LOW TEMPERATURE DEPOSITION OF TITANIUM NITRIDE

TITANIUM NITRIDE (TIN) HAS BEEN FOUND TO BE AN EXCELLENT COATING FOR MANY WEAR APPLICATIONS. FOR EXAMPLE, A VERY HIGH PERCENTAGE OF TOOL INSERTS ARE COATED WITH TITANIUM NITRIDE. HOWEVER, THE TEMPERATURE AT WHICH IT IS DEPOSITED, EVEN FOR "LOW TEMPERATURE" PROCESSES, SUCH AS CATHODIC ARC DEPOSITION, IS STILL TOO HIGH FOR COATINGS ON ALUMINUM, POLYMERS, MANY STEELS, AND SOME OTHER MATERIALS WITHOUT REDUCING THE STRENGTH OF THE BASE MATERIALS OR CREATING OTHER PROBLEMS. THE TEMPERATURE AT WHICH TITANIUM NITRIDE IS DEPOSITED BY CONVENTIONAL PHYSICAL VAPOR DEPOSITION PROCESSES, SUCH AS ELECTRON BEAM EVAPORATION, SPUTTERING, AND CATHODIC ARE DEPOSITION, MUST BE HIGH IN ORDER TO PREVENT EXCESSIVE STRESS BUILD-UP IN THE COATING AND TO A ACHIEVE THE DESIRED MICRO-STRUCTURE. A PROCESS FOR CATHODIC ARC DEPOSITION HAS BEEN DEVELOPED WHEREBY A PULSED, HIGH VOLTAGE BIAS APPLIED TO THE WORK PIECE ALLOWS DEPOSITION AT NEAR ROOM TEMPERATURE WITHOUT EXCESSIVE STRESS BUILD-UP AND WITH SUPERIOR ADHESION. THIS PROJECT WILL EXTEND THIS TECHNOLOGY TO THE DEPOSITION OF TITANIUM NITRIDE ON ALUMINUM, STEEL, AND OTHER MATERIALS THAT ARE NOT ABLE TO WITHSTAND THE HIGHER TEMPERATURES ASSOCIATED WITH CONVENTIONAL DEPOSITION TECHNOLOGIES. PHASE I WILL ESTABLISH THAT TIN CAN BE DEPOSITED AT LOW TEMPERATURES USING A PULSED, HIGH VOLTAGE BIAS ALONG WITH THE CONVENTIONAL BIAS. THE COATINGS SHOULD HAVE LOW RESIDUAL STRESS AND GOOOD ADHESION WITHOUT LOSS OF MECHANICAL PROPERTIES.