Patent ID: 8075744

Claim:
A method of making a cutting tool insert comprising: a substrate selected from the group consisting of cemented carbide, cermet, ceramics, cubic boron nitride based material, and high speed steel; and a hard and wear-resistant coating comprising laminar polycrystalline metal nitrides layers; said laminar polycrystalline metal nitrides layers having a repetitive form . . . A/B/A/C/A/B/A/C/ . . . with a total thickness of about 0.5 μm to about 5 μm; wherein layer A is a cubic structured MeN, and Me is one or more of metal elements selected from the group consisting of Ti, Nb, Hf, V, Ta, Zr, Cr, and Al; wherein layer B is a cubic structured (Ti,Al)N; and wherein layer C is a cubic structured (Ti,Si)N; wherein the average composition of said coating is about 46 atomic share (at-%)<Zr+Hf+V+Cr+Nb+Ta+Ti+Al+Si<about 54 at-% and balance N; wherein an average thickness of each of said layer A (d A ) is about 2 nm<d A <about 100 nm; wherein an average thickness of each of said layer B (d B ) is about 4 nm<d B <about 150 nm; and wherein an average thickness of each of said layer C (d C ) is about 4 nm<d C <about 150 nm; and wherein said average thickness of each of said layer A, said layer B, and layer C is substantially constant throughout said coating; said method comprising the steps of: growing each of said layers into said repetitive form . . . A/B/A/C/A/B/A/C/ . . . by cathodic are evaporation to a total coating thickness of 0.5 to 5 μm with an evaporation current between about 50 A and about 200 A, in an atmosphere comprising a gas selected from the group consisting of Ar, N 2 , and combinations thereof, at a total pressure between about 0.5 Pa and about 7.0 Pa, with a substrate bias between about −10 V and about −80 V, at a temperature between about 350° C. and about 700° C.; wherein said layer A is grown using a pure or alloyed Me cathode; wherein said layer B is grown using a Ti+Al-cathode with a composition between about (70 at-% Ti+30 at-% Al) and about (5 at % Ti+95 at-% Al); and wherein said layer C is grown using a Ti+Si-cathode with a composition between about (95 at % Ti+5 at % Si) and about (75 at % Ti+25 at % Si).