Investigation of tribological and mechanical properties of Nb-Al-N coatings before and after annealing
Coatings Nb-Al-N were deposited on a silicon substrate under argon and nitrogen by magnetron sputtering at a substrate temperature of 350 °C and a constant current of 250 mA at the aluminum cathode. The analysis of the dependence chemical composition, morphology, structure and mechanical properties of the annealing temperature were performed for different series of coatings. Coatings demonstrated high thermal stability after annealing to 1000 °C.
Certain features of high-dose and intensive implantation of Al ions in iron
Abstract Using a proton microbeam PIXE and RBS, a formation of local surface segregations of aluminum in an iron layer has been found, for the first time, at an initial stage of high-dose intensive implantation (from 8×1016 to ×1017 cm−2). Using a slow positron beam, a profile of vacancy defects, which depth is comparable to a depth profile of Al ions implanted into iron with 5×1017 cm−2 has been measured. Complex carbides (Fe3Al)C and Fe3C have been found in a near surface layer (TEM measurements) as well as segregations of an ordered phase Fe3Al (which with a dose increased are partially amorphized). In addition, high dislocation density of 1.2×1010 cm−2 has been found in the near surface layer, and fields of elastic stresses are formed, which results in the increased friction wear resistance and microhardness.
The effect of nitrogen pressure on cathodic arc deposited NbN thin films
Abstract NbN thin films were deposited on non-standard grade high speed steel (HSS) (79.90 wt.% Fe, 0.71 wt.% C, 6.09 wt.% W, 4.52 wt.% Mo, 3.95 wt.% Cr, 1.82 wt.% Co, 1.75 wt.% V and a hardness of 65 HRC) using cathodic arc deposition at 0.125, 0.5, 1.0 and 1.5 Pa nitrogen pressures (PN2), with a bias voltage of − 150 V. X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Nanoindentation and Rockwell C analysis were used to characterize the thin films in order to identify the NbN phases and to investigate the influence of PN2 on mechanical properties. Hexagonal β-Nb2N, e-NbN and δ′-NbN0.95 are identified in XRD analysis. Hardness values derived by nanoindentation technique are 20 GPa for β-Nb2N, e-NbN and 40 GPa for δ'-NbN0.95. Due to the complexity of phase system special attention was focused on identification of NbN phases by deconvolating the XRD peaks especially at 0.5 Pa in which both e-NbN and β-Nb2N were found. Rockwell C analysis revealed that the film adhesion is found to be poor at lower PN2, due to the brittle nature of β-Nb2N.