A Strategy for Alleviating Micro Arcing during HiPIMS Deposition of DLC Coatings

In this work, we investigate the use of high power impulse magnetron sputtering (HiPIMS) for the deposition of micrometer thick diamond like carbon (DLC) coatings on Si and steel substrates. The adhesion on both types of substrates is ensured with a simple Ti interlayer, while the energy of impinging ions is adjusted by using RF (Radio Frequency) biasing on the substrate at -100 V DC self-bias. Addition of acetylene to the working Ar+Ne atmosphere is investigated as an alternative to Ar sputtering, to improve process stability and coatings quality. Peak current is maintained constant, providing reliable comparison between different deposition conditions used in this study. The main advantages of adding acetylene to the Ar+Ne gas mixture are an increase of deposition rate by a factor of 2, when comparing to the Ar+Ne process. Moreover, a decrease of the number of surface defects, from similar to 40% surface defects coverage to similar to 1% is obtained, due to reduced arcing. The mechanical and tribological properties of the deposited DLC films remain comparable for all investigated gas compositions. Nanoindentation hardness of all coatings is in the range of 25 to 30 GPa, friction coefficient is between 0.05 and 0.1 and wear rate is in the range of 0.47 to 0.77 x 10(-6) mm(3) N(-1)m(-1)

Functionalized Carbon Nanotubes for Chemical Sensing: Electrochemical Detection of Hydrogen Isotopes

In this study, we propose a palladium-functionalized CNT composite working as a sensitive material to evaluate the deuterium concentration in aqueous samples. The sensitive material was prepared by the deposition of Pd nanoparticles onto MWCNT–OH by the micellization process. A modified electrode was prepared by drop casting 60 μL of Pd-decorated MWCNT suspension on a clean glassy carbon electrode surface. The sensing behavior was investigated in a series of deuterium-enriched solutions ranging from 25 to 10,000 ppm. We performed cyclic voltammetry and impedance spectroscopy studies on the samples. The process is quasi-reversible with the reduction curve more pronounced than the oxidation curve, which indicates a low tendency to desorption for the hydrogen atoms

NANOCOATING PROCESS FOR TEXTILES APPLICATIONS AND WOOD PROTECTION

This paper presents the research results obtained in ERA NET MANUCOAT project, coordinated by INCDTP in collaboration with the following partners: INCDMNR-IMNR, SC MGM STAR CONSTRUCT SRL –Romania and IRIS-Spain. The objective of the research was to develop and obtain textile and wood surfaces with self-cleaning, photo catalytic, antibacterial and antifungal properties. An innovative method of manufacturing nanoparticles by hydrothermal process in a single step without any further heat treatment and controlled stoichiometry, tested spray coating technology (sputtering) were developed. Full characterization of nanostructured powders in terms of chemical, physical, structural, thermal and technological characteristics was performed. The most important features to be considered in the treatment of wood by sputtering in order to deposit thin layers of TiO2 NPs or TiO2/Ag as the humidity should be below 12% and the maximum roughness P150, depending on the species of wood. Future works envisage optimizing the existing sputtering systems for pilot stage, in order to make nanoparticles deposits on large areas of textile and wood. The results of the research are photocatalytic textiles for surgical gowns, operative fields, hospital bed sheets and curtains and drapes for public spaces

Structural and mechanical properties of CrN thin films deposited on Si substrate by using magnetron techniques

Chromium Nitride thin films are known for their good mechanical properties. We present the characteristics of ultrathin Chromium Nitride films under 400 nm thickness deposited on silicon substrates by direct current and high-power impulse magnetron sputtering techniques. The methods of investigation of the CrN films were scanning electron microscopy, atomic force microscopy, and nanoindentation. Qualitative and quantitative analysis were performed using the AFM and SEM images by fractal dimension, surface roughness and gray-level co-occurrence matrix methods. Our results show that using the mag-netron techniques, ultrathin CrN films with excellent mechanical properties can be obtained

Structural and Mechanical Properties of CrN Thin Films Deposited on Si Substrate by Using Magnetron Techniques

Chromium nitride thin films are known for their good mechanical properties. We present the characteristics of ultrathin chromium nitride films under 400 nm thickness deposited on silicon substrates by direct current and high-power impulse magnetron sputtering techniques. The methods of investigation of the CrN films were scanning electron microscopy, atomic force microscopy, and nanoindentation. Qualitative and quantitative analyses were performed using AFM and SEM images by fractal dimension, surface roughness and gray-level co-occurrence matrix methods. Our results show that using magnetron techniques, ultrathin CrN films with excellent mechanical properties were obtained, characterized by values of Young’s modulus between 140 GPa and 250 GPa for the samples obtained using high-power impulse magneton sputtering (HiPIMS) and between 240 GPa and 370 GPa for the samples obtained using direct current sputtering (DC). Stiffness measurements also reveal the excellent mechanical properties of the investigated samples, where the samples obtained using HiPIMS sputtering had stiffness values between 125 N/m and 132 N/m and the samples obtained using DC sputtering had stiffness values between 110 N/m and 119 N/m

Structural and Mechanical Properties of CrN Thin Films Deposited on Si Substrate by Using Magnetron Techniques

Chromium nitride thin films are known for their good mechanical properties. We present the characteristics of ultrathin chromium nitride films under 400 nm thickness deposited on silicon substrates by direct current and high-power impulse magnetron sputtering techniques. The methods of investigation of the CrN films were scanning electron microscopy, atomic force microscopy, and nanoindentation. Qualitative and quantitative analyses were performed using AFM and SEM images by fractal dimension, surface roughness and gray-level co-occurrence matrix methods. Our results show that using magnetron techniques, ultrathin CrN films with excellent mechanical properties were obtained, characterized by values of Young’s modulus between 140 GPa and 250 GPa for the samples obtained using high-power impulse magneton sputtering (HiPIMS) and between 240 GPa and 370 GPa for the samples obtained using direct current sputtering (DC). Stiffness measurements also reveal the excellent mechanical properties of the investigated samples, where the samples obtained using HiPIMS sputtering had stiffness values between 125 N/m and 132 N/m and the samples obtained using DC sputtering had stiffness values between 110 N/m and 119 N/m

The Characteristics of Light (TiCrAl_0.5NbCu)C_xN_y High-Entropy Coatings Deposited Using a HiPIMS/DCMS Technique

Multi-component high-entropy (TiCrAl0.5NbCu)CxNy coatings targeting applications requiring medium-to-high friction and wear-resistant surfaces were fabricated through the co-sputtering of elemental targets in an Ar + CH4 + N2 reactive atmosphere using a hybrid HiPIMS/DCMS technique. Two sets of samples were fabricated: (a) (TiCrAl0.5NbCu)Cx high-entropy carbides (HEC) and (b) (TiCrAl0.5NbCu)CxN0.13 high-entropy carbonitrides (HECN), 0 ≤ x ≤ 0.48. The structural, mechanical, tribological, and corrosion resistance properties were thoroughly investigated. The metallic sample exhibits a single BCC structure that changes to FCC via an intermediary amorphous phase through the addition of C or N to the content of the films. The crystallinity of the FCC phases is enhanced and the density of the films decreases down to 5.5 g/cm3 through increasing the carbon fraction up to 48%. The highest hardness of about 16.9 GPa and the lowest wear rate of about 5.5 × 10−6 mm3/Nm are presented by the samples with the largest carbon content, x = 0.48. We found a very good agreement between the evolution of H/E and H3/E2 parameters with carbon content and the tribological behavior of the coatings. The best corrosion resistance was presented by the low-carbon carbonitride samples, showing a charge transfer resistivity of about 3 × 108 Ω∙cm, which is more than three times larger than that of the metallic HEA. The best tribological characteristics for envisioned application were presented by (TiCrAl0.5NbCu)C0.3N0.13, showing a coefficient of friction of 0.43 and a wear rate of about 7.7 × 10−6 mm3/Nm