Thermal stability, mechanical and tribological behavior of Ti-Al-Si-N ion-plasma coating

Abstract

Abstract It is shown that the elemental and phase composition does not change, and the architecture with clearly defined layer boundaries is preserved when annealing the amorphous-nanocrystalline Ti-Al-Si-N multilayer coatings in the vacuum at temperatures of 700-1100 °C. At the same time, the coherent scattering regions of X-ray radiation increase from 8.5-9.5 to 11-12 nm while the microstrains in the crystal lattice decrease from 1.1 to 0.6-0.7%. Structural changes are accompanied by a slight decrease in hardness. Thermal treatment does not change the nature of cohesive fracture of coatings and does not affect their adhesive strength. The decrease in wear resistance after thermal treatment of coatings, manifested in the increasing wear and friction coefficient, is probably due to the changing nature of the cohesive fracture accompanied by the appearance of large fragments that act like high-abrasive particles between friction surfaces. Ti-Al-Si-N coating is characterized by partial oxidation when heated in air up to 800 °C and complete nitride phases transition to oxides and oxynitride compounds at 900 °C.