| 摘要 |
The present invention relates to a coated cutting tool insert and a texture-hardened α-Al2O3 layer to be used in metal machining. The alumina layer is characterized by the improved toughness and it adheres to the substrate covering all functional parts thereof. The coating is composed of one or more refractory layers of which at least one layer is a texture-hardened α-Al2O3 having a thickness ranging from 2 to 20 μm being composed of columnar grains with a length/width ratio of 2 to 12. The α-Al2O3 exhibits a strong (0006) diffraction peak. The improved wear resistance and toughness can be obtained when the texture coefficient (TC) for the (0006) reflection is larger than 1.33 ln h+2, where h is the α-Al2O3 layer thickness and when the surface of the α-Al2O3 layer is wet-blasted to an Ra-value <1 μm. The alumina layer with a strong (0001) texture is applied on Binder phase enriched cemented carbide substrates. This combination contributes to enhanced wear resistance and toughness.
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