Adhesive Wear Resistance Research Articles

A comparative investigation on bi-layer Al–Cr/Al–Si coating and mono-layer Al–Cr–Si coating synthesized on Ti–6Al–4V alloy substrate by mechanical alloying method

Abstract A bi-layer Al–Cr/Al–Si coating and a mono-layer Al–Cr–Si coating were respectively produced on the Ti–6Al–4V alloy substrate by mechanical alloying method. The bi-layer coating had an inner composite Al–Si layer and an outer composite Al–Cr layer, which was obtained by milling in Al–Si powder and Al–Cr powder successively. The mono-layer coating was a Sip and Crp reinforced Al matrix coating. The adhesion behavior, the microhardness, the friction and wear resistance, and the high-temperature oxidation resistance of the coatings were investigated and compared. The results indicated that the mono-layer coating had better adhesion behavior compared with the outer layer of the bi-layer coating. Both the mono-layer and the bi-layer coatings could improve the surface microhardness of the substrate. The mono-layer coating had higher surface microhardness. But the bi-layer coating had an inner cushioning layer to maintain the hardness and prevent its sharp decrease with the increase of coating depth. The mono-layer coating had better friction and wear resistance. The bi-layer coating had lower mass gain and oxidation rate compared with the mono-layer coating. A continuous Al3Ti layer formed during oxidation of the bi-layer coating, which could protected the substrate effectively at the elevated temperature. The mono-layer coating was severely oxidized and porous structure formed in the coating. The bi-layer coating had advantages in protecting the substrate at elevated temperature.

Surface Modification of Titanium by Producing Ti/TiN Surface Composite Layers via FSP

In this paper, we report the use of blowing nitrogen gas for the successful fabrication of a composite layer composed of Ti/TiN on a substrate of commercially pure titanium (cp-2) using the friction stir processing technique. The prepared composite layer was characterized by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectrometry. The maximum microhardness of the Ti/TiN composite reached 1024 HV, which is 6.4 times higher than that of the titanium substrate. The results of wear test indicated that the Ti/TiN composite layer possesses excellent abrasive and adhesive wear resistance because of the formation of the TiN and its high hardness.

Influence on the wear resistance of the particle size used in coatings of Alumina

In the literature, it is common to find that the size of the particles used in coatings through thermal spraying processes influences the hardness and wear resistance thereof; this project aimed to quantify the importance of this parameter in the adhesive and abrasive wear resistance when aluminium oxide is deposited on a substrate of AISI 1020 steel, through a thermal spraying by flame process. The methodology consisted of: a) morphological characterization of the powder used in the coatings by scanning electron microscopy, b) deposition of coatings, c) testing of adhesive and abrasive wear (ASTM G99-05 Standard test method for wear testing with a pin-on-disk apparatus and ASTM G65–04 Standard test method for measuring abrasion using dry sand/rubber wheel apparatus), and d) statistical analysis to determine the influence of particle size on wear resistance. The average size of the powder used for coatings was 92, 1690, 8990 and 76790nm. The obtained results allow to identify an inversely proportional behaviour between particle size and wear resistance, in both types of wear (adhesive and abrasive) is shown a logarithmic trend indicating an increase in loss mass during the test as the particle size is also increased and therefore a decrease in wear resistance of the coating.

Features of the Formation of Wear-Resistant Coatings from Powders Prepared by a Micrometallurgical Process of High-Speed Melt Quenching

Development of compositions and application of coatings by cold gas-dynamic deposition from powders prepared by means of a micrometallurgical method is studied. In addition, use of mechanical alloying technology is substantiated during composite powder preparation based on aluminum for creation of wearresistant coatings. Results are given for the effect of reinforcing component concentration and powder composite preparation method on the main wear-resistant coating properties for a metal–nonmetal system. Results are provided for an experimental study of adhesive strength, microhardness, porosity, and wear resistance of coatings made from powder matrix material of the Al–Sn–Zn system prepared by a micrometallurgical process of high-speed melt quenching, and also composite powder of the system Al–Sn–Zn–Al2O3.

Effect of QPQ nitriding time on microstructure and wear resistance of SAF2906 duplex stainless steel

QPQ salt bath treatment of SAF2906 duplex stainless steel was conducted at 570 °C for 60 min, 90 min,120 min,150 min and 180 min, followed by post-oxidation process with heating temperature of 400°C and holding duration of 30 min. The effect of QPQ nitriding time on microstructure and wear resistance of SAF2906 duplex stainless steel was investigated by means of OM, SEM, XRD, microhardness test, adhesion strength test and wear resistance test. Microstructure observation showed outer layer was composed of Fe3O4. The main phase of the intermediate layer was CrN, αN and Fe2-3N. The main phase of the inner layer was CrN and S. The adhesion strength test of the surface layer-substrate showed the QPQ treated samples have favorable adhesion strength of HF-1 level. With the increase of nitriding time, the growth rate of the compound layer gradually slowed down and the surface hardness first increased and then decreased, and the maximum hardness was 1283 HV0.2 at 150 min. The dry siliding results showed that the wear resistance of the QPQ treated samples was at least 20 times than that of the substrate, and the optimum nitriding time to obtain the best wear resistance is 150 min. The worn surface morphology observation showed the main wear mechanism of the substrate was plough wear, while micro-cutting is the main wear mechanism that causes the damage of the QPQ treated samples.

Production of Aluminide Layers on Copper and Copper Alloy

Abstract Intermetallic coatings were produced on pure copper and aluminum-bronze substrates using the powder aluminizing process. The treatments were carried out at 550°C and 600°C during 30, 60, 120, and 180 min. The layers were characterized by optical and scanning electron microscopy (SEM) associated with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and wear and hardness testing. The treatments performed at 600°C resulted in larger layer thicknesses compared to those produced at 550°C for both copper and bronze substrates. XRD analysis indicated the presence of intermetallic phases FeAl, FeAl3, and CuAl on aluminum-bronze. The layers produced on the Cu and aluminum-bronze substrates exhibited maximum hardness of approximately 750 HV and 870 HV, respectively. The adhesive wear resistance of all formed layers was higher than those of low-hardness substrates (100 HV in the case of copper and 300 HV for the aluminum-bronze). There were no significant differences in the wear resistances of the layers produced on the same substrate. The abrasion resistance of the aluminum-bronze layers were higher than those of the copper layers, because of the greater hardness of the layers formed on the aluminum-bronze.

Study of Selected Properties of Thermally Sprayed Coatings Containing WC and WB Hard Particles

Abstract The paper presents results of research of the essential characteristics of two kinds of advanced coatings applied by HVOF technology. One studied coating: WB-WC-Co (60-30-10%) contains two types of hard particles (WC and WB), the second coating is eco-friendly alternative to the previously used WC-based coatings, called “green carbides” with the composition WC-FeCrAl (85-15%). In green carbides coating the heavy metals (Co, Ni, NiCr) forming the binding matrix in conventional wear-resistant coatings are replaced by more environmentally friendly matrix based on FeCrAl alloy. On the coatings was carried out: metallographic analysis, measurement of thickness, micro-hardness, adhesion, resistance to thermal cyclic loading and adhesive wear resistance (pin-on-disk test). One thermal cycle consisted of heating the coatings to 600°C, dwell for 10 minutes, and subsequently cooling on the still air. The number of thermal cycles: 10. The base material was stainless steel AISI 316L, pretreatment prior to application of the coating: blasting with white corundum, application device JP-5000.

Research on wear resistance of plasma remelted FeNiCrAl sprayed coating

To improve the microstructure density of high-velocity arc spraying coating and enhance its adhesive strength and wear resistance, a plasma remelting investigation of the FeNiCrAl sprayed coating was carried out in this study. The microstructure and phase composition of the sprayed coating and the remelted coating were compared by using metalloscope, scanning electron microscope and X-ray diffractometer. The microhardness distribution and friction wear characteristics of the plasma remelted FeNiCrAl sprayed coating were investigated by microhardness tester and CETR sliding friction wear testing machine. The results showed that the remelted coating has more compact microstructure and presents metallurgical bonding with the substrate. The generation of hard phases such as (Fe,Cr)7C3 and Cr23C6 as well as solid solution (Fe,Cr) increases the microhardness of the remelted coating significantly, about 1.4 times higher than that of the sprayed coating. According to sliding friction wear test, the abrasion losses of the sprayed coating under 10 N and 20 N loads are 4.6 and 10.5 times higher than those of the remelted coating, indicating the better wear resistance of the remelted coating.

The Influence of High Temperature Exposure on the Wear of Selected HVOF Sprayed Coatings

The influence of high temperature exposure on the mechanical and wear properties of selected HVOF sprayed CrC and No/Co – based alloy coatings were tested. Comparison of as-sprayed and 600°C/116 h annealed coatings’ microhardness, cohesive strength, abrasive and adhesive wear resistance showed that the Co-based Stellite 6 coating’s wear properties were deteriorated by heat exlosure despite of the increase of its hardness and cohesive strength. The heat exposure was found to be beneficial for both mechanical and wear properties of NiCrBSi self-fluxing coating. On the contrary, mechanical properties of Cr3C2-NiCr coating slightly decreased, while its wear resistance slightly increased as a result of high temperature exposure.

Surface modification of austenitic thermal-spray coatings by low-temperature nitrocarburizing

Thermal-spray coatings of austenitic materials are mainly used under corrosive conditions. The relatively poor wear resistance strongly limits their use. In comparative studies between nitrocarburized and untreated thermal-spray coatings, the influence of the nitrogen and carbon enrichment on the properties of the coatings and the microstructure was investigated. The cross-section micrograph of the nitrocarburized coating shows the S-phase formation in the surface layer region. The depth profile of the nitrogen and carbon concentration was determined by glow discharge optical emission spectroscopy (GDOS) analysis. A selective enrichment of the surface layer region with nitrogen and carbon by means of thermochemical heat treatment increases the wear resistance. The interstitially dissolved nitrogen and carbon causes the formation of strong compressive residual stresses and high surface hardness. Increases in the service life of existing applications or new material combinations with face-centred cubic friction partners are possible. In the absence of dimensional change, uniform as well as partial nitrogen enrichment of the thermal spray coating is possible. Nitrocarburized coatings demonstrate a significant improvement in adhesive wear resistance and extremely high surface hardness.

Effect of Heat Treatment on the Microstructure and Properties of HVOF-Sprayed Co-Cr-W Coating

Co-Cr-W HVOF-sprayed protective coatings are used for their high oxidation and wear resistance. Apart from the oxidation resistance, the stability of their mechanical properties in relation to thermal loading is crucial with respect to the most common high-temperature application areas. This work is focused mainly on evaluation of the heat-induced changes in the phase composition and related mechanical properties. It was shown that the original powder, composed fully from face-centered cubic Co-based alloy, partly changes its phase composition during spraying to a hexagonal close-packed (hcp) structure. The annealing further increases the ratio of the hcp phase in the structure. The heat-induced phase changes are accompanied by an increase in the coatings’ hardness and cohesion strength. The abrasive and adhesive wear behavior was evaluated. While the coatings’ heat treatment had a positive effect on the coefficient of friction, the abrasive and adhesive wear resistance of annealed coating was lower compared to as-sprayed coating.

Reciprocating wear behavior of mild steel carburized using Na2CO3–NaCl

The surface of the mild steel carburized using Na2CO3–NaCl was dominated by retained austenite. Towards the core, the amount of austenite reduced while the amount of martensite increased. Increasing the duration of the carburization resulted in higher peak hardness and case depth. It also increased the amount of cementite in the grain boundaries and the austenite grains size, rendering the steel more susceptible to cracking. The superior wear resistance of the martensite, as compared to the austenite, could be attributed to its high cracking and adhesive wear resistance owing to its high hardness and tendency to form oxides. The friction was governed by the wear mechanism and the type of microstructure at the worn scar sliding on the carbide ball.

On the modeling of dry sliding adhesive wear parameters of vanadium additive iron-based alloys at elevated temperatures

Abstract In this paper, three different vanadium additive iron based hardfacing alloys were developed using shielded metal arc welding process with pre-placement technique — a newly developed approach to produce hardfaced coatings. The influence of the increased vanadium content on the hardness and dry sliding adhesive wear characteristics of alloys was investigated. A reciprocating wear test rig was used to study the effect of load and temperature on the alloys having variation in their vanadium content using a full factorial design of experiment approach. The increased vanadium content was found to be beneficial to enhance the macrohardness and adhesive wear resistance of the vanadium additive alloys in comparison to the non-vanadium additive alloy with no evidence of cracks or porosity. A significant reduction in weight loss of alloys containing higher vanadium content was observed from the main effect plots. Based on the significance of interactions, the regression equation was developed and validated with a number of test cases. The optimization of the control factors was also performed using a multi-response optimization technique. The confirmatory tests carried between the predicted and the experimental results exhibited the accuracy of the optimized input variables within ± 4.63% against an output of 0.007 g.

Combining magnetic filtered cathodic arc deposition with ion beam sputtering to afford superhard TiSiN multilayer composite films with tunable microstructure and mechanical properties

A series of superhard TiSiN multilayer composite films were prepared on silicon wafer by combining magnetic filtered cathodic arc deposition with ion beam sputtering. As-prepared multilayer composite films were characterized by means of high-resolution transmission electron microscopy, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, and their mechanical properties such as hardness, adhesion strength and wear resistance were evaluated as well. It was found that as-prepared TiSiN multilayer composite films, consisting of six sub-layers of alternately deposited crystal phase TiSiN solid solution and TiSiN solid solution/α-Si3N4 composite, and with sub-layer hardness increased from 23 to 26 GPa to the surface, exhibit extremely high hardness (>40 GPa) as well as good adhesion strength and wear resistance. Besides, the microstructure and mechanical properties of TiSiN sub-layers vary with varying Si content in the sub-layers, and varying Si content in the sub-layers leads to changes in the crystal lattice parameters of TiSiN solid solution at the inter-sub-layer interfaces thereby generating internal stress field to block dislocation movement and crack propagation. This means that the present approach could be of special significance in developing high-performance TiSiN multilayer composite films, since, based on the elaborate design of the sub-layers and the proper adjustment of the deposition conditions, it provides the feasibility to well manipulate the microstructure and mechanical properties of TiSiN multilayer composite films even under relatively low levels of deposition temperature and ion energy.

Effects of Deep Cryogenic Treatment on the Wear Resistance and Mechanical Properties of AISI H13 Hot-Work Tool Steel

In this study, a number of wear and tensile tests were performed to elucidate the effects of deep cryogenic treatment on the wear behavior and mechanical properties (hardness and tensile strength) of AISI H13 tool steel. In accordance with this purpose, three different heat treatments (conventional heat treatment (CHT), deep cryogenic treatment (DCT), and deep cryogenic treatment and tempering (DCTT)) were applied to tool steel samples. DCT and DCTT samples were held in nitrogen gas at −145 °C for 24 h. Wear tests were conducted on a dry pin-on-disk device using two loads of 60 and 80 N, two sliding velocities of 0.8 and 1 m/s, and a wear distance of 1000 m. All test results showed that DCT improved the adhesive wear resistance and mechanical properties of AISI H13 steel. The formation of small-sized and uniformly distributed carbide particles and the transformation of retained austenite to martensite played an important role in the improvements in the wear resistance and mechanical properties. After cleavage fracture, the surfaces of all samples were characterized by the cracking of primary carbides, while the DCT and DCTT samples displayed microvoid formation by decohesion of the fine carbides precipitated during the cryo-tempering process.

Vanadium nitride and titanium nitride coatings for anti-galling behavior in ironing of aluminum alloy cups

The anti-galling behavior of vanadium nitride (VN) and titanium nitride (TiN) coatings were investigated. VN and TiN coatings were deposited on JIS-SKH51 high-speed steel substrates by direct current magnetron sputtering. The coatings were characterized for phase composition using X-ray diffraction (XRD), hardness using nano-indentation and load-to-failure between the coating and substrate using scratch testing. Ring-on-disc testing was conducted to evaluate the tribological properties between AA1050 aluminum alloy ring sliding against SKH51 discs (both uncoated and coated discs) under a lubricating condition. The coated disc samples were cathodic arc TiN, 225W–TiN, 265W–TiN, 225W–VN and 265W–VN. Imaging and chemical analyses of the wear tracks were performed using a scanning electron microscope equipped with energy dispersive X-ray spectroscopy. The chemical analysis results of wear tracks showed that aluminum did not adhere to the 225W–TiN surface as readily as the other coated samples, as evidenced by the lowest amount of aluminum transfer. Results of the transition load for adhesion revealed that all of the coated surfaces improved the adhesive wear resistance i.e., resistance to aluminum adhering on the surface, compared with the uncoated surface. The 225W–TiN coating was further evaluated using an aluminum cup ironing process. The surface quality of the cups was found to be dependent on the Al transfer to the die surface. The cups ironed by the 225W–TiN coated die were superior to the cups obtained from an uncoated die.

Investigation on microstructures and mechanical properties of AlCrN coatings deposited on the surface of plasma nitrocarburized cool-work tool steels

AlCrN coating which has been widely applied in industrial application was produced on the surface of nitrocarburized SKD 11 cool-work tool steel by physical vapor deposition (PVD) method. The effects of nitrocarburizing pretreatment and PVD deposition temperature on microstructures, mechanical and tribological properties of the coatings were investigated. The results show that the AlCrN coating consists of an inner CrN adhesion layer with columnar growth and an outmost AlCrN work layer with planar growth, and the AlCrN coating shows a superior hardness of about 43 GPa. The nitrocarburizing pretreatment considerably improve adhesion strength, load capacity and wear resistance of duplex coated samples when compared with the single AlCrN coated samples. The improved mechanical and tribological properties are mainly related to the thicker nitrocarburizing layer and the gradient in the hardness profile of the duplex coating. In addition, the nitrocarburizing-PVD AlCrN duplex coated samples can be further enhanced by increasing deposition temperature of PVD coatings. The main wear mechanisms of duplex coated samples are oxidation wear or oxidation wear and adhesion wear, whereas the main wear mechanisms of single AlCrN coated samples are spalling and chipping wear as well as oxidation wear.

Wear and oxidation behavior of reactive sputtered δ-(Ti,Mo)N films deposited at different nitrogen gas flow rates

The wear properties of δ-(Ti,Mo)N films deposited at low and high nitrogen gas flow rates (fN2) were investigated. The film at fN2=2.0sccm showed better adhesive wear resistance than that at fN2=0.3sccm. Such improvement in the film at fN2=2.0sccm was due to the formation of Mo oxide debris by wear oxidation. It was found that Mo oxidation more easily occurred in the film at fN2=2.0sccm than in the film at fN2=0.3sccm. Thermodynamic consideration indicated that since the activity of Ti in δ-(Ti,Mo)N decreases with increasing N content, Mo oxidation is promoted in the film at fN2=2.0sccm, which leads to better wear properties.

Comparison of Black Oxide and Tungsten Carbide–Reinforced Diamond-Like Carbon (WC/a-C:H) Surface Treatments for Rolling Element Bearings

Surface-initiated damage increasingly limits the service life of rolling element bearings in challenging environments. In particular, operation in the boundary lubrication regime and/or conditions that produce excessive rolling element–raceway slip require the use of surface treatments on roller bodies and raceways to extend surface durability and component life. The tribological performance of two approaches is compared and contrasted: black oxide chemical conversion treatment and tungsten carbide–reinforced diamond-like carbon (WC/a-C:H) thin film hard coating. Black oxide treatment is performed on both rollers and raceways, whereas WC/a-C:H coatings are deposited on rollers only. The cross-sectional layer structure is compared using transmission electron microscopy, and mechanical properties are measured using nanoindentation. Ring-on-ring friction and wear testing is conducted to obtain Stribeck curves and evaluate adhesive wear resistance and cyclic acceleration performance. Tapered roller bearing fatigue test results are reported for treated bearings. Results from both bench-scale tribological tests and bearing fatigue tests indicate the superiority of WC/a-C:H coatings in protecting against severe adhesive wear damage and extending bearing fatigue life in boundary-lubricated conditions.

Feeding and Cooling and Time of Thermal Treatment of a Massive Bush Made of the Complex Aluminum Bronze Cast by the Lost Foam

Abstract Small additions of Cr, Mo and W to aluminium-iron-nickel bronze are mostly located in phases κi (i=II; III; IV),and next in phase α (in the matrix) and phase γ2. They raise the temperature of the phase transformations in aluminium bronzes as well as the casts’ abrasive and adhesive wear resistance. The paper presents a selection of feeding elements and thermal treatment times which guarantees structure stability, for a cast of a massive bush working at an elevated temperature (650-750°C) made by means of the lost foam technology out of composite aluminium bronze. So far, there have been no analyses of the phenomena characteristic to the examined bronze which accompany the process of its solidification during gasification of the EPS pattern. There are also no guidelines for designing risers and steel internal chill for casts made of this bronze. The work identifies the type and location of the existing defects in the mould’s cast. It also proposes a solution to the manner of its feeding and cooling which compensates the significant volume contraction of bronze and effectively removes the formed gases from the area of mould solidification. Another important aspect of the performed research was establishing the duration time of bronze annealing at the temperature of 750°C which guarantees stabilization of the changes in the bronze microstructure - stabilization of the changes in the bronze HB hardness.