing refractory metal compounds, said composition further characterized in containing less than 1% total of the iron group metals and mixtures thereof.

Claim 13

A high toughness ceramic cutting tool consisting essentially of a dense, homogeneous body of a composition consisting essentially of, on a volume percent basis, about 4 to about 20% zirconia, about 60 to about 90% alumina, and about 3 to about 30% of a refractory metal compound selected from the group consisting of: the carbides, nitrides and carbonitrides of the Group IVB and VB metals of the periodic table; the carbides of the Group VIB metals of the periodic table; and mixtures of any of the foregoing refractory metal compounds, said composition further characterized in containing less than 1% total of the iron group metals and mixtures thereof.

Claim 14

The cutting tool as defined in claim 11 wherein said composition consists essentially of about 5 to about 14% zirconia and from about 86 to 90% alumina.

Claim 15

The cutting tool as defined in claim 11 wherein said composition contains about 8 to about 12% zirconia.

Claim 16

The cutting tool as defined in claim 11 wherein said refractory metal compound is present in an amount of about 4 to about 20%.

Claim 17

The cutting tool as defined in claim 11 wherein said refractory metal compound is present in an amount of about 5 to about 15%.

Claim 18

The cutting tool as defined in claim 11 wherein said refractory metal compound is present in an amount of about 6 to about 10%.

Claim 19

The cutting tool as defined in claim 11 wherein said iron group metals are present in an amount less than about 0.5%.

Claim 20

The cutting tool as defined in claim 11 wherein said iron group metals are present in an amount less than about 0.25%.

Claim 21

The cutting tool as defined in claim 11 in which said refractory metal compound is chosen from the group consisting of titanium carbide, titanium nitride, tungsten carbide, a 60:40 mixture of hafnium carbide:niobium carbide and mixtures thereof.

Claim 22

The cutting tool as defined in claim 11 consisting essentially of 88-90% alumina and about 8-12% zirconia.

Claim 23

The cutting tool as defined in claim 11 consisting essentially of from about 78 to 86% alumina, from about 8 to 12% zirconia and from about 6 to 10% of said refractory metal compound.

Claim 24

The cutting tool of claim 21 wherein said refractory metal compound is chosen from the group consisting of titanium carbide, titanium nitride, tungsten carbide and a 60:40 mixture of hafnium carbide:niobium carbide and mixtures of the foregoing.

Claim 25

The cutting tool as defined in claim 11 consisting essentially of from about 4 to about 20% zirconia and from about 80% to 90% alumina.