Wear Resistance Of Hard Coatings Research Articles

Deposition of Wear-Resistant Nanocomposite Coatings from Accelerated С<sub>60</sub> Ions

Hard wear-resistant carbon coatings were deposited from accelerated C60 ions at temperatures of 200 and 300°C. It has been established that the mechanical properties of the coatings are determined by the substrate temperature (Ts) and the energy composition of the beam. The hardness of coatings deposited from C+60 ions with an energy of 7 keV exceeds 50 GPa and is virtually independent of Ts. The presence of C602+ and C603+ with an energy of ~14 and 21 keV, respectively, in the beam leads to a result that is not typical for carbon coatings – the hardness increases by more than 1.3 times with an increase in Ts from 200 to 300°C (from 31.6 GPa to 41.6 GPa). In this case, according to Raman spectroscopy data, the size of graphite nanocrystals in the coating increases with temperature up to almost 2 nm. Coatings obtained under conditions of irradiation with C602+ and C603+ ions are characterized by minimal wear (1.5×10–8 mm3/N∙m, Ts = 200°C) and minimal friction coefficient (µ = 0.05 for Ts = 300°C). We attribute the unusual dependence of hardness on Ts and the improvement in the tribological properties of coatings to the formation of a composite structure based on a diamond-like matrix and graphite nanocrystals in this range of Ts.

Machining of Ni-based superalloys using CAPVD coated carbide tools

The ever-increasing demand for cost-effective machining of Ni (Nickel) based superalloys has made it necessary to explore nanocomposite coatings as a potential surface engineering solution. The present study aims to investigate the variation in machining performance of new-generation hard wear-resistant coatings in milling of IN 718 (Inconel 718), IN 625 (Inconel 625), and IN 617 (Inconel 617). TiAlSiN and CrAlSiN coatings were grown in-house over tungsten carbide (WC) milling inserts through the cathodic-arc PVD route. The TiAlSiN coating improved the tool life by 80 % and 60 % in the case of IN 718 and IN 625, respectively. However, in the case of IN 617, the TiAlSiN-coated tool could not even reach the uncoated tool life. The CrAlSiN coating, on the other hand, improved the tool life by more than 200 % in the milling of IN 617. Tool-chipping was the dominant failure mode among all observed, which included flank wear and workpiece adhesion. The repeated adhesion and removal of the workpiece layer from the tool surface was a major cause of tool failure. The coating layer delayed the initiation of the chipping and prolonged the flank-wear-dominated machining time, resulting in improved tool life. The wear resistance of coatings in machining different workpiece materials was greatly influenced by the relative affinity of constituting elements of workpieces for employed coatings. The machining chips exhibited shear bands and saw-tooth (serrated/segmented) morphology in almost all cases. The degree of segmentation showed a direct correlation with tool life. The present work helps identify the optimum coating and machining conditions for three different grades of Ni-based superalloys. Additionally, the underlying mechanisms were analyzed and discussed with scientific observations.

BRIEF OVERVIEW OF METHODS FOR PRODUCING TiSiCN COATINGS AND THE METHOD OF REACTIVE PLASMA SPRAYING

Modern materials science sets itself the task of developing new materials with multifunctional coatings. Materials with such coatings are widely used in various fields of technology: construction and energy, microelectronics, aviation and others. The main reason for the emergence and development of technology for applying multifunctional protective coatings is the desire to increase the durability of parts and assemblies of various machine mechanisms. Wear-resistant hard coatings based on transition metal nitrides and carbonitrides are widely used to extend the life of forging and extrusion dies and high-speed machining tools. Over the past two decades, the widespread use of these coatings has stimulated and supported the development of new processes and materials in an attempt to further improve their properties. Among these coatings, the higher hardness, excellent oxidation resistance and high thermal stability of coatings such as TiSiN and TiSiCN make them the most promising candidates for demanding tribological applications. In addition, TiSiCN coating is a promising material used in marine environments due to its excellent anti-wear and corrosion resistance, as well as high hardness and low friction coefficient. These combinations of properties make TiSiCN coatings potential candidates for protective layers in the automotive and petroleum industries.The article briefly examines the possibilities of producing TiSiCN coatings using different deposition methods to control the properties of the resulting films and the features of the reactive plasma spraying method. The work describes the most common methods and technologies for producing carbonitride coatings currently used. The latest developments and current trends in the field of plasma spray coating technologies are reviewed, taking into account important innovations for industrial coatings. New conclusions that were obtained as a result of fundamental and applied research in physics or chemistry are based on them. The article provides a comparative review of the characteristics of obtaining wear-resistant TiSiCN coatings and the features of using reactive plasma spraying to obtain wear-resistant coatings. Based on an analysis of the literature, it can be argued that the further development of reactive plasma technology is associated with the development of a new resource-saving method for the formation of composite coatings with increased corrosion and tribological characteristics, which corresponds to the development trends of world science.

The tribological properties of two-phase hard and soft composite wear-resistant coatings on titanium alloys

There are still problems associated with the use of conventional modified coatings on titanium alloys despite their attempts to improve wear resistance. These problems include incompatibility of mechanical properties, a poor interface bond, and an abundance of debris. The development of wear-resistant coatings with high reliability and long life is a vital component of expanding the use of titanium alloy in medical implants. The purpose of this study was to produce a composite coating with antifriction and wear-resistant properties by combining the high hardness TiN layer with the soft phase lubricated Cu layer produced by ion implantation and electroless plating. The implantation of Cu ions provided the nucleation sites for electroless copper plating and improving interfacial bonding. There was a reduction in adhesive wear due to the composite coating. By comparing the tribological test results of the composite coating and substrate, the volume loss of coatings decreased by 95 % for the same sliding length, the wear rate decreased from 2.55 × 10−13 m3/N·m to 1.28 × 10−14 m3/N·m, the friction coefficient reduced by 10 % and smoother. As a result of the synergistic effects between the soft and hard phases in the composite coating, titanium alloy exhibited an enhanced wear resistance as the wear process progressed.

Синтез карбида и диборида титана для металлообработки и получения керамики

Introduction. Titanium carbide and diboride are characterized by high values of hardness, chemical inertness and for this reason are widely used in modern technology. This paper provides information on the synthesis of titanium carbide and diboride by carbothermal and carbide-boron methods, respectively, on the use of titanium carbide as an abrasive and in the manufacture of tungsten-free hard alloys, carbide steels, wear-resistant coatings, as well as titanium diboride in the production of cutting tools and ceramics based on boron carbide The aim of this work is to study the processes of synthesis of highly dispersed powders of titanium carbide and diboride, which are promising for the manufacture of cutting tools, wear-resistant coatings, abrasives and ceramics. Research methods. Titanium oxide TiO2, nanofibrous carbon (NFC), and highly dispersed boron carbide were used as reagents for the synthesis of titanium carbide and diboride. Experiments to obtain titanium carbide were carried out in a resistance furnace, and titanium diboride in an induction furnace. X-ray studies of the phase composition of titanium carbide and diboride samples were carried out on an ARL X-TRA diffractometer (Thermo Electron SA). The determination of the content of titanium and impurities in the samples of titanium carbide and diboride was carried out by the X-ray spectral fluorescence method on an ARL-Advant'x analyzer. The total carbon content in the titanium carbide samples was determined on an S-144 device from LECO. The content of boron and other elements for titanium diboride samples was determined by inductively coupled plasma atomic emission spectrometry (ICP AES) on an IRIS Advantage spectrometer (Thermo Jarrell Ash Corporation). The surface morphology and particle sizes of the samples were studied using a Carl Zeiss Sigma scanning electron microscope (Carl Zeiss). The determination of the particle/aggregate size distribution was performed on a MicroSizer 201 laser analyzer (BA Instruments). Results. The paper proposes technological processes for obtaining highly dispersed powders of titanium carbide and diboride. The optimum synthesis temperature for titanium carbide is 2,000…2,100 oC, and for titanium diboride 1,600…1,700 oC. The content of the basic substance is at the level of 97.5…98.0 wt. %. Discussion. A possible mechanism for the formation of titanium carbide and diboride is proposed, which consists in the transfer of vapors of titanium oxides to the surface of solid carbon (synthesis of titanium carbide) and vapors of boron and titanium oxides to the surface of solid carbon (synthesis of titanium diboride). Due to the high purity and dispersion values, the resulting titanium carbide powder can be used as an abrasive material and for the manufacture of tungsten-free hard alloys, carbide steels, wear-resistant coatings, and titanium diboride powder can be used for the preparation of cutting tools and ceramics based on boron carbide.

Crack and Wear Resistance of Hard Coatings

Crack and Wear Resistance of Hard Coatings

A Quick and Accurate Method to Determine Submicron Size Coating Thickness Using Micro-Indentation along with a Mathematical Model

Hard and adherent wear-resistant thin surface coatings are synthesized on an aerospace alloy AA2219-T6 alloy using plasma-assisted physical vapor deposition. Submicron size TiN coatings with Ti interlayers are deposited and evaluated as a function of different deposition temperatures varying from 100 °C to 200 °C. Features of deposited surface layers are evaluated using different techniques; these include field emission scanning electron microscopy equipped with energy dispersive spectroscopy and X-ray diffraction. Mathematical models developed by Yu. A. Bykov and S. Hogmark are considered to estimate the coating thickness using the Composite Hardness measurements. The values predicted by Bykov’s model grossly underestimated the thickness values and thus a correction factor is proposed. The actual coating thickness is measured by sandwiching the thin coating between the substrate and electrolytically deposited nickel layer; the observations are made using field emission scanning electron microscope. The present study successfully used corrected Bykov’s Model along with micro-indentation proved to be an easy, quick and accurate method to estimate the coating thicknesses of thin hard coatings on the soft substrate over a wide range coating thicknesses.

Improving the Wear Resistance of Piston Rings of Internal Combustion Engines when Using Ion-Plasma Coatings

Modern designs of piston rings of internal combustion engines and wear-resistant coatings used for them are considered. It is noted that the upper (compression) ring undergoes the most intense wear. Among the traditionally used wear-resistant coatings of compression rings, galvanic chrome plating and thermal spraying with molybdenum are most often used. The paper proposes the use of the ion-plasma spraying method for applying hard wear-resistant coatings to the working surface of piston rings based on titanium and molybdenum nitrides. The specified method relates to vacuum coating technologies (PVD methods), in which layers of high-strength materials are sprayed directly onto the surface of the product. The present work aimed to carry out comparative tribotechnical tests of piston ring samples having hard coatings obtained by ion-plasma spraying and to compare them with traditional galvanic chromium plating. A technique has been developed for a comprehensive assessment of comparative tribological characteristics, including the critical load during testing, the specific load of seizing, the coefficients of friction, scoring resistance, and wear resistance. The test results of samples with the galvanic coating with chromium, ion-plasma spraying with titanium nitride, and molybdenum nitride are shown. In contrast, it is shown that samples with an applied ion-plasma coating surpass samples that are electrolytically chrome plated by all tribological parameters. The results obtained allow concluding that the ion-plasma coating of molybdenum nitride is promising for piston rings, as well as other critical parts of internal combustion engines.

Hybrid Technology Combining Vacuum Electrospark Alloying, Cathodic Arc Evaporation, and Magnetron Sputtering for the Deposition of Hard Wear-Resistant Coatings

A novel technology for the deposition of multilayer coatings is proposed. This technology combines electrospark alloying (ESA), pulsed arc evaporation (PAE), and magnetron sputtering (MS) in one vacuum production process. Layers can be deposited using one electrode material at operating pressures from 0.1 Pa to atmospheric pressure. The lower ESA layer provides increased substrate rigidity, perfect adhesion, and a relatively high (up to 100 μm) coating thickness. The upper PAE or MS layer, up to 10 μm in thickness, yields high mechanical and tribological characteristics. The deposition technology of bilayer PAE–ESA and MS–ESA coatings is approved for substrates made of structural and tool steels, titanium alloys using electrodes made of cemented carbides (WC–Co, TiCNiAl), and carbon.

High Wear Resistance of Magnetron Sputtered Cr80Si20N Nanocomposite Coatings: Almost Independent of Hardness

Hardness has been popularly considered as an essential factor defining the wear resistance of hard coatings. Here, we report magnetron sputtered Cr80Si20N nanocomposite coatings, of widely varied packing densities, that exhibited identical specific wear rates, while the hardness changed over a wide range (from ~12 to ~36 GPa). All the Cr80Si20N coatings were free of extended and uninterrupted columnar boundaries, and retained low specific wear rates in the ball-on-plate sliding tests against Al2O3 counterpart with a normal load of 5 N (less than 3.0 × 10−16 m3/N m under ambient condition and less than 2.0 × 10−15 m3/N m under 3.5 wt% NaCl solution, respectively). Post examination reveals extensive interruption or termination of cracks in the wear tracks of the under-dense coatings, indicative of extrinsic toughening mechanisms by effective relief of local contact stress. Our results suggest that a critical role of toughening rather than hardening, played in enhancing the wear resistance of hard coatings, and thus would pave a way to develop highly wear-resistant coatings with a low hardness.

Effect of Ti interlayer on mechanical properties of TiZrN coatings on D2 steel

The objective of this study was to investigate the effect of Ti interlayer on the stress relief and mechanical properties of TiZrN coatings with thickness up to 3 μm. TiZrN coatings with 250-nm Ti interlayer (TiZrN/Ti) were deposited on AISI D2 steel substrate using unbalanced magnetron sputtering. In addition to TiZrN/Ti specimens, two more sets of specimens were prepared for comparison, namely, TiN and TiZrN monolayer coatings. The results showed that Ti interlayer can enhance the (111) preferred orientation of the thinner TiZrN coatings (≤1 μm); however, the preferred orientations of the thicker coatings (>1 μm) showed weak dependence on the Ti interlayer. The stresses in the TiZrN top layer, Ti interlayer and steel substrate were respectively measured using cos2αsin2ψ X-ray diffraction method. The results indicated that the stress in the top TiZrN layer was relieved by both Ti interlayer and the steel substrate for most of the TiZrN/Ti specimens, except for the specimen with 0.53 μm TiZrN, where the stress in the top TiZrN layer was mainly relieved by Ti interlayer. The stress relief reached a maximum in sample with 1.46 μm TiZrN. Then, the stress in TiZrN increased with the film thickness up to 3 μm, where the stress relief was mainly by the steel substrate. The results of scratch test showed that Ti interlayer could increase the adhesive strength. The wear resistance cannot be evaluated by individually considering residual stress or coating thickness. Instead, the elastic stored energy (Gs) combining the residual stress and coating thickness is a better index for evaluating the wear resistance of hard coatings. Adding a Ti interlayer may increase the wear resistance for coatings ≤1 μm; however, the wear resistance may decrease for thicker TiZrN coatings (>1.5 μm) due to the increase of Gs which decreases the capacity in absorbing the external input energy.

Systematic ab initio investigation of the elastic modulus in quaternary transition metal nitride alloys and their coherent multilayers

We give a comprehensive overview of the elastic properties of cubic quaternary transition metal nitride alloys and coherent nitride multilayers for design of wear resistant hard coatings. The elastic stiffness constants of the alloys are calculated using the special quasirandom structure method. For multilayers with sharp interfaces we prove the applicability of a linear-elasticity approximation and show that it can be used with success instead of performing direct computationally demanding ab initio calculations. We explore the trends and the potential of multicomponent alloying in engineering the strength and ductility of both, quaternary alloys and their multilayers. We investigate X(1−x−y)TixAlyN alloys where X is Zr, Hf, V, Nb or Ta, and present an analysis based on increasing x. We show that with increasing Ti content ductility can increase in each alloy. Elastic isotropy is observed only in (Zr,Hf,V)(1−x−y)TixAlyN alloys in the middle of the compositional triangle, otherwise a high Young's modulus is observed along [001]. We predict that coherent TiN/X(1−x−y)TixAlyN and ZrN/X(1−x−y)TixAlyN alloy multilayers with the [111] interfacial direction show increasing ductility with increasing x, while the multilayers with the [001] orientation become more brittle. We show that the Young's moduli variation in the parent bulk quaternary nitride alloy provide a reliable descriptor to screen the Young's modulus of coherent multilayers in high-throughput calculations.

Structure and Properties of the Tool Ceramics with Hard Wear Resistant Coatings

Abstract This work presents studies of the structure and functional properties of coatings deposited onto indexable inserts made of nitride and sialon tool ceramics with the required properties, i.e. high adhesion, microhardness, high resistance to abrasive and diffusion wear in working conditions of high-performance cuttings tools. In the present paper the results of the investigations of the structure, texture, mechanical and functional properties of the Ti(C,N), (Ti,Al)N, Ti(C,N)+(Ti,Al)N coatings were presented. The 80% increase in the hardness of the coatings in comparison to the substrate material was reported. Test coatings are characterized by good adhesion to the substrate. The maximum Lc load of (Ti,Al)N coat applied to the substrate from the nitride ceramics is equal to 42 N. In the studied coatings compressive stresses were found. The results of mechanical properties investigations, especially tribological ones correlate with the results of exploitation tests carried out during the cutting test.

Mechanical properties and high temperature oxidation of CrAlSiN/TiVN hard coatings synthesized by cathodic arc evaporation

Abstract Wear resistant hard coatings are highly demanded in modern manufacturing industry to ensure good performance of cutting and forming tools. In this study, TiVN, CrAlSiN and multilayered CrAlSiN/TiVN coatings were synthesized by cathodic-arc evaporation (CAE). TiV and CrAlSi alloy cathodes were used for the deposition of multilayered CrAlSiN/TiVN coatings. The cathode current and bias voltage of both TiV and CrAlSi cathodes were controlled at 70 A and − 120 V, respectively. By controlling the rotation speed of 4 rpm, a stepwise columnar structure containing periodic CrAlSiN and TiVN layers was found in this multilayered CrAlSiN/TiVN coating. The modulation period of the deposited CrAlSiN/TiVN coatings was 9 nm. The CrAlSiN/TiVN coatings possessed higher hardness of 33 GPa as compared to TiVN and CrAlSiN (24 GPa26 GPa). After oxidation at 500 °C, the TiVN revealed the presence of TiO 2 , V 2 O 5 and VO 2 on the surface. Small fraction of oxygen displaced nitrogen. Titanium and vanadium oxides were formed. The XPS, XRD and SEM analyses only suggested small amounts of titanium and vanadium oxides on the surface of the multilayered CrAlSiN/TiVN after oxidation at 500 °C. To study the impact fracture resistance, an impact test using a cyclic loading was conducted. The multilayered CrAlSiN/TiVN coating exhibited the best impact resistance (higher than 4 × 10 5 impacts) at room temperature and 500 °C, indicating the best resistance to impact fracture, among the studied coatings. The multilayered structure with TiVN and CrAlSiN is responsible for the enhanced mechanical properties, oxidation resistance and impact resistance.

Structure, tribocorrosion and biocide characterization of Ca, P and I containing TiO2 coatings developed by plasma electrolytic oxidation

In hip joint implants, in particular in the stems, wear-corrosion effects can accelerate the degradation of the biomaterial. The lack of osseointegration and the risk of contracting implant-associated infections may be other reasons for a premature failure of the implant. In this work, TiO2 coatings have been developed by means of plasma electrolytic oxidation (PEO) technique in order to achieve wear-resistant hard coatings with osseointegration ability and biocide characteristics. During the PEO process, elements that favor cell growth, like Ca and P, were introduced into the coating. With the purpose of providing the coating with antibacterial properties iodine was added like biocide agent. The microstructure and chemical composition of the developed coatings were analyzed in order to see if the surface of the films was suitable for the cell attachment. The effect of wear-corrosion synergy was studied by means of tribocorrosion tests. Finally, the biocide capacity of iodine against Staphylococcus aureus and Staphylococcus epidermidis was analyzed through bacterial adhesion tests. High wear and corrosion resistance was shown in one of the developed coatings. The achieved surface microstructures seem to be appropriate to improve the osseointegration with proper pore size and porosity index. The antibacterial capacity of iodine was confirmed for S. epidermidis.

Advanced characterization methods for wear resistant hard coatings: A review on recent progress

Abstract Due to economical demands to further increase the efficiency of production processes, it is essential to exploit the full potential of wear resistant hard coatings. This is, however, possible only if the coating microstructure and properties are well characterized. Thus, in the present work, recently suggested advanced characterization techniques for coatings are reviewed. The application of atom probe tomography, electron backscatter diffraction and synchrotron X-ray nanodiffraction enables previously unrevealed insights in their chemical composition, microstructure and crystallographic structure. For the determination of mechanical and tribological properties at elevated temperatures, high-temperature nanoindentation and high-temperature ball-on-disk tests in combination with in-situ measurement techniques are discussed. Utilization of micromechanical tests for coatings provides information about their fracture toughness and rupture strength. High-temperature X-ray diffraction and biaxial stress temperature measurements for the determination of the coefficient of thermal expansion are compared. The thermal conductivity as well as the specific heat capacity of coatings can be studied using the 3- ω technique, time domain thermoreflectance and differential scanning calorimetry. The introduced portfolio of characterization techniques enables the determination of a complementary microstructural, mechanical and thermo-physical fingerprint of wear resistant hard coatings, which allows to understand the complex structure–property relations in these materials and subsequently to further improve their performance.

Nanoscale friction as a function of activation energies

Understanding the scale-dependence of friction is increasingly viewed as a critical quest. With progressively thinner films, mixed and boundary regimes of lubrication have become commonplace. Therefore, at the micro-scale a greater need for mitigating friction is desired in order to improve operational efficiency of many machines and mechanisms. Furthermore, there is a growing tendency to use low friction hard wear-resistant advanced coatings to guard against wear. In parallel, there has been much attention paid to lubricant rheology and formulation. However, only in recent times there has been an emerging view of lubricant–surface combination as a system. In this perspective it is essential to relate the observed and measured friction at component level to the underlying interactions in micro/nano-scales. This is the approach in this paper. Observed phenomenon at micro-scale are related back to the activation energies of lubricant–surface system, providing in particular results for surface modified Ni–SiC coated specimen in combination with formulated lubricants, the combination of which represent the lubricant–surface system of choice in cylinders of high performance race engine. The nano-scale conjunction of an AFM tip with lubricated surface-engineered specimen, subjected to various conjunctional loading and sliding kinematics is investigated. It is shown that the measured frictional characteristics can be adequately described in terms of activation energies in line with the Eyring’s thermal activation model for cases of fairly smooth asperity tip contact conjunctions.

Electrospark-Deposited Coatings from Titanium and Tungsten Carbide Alloys: Mass Transfer Kinetics, Structurization, and Properties

New WC, TiC, and TiB2 electrode materials have been developed for hard wear-resistant electrospark-deposited coatings on a metal substrate. The phase formation and structurization during hot pressing of these materials are studied. The effect of electrode production process on the mass transfer and coating properties is analyzed. The alloys have fine structure with 1–2 μm grains of the major fraction and 26–30 GPa hardness. The structure and functional properties of the electrospark-deposited coatings are examined. Their hardness is 14–24 GPa and thickness 40–120 μm. The new electrode materials show significantly higher scale resistance than T15K6 alloy coatings, and their abrasion and wear resistance in dry friction conditions suggests that they may be efficiently used to strengthen rapidly wearing parts of machines and mechanisms.

Dry Sliding Wear Behavior and Wear Mechanisms of Thermally Sprayed WCCo-Coatings

Thermal spraying is one of the most efficient methods to deposit hard wear resistant coatings. The coatings deposited by High-Velocity-Oxygen-Fuel spraying (HVOF) are characterized by high wear resistance and outstanding tribological characteristics. One of the most challenging tasks for tribologists is to develop surface treatments that allow for both operating the component without lubricants and at the same time minimize wear. WC-based cermets are a group of thermally sprayed coatings known to have high wear resistance under sliding friction conditions. An experimental study on the dry sliding wear behavior of WCCo HVOF-sprayed coating deposited onto a steel substrate is presented in the current paper. A pin-on-disc tribometer was used to carry out the wear tests.

Hard wear-resistant coatings with anisotropic thermal conductivity for high thermal load applications

High thermal load applications such as high speed dry cutting lead to high temperatures in the coated tool substrate that can soften the tool and high temperature gradients that can put stress on the coating/tool interface. In this work, theoretical considerations are presented for multilayer and graded protective coatings that can induce a significant anisotropy in their thermal conductivity. Solution of the heat equation shows that anisotropy of thermal conductivity has the potential to reduce temperatures and temperature gradients arising due to brief, localized heat at the coating surface (“hot-spots”). Experimental realization of high anisotropy is demonstrated in TiN/AlCrN multilayer coatings with variable layer thickness. In the coating with 50 nm bilayer periodicity, the highest anisotropy was obtained with a value of κ||/κ⊥=3.0±0.9. Time-domain thermoreflectance is used to measure in-plane and cross-plane thermal conductivity of fabricated coatings. The observed high values of anisotropy of thermal conductivity are compared with theoretical predictions and its realisation is discussed with regard to the coating microstructure.