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The results have been presented of an experimental study of the tribological behavior of diamond-like carbon coatings (DLC) doped with chromium and molybdenum obtained by reactive magnetron sputtering. The effect of alloying with these metals on the tribological characteristics of boundary lubrication of a DLC coating/steel contact has been studied for the case of three model lubricants (inactive, surfactant, and chemically active). It has been shown that doping with chromium and molybdenum improves both the tribological characteristics of coatings under dry friction and the lubricating properties of the model oils, while alloying with molybdenum provides lower coefficients of friction and less wear at dry and boundary friction than alloying with chromium.

Optical elements used in outer space must be designed considering the effects of such factors as space vacuum, atomic oxygen in low Earth orbit, solar and space radiation, large temperature drops, gas release of spacecraft materials and structural elements, space dust and debris. In order to harden and protect mirror surfaces of optical elements from external factors, it has been promisingly applied diamond-like carbon coatings on their surface. These coatings are characterized by high strength and wear-resistant properties, in particular, high hardness, low friction coefficient, high wear resistance and chemical inertness. This leads to their widespread use in various fields of science and technology, including optical instrumentation. This paper presents the results of testing an aluminum mirror with a diamondlike carbon coating under the effect of cyclic temperature changes for determining their ability to withstand a rapid cyclic ambient temperature change, and specifically, to maintain optical and mechanical properties.

The present generation of Micro-Pattern Gaseous Detectors (MPGDs) are radiation hard detectors, capable of detecting efficiently particle rates of several MHz/cm$^2$ , while exhibiting good spatial resolution ($\leq$ 50 $\mu$m) and modest time resolution of 5-10 ns, which satisfies the current generation of experiments (High Luminosity LHC upgrades of CMS and ATLAS) but it is not sufficient for bunch crossing identification of fast timing systems at FCC- hh. Thanks to the application of thin resistive films such as Diamond-Like Carbon (DLC) a new detector concept was conceived: Fast Timing MPGD (FTM). In the FTM the drift volume of the detector has been divided in several layers each with their own amplification structure. The use of resistive electrodes makes the entire structure transparent for electrical signals. After some first initial encouraging results, progress has been slowed down due to problems with the wet-etching of DLC-coated polyimide foils. To solve these problems a more in-depth knowledge of the internal stress of the DLC together with the DLC-polyimide adhesion is required. We will report on the production of DLC films produced in Italy with Ion Beam Sputtering and Pulsed Laser Deposition, where we are searching to improve the adhesion of the thin DLC films, combined with a very high uniformity of the resistivity values., Comment: MPGD2019 proceedings, presented by Piet Verwilligen

The study’s purpose is to determine the rational Si content in the DLC-Si external layer of (CrAlSi)N/DLC-Si coatings deposited on α/β-SiAlON + TiN ceramics. The influence of Si content on physical and mechanical properties of coatings such as microhardness, modulus of elasticity, and friction coefficient, and wear resistance of solid ceramic end mills in machining nickel alloy NiCr20TiAl is determined.

Pulsed hydrocarbon ions produced in a plasma focus device were used to irradiate different substrate materials (Si, Ti, Mo and W) and to deposit thin films of carbon material over it. High energetic and high intensity pulsed hydrocarbon ions were produced when plasma focus device was filled with 0.5 mbar of acetylene gas and operated at 2 kJ. Effects of substrate materials properties, its thermal evolution under pulsed irradiation of energetic ions and plasma streams on the deposited films have been studied. Visible Raman spectroscopic measurements confirmed that deposited films were of diamond-like-carbon. Fraction of sp3 bonded carbon in films on different substrate materials (16%, 8.7%, 13% and 18.9% on Si, Ti, Mo and W respectively) was found to be correlated to substrate materials thermal properties i.e. high fraction of sp3 bonded carbon was observed over substrate materials having high thermal conductivity. Carbon atom concentrations were measured to be different (22.46 at. %, 22.7 at. %, 10.4 at. % and 32 at. % on Si, Ti, Mo and W respectively) over different substrates. Surface morphologies of DLC were also observed to be different for different substrates. On inserting graphite at anode tip, fraction of sp3 bonded carbon in DLC coating over Si substrate increased to 19.5%.

DLC films were deposited on Ge substrates using direct ion beam deposition method, followed by investigating the influence of O2 doping on their morphological, electrical, and structural properties. The films were doped with oxygen under flow rates of 5, 10, 20, and 40 sccm (standard cubic centimeters per minute). The structure of the films was studied by Raman spectroscopy. Result showed that by increasing oxygen incorporation, sp2 content decreases, sp3 content increases, and the C-C bonding loses its order. The hydrophilicity of the layers was analyzed by the contact angle measuring experiment. The results showed that by increasing the O2 flow ratio from 5 to 40 sccm, the percentage of O2 increases from 1.1 to 3.9%. The water contact angle measurement showed that an increase in oxygen flow ratio results in a decrease in contact angle from 82.9° ± 2.1° to 50° ± 3°.

The Multi-gap Resistive Plate Chamber (MRPC) has been used in many high energy physics and nuclear experiments in the last decade, such as ALICE [1] and STAR [2]. Normally, the MRPC is built with commercial floating glass (bulk resistivity ρ≈ 1012Ω· cm), which limits the rate capability to less than 1 kHz/cm2. In modern high energy physics, with the increase of colliders beam energy and luminosity, the rate capability of MRPC has to be enhanced accordingly. One normal way is to decrease the bulk resistivity ρ of the resistive plate, as the low resistive glass developed by Tsinghua University for the CBM experiment [3]. Alternatively, the surface of the electrode is also a possible path for the neutralization of the avalanche charges. Recently, we managed to carry this method out by coating a Diamond-Like-Carbon (DLC) layer on the surface of the floating glass. The DLC layer, realized by the magnetron sputtering method, has very good physical and chemical stability. The demanded surface resistivity can be achieved easily. A series of DLC-coated glasses with different resistivity has been tested in our lab. We have also made some MRPC prototypes and tested them with cosmic rays. Some preliminar results, including the operating current, the efficiency and the time resolution, have been achieved. More research is ongoing to improve the design and performance of this new method of increasing the rate capability of MRPC.

High-quality diamond-like carbon film was deposited on silicon substrate by magnetic field-enhanced pulsed laser deposition. The motion tracks of carbon ions in the inhomogeneous magnetic field were simulated. The thickness and surface morphology of carbon film were characterized by surface profilometer and atomic force microscopy, respectively. Mechanical property was evaluated by an indenter. The results showed that the deposition rate of the carbon film prepared under the magnetic field increased 1.7 times than that of the carbon film without magnetic field. The surface of the carbon films constructed of columnar particle arrays with the size ranging from 20 nm to 30 nm was improved and the roughness was decreased from 3.22 nm to 0.93 nm. The nano-hardness of the carbon film was 53.4 GPa, which increased by 18.1% than that of carbon film deposited without magnetic field. The experiment and simulation on the magnetic field-enhanced pulsed laser deposition proved that the new method of film preparation by magnetic filtration laser plasma deposition is feasibility.

The results have been presented of the vacuum deposited diamond-like carbon (DLC) coatings alloyed with chromium investigation devoted to elucidate the mechanisms of their friction and wear in the conditions of unlubricated and partially lubricated tribological contact. It has been demonstrated that in these coatings the features of their micro- and nanocomposite structure formed by the nanosized inclusions of metallic chromium and its interstitials in the DLC matrix have a significant influence on the tribological behavior under dry friction. In the case of a boundary lubricated contact the common practice is to associate the main role of alloying elements with the peculiarities of their tribochemical interaction with the chemically active components of the lubricant. However the present investigation has not confirmed the existence of such a synergistic effect of to tribochemical interaction of alloying metal and chemically active lubricant additives for the coatings obtained via magnetron sputtering of chromium in acetylene-based reactive atmosphere.

Carbon nanoparticles (CNPs) incorporated diamond-like carbon (DLC) films have been fabricated by a combination of rf sputtering and plasma chemical vapor deposition. Spherical CNPs with a mean size of 21.2 nm are sandwiched between DLC layers with a mass density of 1.7 g/cm3. The film stress is decreased to 119 MPa, by depositing the CNPs over the base DLC layer at a surface coverage of 10.7%. This reduction is approximately half of that without CNPs. Raman spectroscopy indicates the insertion of CNPs barely alters the bonding structure of the upper DLC layer.

Punched by needle, spinneret is a critical component of chemical fiber production equipment. Increasing order and short lifetime of punching needle seriously drags the production schedule of enterprise. W-DLC (wolfram-doped diamond-like carbon) film was deposited on the needle in a magnetron sputtering system, and the doping content of wolfram was controlled by adjusting the ratio of Ar to C2H2. A systematic investigation was conducted on the structural and punching performances of the coated needle. The results show that, (1) W-DLC film has a dense structure, and W element exists in phase of W1-XC. (2) W-DLC film plays an important role of the needle protection, and can prolong its lifetime in evidence. (3) W-DLC film coated punching needles can punch up to 6000 times per needle, and its lifetime can be increased to about 200% in the production line.

Diamond-like Carbon (DLC) film has the ability to change the refractive index value achieved high transmittance for potential applications of antireflection coating. DLC films were deposited on heterojunction solar cells by the ECR-CVD (Electron Cyclotron Resonance Chemical Vapor Deposition) method using Acetylene (C2H2) and Argon (Ar) gases. DLC coating affects ITO (Indium tin oxide), causing the electrical and resistivity of heterojunction solar cell vary according to the coating time. The surface and thickness of the DLC films was measured with an atomic force microscope. Illuminated I-V characteristic was investigated by photo-I–V measurements. The suitable acetylene anti-reflection deposition time at 0.40 minutes. Therefore, heterojunction solar cell was fabricated on a substrate using the optimized DLC films as an anti-reflection coating and it obtained an increase efficiency of about 1%.

During the last decade, a major improvement in the field of the Micro-Pattern Gaseous Detectors has been reached by adding a layer of resistive strips above the readout strips to reduce drastically the effect of discharges. The resistive strips are separated from the readout strips by a thin layer of insulator. When the detector is operated some gain reduction is observed over the first seconds or minutes after switch-on, stabilising after some time. Is this related to the presence of the insulator or are there other mechanisms at work? We report here the results of a detailed study of this effect and compare resistive-strip and Diamond Like Carbon (DLC) Micromegas detectors. We will present and quantify the main characteristics of this effect, i.e, the relative gain drop and the time to reach a stable regime, as a function of the detector configuration and rate. In addition we studied the influence of the pillars that support the mesh on the behaviour of bulk and non-bulk Micromegas detectors.

Diamond-like carbon (DLC) film was prepared by magnetron sputtering method on glass substrate. The microstructure, transmittance, and wear resistance of the diamond-like carbon film were investigated and analyzed. This study clearly showed the significance of sputtering power, Ar pressure and substrate temperature in controlling the transmittance and wear resistance of DLC film. The sp3 bond in the film had a greater impact on the transmittance and wear resistance of DLC film. The optimized deposition parameters obtained through experiments were: Ar pressure of 0.7 Pa, sputtering power of 100 W, and substrate temperature of 150 °C.

KrF laser and Ti:Sapphire femto-second laser were used to deposit diamond-like carbon(DLC) films on silicon substrates which were double polished. Optical transmittance and corrosion resistance of these samples were compared. The transmittance of DLC film sample which was deposited by Ti:Sapphire laser in oxygen atmosphere was higher than the sample which was deposited by KrF laser in vacuum. Both samples could pass the salt solubility test and salt fog test. But when dipped in NaOH liquor, the result showed that surface of the sample deposited by Ti:Sapphire laser in oxygen atmosphere appeared corrosive spots first. Reasons were analyzed according to corrosive mechanism.

Diamond-like phases which are three-dimensional carbon nanostructures consist of sp 3-hybridized atoms is of high interest in terms of their mechanical properties. The important issues are the stability of such novel structures and their deformation behavior under various conditions. In the present work, the molecular dynamics method is used to study diamond-like phases of two classes: fulleranes and tubulanes. Twelve stable structures are found Studying the deformation behavior shows that some phases have a very small elastic regime which not allow calculating elastic constants. Under hydrostatic compression, the main deformation mechanisms are changing the lattice parameters and valent angles. At high pressure, transformation to the amorphous phase takes place for several diamond-like phases.

Nowadays, titanium alloy is widely used as orthodontic mini-screw implants due to its suitable mechanical properties and excellence in biocompatibility. However, the excessive torques applied during the insertion of orthodontic mini-screw implant can cause necrosis of the surrounding bone. In this article, the insertion torque of orthodontic mini-screw implants is aimed to reduce during treatment by means of surface coating. The three types of coatings, namely, DLC, F-DLC 2:1 and Si-DLC 2:1 coated on orthodontic mini-screw implants were chosen to take into account the insertion torque values compared with uncoated surface. The friction behaviors of the films in ambient air and dry air were assessed using ball-on-disk friction testing. Cytotoxicity tests were performed using MTT assay. The insertion torque values were measured by physiodispenser. The results indicated that, both measured in ambient air and dry air, the addition of F into the DLC films slightly influenced the friction coefficients, while doping with Si strongly influenced the films. These films also exhibited less cytotoxicity on their surfaces. Furthermore, the insertion torque values decreased when coated orthodontic mini-screw implants with F-DLC 2:1 and Si-DLC 2:1 films. Therefore, the F-DLC 2:1 and Si-DLC 2:1 films can be considered to apply on orthodontic mini-screw implant for reducing the insertion torque.

DLC(a-C:H) film are known for their excellent tribological properties however, possess poor adhesion on metallic substrate causing film delamination. Introduction of adhesive silicon interlayer has showed improvement in the adhesion of DLC-H on metallic substrate. In the present study DLC-H was deposited on tappet valve and silicon wafer using PECVD. The as-deposited DLC-H was characterized using XRD, EDS and Raman spectroscopy. SEM was also used to measure the thickness of the DLC-H coating and the average surface roughness (Ra) was measured using 3D Profilometry. Scratch test was used to determine the COF, adhesion and hardness of the DLC-H coating. The DLC-H coating on tappet valve had weak adhesion compared with DLC-H coating deposited on silicon substrate, which had good adhesion. The result of the Raman spectroscopy revealed a sp3 fraction of 0.43 for the DLC-H deposited on silicon substrate. The thickness of the as-deposited DLC-H film was 1.78 µm, which was measured using SEM to view the cross-section of the as-deposited DLC-H coating on the silicon substrate. The surface roughness of the as-deposited DLC-H coating on silicon substrate was 26.59 nm. Silicon substrate coated with DLC-H had the lowest COF, ranging from 0.06 to 0.09.

In modern particle accelerators, the build-up of electron cloud is a main limiting factor for the achievement of high-quality beam. Among the techniques to mitigate it, coating the internal walls of the beam pipes with a thin film which has a low secondary electron yield (SEY) is considered to be one of the most effective means. From several earlier studies, it was found that diamond-like carbon (DLC) thin films are potential coatings. This paper is mainly about the research on secondary electron emission characteristics of DLC thin films. The secondary electron emission (SEE) tests were done at temperature of 298 K and vacuum pressure of 2 × 10–9 Torr. Here, we obtained the characteristics of the SEE from DLC film coatings with different thickness under ultrahigh-vacuum (UHV) conditions. The maximum secondary electron yield (SEY), δmax, of the DLC thin films under different primary electron doses were also obtained, respectively.

The effect of copper (Cu2+) ions (300 keV) irradiation on the morphological, structural and electrical properties of palladium (Pd) doped diamond like carbon (Pd-DLC) thin films have been studied. The DLC and 5% Pd-DLC thin films are prepared by using RF magnetron sputtering technique. 5% Pd-DLC films are irradiated with Cu2+ (300 keV) ions having 2 × 104 and 4 × 104 atoms/cm2/s fluence rate. SEM, Raman and four point probes are used to analyze morphological, structural and electrical properties of these thin films, respectively. Raman spectroscopy results confirmed about the reduction in internal stress and increase in graphitization nature of films due to Pd and Cu ions incorporation. The maximum graphitization character is obtained at 4 × 104 ions cm−2 s−1 fluence rate. SEM results showed that Pd-Cu metal's cluster formation on the surface of doped and irradiated films. This conducting metal's cluster formation is responsible for the enhancement in electrical properties of Pd-DLC thin films. Four point probes results showed the highly improved electrical properties at fluence rate of 4 × 104 atoms/cm2/s. These results can be applied in various electronics industries due to high conductivity.

Laser micro texturing technique has shown its potential in reducing friction and wear at various mechanical interfaces such as automotive and cutting tools etc. Automotive parts are coated with Diamond-like Carbon (DLC) coatings to enhance their performance. Due to stringent condition at the automotive contacts and demand for performance enhancement, increase in performance of DLC coatings is required. In this study laser micro texturing is being combined with tungsten doped DLC coating. In order to analyze the benefits of laser micro texturing on tungsten doped DLC coating. Tribological testing was conducted on a reciprocating test rig at various loading conditions. The results indicated that laser textured tungsten doped DLC coating showed the lower coefficient of friction compared to un-textured tungsten doped DLC coating at a load of 15 N, 25 N and 35 N. Higher graphitization was observed in the case of un-textured coating at 35 N load.

The roller-shoe assembly is a known and efficient mechanism used for movement transmission in order to obtain mechanical energy. This mechanism is found in high pressure pumps and its role is to change the rotating motion in a translation one. During the running time, some wear types can be identified such as scuffing, corrosion, material removal. Scuffing is the main type of wear appearing in this mechanism. The aim of our paper is to analyse the behaviour of these two components (roller and shoe) over an aggravating test. The main defect is low clearance between components. The roller and shoe assembly is mounted in a diesel fuel pump for test. The test chosen for this experiment is Low Sommerfeld Number. It was stopped after 10% from time set. After visual analysis, it was observed the roller-shoe scuffing. The shoe was analysed and it was observed that the diamond like carbon (DLC) layer is non-conform. In the same pump, the affected components were replaced with new components to be convinced that the wear was caused by low clearance between them correlated to non-conform DLC layer. The test results confirm the reason of scuffing.

The present work aims to investigate the magnetoimpedance (MI) behaviour of electrodeposited nickel incorporated carbon (Ni–C) composite thin films of varying nickel content. Ni–C thin films were synthesized by electrodeposition method at room temperature with low voltage. Low nickel content thin films exhibited diamond-like carbon (Ni–DLC) phase. Considering the variation of magnetoimpedance due to change in transverse magnetic permeability of Ni–C thin films, magnetoimpedance measurements were performed with frequency by applying dc magnetic field in the plane of the film in the range of −1000 Oe < H < 1000 Oe. MI measurements were carried out, by passing alternating current of 1 mA through the samples perpendicular to the magnetic field, at room temperature within a low excitation frequency (up to 100 kHz) range. Magnetoimpedance peaks were observed at 9 kHz in each thin film. Variations in the intensity of MI peaks with magnetic field were also observed. Maximum MI ratio achieved for our samples was 123%, while Ni–DLC thin film showed an MI of 110%. The values of maximum magnetoimpedance of the films were found to change with nickel content in the Ni–C thin films.

Nanocomposite coatings formed by metal (Ti, Al, Cr, etc)-doped diamond like carbon coatings can exhibit excellent tribological properties due to the combined improvement in hardness and toughness in optimized deposition conditions. In this work, Ti-doped a-C:H coatings are successfully deposited at C2H2 flow rate (f C2H2) of 50?250 sccm on Si (100) and AISI 304 L stainless steel substrates using filtered cathodic vacuum arc. Chemical bonding state, microstructure, and mechanical and tribological properties of Ti-doped a-C:H coatings were investigated using XPS, FESEM, nanoindentation and ball-on-disc tribometer, respectively. Nc-TiC/a-C:H nanocomposite coating with dense microstructure and smooth surface morphology are obtained at f C2H2 of 50?250 sccm thanks to high-efficiency magnetic filtered depositions. The sp2/sp3 ratio gradually decrease from 1.6 to 1.1, while (Ti?C)/(C?C) ratio shows a sharp decrease from 0.361 to 0.047. Hardness and H/E* and H3/E*2 ratios decrease from 41.2 GPa, 0.098 and 0.41 at 50 sccm to 22.9 GPa, 0.071 and 0.117 at 250 sccm, respectively. Residual stress ranges from ?0.39 to ?1.72 GPa. Superhard nc-TiC/a-C:H nanocomposite coating with the low residual stress, high H/E* and H3/E*2 exhibit low coefficient of friction of 0.07 and low wear rate of 5.4?×?10?9 mm3 N?1 m?1, which is ascribed to the high sp2/sp3 and (Ti?C)/(C?C) ratios, dense microstructure and smooth surface morphology.

The paper presents the results of erosion tests and metallographic studies of titanium alloy samples manufactured by using 3D printing and traditional technological methods without coatings and with various types of ion-plasma coatings. As a result of the tests, the kinetic curves of erosion wear of the studied alloys and coatings were obtained, showing that the best type among those considered is a DLC (Diamond Like Carbon) coating, which increases the relative erosion resistance of uncoated samples in incubation period duration of the water droplet erosion process by not less than in 1.8 times.

A cylindrical hollow cathode discharge (HCD) in CH4/Ar gas mixture at pressure of 20-30 Pa was used to deposit diamond-like carbon (DLC) films on the inner surface of a stainless steel tube. The characteristics of the HCD including the voltage-current curves, the plasma images and the optical emission spectrum (OES) were measured in Ar and CH4/Ar mixtures. The properties of DLC films prepared under different conditions were analyzed by means of Raman spectroscopy and scanning electron microscopy (SEM). The results show that the electron excitation temperature of HCD plasma is about 2400 K. DLC films can be deposited on the inner surface of tubes. The ratio of sp3/sp2 bonds decreases with the applied voltage and the deposition time. The optimizing CH4 content was found to be around CH4/Ar = 1/5 for good quality of DLC films in the present system.

Multilayer coatings [(TiCx/Ti/a-C)+ta-C]n with different composition of composite (TiCx/Ti/a-C) layers are studied. The dependences of abrasive wear resistance and H3/E2 ratio (H – hardness, E – elastic modulus) of multilayer coatings on the carbon content in the composite layer are determined. The phase composition of the (TiCx/Ti/a-C) layer, the ratio of volume fractions of the phases and the volume fraction of interface component, interlayer adhesion and adhesion to the substrate of the multilayer coating have a synergistic effect on the wear resistance of the testing coatings.

In recent years, diamond-like carbon films (DLC) have been given more attention in research in the biomedical industry due to their potential application as surface coating on biomedical materials such as metals and polymer substrates. There are many ways to prepare metal containing DLC films deposited on polymeric film substrates, such as coatings from carbonaceous precursors and some means that incorporate other elements. In this study, we investigated both the surface and biocompatible properties of titanium containing DLC (Ti-DLC) films. The Ti-DLC films were prepared on the surface of poly (ethylene terephthalate) (PET) film as a function of the deposition power level using reactive sputtering technique. The films' hydrophilicity was studied by contact angle and surface energy tests. Their surface morphology was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Their elemental chemical composition was analyzed using energy dispersive X-spectra (EDX) and X-ray photoelectron spectroscopy (XPS). Their blood and cell compatibility was studied by in vitro tests, including tests on platelet adhesion, thrombus formation, whole blood clotting time and osteoblast cell compatibility. Significant changes in the morphological and chemical composition of the Ti-DLC films were observed and found to be a function of the deposition level. These morphological and chemical changes reduced the interfacial tension between Ti-DLC and blood proteins as well as resisted the adhesion and activation of platelets on the surface of the Ti-DLC films. The cell compatibility results exhibited significant growth of osteoblast cells on the surface of Ti incorporated DLC film compared with that of DLC film surface.