Microstructure and mechanical properties of Cr–V–C–N films

Abstract

Quaternary Cr-V-C-N films were deposited on Si wafers through a hybrid system of arc ion plating and sputtering techniques in an Ar/N 2 /CH 4 gaseous mixture. In this work, the effects of vanadium on the microstructural evolution, mechanical properties and friction mechanism of Cr-V-C-N films were investigated. The results showed that quaternary Cr-V-C-N films consisted of nanosized crystallites of (Cr,V)(C,N) and amorphous VCN phases. The Cr-10?4 at-%V-C-N film possessed the higher hardness value of 34 GPa, compared to the 27 GPa of a Cr(C,N) film. Additionally, the friction coefficients of the Cr-V-C-N films were reduced from 0?38 for the Cr-C-N film to 0?27 for the Cr-10?4 at-%V-C-N film. Atomic force microscopy (AFM) and Auger electron spectroscopy (AES) analyses also revealed that the amorphous phase VCN phases played a role in reducing the friction coefficients of the films. The a-VCN phase (vanadium rich) was believed to cause a tribochemical reaction with ambient air during the wear process.

Effect of carbon content on structural, mechanical and tribological properties of Cr-V-C-N coatings

“…However, the measured hardness of 28.3 (± 0.6) GPa is lower than the value given in a previous work reported by S.Y. Heo et al [16]. The difference between the two hardness values can be explained by the low compressive internal stress in grown coatings [32].…”

“…Cr-N coatings with carbon and vanadium atoms embedded in a nanocrystalline Cr-V-N and Cr-C-N matrix. The structure of these coatings provides an extremely high hardness to these ternary systems and can prevent dislocation movements and micro-cracking, thereby improving their mechanical and tribological properties [15,16].…”

“…In the literature, we can find few researches focused on studying the chromium-based carbonitride quaternary system. Heo et al [16] investigated Cr-V-N and Cr-V-C-N coatings deposited on steel substrates. They studied the influence of carbon content on structure, mechanical properties and wear resistance of sputtered V-C-N coatings.…”

“…Moreover, the friction coefficient of the Cr-V-C-N coating was lower (µ = 0.27) than this of Cr-C-N coating (µ = 0.38), which is largely dependent on the vanadium content and tribo-chemical reaction during the wear process. However, the corrosion resistance of Cr-V-C-N coatings has not yet been thoroughly studied, due to the synergy problems highly observed in steel devices [16].…”

Mechanical and tribological properties of V–C–N coatings as a function of applied bias voltage

“…When the nitrogen gas flow rate is around 16 sccm and r.f. negative bias voltages from 0 to -100 V are used, V access to the deposition surface is facilitated; hence, the fcc structure is determined by a partially ordered structure with V atoms, creating vacancies in nonmetallic sublattices [9,10]. On the other a b hand, it was observed that the V-C-N (111) peak position suffers a great deviation from bulk value for (VC and VN) materials, indicating thus a possible stress evolution of V-C-N single layers with the applied r.f.…”