Patent ID: 7348051
Filing Date: 2008-03-25
Classification: C23C,Y10T

Abstract:
1. A surface-coated cermet cutting tool, comprising: a hard coating layer coated on a surface of a tool substrate made of tungsten-carbide-based cemented carbide or titanium-carbonitride-based cermet, the hard-coating layer including a lower layer and an upper layer: the lower layer containing titanium compound layers having at least two of a titanium carbide layer, a titanium nitride layer, a titanium carbonitride layer, a titanium carbooxide layer and a titanium oxycarbonitride layer, the titanium compound layers having a total average layer thickness of 3 to 20 μm; and the upper layer containing an aluminum oxide layer having an average layer thickness of 1 to 15 μm, wherein one layer of the titanium compound layers in the lower layer comprises a titanium carbonitride layer which has an average layer thickness of 2.5 to 15 μm, and the one layer has properties indicated by a tilt-angle frequency distribution graph in which the highest peak exists in a tilt angle section ranging 0 to 10° and the total sum of frequencies existing in the range of 0 to 10° occupies a ratio of 45% or more of the total frequencies in the tilt-angle frequency distribution graph, the tilt-angle frequency distribution graph being obtained by utilizing a field-emission scanning electron microscope, irradiating electron beams to individual crystal particles with a cubic crystal lattice existing in a measurement range of a polished plane, measuring a tilt angle formed by the normal line of the polished plane and the normal line of {112} plane as a crystal plane of the crystal particles, sectioning the measured tilt angles belonging to a range of 0 to 45° every pitch of 0.25°, and collecting the frequencies existing in each section.