| 摘要 |
<p>The present invention relates to a coated cutting tool insert and a texture-hardened ±-Al 2 O 3 layer to be used in metal machining. The alumina layer is characterised 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 ±-Al 2 O 3 having a thickness ranging from 2 to 20 µm being composed of columnar grains with a length/width ratio of 2 to 12. The ±-Al 2 O 3 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 In h+2, where h is the ±-Al 2 O 3 layer thickness and when the surface of the ±-Al 2 O 3 layer is wet-blasted to an R a 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.</p> |
