Patent ID: 6521349
Filing Date: 2003-02-18
Classification: C23C,Y10T

Abstract:
A method of producing a molybdenum sulfide coating on a cutting insert for machining metal, comprising the steps of:(a) depositing on a cutting insert body of a material selected from the group which consists of hard metal, cermet, ceramic and steel as a sole layer or as the outermost layer or a layer underlying the outermost layer of a multiple layer coating a molybdenum sulfide layer containing a mixture of the sulfide phases MoS2 and Mo2S3 by chemical vapor deposition from a gas mixture of molybdenum chloride, hydrogen sulfide, a noble gas and hydrogen; (b) maintaining a temperature during the chemical vapor deposition of 500Â° C. to 900Â° C. during the chemical vapor deposition; (c) maintaining a pressure between 0.1 kPa and 50 kPa during the chemical vapor deposition; (d) maintaining a molar ratio of hydrogen sulfide/molybdenum chloride between 0.1 and 4 during the chemical vapor deposition; (e) maintaining a total of the hydrogen and noble gas content between 80 and 99 volume percent during the chemical vapor deposition; and (f) varying the molar ratio of hydrogen sulfide/molybdenum chloride alternately for respective time intervals from a low molar ratio to a high molar ratio at 7 to 10 times the low molar ratio so that with the high molar ratio pure MoS2 is deposited and at the low molar ratio a phase mixture of MoS2 and Mo2S3 is deposited.