PHASE COMPOSITION, THERMAL STABILITY, PHYSICAL AND MECHANICAL PROPERTIES OF SUPERHARD ON BASE Zr-Ti-Si-N NANOCOMPOSITE COATINGS

摘要

Zr-Ti-Si-N coating had high thermal stability of phase composition and remained structure state under thermal annealing temperatures reached 1180℃ in vacuum and 830℃ in air. Effect of isochronous annealing on phase composition, structure, and stress state of Zr-Ti-Si-N-ion-plasma deposited coatings (nanocomposite coatings) was reported. Below 1000℃ annealing temperature in vacuum, changing of phase composition is determined by appearing of siliconitride crystallites (B-Si_3N_4) with hexagonal crystalline lattice and by formation of ZrO_2oxide crystallites. Formation of the latter did not result in decay of solid solution (ZrTi)N but increased in it a specific content of Ti-component. Vacuum annealing increased sizes of solid solution nanocrystallites from (12 to 15) in as-deposited coatings to 25nm after annealing temperature reached 1180℃. One could also find macro- and microrelaxations, which were accompanied by formation of deformation defects, which values reached 15.5 vol.%. Under 530℃ annealing in vacuum or in air, nanocomposite coating hardness increased. When Ti and Si concentration increased and three phases nc-ZrN, (Zr, Ti)N-nc, and α-Si_3N_4 were formed, average hardness increased to 40,8 ± 4GPa. Annealing to 500℃ increased hardness and demonstrated lower spread in values H = 48 ± 6GPa and E = (456±78)GPa.