COATING LAYER FOR CUTTING TOOL

摘要

The present invention relates to a hard coating layer in which a TiN layer, a TiCN layer, a coupling layer, an alumina (Al2O3) layer, and a cover layer are stacked in order from the bottom on a base material, according to a chemical vapor disposition (CVD) method, wherein surface residual stress of the coating layer can be maintained as compressive stress by adjusting the composition of the over layer, even without applying a separate and additional step, such as blasting, or using a combined CVD and PVD step, and the cover layer can be also utilized as a abrasion-resistant layer, thereby improving cutting performance. The coating layer, according to the present invention, is the coating layer formed by applying a CVD method to the surface of the base material, comprising: the alumina layer, which is formed in an a phase on the base material, and has a composite structure of a columnar crystal structure and an equiaxed crystal structure; and the cover layer, which is formed on the alumina layer, comprising AlxTiySizCrwN (wherein x+y+z+w=1, x=0.75, y=0.2, 0=z=0.06, 0=w=0.08).