Distribution of profiles and macroparticles in coatings obtained by continuous cathodic arc using a straight magnetic concentrator

Abstract

Thin films of Ti and Cu were deposited on 316 stainless steel substrates by the continuous cathodic arc technique with magnetic concentrator in a straight duct. Samples obtained at different cathode-substrate distances, for positions within the magnetic concentrator. The morphology of the surface was determined by electron scanning microscopy (SEM). The average thickness of the films was measured from the deposited mass; the profiles of the films were also studied from measurements with a Calotest in different points of the samples and with a profilometer, the coefficient of friction and wear were characterized with a tribometer; the hardness with a nanoindenter. The results showed that the average thickness increased by the action of the magnetic concentrator, although this causes the samples to have a central region of maximum thickness and that the thickness decreased up to 50% in a radius of about 1 cm. The films were rough with presence of macroparticles. The number of macroparticles, the film roughness and the deposition rate were also analyzed; the deposition rate depended on the axial position inside the duct. The number of macroparticles diminished with increasing axial position, the friction coefficient and wear rate diminished when the substrate was placed farther from the cathode, inside the magnetic duct. The hardness value measured with a nanoindenter is about the order as the reported in the literature; the lowest coefficients of friction, the least wear and the highest values of hardness were obtained in the region where the magnetic field is highest.