Physical-Mechanical Properties of Superhard Nanocomposite Coatings on Base Zr-Ti-Si-N

Alexandr POGREBNJAK, Viacheslav BAIDAK, Vyacheslav BERESNEV, Petr TURBIN, Nemat MAKHMUDOV, Maxim IL’YASHENKO, Dmitrii KOLESNIKOV, Mannab TASHMETOV

Abstract


Hard and super hard coatings of Zr-Ti-Si-N of from 2.8 μm to 3.5 μm thickness were fabricated using a vacuum arc source with high frequency stimulation. The samples were annealed in vacuum and in air at 1200 °C. It was found that films with a high Zr and Ti content were thermally stable up to 1180 °C. At the same time, a thin oxide layer of 180 nm to 240 nm was found on the surfaces, which protected the sample from destruction. Below 1000 °C annealing temperature in vacuum, changing of phase composition is determined by appearing of siliconitride crystallites (ß-Si3N4) with hexagonal crystalline lattice and by formation of ZrO2 oxide crystallites. Size of grains of a substitution solid solution (Zr, Ti)N varied from (10 12) nm to 25 nm, but Ti concentration in the solid solution increased. In the process of annealing, hardness of the best series of samples increased from (39.6 ±1.4) GPa to 53.6 GPa, which seemed to indicate that a spinodal segregation along grain interfaces was finished.

DOI: http://dx.doi.org/10.5755/j01.ms.19.2.4429


Keywords


superhard; nanocomposite; compressive stress; spinodal phase segregation

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Print ISSN: 1392–1320
Online ISSN: 2029–7289