Cutting tool
AssigneeKYOCERA Corporation
InventorTakashi Watanabe
Life of this patent
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Abstract
A cutting tool including a substrate composed of a silicon nitride-based sintered body and a coating layer. The coating layer includes first, second, third and fourth layers. The first layer is located on the surface of the substrate and is composed of TiN having an average crystalline width of 0.1 to 0.4 μm. The second layer is located on the first layer and composed of Al2O3 having an average crystalline width of 0.01 to 1.5 μm. The third layer is located on the second layer and is composed of TiN having an average crystalline width of 0.01 to 0.1 μm which is smaller than that of the first layer. The fourth layer is located on the third layer and is composed of Al2O3 having an average crystalline width of 0.01 to 1.5 μm.
Claims8
A cutting tool comprising:
- a substrate composed of a silicon nitride-based sintered body;
- and
- a coating layer, the coating layer comprising:
- a first layer directly disposed on the surface of the substrate, composed of TiN having a first average crystalline width of 0.1 to 0.4 μm;
- a second layer on the first layer, composed of Al2O3 having a second average crystalline width of 0.01 to 1.5 μm;
- a third layer on the second layer, composed of TiN having a third average crystalline width of 0.01 to 0.1 μm which is smaller than that of the first layer;
- and
- a fourth layer on the third layer, composed of Al2O3 having a fourth average crystalline width of 0.01 to 1.5 μm.
Dependencies are inferred from the claim text.