Kinetic Monte Carlo simulation of random deposition and scaling behavior with respect to the germination length

This work aims at analyzing the scaling behavior and develop correlations during surface growing for different germination lengths. The surface growing by random deposition is simulated using a kinetic Monte Carlo approach, by considering different germination lengths. Different surface descriptors are extracted, among them the roughness and the correlation. The former allows extracting the scaling behavior, while the latter proves the existence of correlations independent of the system size but dependent on the germination length. Moreover, as in the case of random deposition with a null germination length, the growing roughness never saturates

Air and Vacuum Annealing Effect on the Highly Conducting and Transparent Properties of the Undoped Zinc Oxide Thin Films Prepared by DC Magnetron Sputtering

In this study, we aim to investigate the effect of zinc interstitials (Zni) and oxygen vacancies (VO) on the ZnO electrical conductivity. ZnO films were synthesized via DC magnetron sputtering process using pure Zn target in gases mixture of Ar/O2 = 80/17.5 (sccm). In order to improve the optical and electrical prosperities, the obtained films were subjected to air and vacuum annealing treatment. Several techniques such as field emission scanning electron microscopy (FESEM), Grazing Incidence X-ray Diffraction (GIXRD), Raman spectroscopy, photoluminescence spectroscopy (PL) and UV-visible were used to study the influence of heat treatment on structural and physical properties of ZnO films. Electrical conductivity of ZnO thin films was determined by measuring the sheet resistance and thickness of the films.  XRD results confirm the synthesis of annealed ZnO films of the hexagonal structure with a preferential orientation along the (002) plane. The average crystallite size is altered between 22.6 to 28.4 nm dependent on the plan orientation of the ZnO film. Morphology and crystallinity of the ZnO structure could efficiently control the transmittance, electrical resistivity and optical band gap. As deposited ZnO film showed a lower electrical resistivity of 2.72×10-3 Ωcm due to the Zn-rich conditions. Under vacuum annealing, a combination of low resistivity (1.17×10-2 Ωcm) and better optical transmittance (87 %) are obtained. ZnO films developed in this study with high transmittance and low resistivity and good electro-optical quality supports their use in transparent and conductive electrode applications. The plan presentation was visualized using Vesta, with the lattice parameter set as follows: a = b = 3.249 Å; c = 5.207 Å; α = β = 90°; γ = 120°. Based on the construction and optimization of primitive cells, the supercells were constructed and then optimized. Finally, (002) and (103) planes were cut and the planar supercell structure was constructed. In order to make a plane representation for the solid bulk with 10 Å of thickness

Mechanical and Tribological Behaviors of Nanocomposite Titanium Nitrides Coatings

TiN coatings with a thickness of 2 μm were deposited using the magnetron sputtering has developed rapidly over the last decade in such a way that it has become an established process of choice for the deposition of a wide range in various applications for different domains as it gives excellent performance in many aspects. In view of this, we have deposited the TiN coatings by magnetron sputtering using Ti target at different nitrogen content to study the influence of the nitrogen content on the mechanical properties and tribological behaviors of the TiN coatings were systematically investigated using nanoindentation and a pin-on-disk tribometer. Nanoindentation results shows that the hardness and Young's modulus of the TiN coatings increase with increasing N content in the coatings.Wear test results indicate that the wear rate and friction coefficient of the XC100 steel substrate were significantly reduced by deposition of the TiN coatings, and the tribological behaviors of the TiN coatings are strongly dependent on the nitrogen content in the coatings

Influence of film thickness and Ar N2 plasma gas on the structure and performance of sputtered vanadium nitride coatings

We investigated the effect of film thickness on the structure and properties of VN coatings deposited by magnetron sputtering in an argon and nitrogen atmosphere. The nitrogen percentage was changed between 10 and 20%. Firstly, structural and morphological properties of VN films were observed, analyzed and subsequently followed by a detailed investigation on the mechanical and tribological properties of these coatings. It has been shown that film structure, hardness and wear resistance significantly changed with varying the film thickness and the nitrogen percentage. In the case of films deposited under 10%N2, the presence of V2N phase was evident. With increasing nitrogen ratio in the deposition chamber from 10 to 20%, the structure was changed from (hc)V2N to multi phases of V2N and (fcc) VN (formation of different vanadium nitrides). The thick films containing more nitrogen were slightly dense compared to the thinner ones presenting rough surface and columnar morphology. Nanoindentation measurements showed that film mechanical behavior depends on its thickness, nitrogen percentage and microstructural features. The film hardness first increased with its thickness and then decreased. The highest hardness of 26.2 GPa was obtained for the film deposited under 20%N2, which is correlated with its dense structure and film stoichiometry. The film thickness has a significant effect on the tribological properties of VN films. The minimum friction coefficient of 0.4 was found for the thickest film of 2500 nm. The wear rate gradually decreased with increasing the film thickness, due to the high hardness, presence of VN phase and the strong adhesion between film and substrate

Friction and Wear Performance of Biomaterials Alloy AISI 316L and Ti-6Al-7Nb

We became interested in this work to study the tribological behavior of two total hip replacements steel AISI 316L and titanium alloy Ti-6Al-7Nb tests performed in this work are essays with reciprocating movement. The tribological properties of wear by sliding (reciprocating) for the different samples were evaluated in the air on a tribometer with a tribotester software software following standards: ISO 7148, ASTM G99-95a, ASTM G 133-95, with a relative humidity of 33-38% at a temperature 24 to 27°C and a non-lubricated state. The ball 100C6 steel of 10 mm diameter, 835 HV hardness and Young’s modulus 310 GPa was chosen as the antagonist to prevent further chemical reactions. Three different speeds (1, 6 and 15 mms-1) and four normal forces (2, 4, 6 and 10 N) were applied, which allowed us to test twelve different conditions. The values of the friction coefficient obtained in this work are confirmed by the bibliographical results and meet the standards imposed by biomedical particularly at the joint surface state of hip prostheses

Magnetron Sputtering of Transition Metal Nitride Thin Films for Environmental Remediation

The current economic and ecological situation encourages the use of steel to push the technological limits and offer more cost-effective products. The enhancement of steel properties like wear, corrosion, and oxidation resistance is achieved by the addition of small amounts of chemical elements such as Cr, Ni, Si, N, etc. The steel surface can be protected by different treatments such as heating and coating, among others. For many decades, coatings have been an effective solution to protect materials using thin hard films. Several technologies for thin film deposition have been developed. However, some of them are restricted to certain fields because of their complex operating conditions. In addition, some deposition techniques cannot be applied to a large substrate surface type. The magnetron sputtering deposition process is a good option to overcome these challenges and can be used with different substrates of varying sizes with specific growth modes and for a wide range of applications. In this review article, we present the sputtering mechanism and film growth modes and focus on the mechanical and tribological behavior of nitride thin films deposited by the magnetron sputtering technique as a function of process conditions, particularly bias voltage and nitrogen percentage. The biomedical properties of transition metal nitride coatings are also presented

Influence of vanadium on structure,

This work aims to show the characterisation of Cr–V–N coatings, with the varied amounts of Cr and V. CrN, VN and Cr–V–N coatings were deposited onto silicon and XC100 steel substrates by reactive radio frequency magnetron sputtering and characterised with X-ray diffraction, X-ray photoelectron spectroscopies, energy dispersive X-ray spectroscopy, scanning electron microscopy, nanoindentation, pin on disc tribological tests and scratch tests. The residual stress was calculated using the Stoney formula. Compared to the CrN system, the Cr–V–N films presented a rough surface based on pyramidal morphology. A hardness of 19?53 GPa and a friction coefficient of 0?55 were obtained for CrN; in contrast, Cr–V–N coatings presented a weak hardness of 6?23 GPa. In the case of wear against a 100Cr6 ball, the Cr–V–N films were completely removed from the substrate, even though the Cr–V–N coating presented a low friction coefficient (0?39). However, the VN film showed good tribological performance.Ministère algérie

Structural and mechanical properties of Cr–Zr–N coatings with different Zr content

Cr–Zr–N films have been synthesised using R.F reactive magnetron sputtering system on Si (100) wafer and XC100 steel substrate without heating. The structural, mechanical and friction coefficient evolution as a function of the Zr content were investigated by XRD, (EDS, WDS), WPS, XPS, SEM, AFM, nanoindentation, Scratch adhesion and pin-on-disc sliding wear tests. The results show, that, with increasing Zr content, the film structure changed with the coexistence of (Cr–N, Zr–N) crystallographic orientation mixture. The films formed a (Cr, Zr) N solid solution where Zr atoms substitute Cr atoms. CrN lattice parameter increased from 4.17 to 4.32 Å with the crystallite size refinement. The mechanical parameters (H, σ, E, H/E and H3/ E2) were significantly improved in comparison to binary films, especially at 29 at.-% Zr. The friction and wear behaviour of the Cr–Zr (29 at.-% Zr)–N coating also showed a significant improvement

Influence of the carburization time on the structural and mechanical properties of XC20 steel

This study focuses on the effect of carburization time on the structural and mechanical properties of low carbon XC20 mild steel (C. Wt.% <0.25). The XC20 steel was carburized with activated carbon with a carbon potential Cp1 = 1.1%, at 910 C at different carburization times of 2, 4 and 6 h. The results obtained show that XC20 steel (non-carburized) has a ferrite-pearlitic structure with a hardness and a Young's modulus of the order of (150 HV, 26 KN/mm2). After carburization, the structure of the carburized layer is transformed in martensite (Fe γ) in which cementite (Fe3C) is imbricated. The depth of the carburized layer and the amount of carbon on the surface gradually increase with increasing carburization time. In addition, the carburized XC20 steel becomes hard and brittle where the hardness and Young's modulus have been increased for a high holding time until reaching maximum values (845 HV, 48 KN mm-2) after 6 h of carburization . However, the toughness of XC20 steel has been reduced from 163 to 40 J cm-2

Effect of Replacing Vanadium by Niobium and Iron on the Tribological Behavior of HIPed Titanium Alloys

This study aims to examine the effect of replacing vanadium by niobium and iron on the tribological behavior of hot-isostatic-pressed titanium alloy (Ti–6Al–4V) biomaterial, using a ball-on-disk-type oscillating tribometer, under wet conditions using physiological solution in accordance with the ISO7148 standards. The tests were carried out under a normal load of 6 N, with an AISI 52100 grade steel ball as a counter face. The morphological changes and structural evolution of the nanoparticle powders using different milling times (2, 6, 12 and 18 h) were studied. The morphological characterization indicated that the particle and crystallite size continuously decrease with increasing milling time to reach the lowest value of 4 nm at 18-h milling. The friction coefficient and wear rate were lower in the samples milled at 18 h (0.226, 0.297 and 0.423; and 0.66 × 10−2, 0.87 × 10−2 and 1.51 × 10−2 µm3 N−1 µm−1) for Ti–6Al–4Fe, Ti–6Al–7Nb and Ti–6Al–4V, respectively. This improvement in friction and wear resistance is attributed to the grain refinement at 18-h milling. The Ti–6Al–4Fe samples showed good tribological performance for all milling times