Oxidation Performance of Nano-Layered (AlTiZrHfTa)Nx/SiNx Coatings Deposited by Reactive Magnetron Sputtering.

This work uses the direct current magnetron sputtering (DCMS) of equi-atomic (AlTiZrHfTa) and Si targets in dynamic sweep mode to deposit nano-layered (AlTiZrHfTa)Nx/SiNx refractory high-entropy coatings (RHECs). Transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) are used to investigate the effect of Si addition on the oxidation behavior of the nano-layered coatings. The Si-free nitride coating exhibits FCC structure and columnar morphology, while the Si-doped nitride coatings present a FCC (AlTiZrHfTa)N/amorphous-SiNx nano-layered architecture. The hardness decreases from 24.3 ± 1.0 GPa to 17.5 ± 1.0 GPa because of the nano-layered architecture, whilst Young's modulus reduces from 188.0 ± 1.0 GPa to roughly 162.4 ± 1.0 GPa. By increasing the thickness of the SiNx nano-layer, kp values decrease significantly from 3.36 × 10-8 g2 cm-4 h-1 to 6.06 × 10-9 g2 cm-4 h-1. The activation energy increases from 90.8 kJ·mol-1 for (AlTiZrHfTa)Nx nitride coating to 126.52 kJ·mol-1 for the (AlTiZrHfTa)Nx/SiNx nano-layered coating. The formation of a FCC (AlTiZrHfTa)-Nx/a-SiNx nano-layered architecture results in the improvement of the resistance to oxidation at high temperature.

Data on nitridation effect of AlTiTaZrHf(-N) high entropy films by X-ray photoelectron spectroscopy.

The data presented in this article are related to the published research of "Effect of nitrogen content on structural and mechanical properties of AlTiZrTaHf(-N) high entropy films deposited by reactive magnetron sputtering". This database contains X-ray photoelectron spectroscopy (XPS) measurements, performed in order to determine the extents of nitrides formed in AlTiTaZrHf high entropy films. The latter were prepared by DC magnetron sputtering technique in reactive mode by adding the nitrogen to argon gas. The nitrogen flow rate is calculated by RN2 = N2/(N2+Ar). XPS measurements were done one month later. Oxides were detected on the top surface of the samples. 2p, 3d and 4f core level peaks were fitted in order to determine accurately the chemical composition of the nitride films. Al2p, Ti2p, Zr3d, Ta4f, and Hf4f reveal the formation of nitrides of all elements constituting the films. Atomic percentage of each element was calculated revealing an increase of nitrogen loading and decrease of the metallic fractions of the elements as RN2 grows from 5% to 50%. Nitridation behaviour of each element, as a function of the nitrogen flow rate, is investigated and presented.

Combining Low-Emissivity Thin Coating and 3D-Printed Original Designs for Superior Fire-Protective Performance.

Three-dimensional (3D) printing is a very flexible process to design various objects of original shapes. Previous works highlighted the preparation of new multimaterials composed of an original sandwich structure made of the ethylene vinyl acetate copolymer containing 30 wt % of aluminum trihydroxide in which a hydrogel phase made of agar and vermiculite was incorporated. This original material revealed an extremely low heat release rate (HRR) (with a reduction of 86 and 64% with regard to the peak of the HRR and total heat release, respectively, when compared to the same sample without hydrogel filling) during its heat exposure at 50 kW/m2 according to the mass loss cone calorimetry test. However, the time to ignition (TTI) of this material was not improved. This work consequently focuses on delaying the time to ignition of this hydrogel sandwich 3D-printed multimaterial. Solution consists in depositing by pulsed DC magnetron sputtering a low-emissivity thin coating on the exposed skin surface. This coating reflects most of the infrared rays responsible for heat absorption and thus delays the ignition of the underlying material. The thermal resistance performances of this coated sandwich 3D-printed multimaterial were evaluated, and a mechanism of action was proposed to explain the dramatic enhancement of the properties.

Biological responses at the interface of Ti-doped diamond-like carbon surfaces for indoor environment application.

Diamond-like carbon (DLC) and titanium-doped DLC coatings were prepared by hybrid PECVD/direct current magnetron sputtering (DCMS). In this study, we show that the operating conditions of titanium-doped DLC coatings used for implants in surgical devices significantly modify their surface properties and consequently their interaction with cells. The coatings showed uniform distribution on the substrate and their biocompatibility was tested by way of rat calvaria osteoblasts. Doping DLC with Ti changed the roughness and wettability of the film interface. The autoclaving of the samples led to the surface oxidation and the formation of TiO2 on the top-most layers of Ti-doped DLC. This was quantitatively assessed by X-ray photoelectron spectroscopy (XPS) and revealed the presence of Ti3+ and Ti4+ species in redox reactions during their interactions with cells. By XPS analysis, the oxidative carbonaceous species C=O and O=C-C were detected during the bacterial inactivation. Reactive oxygen species (ROS) were identified on the sputtered samples and the ⦁OH radical was identified as the most important oxidative radical intermediate leading to bacterial disinfection. The position of the intra-gap of the oxidized C species is suggested within the TiO2 bandgap.

Beneficial effect of Cu on Ti-Nb-Ta-Zr sputtered uniform/adhesive gum films accelerating bacterial inactivation under indoor visible light.

This article presents the evidence for the significant effect of copper accelerating the bacterial inactivation on Ti-Nb-Ta-Zr (TNTZ) sputtered films on glass up to a Cu content of 8.3 at.%. These films were deposited by dc magnetron co-sputtering of an alloy target Ti-23Nb-0.7Ta-2Zr (at.%) and a Cu target. The fastest bacterial inactivation of E. coli on this later TNTZ-Cu surface proceeded within ∼75min. The films deposited by magnetron sputtering are chemically homogenous. The film roughness evaluated by atomic force spectroscopy (AFM) on the TNTZ-Cu 8.3 at.% Cu sample presented an RMS-value of 20.1nm being the highest RMS of any Cu-sputtered TNTZ sample. The implication of the RMS value found for this sample leading to the fastest interfacial bacterial inactivation kinetics is also discussed. Values for the Young's modulus and hardness are reported for the TNTZ films in the presence of various Cu-contents. Evaluation of the bacterial inactivation kinetics of E. coli under low intensity actinic hospital light and in the dark was carried out. The stable repetitive bacterial inactivation was consistent with the extremely low Cu-ion release from the samples of 0.4 ppb. Evidence is presented by the bacterial inactivation dependence on the applied light intensity for the intervention of Cu as semiconductor CuO during the bacterial inactivation at the TNTZ-Cu interface. The mechanism of CuO-intervention under light is suggested based on the pH/and potential changes registered during bacterial disinfection.