Tribological Properties Of Coatings Research Articles

Characterization of Ni-Based Alloy Submicron WS<sub>2</sub>/CaF<sub>2</sub> Composite Coatings Deposited by High Velocity Oxy-Fuel (HVOF) Spray Process

Ni-based alloy submicron WS2/CaF2 composite coatings were successfully produced through high velocity oxy-fuel (HVOF) spraying process. Microstructure characterization and morphology analysis on coatings were conducted using scanning electron microscopy and X-ray diffractometry. Tribological properties of coatings were carried out using a pin-on-ring tribometer at room temperature and 500°C, respectively. Results showed that WS2 in particles did not entirely decomposed during spraying process, submicron WS2 and CaF2 were uniformly distributed throughout the coating. Which lead a dense coating and a lower friction coefficient and better wear resistance. In ambient temperature, WS2 in coatings played a main role of lubrication, friction coefficient of coatings was in the rage of 0.25~0.35. But with the increasing of temperature, WS2 failed to provide solid lubricating films for pyrolysis, and CaF2 did not fully transfer from brittleness to plasticity, restrained solid lubricating film forming, friction coefficient reached to 0.45. Furthermore, average adhesive strength between coating/substrate was above 30MPa, which had positive affect on wear resistance of coatings.

Structure and tribological properties of MoCN-Ag coatings in the temperature range of 25–700 °C

The preparation of hard coatings with low friction coefficient over a wide temperature range is still a challenge for the tribological community. The development of new nanocomposite materials consisting of different metal-ceramic phases, each of which exhibiting self-lubricating characteristics at different temperatures, may help to solve this problem. We report on the structure and tribological properties of MoCN-Ag coatings deposited by magnetron co-sputtering of Mo and C (graphite) targets and simultaneous sputtering of an Ag target either in pure nitrogen or in a gaseous mixture of Ar+N2. The structure and elemental composition of the coatings were studied by means of X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, Raman spectroscopy, and glow discharge optical emission spectroscopy. The tribological properties of the coatings against an Al2O3 ball were investigated first at discrete temperatures of 25, 500, and 700°C, and then during continuous heating in the temperature range of 25–700°C. The coating structure and their respective wear tracks were also examined to elucidate their phase transformations during heat treatments. The lowest friction coefficients (<0.4) were observed in the temperature ranges of 25–100°C and 400–700°C and can be explained by the presence of a free amorphous carbon phase, which served as a lubricant at low temperatures, and by a positive role of silver and two phases forming at elevated temperatures, molybdenum oxide and silver molybdate, which provided lubrication above 400°C. In the temperature range between 100 and 400°C, the friction coefficient was relatively high. This problem is to be addressed in future works.

Study on Tribological Properties of ZrO&lt;sub&gt;2&lt;/sub&gt; Ceramic Coating with APS

TheY2O3 partially stabilized in ZrO2 and the MgO partially stabilized in ZrO2 ceramic coating were sprayed by APS on 45 steel substrate, and the tribological properties of coatings were tested on the MMW-1 vertical universal friction and wear tester at room temperature and dry sliding conditions. With FA2004 electronic balance, the amount of the loss of coating is measured. The wear of the coating surface morphology is observed by scanning electron microscopy. The test results show that wear resistance of Y-PSZ coating is better than Mg-PSZ coating. There are some cracks, voids and peeling pits in two kinds of coating. A material transfer is occurred during the friction and wear.

Effects of vanadium ion implantation on microstructure, mechanical and tribological properties of TiN coatings

TiN coatings were deposited on the substrates of cemented carbide (WC–TiC–Co) by Magnetic Filter Arc Ion Plating (MFAIP) and then implanted with vanadium through Metal Vacuum Vapor Arc (MEVVA) ion source with the doses of 1×1017 and 5×1017 ions/cm2 at 40kV. The microstructures and chemical compositions of the V-implanted TiN coatings were investigated using Glancing Incidence X-ray Diffraction (GIXRD) and X-ray Photoelectron Spectroscopy (XPS), together with the mechanical and tribological properties of coatings were characterized using nano-indentation and ball-on-disk tribometer. It was found that the diffraction peaks of the V-implanted TiN coatings at the doses of 5×1017 ions/cm2 shifted to higher angles and became broader. The hardness and elastic modulus of TiN coatings increased after V ion implantation. The wear mechanism for both un-implanted and V-implanted TiN coatings against GCr15 steel ball was adhesive wear, and the V-implanted TiN coatings had a lower friction coefficient as well as a better wear resistance

Mechanical and Tribological Properties of Diamond-Like Carbon Coatings with Different Ni Content

Ni-doped diamond-like carbon coatings were deposited on silicon wafer by magnetron sputtering. The Ni content was controlled by changing the Ni target current. The Ni content, mechanical properties and tribological properties of the coatings were systematically studied by Raman spectroscopy, nano-indentation and ball-on-disc tester. The highest hardness and internal stress are obtained at the Ni content of 2.3%. The friction coefficient and wear rate lower with the decreased of the Ni content, which may be responsible for the excellent tribological properties.

Tribological Properties of Plasma-Sprayed 20 wt. % Z&lt;sub&gt;r&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;-17 wt.% TiO&lt;sub&gt;2&lt;/sub&gt; Coatings on Plain Carbon Steel Substrate

In the present study, 20 Wt. % ZrO2-Al2O3-17 wt.% TiO2 powders were sprayed using a plasma-spray technique after a NiAl bond layer was deposited on plain carbon steel substrate. The produced coatings were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) including energy-dispersive spectroscopy (EDS). The tribological properties of coatings against hard alloy ball were investigated by using a pin-on-disc tribo-meter under dry environments. The predominant wear mechanism of coating is fatigue.

Tribological investigation of MoS2 coatings deposited on the laser textured surface

Deposition of solid lubricant on the textured surface is an effective way to improve tribological properties of counterparts. In this paper, MoS2 solid lubricant coating was fabricated by a combination technology of laser texturing and hot-pressing. The influences of preparation methods and texture density on the tribological properties of coatings were also investigated. Research results show that a thicker and denser coating having better adhesion with the textured steel substrate was fabricated by this combination technology, which results in excellent tribological properties. The friction coefficients of hot pressed coatings are less than 0.1. The wear life of hot pressed coating can be reached 90min with a texture density of 8.5%, which is 15 times higher than that of coating fabricated by burnishing. In addition, the wear life of hot pressed coating significantly increases with the increase of texture density. The possible friction reduction and wear resistant mechanisms are discussed.

The effect of surface pre-treatment and coating post-treatment to the properties of TiN coatings

Nowadays physical vapour deposited (PVD) coatings are widely used in a variety of different applications to reduce the wear of tools. Thin hard coatings have good wear resistance only when they have good adhesion and certain surface roughness. Thus, dry micro-abrasive blasting method with SiC abrasive was implemented as a pre-treatment process on WC-Co substrates. Post-treatment was conducted by using drag grinding method. The effect of surface pre- and post-treatment on the adhesion and tribological properties of TiN hard coatings have been investigated. TiN hard coatings were deposited by means of lateral rotating cathode arc method with the thickness of 2.3 µm. The surface roughness was measured by means of Mahr Perthometer and the standard Rockwell adhesion test was implemented to evaluate the adhesion of PVD TiN coatings. Tribological properties were determined by ball-on-disk method. The experimental part was focused on the effect of microblasting on the tribological properties of the coating. The relation between post-treatment of the coating and friction coefficient is indicated.

Effect of Ce on Wear Behavior of Plasma Spray Welded Novel Aluminum Bronze Coatings

Aluminum bronze powders with free and 0.1wt%Ce were plasma spray welded on 45# carbon steel substrate, Effects of rare earth Ce on the microstructure and wear resistance of plasma spray welded novel aluminum bronze coatings were investigated. Tribological properties of coatings were tested on reciprocating sliding tester. Results showed that a small amount of Ce (0.1wt %) in novel aluminum bronze coating can refine the coating microstructure and the coating with 0.1wt%Ce process higher wear resistance compared to the Ce-free coating. Both of the coatings have different wear mechanisms.

Influence of TiC/a-C phase on tribological properties of composite coatings

Gas phase carburisation of titanium in CH4 atmosphere was carried out in a thermogravimetric analyser. The analysis revealed the formation of TiC phase embedded in an amorphous carbon (a-C) matrix. Raman scattering investigation revealed the evolution of two separate peaks corresponding to D and G band vibrational modes in a hexagonal sp phase of the graphite-like structure. The tribological properties of this coating relied significantly on the relative extent of D and G band modes with the evolution of TiC phase. A sharp transition of friction from lower to higher value was observed due to the wearing out of tribolubricant phases of TiC with disordered graphite-like structure present in the a-C matrix. In case of thicker coating, a lower regime of friction was observed with longer wear distances.

Ways of improving the tribological properties of steel gas-flame coatings

The paper reports the results of study of the structure and properties of steel gas-flame coatings. The effect of the formation of an abnormally great amount of retained austenite during the deposition of coatings from steel wire is found. Techniques for implementing the “austenite effect” to improve the wear resistance of the coatings are proposed. A method for introducing a solid lubricant into the coating during its deposition is developed. A possibility of enhancing the tribological properties of the coatings for friction members is shown. It is based on thermochemical treatment (nitrocarburizing) and tribomodification of the friction surfaces during running-in with a lubricant containing nanosized modifiers.

The Effects of Mechanical and Tribological Properties of Coatings on Scratch Generation in Chemical-Mechanical Polishing

In chemical mechanical polishing, even the soft pad asperities may, under certain conditions, generate scratches on relatively hard surfaces. The present study, accordingly, focuses on the effects of coating and pad hardnesses and of interfacial friction on scratch generation. The hardness of various thin films (Al, Cu, SiO2, Si3N4, TiN and three low-k dielectrics) and of a CMP pad were determined by a Hysitron Triboindenter. Additionally, the coefficients of friction between the pad and the coatings were determined by sliding friction experiments. Scratches were produced only on the Al and Cu coatings, whose hardness and friction conditions fall in the scratching regime of the scratch-regime map. No scratches were produced, not surprisingly, on hard coatings even at high friction.

The Effects of Mechanical and Tribological Properties of Coatings on Scratch Generation in CMP

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The Influence of Plasma Nitriding Pre-Treatment on Tribological Properties of TiN Coatings Deposited by PACVD

The aim of this study is to investigate the effect of plasma nitriding pre-treatment (PN) on mechanical and tribological behavior of TiN coatings produced by plasma-assisted chemical vapor deposition (PACVD). The heat treatment of quench and temper was carried out on hot work AISI H11 (DIN 1.2343) steel samples. A group of samples were plasma nitrided at 500 °C for 4 h in an atmosphere containing 25 vol.% nitrogen and 75 vol.% hydrogen. Then TiN layer was deposited on all of samples at 520 °C temperature, 8 kHz frequency, and 33% duty cycle. The microstructural, mechanical, and tribological properties of the coatings were investigated using SEM, WDS, AFM, microhardness tester, and pin-on-disc wear test. The load of wear test was 10 N and the samples were worn against different pins, ball-bearing steel (DIN 1.3505), and cemented tungsten carbide (WC-Co). The results indicate that the difference of hardness between the samples with PN-TiNlayer and those samples with only TiN layer without PN was 450 HV and the former samples showed a significant amount of wear resistance in comparison to the latter ones.

Tribological properties of SiC coatings deposited by r.f. magnetron sputtering as a function of substrate temperature

Silicon carbide coatings have been deposited by r.f. magnetron sputtering on AISI 304LN stainless steel at four different substrate temperatures. At the lowest substrate temperature of 300°C, the film was amorphous whereas at a substrate temperature of 600°C a crystalline SiC phase was obtained. However, at substrate temperature of 800°C, the films were amorphous again. The tribological properties of the coatings were also found to change with substrate temperature. The coefficient of friction was found to be low for the crystalline films. Such a low value of coefficient of friction is indicative of superior wear resistance. A higher coating thickness enhanced the tribological properties while any surface roughness of the substrate and coating was found to degrade these properties. Micro-Raman spectra of the films varied with substrate temperature. Some phases were found to disappear and new phases were observed in the wear track with progressive sliding.

기판 바이어스 DC 전원의 종류와 반응가스 분압비가 3성분계 B-C-N 코팅막의 합성과 마찰 특성에 미치는 영향

Ternary B-C-N coatings were deposited on Si(100) wafer substrate from target by RF magnetron sputtering technique in gas mixture. In this work, the effect of reactant gas ratio, on the composition, kinds and amounts of bonding states comprising B-C-N coatings were investigated using two different bias power sources of continuous and unipolar DCs. In addition, the tribological properties of coatings were studied with the composition and bonding state of coating. It was found that the substrate bias power had an effect on chemical composition, and all of the obtained coatings were nearly amorphous. Main bonding states of coatings were revealed from FTIR analyses to be h-BN, C-C, C-N, and B-C. The amount of C-C bonging mainly increased with increase of the reactant gas ratio. From our studies, both C-C and h-BN bonding states improved the tribological properties but B-C one was found to be harmful on those. The best coating from tribological points of view was found to be composition.

Tribological properties of nanostructured TiC coatings deposited on steel and silicon substrates using pulse laser deposition technique

Thin coatings of nanostructured titanium carbide (TiC) were deposited on silicon (Si) and stainless steel (AISI 304LN SS) substrates using pulse laser deposition technique. In these experiments, the deposition parameters were kept constant except deposition pressure. Change in the deposition partial pressure of CH4 gas did not significantly influence the morphology and phase constituents of TiC coatings. In this regard, the tribological properties of these coatings were found to be almost similar. Coating thickness and surface roughness were found to alter with the type of substrate used. The tribological properties of these thin coatings were evaluated as a function of the different sliding counter bodies. The tribological properties were also studied on Si and SiO2 to find out the role of substrate on friction and wear. The contact deformations as well as the morphologies of wear scars were found to influence the coefficient of friction.

Multilayer nanostructured heat-generating coatings. Preparation and certification of mechanical and tribological properties

The state of problems for preparing and using multilayer nanostructured heat-generating films and coatings is considered. A method is proposed for preparing binary Ti/Al coatings. The composition, structure, adhesion and tribological properties of coatings on substrates of various materials are studied. It is shown that the hardness of a Ti/Al coating increases with a reduction in single layer thickness.

Effect of a multilayer structure and lubrication on the tribological properties of coatings of Fe-W alloys

The methods for expanding the use of nanocrystalline electrolytic Fe-W alloys by creating a multilayer structure and using oil lubrication were studied. It was shown that lubricants can reduce the coefficient of friction and oxygen penetration into the sliding pairs, thus enhancing the wear resistance behaviour of Fe- W coatings as compared to that at dry friction, when the surface tribo-oxidation dominates. The electrodeposition of multilayer Fe-W/Cu coatings from a single bath was shown to be feasible. The tribological and mechanical properties of such coatings were investigated. The multilayer structure was found to improve the wear resistance characteristics of the coatings even at dry friction and at a relatively high normal load of 10 N.

Study and simulation of the growth of solid lubricant MoSe x coatings during pulsed laser deposition

The chemical composition and tribological properties of the thin-film diselenide molybdenum coatings deposited by pulsed laser deposition in vacuum and a rarefied inert gas (argon) atmosphere are studied. Upon deposition in a gas at a pressure of ∼2 Pa, stoichiometric coatings with improved antifriction properties as compared vacuum-deposited coatings form. However, a too strong increase in the argon pressure (to ∼10 Pa) degrades the tribological properties of the coating. Structure formation in the MoSe x coatings grown by pulsed laser deposition on an unheated substrate is investigated. Deposition in vacuum or argon at a pressure of 2 Pa leads to formation of rather smooth coatings with a dense amorphous structure containing molybdenum nanoinclusions. Deposition at a high argon pressure results in a developed surface relief and a loose coating structure. A mathematical model is developed using the kinetic Monte Carlo method in order to describe structure formation in the coatings that grow during physical deposition of an atomic flux. A comparative analysis demonstrates satisfactory agreement between the simulated and experimentally studied structures in the coatings created by pulsed laser deposition at various gas pressures.