Influence of the Plasma Treatment Regimes on the Surface Morphology and Properties of Films Applied to Steel from Heptane Plasma

Atomic force microscopy, x-ray photoelectron spectroscopy, chemical analysis, and the method of measuring the contact angle were used to reveal the correlation between the surface morphology, physicochemical properties, and texture of films applied to steel by glow discharge in heptane plasma. In the glow zone at low pressure and discharge power, the resulting thin layer is sticky, and its surface has protruding macromolecular conoidal and spheroidal formations. With an increase in the pressure and discharge power, this layer disappears, while the formations become more numerous and then coalesce. The maximum thickness, roughness, and strength of the films and their minimum permeability were found to correlate with the maximum number of the above conoids and spheroids at the film surface. Apparently, they are film growth centers; their formation is caused by the relaxation of internal stresses in the film or lengthy defects in the base metal. In the absence of glow, the sticky film contains no macromolecular formations.[PUBLICATION ABSTRACT]