Patent ID: 6333099
Filing Date: 2001-12-25
Classification: C23C,Y10T

Abstract:
A cutting tool comprising a body selected from the group of sintered cemented carbide, cermet, ceramics and high speed steel, and a thin, adherent, hard and wear resistant coating applied on at least the functioning parts of the surface of the body, said coating comprising a laminar, multilayered structure of refractory compounds in polycrystalline, non-repetitive form having the formula, [(MLX/Al.sub.2 O.sub.3)].sub.y where the alternating layers are MLX and Al.sub.2 O.sub.3, the MLX sublayers comprise a metal nitride or a metal carbide with the metal elements M and L selected from the group consisting of Ti, Nb, Hf, V, Ta, Mo, Zr, Cr, W, Al and mixtures thereof, and wherein the Al.sub.2 O.sub.3 sublayers are crystalline Al.sub.2 O.sub.3 of the gamma (.gamma.) phase, in said coating the sequence of individual layer thicknesses having no repeat period but being essentially aperiodic throughout the entire multilayered structure, the said individual MLX or Al.sub.2 O.sub.3 layer thickness is between 0.1 and 30 nm, said thickness varies essentially at random, and y is a whole number such that the total thickness of said multilayered coating is between 0.5 .mu.m and 20 .mu.m.