Microstructure and mechanical properties of Ti/AlTiN/Ti-diamondlike carbon composite coatings on steel

Abstract

Ti/AlTiN/Ti-diamondlike carbon (DLC) composite coatings were deposited by midfrequency magnetron sputtering and Hall ion source-assisted deposition on high-speed steel W 18 Cr 4 V substrates. The coating microstructure and mechanical properties, including hardness, elastic modulus, coefficient of friction, and wear properties were investigated by scanning electron microscopy, Raman spectroscopy, scratch and ball-ondisk friction tests, respectively. Fairly smooth composite coating with strong interfacial adhesion and good mechanical properties was produced. The substrate bias increases sp 3 bonds contents in the DLC layer, thus coating hardness increased from 14 to 24 GPa and elastic modulus from 190 to 230 GPa with the increased substrate bias. Adhesion of interfaces between Ti-DLC and AlTiN layer, AlTiN and the steel substrate decreased with the substrate bias. The coefficient of friction is between 0.10 and 0.15, except when the substrate bias is 500 V, it is 0.2. Composite coating wear resistance increased with the substrate bias.

Fast deposition of diamond-like carbon films by radio frequency hollow cathode method

“…2 (a) and (b), DLC film deposition rates increased from 17 to 39 nm/min with an RF power increase from 20 W to 100 W, and to 45 nm/min with the pressure increase to 4 Pa. DLC films were deposited in a single cathode configuration, the conventionally used RF-PECVD method. It turns out that under the same deposition conditions, the deposition rate, obtained by a general RF-PECVD process, ranged from 4 to 10 nm/min [16], which is about one fourth of that achieved by a hollow cathode process. The degree of plasma ionization increased with the RF power and pressure, requiring a higher plasma density, which resulted in a higher deposition rate.…”

“…However, this method suffers from a low deposition rate, due to the low plasma density. In previous work, DLC films were prepared using PECVD with a deposition rate of 4-10 nm/min [16]. Z.…”

Tribological properties of (Ti, Al)N films with different Al/Ti atomic ratios deposited by magnetron sputtering

“…Mirosław Szala [20] et al found that with the increase of Al content, the adhesion of (Ti, Al)N film to substrate is higher, and (Ti, Al)N film showed better resistance to plastic deformation. In addition, Pang [21] et al found that the composite film formed by using (Ti, Al)N as the intermediate layer not only improved the bonding strength, but also enabled the stress to be effectively released to achieve the effect of wear resistance. Recently, Du [7] et al studied the Al 1−x Cr x N nano-multilayer film prepared by doping Al in CrN and found that as the grain size of the film increases, the interlayer interface coherence was destroyed, and the mechanical properties of the film also decrease.…”