Slight Abrasive Wear Research Articles

Preparation, mechanical properties and enhanced wear resistance of TiC-Fe composite cermet coating

TiC-Fe based cermet coating with high hardness and superior wear resistance together with low price and environmental friendliness was developed. Initially, the TiC-Fe composite particles were prepared by high energy ball milling, spray drying and plasma spheroidization. These cermet powders not only showed high sphericity and dense microstructure but also presented homogeneous distribution of TiC. Then, the TiC-Fe cermet coating was deposited by high velocity air fuel (HVAF). The results indicated that introducing ceramics would increase the deformation degree of the splats and eliminate the layered structure, which effectively enhanced the microhardness and wear resistance of composite coating. Compared with pure metallic coating, the microhardness of cermet coating increased to 887.5 HV0.3, while the wear rates of cermet coating reduced by 40% and 60% at 10 N and 25 N, respectively. Besides, the TiC-Fe cermet coating showed much less sensitive to the heavy load. The primary wear mechanism of single 316 L coating was a combination of adhesive wear and severe oxidation, while the TiC-Fe cermet coating showed slight abrasive wear combined with oxidation. The excellent wear resistance together with its harmless to human body make the TiC-Fe based composite coating a potential candidate when using at kitchen ware surface.

Microstructure evolution and high-temperature tribological behavior of Ti3SiC2 reinforced Ni60 composite coatings on 304 stainless steel by laser cladding

A series of composite coatings (Ni60-Ti3SiC2) were prepared by laser cladding on 304 stainless steel (SUS304). Then the tribological properties were investigated at room temperature (RT) and 600 °C. From the results, because of the fine-grain and dispersion strengthening caused by the presence of small-sized hard phases, the hardness of coatings was much higher than substrate. Benefiting from the addition of Ti3SiC2 lubricant, the friction reduction and wear resistance were decreased greatly, especially the wear rate and friction stability were enhanced 88.9% and 61.5% respectively at the high temperature. The wear mechanisms changed from serious oxidation adhesive wear on the substrate to the slight abrasive wear under the auxiliary lubrication of oxide films and Ti3SiC2 on the composite coatings.

Effect of cryogenic treatment on tribological behavior of Ti6Al4V alloy fabricated by selective laser melting

Ti6Al4V fabricated by selective laser melting (SLM) is commonly used as an artificial hip joint. However, the inferior tribological properties fall far short of the requirements for biomedical engineering and is harmful to the patients. In this study, cryogenic treatment (CT) was proposed to solve this problem. CT at −196 °C with a soaking time of both 2 h and 72 h were conducted, and their tribological properties were investigated by microstructure observation, Vickers hardness, and wear tests. The results showed that the microstructure of the as-fabricated and cryogenic treated (CTed) for 2 h are mainly composed of acicular martensite (α′ phase). However, the microstructure is transformed into alpha and beta phases after CT for 72 h. Vickers hardness of the specimens as-fabricated, CTed for 2 h and 72 h are 390.79 HV, 388.03 HV, and 371.34 HV, respectively. CT induces a significant improvement in tribological properties, which is correlated with the microstructure evolution. A similar wear mechanism can be observed for the specimens as-fabricated and CTed for 2 h, which is the co-action of severe abrasive wear, adhesive wear, and fatigue wear. While the specimen CTed for 72 h is slight abrasive wear mechanism.

The influence of copper content on the braking performance of iron-based powder metallurgy friction materials

Three iron-based powder metallurgy friction materials with different Cu content were prepared by powder metallurgy. The friction and wear properties of the materials were evaluated by the MM3000 friction and wear tester, and the effect of Cu content on the friction coefficient, wear rate and surface morphology was studied. The results show that with the increase of copper content, the matrix components are alloyed at high temperature, and the hardness and strength are significantly improved. The coefficient of dynamic friction and wear rate decreased significantly, and the coefficient of static friction and friction stability increased at high temperature. When the copper content is low, abrasive wear, spalling wear and fatigue wear are the main causes, while when the copper content is high, only slight abrasive wear occurs.

Microstructure and wear behavior of laser-cladded Ni-based coatings decorated by graphite particles

Abstract In order to improve the anti-friction and wear-resistance properties of 42CrMo steel, Ni-coated graphite composite powder and Ni45 alloy powder were designed to fabricate Ni-based self-lubricating wear-resistant coating with simple process and low cost on 42CrMo steel substrate by laser cladding. The effect of scanning speed on pore defects, graphite particle distribution, microstructure and wear behavior of the coatings were investigated, respectively. Through the synergy between adjusting scanning speed and Ni-coated graphite composite powder, the contradiction among the coating density, the interface bonding strength between graphite and Ni matrix and the excessive loss of graphite caused by ablation and in-situ reaction during laser cladding were resolved. Results showed that Ni-coated layer could effectively prevent the graphite from ablation and delay the reaction between carbon and other components. Ni-based self-lubricating coating with low porosity, uniform microstructure, moderate hardness, low friction coefficient and low wear rate can be prepared at an appropriate scanning speed of 300 mm/s. Its average friction coefficient and wear volume were approximately 0.480 and 6.824 × 10−6 mm3/N·m, respectively. The main wear mechanism is slight abrasive wear and adhesive wear. These results obtained are not only applicable to Ni-based alloy coatings, but also to Ni-based composite coatings reinforced by ceramic particle, and even to other material systems. Particularly, when the reinforcing phase is carbide ceramics, the addition of graphite can also inhibit the dissolution of carbide during laser cladding.

A Novel Oxide Layer Formed on the 800 °C-Annealed CoMoCrSi Coating Significantly Reduced Friction and Wear at Room Temperature

In the present work, we investigated the microstructures and properties of as-sprayed and annealed CoMoCrSi coatings. Specifically, the annealed treatment at 800 °C resulted in good recrystallization, improved microstructure, and enhanced properties of CoMoCrSi coatings. An oxide layer formed on the annealed coating surfaces; it was mainly composed of nano-sized Cr2O3 and micro-sized CoMoO4, and could account for the increased surface microhardness and enhanced anti-wear performance of annealed coatings. In particular, the very hard Cr2O3 played a critical role of resisting press-in and wear during the tests, and the CoMoO4 had a lubricating effect during the friction process. Finally, the annealed coatings exhibited low coefficients of friction (COFs) of 0.4 and wear rates of 0.7–0.8 × 10−6 mm3·N−1·m−1 after a long sliding distance of 1000 m at RT. Consequently, the wear mechanism transferred from brittle fracture coupled with abrasive wear for the as-sprayed coating to slight abrasive wear for annealed coatings.

Simulation and Experimental Study on Wear of U-Shaped Rings of Power Connection Fittings under Strong Wind Environment.

The objective of this study was to investigate the wear characteristics of the U-shaped rings of power connection fittings, and to construct a wear failure prediction model of U-shaped rings in strong wind environments. First, the wear evolution and failure mechanism of U-shaped rings with different wear loads were studied by using a swinging wear tester. Then, based on the Archard wear model, the U-shaped ring wear was dynamically simulated in ABAQUS, via the Umeshmotion subroutine. The results indicated that the wear load has an important effect on the wear of the U-shaped ring. As the wear load increases, the surface hardness decreases, while plastic deformation layers increase. Furthermore, the wear mechanism transforms from adhesive wear, slight abrasive wear, and slight oxidation wear, to serious adhesive wear, abrasive wear, and oxidation wear with the increase of wear load. As plastic flow progresses, the dislocation density in ferrite increases, leading to dislocation plugs and cementite fractures. The simulation results of wear depth were in good agreement with the test value of, with an error of 1.56%.

An Experimental Study on the Fretting Corrosion Behaviours of Three Material Pairs at Modular Interfaces for Hip Joint Implants

The fretting corrosion behaviours of Al2O3 ceramic/Ti6Al4V alloy, 316 L stainless/Ti6Al4V alloy, and CoCrMo alloy/Ti6Al4V alloy pairs were studied in an in-house developed fretting-corrosion tester. The fretting behaviours were characterized by the Ft-D-N and Ft/Fn curves. The morphology of the worn surface was analyzed by energy dispersive X-ray spectrometry (EDX), a scanning electron microscope (SEM), and a white light interferometer (WLI). The fretting regimes were found to vary from slip regime (SR) to mixed fretting regime (MFR), with an increase in loads for the Al2O3/Ti6Al4V and 316 L/Ti6Al4V pairs, while for the CoCrMo/Ti6Al4V pair the fretting always remained in SR. The damage mechanism of the Al2O3/Ti6Al4V pair was mainly abrasive wear and corrosive wear, while for the 316 L/Ti6Al4V pair and CoCrMo/Ti6Al4V pair, the wear mechanism was mainly adhesive wear and corrosive wear with slight abrasive wear. The electrochemical impedance spectrum results show that the material transfer layer formed on the surface of the material can protect the material from corrosion for the 316 L/Ti6Al4V and CoCrMo/Ti6Al4V pairs.

Fretting wear mechanism of plasma-sprayed CuNiIn coating on Ti-6Al-4V substrate under plane/plane contact

The fretting wear mechanism of plasma-sprayed CuNiIn coating on Ti-6Al-4V substrate under plane/plane contact conditions was investigated systematically using a bench level test. The obtained experimental results showed that the fretting wear mechanism of the CuNiIn coating can be divided into three stages: (I) In the initial stage, the asperities on the rough surface were flattened to form debris and fill the nearby pits. The contact surface gradually flattened, which was accompanied by slight abrasive wear. (II) With increasing number of fretting cycles, the fretting wear process of the CuNiIn coating entered the delamination wear stage. Under the action of alternating shear loads, the lamellar structure and pores in the CuNiIn coating rapidly cracked and propagated to the surface. In addition, some fatigue cracks propagated into the matrix along the direction of maximum shear stress. (III) Eventually, the CuNiIn coating entered a stable wear state under the lubrication of a third body, which was accompanied by local delamination. The lamellar structure greatly enhanced the fretting wear resistance of the CuNiIn coating. In the process of fretting wear, the lamellar structure of the CuNiIn coating effectively hindered fatigue crack growth, guided crack deflection along the lamellar interface, and induced crack bifurcation. In addition, the pores can blunt the crack tip. • A new self-balancing device was developed to improve geometrical adaptation of friction pairs with plane/plane contact. • The fretting wear resistance of CuNiIn coating was better than that of Ti-6Al-4V. • The wear rate of the CuNiIn coating was non-monotonic with increasing number of cycles. • The lamellar structure of CuNiIn coating was conducive to delamination wear. • The lamellar structure of CuNiIn coating could induce crack deflection, stop crack propagation, and guide crack bifurcation.

In-situ formation ceramic particles reinforced Fe-based composite coatings produced by ultrasonic assisted laser melting deposition processing

In situ TiB2-TiC ceramic particles reinforced Fe-based composite coatings were produced on the surface of 5CrNiMo steel by ultrasonic assisted laser melting deposition processing. Effect of the ultrasonic vibration on the phase structure, distribution of ceramics and wear properties of the coatings were investigated. It was found that ultrasonic vibration did not change the phase structure of the coatings but improved the formation of the coatings. With the increase of ultrasonic vibration output power, microstructure was refined and amount of ceramics increased, as well as distribution of ceramics became more uniform. Wear resistance of the coating produced by 300 W ultrasonic vibration assisted laser melting deposition was about 1.7–2.4 times of that of the coating without ultrasonic vibration, and 3.9–4.6 times higher than that of the substrate. After introducing ultrasonic vibration, wear mechanism of the coating changes from adhesive with abrasive wear to slight abrasive wear.

Improved Friction and Wear Properties of Al6061-Matrix Composites Reinforced by Cu-Ni Double-Layer-Coated Carbon Fibers

The friction and wear properties of an Al6061 alloy reinforced with carbon fibers (CF) modified with Cu-Ni bimetallic layers were researched. Cu-Ni double layers were applied to the CF by electroless plating and Al6061-matrix composites were prepared by powder metallurgy technology. The metal-CF/Al interfaces and post-dry-wear-testing wear loss weights, friction coefficients, worn surfaces, and wear debris were characterized. After T6 heat treatment, the interfacial bonding mechanism of Cu-Ni-CF changed from mechanical bonding to diffusion bonding and showed improved interfacial bonding strength because the Cu transition layer reduced the fiber damage caused by Ni diffusion. The metal–CF interfacial bonding strongly influenced the composite’s tribological properties. Compared to the Ni-CF/Al and Cu-CF/Al composites, the Cu-Ni-CF/Al composite showed the highest hardness, the lowest friction coefficient and wear rate, and the best load-carrying capacity. The wear mechanisms of Cu-Ni-CF/Al composite are mainly slight abrasive wear and adhesive wear.

Tribological properties of MAO/MoS2 self-lubricating composite coating by microarc oxidation and hydrothermal reaction

To decrease coefficient of friction (CoF) of the 6063 aluminum alloy modified by microarc oxidation (MAO) treatment, a MoS2 lubricating layer was synthesized on the MAO coating by hydrothermal reaction. The as-synthetized MoS2 powders demonstrated high purity and interesting micro-spheres structure assembled by many nano-lamellae. The prepared MoS2 layer was ~11 ± 3.3 μm thick, and padded the surface porosity of MAO ceramic coatings. These composite coatings were slidden against GCr15 steel counterparts in air at variable applied loads. According to the results of tribological test, the CoF of MAO/MoS2 composite coatings reduced by ~31.4%, 45.5% and 42.1% compared to single MAO coatings at 2, 4 and 6 N loads, respectively, due to the low shear strength of MoS2. The wear track of MAO/MoS2 composite coatings also displayed more uniform and smoother, causing more stable sliding process. Additionally, the existence of MoS2 layer significantly decreased the wear rate of both coatings and related counterpart balls, implying the enhanced anti-wear properties. Scanning electron microscopy (SEM) and Raman spectrometer revealed that the primary wear mechanism of single MAO coating was a combination of adhesive wear, abrasive wear and oxidation, while the MAO/MoS2 self-lubricating composite coating only showed slight abrasive wear combined with oxidation occurrence.

Microstructure and friction-wear performances of laser-cladded nano-CeO2–reinforced NiCoCrAlY coatings at high temperature

Nano-CeO2–reinforced NiCoCrAlY coatings were fabricated on Ti6Al4V alloy using laser cladding. The morphologies, chemical compositions, and phases of obtained coatings were analyzed using a scanning electron microscope, energy-dispersive spectrometer, and X-ray diffraction, respectively, and the effects of nano-CeO2 mass fraction on the coefficient of friction and the wear rate of NiCoCrAlY coating at 600 °C were investigated using a ball-on-disk wear test. The results show that the nano-CeO2–reinforced NiCoCrAlY coating is mainly composed of NiTi2, Ti3O, CoO, and β-Ti phases, while the new phases of AlTi3 and (Ni, Co)2Ti4O are formed after the wear test. The average coefficients of friction of NiCoCrAlY coatings with the nano-CeO2 mass fractions of 0%, 2%, 4%, and 6% are 0.699, 0.655, 0.636, and 0.615, respectively, and the corresponding wear rates are 4.04 × 10−7, 3.95 × 10−7, 3.13 × 10−7, and 2.35 × 10−7 mm3 N−1 m−1, respectively, which decrease with the increase of nano-CeO2 mass fraction. The wear mechanism is primary adhesive wear and oxidation wear, accompanied by slight abrasive wear, and the addition of nano-CeO2 is the main factor that is enhancing wear resistance.

Investigation on the Microstructure and Wear Behavior of Laser-Cladded High Aluminum and Chromium Fe-B-C Coating.

In this study, a high aluminum and chromium Fe-B-C coating was prepared using laser cladding on 2Cr13 steel substrate. The microstructure, microhardness, and wear resistance of the high aluminum and chromium Fe-B-C coating were investigated. The results show that this dense coating possesses good metallurgical bond with the substrate. The microstructure is mainly composed of α-(Fe, Cr, Al) lath martensite, orthorhombic M2B boride, orthogonal M3C2, and orthorhombic M7C3 carbides. The microhardness of the coating can reach 620 HV which is 3.3-times higher than that (190 HV) of the substrate. The coating shows a lower friction coefficient of 0.75 than that of the substrate (1.08). The wear rates of the substrate and the coating are 0.295 mg/min and 0.103 mg/min, respectively, indicating the coating exhibits excellent wear resistance. The wear mechanism transforms severe adhesive wear and abrasive wear of the substrate to slight abrasive wear of the coating. The results can provide technical support to improve the properties of the Fe-based laser cladded coating.

Dry friction and wear properties of several hard coating combinations

According to the design requirement of friction pairs in MicroElectroMechanical Systems (MEMS), four kinds of hard coatings TiN, TiCN, AlTiN and diamond like carbon (DLC) were selected to form 16 kinds of combinations. The tribological characteristics of the 16 kinds of combinations were investigated by using ball-on-disc tester. The wear mechanisms of the coating combinations were analyzed by scanning electron microscopy (SEM), Energy-dispersive spectroscopy (EDS) and Raman spectroscopy. The results show that the combinations of AlTiN balls/different coated discs and DLC discs/different coated balls have smaller wear and friction coefficient (less than 0.2). Among them, the wear mechanism of the friction pairs composed of AlTiN balls and four kinds of coated discs is extremely slight abrasive wear. The wear mechanism of the combinations of DLC discs and the coated balls (except for the AlTiN ball) is mainly adhesive wear, accompanied by slight abrasive wear. Furthermore, in the design of the coating combination, the coating with high hardness and good wear resistance should be chosen as the fixed part, while the coating with slightly lower hardness and surface roughness is selected as the moving part. Such design principle can ensure good tribological characteristics of coating friction pairs in the MEMS.

Tribological performance and dry sliding-induced microstructure evolution in T20Z alloy under different atmospheric conditions

This study focused on the tribological performance and microstructure evolution of T20Z alloy after dry sliding in air and vacuum. After the tribological tests, normal load and sliding velocity were considered to be optimized based on specific wear rates using Taguchi technique. The results of S/N ratio showed that the optimization of the parameters was 10 N, 0.59 m s−1 for obtaining the minimum wear rates in both air and vacuum. Also, the worn surface and cross-section of T20Z alloy as well as wear debris and counterpart steel balls were analyzed by scanning electron microscopy. Raman spectrometer was performed to further analyze the worn surface. The topography of wear scar was observed using a three-dimensional optical profilometer. The microstructure evolution of T20Z alloy was analyzed by transmission electron microscopy. The results showed that the wear mechanisms in air varied from abrasive wear to delamination wear and severe abrasive wear, and the grain size was finally refined to nanoscale. In vacuum, however, wear mechanisms changed from slight abrasive wear to delamination wear and severe plastic deformation, and only the β phase was deformed.

Effects of Process Parameters on Geometrical Characteristics, Microstructure and Tribological Properties of TiB2 Reinforced Inconel 718 Alloy Composite Coatings by Laser Cladding

The TiB2 reinforced Inconel 718 alloy composite coatings were prepared on carbon steel by laser cladding. The energy input (the ratio of laser power and scanning speed, E) was introduced to investigate the effects of process parameters on geometrical characteristics, microstructure and tribological properties of composite coatings. The results show that the dilution rate decreases and the contact angle increases, respectively, as E decreases from 200.00 J/mm to 80.00 J/mm, which causes the decrease of the boding strength from 1.91 GPa to 0.39 GPa. The composite coatings contain the phases of γ-(Ni, Fe), Laves, TiB2, TiB, TiC, Ni3B, CrB4 and Cr23C6. As E decreases from 200.00 J/mm to 133.33 J/mm, the primary dendrite arm spacing (PDAS) and the Laves content of the composite coating decrease for the increase of cooling rate, leading to the increase of microhardness, the improvement of tribological properties and the change of wear mechanism from the severe multi-plastic deformation wear, adhesive wear and oxidative wear to the slight abrasive wear. However, as E decreases from 133.33 J/mm to 80.00 J/mm, for the weak Marangoni convection, TiB2 particles are prone to aggregate in the top of the composite coating which causes the increase of the PDAS and the Laves content, leading to the decrease of the microhardness and the degradation of tribological properties, and the wear mechanism change to the multi-plastic deformation wear and abrasive wear gradually.

Design and high-temperature tribological properties of CoCrW with rare earth fluoride composites

CoCrW matrix containing rare earth LaF3 self-lubricating composites were fabricated by using hot-pressing method. The microstructure, phases and high-temperature tribological properties of obtained composites were systematically studied. Friction and wear behaviors were evaluated by using ball-on-disc tribo-tester from RT (24 °C) to 1000 °C. Metal matrix consisted of two allotropes: ε (hcp) and γ (fcc). Mo had a solid solution strengthening effect and lubricating effect when it changed into compounds. Rare earth LaF3 and its compounds showed lubricating effect at elevated temperatures. The friction coefficients and wear resistance of reinforced composites were greatly enhanced with little hardness dropping. It was ascribed to the synergistic effect of in-situ formed and extra added solid lubricants (silver, LaCrO3, Ag2MoO4, AgF3 and metal oxides) as well as oxides film which changed the wear model of tribo-couples during sliding. The wear rate of CoCrW-10LaF3-8Mo-9Ag was about 10 times lower than those of reported Ni and ZrO2 matrix composites. The composites showed the slight abrasive wear and oxidative wear at elevated temperatures.

Investigation on Wear Behavior of Cryogenically Treated Ti-6Al-4V Titanium Alloy under Dry and Wet Conditions.

Titanium alloys are widely used in many fields because of their excellent comprehensive properties. However, its poor friction and wear properties limit its many potential applications. In general, the surface roughness of important parts manufactured by titanium alloy should meet certain requirements. As a low-cost and high-efficiency processing method, barrel finishing has been used for the surface finishing of titanium alloys. The main material removal mechanism of barrel finishing is micro-cutting/grinding, which is similar to the material wear mechanism under some conditions. In addition, titanium alloys are subjected to a low force in common surface finishing processes. Cryogenic treatment is a method that can improve the comprehensive properties of titanium alloys. Therefore, the friction and wear behavior of cryogenically treated Ti-6Al-4V titanium alloy (CT Ti alloy) and non-cryogenically treated Ti-6Al-4V titanium alloy (NT Ti alloy) at a low load and scratch speed was studied comparatively in this paper. The results show that the CT Ti alloy exhibits a lower friction coefficient and wear rate under both dry and wet wear conditions. Under wet conditions, the stabilized friction coefficient is lower than that under dry conditions. The stabilized friction coefficient of CT Ti alloy is 0.18 after reaching a stable wear stage under wet conditions. Under dry wear conditions, the NT Ti alloy mainly showed typical abrasive wear, heavy adhesion wear and oxidation wear characters. The wear mechanisms of CT Ti alloy are mainly abrasive wear, slight adhesion wear and oxidation wear. Under wet wear conditions, the wear mechanism of NT Ti alloy is abrasive wear and slight adhesion wear. After cryogenic treatment, the mechanism for CT Ti alloy is slight abrasive wear.

Corrosion properties of the deposited coatings of the system fe-15cr

Coating of machine parts and mechanisms operating in a corrosive environment is an important task of modern engineering. The surfacing of working surfaces by chromium steels has wide possibilities for the formation of corrosion-resistant coatings. The basis of most of these steels is the system Fe-Cr. For surfacing of corrosion-resistant coatings it is efficient to use economically alloyed flux-cored wire of the system Fe-15Cr. At the same time, the corrosion resistance of the deposited metal of such a system has not been studied. In connection with the above, the purpose of the work was to study the corrosion properties of the metal deposited by chromium flux-cored wire of the Fe-15Cr system. Tests for general corrosion were carried out in a salt fog chamber (SFC) at a temperature of 50±1 °C while spraying copper-acetic acid salt solution (neutral brine with the addition of dihydrated copper chloride (CuCl2 + 2H2O) and crystalline acetic acid) for 3 hours every 1 hour. The evaluation of the corrosion behavior in a salt fog chamber of the metal deposited by flux-cored wire PP-Kh15 was carried out in comparison with the metal deposited by standard wire Sv-20Kh13. It is established that the properties of the metal deposited by wire PP-Kh15 at the initial stage of corrosion behavior, estimated at the time until the first signs of corrosion appear, exceed the properties of the metal deposited by standard wire Sv-20Kh13 in 4.8 times, and for long-term corrosion resistance in 1.49 times. The lowalloyed flux-cored wire PP-Kh15 can be recommended for surfacing coatings on parts of equipment used in production, transportation and storage of oil operating in slightly aggressive environments under conditions of slight abrasive wear.