Highly wear-resistant thermal print heads with silicon-doped

Abstract

The invention provides a thermal print head with a protective coating of silicon-doped diamond-like carbon (Si-DLC) which imparts superior wear resistance, and improved lifetime. The Si-DLC is comprised of the elements C, H, Si and possibly O, N and Ar. The highly wear and abrasion-resistant Si-DLC diamond-like carbon coating is deposited by ion-assisted plasma deposition including direct ion beam deposition and capacitive radio frequency plasma deposition, from carbon-containing and silicon-containing precursor gases consisting of hydrocarbon, silane, organosilane, organosilazane and organo-oxysilicon compounds, or mixtures thereof. The resulting Si-DLC coating has the properties of Nanoindentation hardness in the range of approximately 10 to 35 GPa, thickness in the range of approximately 0.5 to 20 micrometers, dynamic friction coefficient of less than approximately 0.2, and a silicon concentration in the range of approximately 5 atomic % to approximately 40 atomic %. Optimum performance is obtained when the Si-DLC coating hardness is in the range of approximately 15 to 35 GPa, preferably in the range of about 15 GPa to about 19 GPa, and the Si-DLC layer thickness is in the range of approximately 2 micrometers to approximately 10 micrometers, dynamic friction coefficient of less than approximately 0.15, and a silicon concentration in the range of approximately 10 atomic % to 30 atomic %, preferably in the range of about 15 atomic percent to about 24 atomic percent.