Patent ID: 9290847
Filing Date: 2016-03-22
CPC Classification: C04B,C23C,Y10T

Claim Text:
1. An Al 2 O 3 coated Si 3 N 4 cutting tool comprising a conductive or non-conductive Si 3 N 4 based substrate body and a coating layer on the substrate body, wherein the coating layer has at least one Al 2 O 3 coating layer consisting of amorphous Al 2 O 3 or nanocrystalline α-, γ-, or κ-Al 2 O 3 , wherein the Al 2 O 3 coating layer is deposited: (a) on a conductive Si 3 N 4 based substrate body by sputtering conductive Al 7 O 3 ceramic target formed by doping conductive material in Al 7 O 3 ; (b) on a conductive Si 3 N 4 based substrate body utilizing reactive sputtering of Al cathode in an O 2 gas or a gas mixture of Ar and O 2 by bipolar pulsed DMS technique; (c) on a non-conductive Si 3 N 4 based substrate body utilizing reactive sputtering of Al cathode in an O 2 gas or a gas mixture of Ar and O 2 by bipolar pulsed DMS technique and using a dual pulsed bias voltage; or (d) on a non-conductive Si 7 N 4 based substrate body utilizing sputtering conductive Al 7 O 3 ceramic target in an Ar gas or a gas mixture of Ar and O 2 and using a dual pulsed bias voltage.