Effect of the sputter cleaning of steel substrates with neutral molecule source on the adhesion of TiN films

The effect of sputtering the surface of a high-speed steel substrate with a neutral molecule source, after alkaline cleaning and boiling water dip-drying, on the adhesion of Arc-PVD TiN coatings was studied. For comparison, the effects of several drying techniques on the adhesion of TiN coatings were also investigated. These samples were all similarly cleaned in alkali but were dried with different techniques such as boiling water dipping, alcohol and hot trichloroethylene dipping. Before coating all the samples were heated and sputter-cleaned with Ti ions. Coatings were all 1.6-1.9 μm thick with hardnesses varying between 34 and 37 kN mm-2. Adhesion was tested with a scratch tester. Surfaces sputtered with neutral molecules exhibited much higher adhesion than surfaces dried with other techniques and cleaned by Ti ions.