Determination by scratch testing of the quality of thin-film oxide coatings formed by vacuum-arc plasma-assisted method

Oxide coatings formed on the surface of medical instruments made of titanium-based alloys help physicians to protect patients from toxic titanium alloying elements and increase the resistance of the instruments to scratching and wearing. As a rule, the formation of a coating/substrate system is accompanied by an analysis of the adhesive properties of the applied coating. This paper presents an analysis of the results obtained by studying the structure and adhesive properties of titanium oxide and zirconium oxide films formed on the surface of titanium alloy samples of Grade 5 by vacuum arc plasma-assisted method with varying discharge current values of the plasma source operating on the basis of an independent arc discharge with glow and hollow cathodes. The studies showed that the oxide films contain droplet fraction particles the characteristics of which are determined by the film deposition mode. It has been established that the critical load force at which destruction of (peeling off) the film from the substrate (titanium alloy Grade 5) is observed in the ZrO₂ film/Grade 5 substrate system is maximum at the “PINK” discharge current I_p = 0 A and minimum at I_p = 90 A. It was found that in the TiO₂ film/Grade 5 substrate system, the maximum value of the critical load force is realized at the “PINK” discharge current I_p = 130 A and minimum at I_p = 0 A.