| 摘要 |
A cutting tool having a hard coating layer including: a Ti compound layer, as a lower layer, formed by vapor deposition, having an average thickness of 0.5 to 20 mum and made of at least one layer chosen from among a carbide of Ti layer, a nitride of Ti layer, a carbonitride of Ti layer, a carboxide of Ti layer and a carbonitroxide of Ti layer; an aluminum oxide layer, as an intermediate layer, which has an average thickness of 1 to 25 mum and a heat transformed alpha-type crystal structure derived from a vapor deposited kappa- or theta-type aluminum oxide layer, and having a structure having cracks therein formed during heat transformation uniformly dispersed; and an aluminum oxide layer, as an upper layer, formed by vapor deposition having an average thickness of 0.3 to 10 mum and an alpha-type crystal structure.
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