Positronics and nanotechnologies: Possibilities of studying nanoobjects in materials and nanomaterials by the method of positron-annihilation spectroscopy

Investigation of Element Profiles, Defects, Phase Composition and Physical and Mechanical Properties of Superhard Coatings Ti-Hf-Si-N

“…It is seen from the figure, where the behavior of the curves differ markedly, that in the case of samples series 2 we have a two-phase system consisting of a-Si 3 N 4 and (Ti, Hf)N. Namely, a two-phase coating is characterized by two peaks (increase S-parameter) in the region of 10 keV and then in the region of 20 keV (near the coating-substrate interface). In the case of samples Series 3, we have a single-phase solid solution of (Ti, Hf)N and the S-parameter value is rather high -0.492 and after reaching the film-substrate interface begins to decrease to value of 0.476 [9][10][11][12]. Figure 7(a)) with the lowest Hf content in solid solution (Ti, Hf)N ( Table 1) has the greatest wear resistance.…”

“…For the analysis of vacancy-type defects in the coatings slow positrons microbeam (Halle, Germany) was applied. Using this method the so called S-parameter was measured as a function of the incident positrons beam energy (1 -20 keV) with the depth of analysis from a few nm to 2.1 µm [8][9][10]. Investigation of mechanical characteristics of the layers was carried by nanoindentation on the device Nanoindenter G200 (MES Systems, USA) with a three-sided Berkovich diamond pyramid with a radius of blunting the apex of about 20 nm.…”

“…It will be demonstrated in this work. From the literature it is well known that if nanograins size of several nanometers, developed by one or two monolayer's of amorphous (or quasi-amorphous phase, such as BN, TiSi 2 , a-Si 3 N 4 ), the coating will demonstrate a superhardness 40 < H < 80 GPa [4][5][6][7][8][9][10][11][12][13][14][15]. But such properties as the resistance to oxidation, high elastic modulus, and plasticity at the same time (non brittleness) are also of a great importance [16][17][18][19][20][21][22][23].…”