| 摘要 |
The present invention relates to a coated cutting tool insert comprising a substrate and a coating to be used in metal machining. The hard and wear resistant coating exhibits an excellent adhesion 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 alpha-Al<SUB>2</SUB>O<SUB>3 </SUB>showing a strong growth texture along <001>. The alpha-Al<SUB>2</SUB>O<SUB>3 </SUB>layer has a thickness ranging from 1 to 20 mum and is composed of columnar grains with a length/width ratio of 2 to 15. The layer is characterised by a strong ( 006 ) diffraction peak, measured using XRD, and by low intensity of ( 012 ), ( 104 ), ( 113 ) ( 024 ) and ( 116 ) diffraction peaks. The <001> textured alpha-Al<SUB>2</SUB>O<SUB>3 </SUB>layers is deposited in a temperature range of 750-1000° C. The texture is controlled by a specific nucleation procedure combined with the use of sulphur- and fluorine containing dopants.
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