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Herein, we evaluated the influence of different experimental parameters to obtain high anti-corrosive anatase TiO2 thin films on stainless steel using a simple and low cost cathodic cage plasma deposition technique at low pressure and temperature. The thin TiO2 films were deposited on duplex stainless-steel (dimension). Different mixtures of O2, H2 and Ar were used and further correlated with resulting structural properties and corrosion resistance. The temperature was kept at 450 °C with a deposition time from 1 to 4 h. Raman spectroscopy, grazing incidence X-ray diffraction and a corrosion test were used to evaluate the TiO2 films. A thin TiO2 adherent, crystalline, protective film was obtained when 60% H2/40% Ar was used. Our proposed method to obtain TiO2 films shows promise for use in different industrial applications.

Super duplex stainless steels are widely used in harsh environments due to their high corrosion resistance. However, the improvement of their tribological properties can contribute to a better performance of these materials in service. In this regard, this study aimed to evaluate the application influence of duplex treatment on the tribological properties of the UNS S32760 super duplex stainless steel. Two treatment times, 2 h and 4 h, were studied for both the nitriding step and the cathodic cage plasma deposition step. The results showed that the combination of the nitrided layer and the TiN film, confirmed with the application of Rietveld refinement on the XRD data, contributes to the wear volume decrease by up to 9.41 times. This behaviour was associated with the increase in surface microhardness and the excellent adhesion conditions (HF1) presented by the film deposited over the nitrided layer. The film provided a change in the wear mechanism, evidenced by the reduction in the tendency to wear by scratches. Additionally, was observed the presence of lower oxygen content in the wear region of the treated samples, that can be associated a lower heating of the samples during the test. Thus, the duplex treatment has a great application potential for improving the wear resistance of UNS S32760 steel.

Diamond-like carbon (DLC) films have been the focus of extensive research in recent years due to its potential application as surface coatings on biomedical devices. It has been already reported that fluorine (F) could increase DLC antibacterial activity. In this paper we investigated the antibacterial activity of fluorinated-DLC (F-DLC) films with various F contents and its correlation with bacterial adhesion mechanism according to thermodynamic theory. F-DLC was grown on a 316L stainless steel substrate using plasma enhanced chemical vapor deposition (PECVD) by varying the ratio of carbon tetrafluoride and methane. The antibacterial tests were performed against E. coli and the influence of F content on composition, surface energy, stress and surface roughness was also investigated. As F content increased, F-DLC films presented lower stress and surface free energy. In addition, the roughness values increased and Raman G-band peak position shifted to higher wave numbers. The results show that bacterial adhesion to F-DLC films decreases with increasing F content and work of adhesion, which is consistent with the thermodynamic theory. PECVD is a simple technique to produce F-DLC films to be used in biomedical applications.

Crystalline diamond (CD) particles are incorporated into diamond-like carbon (DLC) films in order to prevent CD–DLC electrochemical corrosion. In this paper, the influence of the diamond particle sizes on the electrochemical corrosion resistance of CD–DLC films was investigated. The films were grown over 304 stainless steel using plasma enhanced chemical vapor deposition. CD particles with 4 nm, 250 nm, 500 nm and 2–3 µm in diameter were incorporated into DLC during the deposition process. The investigation of CD–DLC electrochemical corrosion behavior was performed using potentiodynamic method. The results show that both protection efficiency and impedance increase with the decrease of I D / I G ratio. It means the increase of sp 3 bonds in DLC films reduces its electrochemical corrosion, improving the electrochemical protection efficiency and the impedance. Our results pointed out that CD–DLC films are promising corrosion protective coatings in aggressive solutions.

Diamond-like carbon (DLC) films have been use in numerous industrial applications due to its mechanical properties such as low friction coefficient, high hardness, and high adherence on different substrate materials. It has been demonstrated that the DLC surface can be modified with oxygen plasma treatment. The purpose of this paper is to study two kinds of surface treatments (atmospheric and low pressures) using oxygen gas for different etching exposure times in DLC films. Plasma durability along the time was also evaluated. DLC films were deposited using plasma enhanced chemical vapor deposition technique. The properties of DLC treated for both techniques in different exposure times were investigated through Raman, AFM and contact angle measurements. D band position slightly shifts toward lower wave numbers after oxygen plasma etching treatment whilst the surface becomes rougher, although the roughness values are still lower. A conventional wetting contact angle method was used to study the surface properties of DLC films with different treatments. The wetting contact angle reduced significantly due to the increase of carbon–oxygen sites on the surface.

Nanocrystalline diamond (NCD) particles are incorporated into diamond-like carbon (DLC) films in order to prevent NCD-DLC electrochemical corrosion. In the current paper, tribological behavior of NCD-DLC films under aggressive solutions is discussed. DLC and NCD-DLC coated steel disks and coated and uncoated steel ball were used under rotational sliding conditions. Raman scattering spectroscopy analyzed the film's atomic arrangements and graphitization level before and after tribocorrosion tests. The NCD-DLC films confirmed to be effective in the corrosion wear resistance under corrosive environments. The results pointed that NCD-DLC films are promising corrosion protective coating in aggressive solutions for many applications.