Dry Sliding Wear Resistance Research Articles

Microstructure and mechanical properties of Mo2FeB2 ceramic-steels with Nb/V addition

ABSTRACTSeven series of Mo2FeB2 ceramic-steels with Nb/V content between 0 and 6 wt-% had been successfully fabricated by liquid phase reaction sintering. The microstructure was studied by means of field emission scanning electron microscope, energy dispersive spectroscopy and X-ray diffractometry. The hardness (HRA), transverse rupture strength (TRS) and wear resistance were also measured. The results reveal that the grain size decreased with the increase of Nb content, but had little change with the increase of V content. With the increase of Nb/V content, the hardness and TRS both enhance first and then descends. Mo2FeB2 ceramic-steels with 4 wt-% Nb content show the highest hardness and TRS of HRA 90.6 and 1970 MPa and the best dry sliding wear resistance.

Effect of rotary electromagnetic stirring during solidification of In-situ Al-TiB2 composites

Al-TiB2 in-situ metal-matrix composite has been synthesized by reaction with commercially pure molten aluminum and potassium hexafluoro titanate (K2TiF6) and potassium tetrafluoro borate (KBF4) adopting stir casting method. Varying amounts of salts based on stoichiometric calculations were added to obtain 0, 5 and 8wt.% of TiB2 in the composites. The melts were allowed to solidify with or without electromagnetic stirring in a rotary magnetic field. The effects of varying percentage of TiB2 reinforcements and magnetic stirring have been characterized by microstructural evolution and consequent improvement in mechanical properties. The application of rotary electromagnetic stirring (EMS) during solidification has shown very prominent effect on the aluminum matrix and the morphology of TiB2 particles and the consequent mechanical properties like hardness, tensile strength, and dry sliding wear resistance.

Dry Sliding Wear Behavior of Palmyra Shell Ash–Reinforced Aluminum Matrix (AlSi10Mg) Composites

ABSTRACTHigh strength, light weight, ease of fabrication, excellent castability, and good wear resistance make aluminum alloy composites suitable for commercial applications. In this work, a silica-rich ash particle (palmyra shell ash) was reinforced with aluminum alloy (AlSi10Mg) composites and its mechanical and tribological properties were studied. The aluminum alloy was reinforced with 3, 6, and 9 wt% of palmyra shell ash particles, and its dry sliding wear behavior was studied using a pin-on-disc machine under different loading conditions. The result shows that the dry sliding wear resistance of Al–palmyra shell ash composites was almost similar to that of fly ash– and rice husk ash–reinforced Al-alloy composites and these composites exhibit better wear resistance compared to unreinforced alloy. The palmyra shell ash particle weight fraction significantly affects the wear and friction properties of the composites. Scanning electron microscopic examination of the worn surface reveals that at various loads palmyra shell ash particles act as load-bearing constituents and the wear resistance of the reinforced palmyra shell ash with a size range of 1–50 µm was superior to that of unreinforced alloy. Mechanical properties (hardness and tensile strength) were also studied and it was observed that the reinforced Al-alloy showed a significant increase in mechanical properties.

Mechanical properties of anodic titanium films containing ions of Ca and P submitted to heat and hydrothermal treatment

Anodic oxidation is a technique widely used to improve the bioactivity of Ti surface. In this study, micro-arc oxidation (MAO) was used to obtain an anodic film incorporating Ca and P ions to evaluate the effect of heat and hydrothermal treatment on the mechanical and in vitro bioactivity properties of these new layers. The MAO process was carried out using (CH3COO)2Ca·H2O and NaH2PO4·2H2O electrolytes under galvanostatic mode (150mA/cm2). The thermal treatments were made at 400°C and 600°C in air atmosphere while hydrothermal treatment was made in an alkaline water solution at 130°C. These surfaces presented desired mechanical properties for biomedical applications owing to the rutile and anatase phases in the anodic film that are more crystalline after thermal treatments; which provided an increase in hardness values and lower elastic modulus. The dry sliding wear resistance increased by performing thermal treatments on the surfaces with one condition still maintaining the film after the test. Bioactivity was investigated by immersion in simulated body fluid during 21 days and hydroxyapatite was formed on all samples. Finally, lower values of contact angle were obtained for heat treated samples.

Preparation, properties and wear performance evaluation of epoxy‐palmyra fiber composites

This article presents a parametric analysis of dry sliding wear process undergone by a new class of composite material consisting of epoxy and short palmyra fibers (SPF). It is an attempt to explore the possibility of improving the dry sliding wear resistance of neat epoxy by reinforcing it SPF. Palmyra fiber is an inexpensive, strong, and naturally available fiber derived from the stalks of palmyra leaf. In the present investigation, epoxy‐based composites with different weight proportions of SPF (0, 4, 8, and 12 wt%) are fabricated although the simple hand‐lay‐up route. The tensile, flexural, and micro‐hardness properties of the samples are found out which is followed by a FTIR spectroscopy of the samples. The composite samples are then subjected to wear trials using a pin‐on‐disc test rig as per ASTM G 99‐05 test standards under different operating conditions. The effects of various operational variables on the dry sliding wear behavior of these epoxy composites with and without SPF reinforcement are studied. The design of experiments approach using Taguchi's L16 orthogonal array is used for parametric analysis of the wear process. Significant parameters affecting the wear rate of epoxy are identified. This study revealed that while the fiber content and the sliding velocities have significant influence on the wear arte of the composites, the effects of sliding distance and normal load are ignorable. An optimal parameter setting for minimum specific wear rate is obtained. The morphologies of the worn surfaces are examined by scanning electron microscopy and possible wear mechanisms are identified. POLYM. COMPOS., 39:1827–1834, 2018. © 2016 Society of Plastics Engineers

Tribocorrosive behaviour of low temperature plasma-nitrided PH stainless steel sliding against alumina under linear reciprocation with and without transverse oscillations

In this work, precipitation hardening (PH) stainless steel was plasma nitrided at low temperatures 400°C and 425°C for 15h. The wear and corrosion-wear behaviour of the untreated and nitrided specimens were investigated under both dry sliding and wet sliding (in 3% NaCl solution) conditions, using both one-dimensional (1D) and two-dimensional (2D) reciprocating motions. The 2D motion was realised by reciprocating the sample stage as the primary motion and at the same time reciprocating the ball (pin) holder at a high frequency and small amplitude as the secondary motion. The results show that 2D sliding has significant effects on the wear behaviour of the test specimens. Under dry condition, 2D sliding leads to a significant increase in wear volume by 70–230%. Nitriding is very effective in increasing dry sliding wear resistance of the steel under both 1D and 2D conditions, with 400°C nitriding being the most effective. Under corrosion-wear (tribocorrosion) condition in 3% NaCl solution, 2D sliding leads to a more significant drop in open circuit potential (OCP) and a more significant increase in anodic current than 1D sliding. While under 1D sliding condition, nitriding is effective in reducing material removal by tribocorrosion, under 2D sliding condition, the effectiveness of nitriding is dependent on nitriding temperature. Nitriding at 425°C results in accelerated material removal during 2D sliding in the corrosive solution. The mechanisms of material removal are discussed in terms of the structures of the nitride layers and their electrochemical response to the corrosive solution.

Fabrication of Co-Based Coatings on Titanium Alloy by Laser Cladding with CeO2 Addition

In this study, Co-based laser cladding coatings reinforced by multiple phases were fabricated on titanium alloy. Co42 Co-based self-fluxing alloy, B4C, and CeO2 mixed powders were used as the precursor materials. The coatings were mainly composed of γ-Co/Ni, CoTi2, CoTi, NiTi, TiC, Cr7C3, TiB2, and TiB phases. A typical TiB2/Cr7C3/TiC composite structure was chosen. It was found that CeO2 did not influence the phase types of the coating significantly, but was effective in refining the microstructure and enhancing the microhardness and dry sliding wear resistance. Compared with the Ti-6Al-4V titanium alloy, the microhardness and wear resistance of the composite coatings were enhanced by 3.44–4.21 times and 14.26–16.87 times, respectively.

Study of the effect of amino-functionalized multiwall carbon nanotubes on dry sliding wear resistance properties of carbon fiber reinforced thermoset polymers

This work investigates the effect of multiwall carbon nanotubes (MWCNTs) on the mechanical and tribological behavior of a fiber reinforced composite (FRC). Fiber reinforced composites and nano-engineered FRCs are manufactured by resin transfer molding. In-plane tensile tests, in-plane shear tests and through-thickness compression tests are used to assess the influence of MWCNTs on the material mechanical behavior. Pin on disk dry sliding tests are used to quantify the effect of MWCNTs on the friction coefficient and the specific wear rate. It was determined that (1) MWCNTs have an influence on the improvement on both the through-thickness compression strength and the specific wear rate, and (2) they do not influence the material stiffness, in-plane tensile and shear strengths and the friction coefficient. It is assumed that the observed improvements are due to the demonstrated positive influence of the MWCNTs effect on the matrix/reinforcement interfacial strength and on the matrix fracture toughness.

Structure and properties of CrSiCN coatings deposited by pulsed dc magnetron sputtering for wear and erosion protection

Abstract CrSiCN nanocomposite coatings were deposited by sputtering a chromium (Cr) target in a gas mixture containing argon, nitrogen, and trimethylsilane (TMS) using middle frequency pulsed dc magnetron sputtering (PDCMS). The coatings with different silicon (Si) and carbon (C) contents were obtained by varying the TMS flow rate from 0 to 12 sccm. Uniform depositions and high deposition rates (8–10 μm per hour) have been achieved. The microstructure of the coatings was studied by means of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The lattice parameter of the coatings first increased with the addition of a small amount of Si (1.7 at.%) and C (5 at.%) by the formation of cubic solid solution, and then decreased with a further increase in the Si and C contents. The microstructure of the coating changed from columnar grains to interconnected fine grains, and finally to nanocomposite structure as the Si and C contents increased, in which cubic Cr(Si, C)N nanocrystallites were surrounded by an amorphous matrix consisting of SiC x , amorphous C, SiN x , and CN x . The volume fraction of amorphous phases increased as the Si and C contents increased. The mechanical properties, dry sliding wear resistance, and solid particle erosion (SPE) resistance of the coatings were analyzed using nanoindentation, ball-on-disc test, and air jet sand erosion test, respectively. As compared to the baseline CrN coating, the addition of a small amount of Si (1.7–5 at.%) and C (5–9.6 at.%) effectively improved the hardness and the H/E ⁎ and H 3 /E ⁎2 of the coatings. The strengthening mechanisms include solid solution hardening and grain boundaries strengthening via the formation of a thin amorphous layer. The improved mechanical properties contributed to excellent wear resistance and SPE resistance of the coatings against alumina at both 30° and 90° incident angles. However, as the Si and C contents were increased respectively to above 10.3 at.% and 16 at.%, the mechanical properties and wear and SPE resistance of the CrSiCN coatings all decreased.

Study the Effect of Shot Penning Time by Steel Ball on Dry Sliding Wear Resistance of (Al-3.5%Cu) Alloy

This research is devoted to investigate the effect of shot penning time by steel ball with diameter 1.5 mm on the wear resistance of (Al-3.5%Cu) alloy. A pin –on- disc technique has been used to evaluate wear rate of the specimens as prepared and the specimens which treated by shot peening at various time (10,15, 25, 35) min ,were slide under dry sliding conditions on the carbon steel disc at various applied loads (9.81, 19.62, 29.43, 39.24 and 45)N and slide periods(30, 60,90 , 120 and 150)min under variable sliding speeds(0.94, 1.88, 2.82, 3.76 and 4.9) m/s.The result show that the wear for all the shot peen times have improved the wear resistance and best resistance has been achieved at time 25 min.

Improving Wear Resistance of AISI 316LN Austenitic Stainless Steel Using Friction Stir Processing

An attempt is made to modify the surface metallurgically and enhance the wear resistance of AISI 316LN austenitic stainless steel using friction stir processing. Friction stir welding tools made up of tungsten based alloy with pin and pinless configuration was used. Fine equiaxed grains were observed in the friction stir processed zone irrespective of tool configuration used. Dry sliding wear resistance was evaluated using pin-on-disc wear tester and it is found that, the friction stir processed zone showed superior wear resistance compared to the base metal. Microstructure, micro hardness, and worn surfaces were used to correlate the results obtained.

Microstructures and properties of TiN reinforced Co-based composite coatings modified with Y2O3 by laser cladding on Ti–6Al–4V alloy

In this study, TiN reinforced composite coatings were fabricated on Ti–6Al–4V substrate by laser cladding with Co42 self-fluxing alloy, TiN and Y2O3 mixed powders. Microstructures and wear resistance of the cladding coatings with and without Y2O3 addition were investigated comparatively. Results showed that the coatings were mainly comprised of γ-Co/Ni, TiN, CoTi, CoTi2, NiTi, TiC, Cr7C3, TiB, Ti5Si3 and TiC0.3N0.7 phases. The coatings showed metallurgical bonding free of pores and cracks with the substrate. Compared with the Ti–6Al–4V substrate, the microhardness and wear resistance of the coatings was enhanced by 3–4 times and 9.5–11.9 times, respectively. With 1.0 wt.% Y2O3 addition, the microstructure of the coating was refined significantly, and the microhardness and dry sliding wear resistance were enhanced further. The effects of Y2O3 were attributed to the residual Y2O3 and decomposed Y atoms.

A comparative study on the microstructure and surface property evaluation of coatings produced from nanostructured and conventional WC–Co powders HVOF-sprayed on Al7075

Conventional and nanostructured WC-12wt.% Co powders were HVOF sprayed on Al7075-T6. The nanocoatings presented slightly less microporosity, higher microhardness, higher fracture toughness but higher decarburization, than the conventional ones. The nanocoatings exhibited greater resistance to general corrosion and localized corrosion in 3.5% NaCl than their conventional counterparts. Other than an occasional removal of WC nanoparticles, corrosion modes appeared similar for both types of coatings, characterized by selective dissolution of Co, formation of protective surface films and crevice corrosion along interlayer boundaries. Both types of coatings exhibited high dry sliding wear resistance. Nevertheless, the wear performance of the nanocoatings was even superior than that of their conventional counterparts. Main wear modes included plastic deformation of binder, oxidative wear leading to the formation of lubricating oxides and adhesive wear leading to the formation of alumina-rich surface depositions (from the Al2O3 counter balls). Coating of Al7075 with nano WC–12Co was proved effective in terms of microstructural features, corrosion and wear behaviour.

Effects of plasma nitriding ion beam flux density and time on the properties of CoCrMo alloy

The effects of plasma nitriding ion beam flux density and deposition time on structural and tribological properties of medical forged CoCrMo alloy were investigated. Plasma nitrided processes under pure nitrogen were conducted at various ion beam flux densities for 2, 4, 6 and 8 h. The active species included in the nitrogen plasma, phase compositions, microstructures and surface microhardness were characterized by means of OES, XRD, SEM and microhardness test techniques. A milliammeter was used to detect the ion beam flux density. Dry wear tests were performed using a ball-on-disc tribotester. The OES data suggested that excited neutral molecules N2∗ and N2+ played important roles in DC plasma nitriding. The experimental analyses confirmed that plasma nitriding process has shown promise in producing thicker, harder, better hydrophilic and more wear resistance layers than the conventional CoCrMo alloys. As compared with untreated CoCrMo alloy, the nitrided CoCrMo alloy showed lower wear rates and wear scar widths, and the specimen nitrided at 5.8 mA/cm2-8 h exhibited the lowest wear rate and better dry-sliding wear resistance. The adhesive wear was the main mechanism for untreated CoCrMo alloy while the wear mechanisms of nitrided specimens were fatigue wear, abrasive wear and slight adhesive wear.

Effects of molybdenum content on the wear/erosion and corrosion performance of low-carbon Stellite alloys

Abstract The strengthening agents of Stellite alloys are commonly various carbides, but intermetallic compounds may play a similar role to the carbides. In this research two low-carbon Stellite alloys with high molybdenum content are developed and studied, which are modified version of Stellite 21. This particular elemental content combination results in large amounts of Co3Mo intermetallic compound precipitated in these alloys. The microstructures of the alloys are analyzed using SEM/EDX/XRD and DSC. The dry sliding wear resistance and solid-particle erosion resistance of the alloys are evaluated experimentally. The corrosion performance of the alloys in 3.5 wt.% sodium chloride (NaCl) aqueous solution is investigated under electrochemical tests. It is shown that the intermetallic compounds enhance hardness and wear resistance as the carbides do in Stellite alloys, but do not favor solid-particle erosion resistance due to their brittleness. The presence of the intermetallic compounds does not worsen corrosion resistance, compared to Stellite 21.

Characterization of micro arc oxidized 6082 aluminum alloy in an electrolyte containing carbon nanotubes

In this study, micro arc oxidation (MAO) process was applied to 6082 aluminum alloy in an alkaline-based electrolyte with and without the addition of carbon nanotubes (CNTs) to the electrolyte. After oxidation, the coatings were investigated by a series of structural, morphological, and tribological tests to understand the effect of CNTs addition to the base electrolyte. X-ray diffraction analyses revealed that an oxide layer composed of α-Al2O3 and γ-Al2O3 in varying intensities was formed on the surface, and the addition of CNTs to the electrolyte may contribute to the formation of more α-Al2O3 after MAO for longer oxidation times. High-resolution SEM micrographs showed that CNTs were successfully incorporated into the pores of the alumina coating generated during the discharging stage of the MAO process. The addition of CNTs to the base electrolyte induced a rougher surface accompanied by a decrement in the coating thickness as compared to the sample treated in the base electrolyte. The surface hardness and dry sliding wear resistance of 6082 aluminum alloy increased by performing the MAO process in the base electrolyte, as expected, due to the formation of an alumina coating at the surface, and the addition of CNTs to the electrolyte resulted in a further increment in the coating hardness and dry sliding wear resistance.

Effect of Heat Treatments on Dry Sliding Wear Resistance of Aluminum –Cupper Alloys.

Effect of Heat Treatments on Dry Sliding Wear Resistance of Aluminum –Cupper Alloys.

Effect of different heat-treatment temperatures on the laser cladded M3:2 high-speed steel

M3:2 high-speed steel (HSS) coating was fabricated on one austenitic stainless steel by laser cladding (LC). The cladded specimen (specimen A) was heat treated at 500°C (specimen B) and 800°C (specimen C). Microstructure, phase structure, residual stress, micro-hardness and wear behavior of the specimens were examined. Dry sliding wear was carried out on each specimen and lubricant sliding wear (emulsifier solution and water served as lubricant) was carried out on specimen C. Results show that the observed microstructure of specimen A is characterized by comparably fine equiaxial grains, dendrites and inter-dendritic network shaped eutectic carbides. This microstructure is composed of supersaturated martensite, retained austenite and MxCy type carbides. Heat treatment, carried out on specimens B and C, leads to the relief of residual stress and phase transformation. Retained austenite enriches and stabilizes in specimen B. Tempered sorbite forms in specimen C. Both specimens show the existence of Fe2O3. Residual stress changes from tensile to compressive stress after heat treatment. The maximum principal stress change rates of specimens B and C compared with that of specimen A are −1.04 and −2.53, respectively. Average micro-hardness of specimen A increases by 4.3% and decreases by 32.5% after heat treated at 500°C and 800°C, respectively. Dry sliding wear resistance shows similar variation tendency with the microhardness of the HSS coating. Wear resistance of specimen B is the best during the dry sliding wear, and that of specimen C is the worst. Addition of lubricant greatly improves the wear resistance of specimen C.

Microstructure and wear properties of AISI M2 tool steel on RF plasma nitriding at different N2–H2 gas compositions

Wear behavior of quenched-tempered AISI M2 tool steel samples has been studied after plasma nitriding at different N2–H2 plasma gas flows containing 25, 50 and 75sccm N2. Plasma nitriding was performed at 450°C for 8h under floating potential using a plasma reactor equipped with a radio frequency power generator. Microstructure, phase composition, nitrided layer thickness, hardness and surface roughness of the samples were studied using optical microscopy, X-ray diffraction, microhardness and surface profilometry measurements. Dry sliding wear resistance of samples was determined by performing ball-on-disc wear testes. The results revealed formation of mainly a diffusion zone at the 25sccm N2–75sccm H2 gas flow and mono-phase ε-Fe2–3N compound layer at higher N2 concentrations. Plasma nitriding increases near surface hardness up to 50% (about 1600HV0.025) irrespective of the N2:H2 ratio, where nitrided layer depth and surface roughness increase with increasing the N2 flow rate in the plasma gas. Depending on the nitrogen content, sliding wear resistance may be improved between 20 and 90% with respect to the un-nitrided substrate. Among the nitrided samples the maximum and minimum wear resistance was obtained at plasma gases containing higher and lower H2 fractions, respectively. Decreasing wear resistance with increasing N2 flow rate in the plasma gas attributed to formation of the hard and brittle compound (white) layer on the sample surface and development of residual stress profiles.

Dry sliding wear and friction behavior of aluminum–rice husk ash composite using Taguchi’s technique

Dry sliding wear and friction behavior of aluminum alloy (AlSi10Mg) reinforced with agriculture waste such as rice husk ash have been investigated using plan of experiments (L27 Orthogonal array) generated through Taguchi technique. Three parameters namely applied load (20, 30, and 40 N), sliding speed (2, 3, and 4 m s−1) and rice husk ash reinforcement (6, 9, and 12%wt.) have been varied to find their effect over the wear and friction behavior of the composites. The analysis of variance and regression equations were also employed to find their interactions over wear rate and coefficient of friction of the composite. “Smaller-the-better” characteristics were chosen to develop a predictive model for analyzing the dry sliding wear resistance. The result reveals that the wear rate and coefficient of friction were influenced highly by percentage reinforcement followed by applied load and sliding speed. Finally, the confirmation test was also carried out to verify the predictive model with the experimental results. Wear surface morphology of the wear pins was analyzed using scanning electron microscope.