Properties of Tisub(x)Csub(1-x) films coated on molybdenum by magnetron sputtering

Properties of Tisub(x)Csub(1-x) (0.3 <= x <= 0.6) films deposited onto molybdenum have been examined as functions of their chemical composition. Tisub(x)Csub(1-x) films about 4-6 μm thick were deposited onto a sintered molybdenum substrate at 6000C by magnetron sputtering. The near-stoichiometric Tisub(x)Csub(1-x) (x approximately 0.5) was found to be the most thermally stable. Titanium excess Tisub(x)Csub(1-x) (x > 0.5) loses titanium by evaporation and changes its surface morphology above 12000C. However, excess titanium will improve the ductility of deposited films. Strong compressive stress was observed in carbon excess Tisub(x)Csub(1-x) (x < 0.5). The carbon excess Tisub(x)Csub(1-x) is more resistant against thermal evaporation than the stoichiometric compound. However, enhanced diffusion of molybdenum atoms into the carbon excess Tisub(x)Csub(1-x) takes place, with the formation of Mo2C. This Mo2C formation nearly prohibits the use of carbon excess Tisub(x)Csub(1-x) films coated on molybdenum as the first-wall material in fusion devices. (Auth.)