Wear最新文献

The article presents a study of tribocorrosion resistance of AISI 420 steel in extracts of allium cepa (onion juice). The tests were conducted for 3 variants of heat treatment and two ball pressures of 4.5 and 14 N on a ball-on-plate test stand. For all AISI 420 martensitic steel specimens tested in tribocorrosion tests, a clear friction-corrosion synergy effect was found, ranging from 30 to 60 % of total tribocorrosion wear. The lowest mechanical wear was found for samples after low-temperature tempering at 200 °C (54 HRC). Under tribocorrosion conditions, samples after medium-temperature tempering at 400 °C (51 HRC) were more resistant to wear. The results of the tests were used to make an onion-cutting blade, which found industrial application in one of the food industry factories.

Ni-W composite coatings that are applied using electrodeposition exhibit excellent mechanical strength, corrosion resistance and wear resistance and are a substitute for hard chrome because they involve fewer environmental hazards than regular chromium plating processes. This study determines the effect of process parameters, such as current density (5, 10 and 15 A/dm²) and SiC concentration (0.5, 1.0 and 1.5 g/L), on the chemical composition, structure, mechanical properties and corrosion resistance of electrodeposited Ni-W/SiC composite coatings and determines the interaction between the mechanical behavior and the electrochemical reactions that occur during corrosion and friction. The experimental results show that there are no cracks on the surface of the coating and that the surface roughness increases as current density increases. As the content of W and SiC particles in the composite coating increases, the hardness and corrosion resistance of the coating increase because of solid solution strengthening and nano-ceramic particle dispersion strengthening.

In order to verify the protective performance of the coating in complex environments, a ball-on-disk abrasion tester and a potentiostat are used to determine the tribocorrosion behavior of the Ni-W/SiC composite coating against the sliding of the Al₂O₃ counter-body. In 3.5 wt%NaCl solution and at +600 mV, the corrosion and wear characteristics of composite coatings that are produce using different process parameters are determined. Analysis of the synergistic effects of corrosion and friction shows that the wear component (△W_wear) is 3–5 times greater than the corrosion component (△_Wcorr), which is the main cause of coating damage. The greater the hardness of the coating, the less mass is lost for the wear component (△W_wear). The results show that the operating parameters for producing ideal Ni-W/SiC composite coatings are a SiC particle concentration 1.0 g/L and a current density of 10A/dm². These settings give the best wear resistance in corrosive environments.

Sulfur-free green lubricant additives have received more attention in industrial production. In this study, tri-octyldodecyl phosphonium diisooctyl phosphate （P/P）with UiO-66 composite environmentally friendly lubricating additives were synthesized. The tribological properties of P/P with UiO-66 composite additive in polyalphaolefin-6 (PAO-6) heavy were systematically conducted. The outcomes showed that 1 % P/P@3000 UiO-66 additive had excellent friction reduction and antiwear properties. This was mainly due to the adsorption of oil-soluble P/P on the surface and within the pores of UiO-66, which effectively reduced the tendency of agglomeration of UiO-66 formed a good synergistic effect. Consequently, a favorable and stable balling effect was achieved, thereby preserving the integrity of the lubricant film, resulting in significantly reducing wear from shear and abrasive.

Thermal expansion mismatch stresses may be a reason for premature failure of sealing and bearing components made of polymer composites that are rubbed against metallic surfaces at elevated temperatures. It is of particular importance for polymer matrix composites loaded with anti-friction inclusions of polytetrafluoroethylene (PTFE) that possesses high coefficient of thermal expansion. In this regard, a study was undertaken to elucidate the effect of the thermal mismatch on wear and friction of amorphous polyetherimide (PEI) matrix loaded with either polytetrafluoroethylene (PTFE) particles (i) or PTFE particles covered with negative thermal expansion zirconium tungstate (ZT) α-ZrW₂O₈ (ii) at temperatures 23 °C, 120 °C and 180 °C. The ball-on-disk testing scheme was used according to standard with AISI 52100 steel balls rubbed against a polymer composite disks at normal force P = 5 N and sliding velocity V = 0.3 m/s. The PEI/PTFE/ZT composite demonstrated a tendency for wear rate (WR) reduction in sliding at 120 °C and 180 °C as compared to corresponding WR enhancement on the PEI/PTFE. The rationale is provided that the ZT additive effectively reduced thermal expansion of the PTFE in the PEI matrix and thus improved wear resistance of the composite. New thermal expansion-controlled wear and friction instability mechanism has been proposed and discussed.

The galling mechanism of Tristelle 5183, an Fe-based hardfacing alloy, was investigated at elevated temperature. The test was performed using a bespoke galling rig. Adhesive transfer and galling were found to occur, as a result of shear at the adhesion boundary and the activation of an internal shear plane within one of the tribosurfaces. During deformation, carbides were observed to have fractured, as a result of the shear train they were exposed to and their lack of ductility. In the case of niobium carbides, their fracture resulted in the formation of voids, which were found to coalesce and led to cracking and adhesive transfer. A tribologically affected zone (TAZ) was found to form, which contained nanocrystalline austenite, as a result of the shear exerted within 30 μm of the adhesion boundaries. The galling of Tristelle 5183 initiated from the formation of an adhesive boundary, followed by sub-surface shear in only one tribosurface, Following further sub-surface shear, an internal shear plane is activated. internal shear and shear at the adhesion boundary continues until fracture occur, resulting in adhesive transfer.

The refractory high-entropy alloys (RHEAs) exhibit great potential as structural components for aerospace equipment. However, their lack of wear resistance and increased coefficient of friction at room temperature (RT) impose limitations on their practical applications. Therefore, further enhancements are required to improve their friction and wear properties under RT. In this context, the development of NbMoWTa(h-BN)_x RHEA ceramic composites in this work offers a viable solution to address this issue. Experimental results demonstrate that the addition of h-BN leads to the in-situ generation of (Nb,Ta)N/(Nb,Ta)₂N and (Nb,Ta)B₂ ceramic phases, significantly enhancing the hardness and wear resistance of the composites. The wear rate of NbMoWTa(h-BN)_0.5 reaching as low as 1.32 × 10⁻⁸ mm³/Nm, which is four orders of magnitude lower than that of the RHEA. The NbMoWTa RHEA exhibits significant adhesive wear, which can be effectively mitigated in composites through the uniform dispersion of ceramic phase particles with lower mean free path. The abrasive particles primarily interact with the hard strengthening phase, effectively inhibiting plastic deformation in their vicinity. Consequently, the reduced mean free path between the ceramic phases limits the likelihood of metal matrix removal. Subsequently, aided by the presence of ceramic phases, the spontaneous formation of protective third bodies further inhibit surface material removal and ultimately ensures exceptional wear resistance.

The damage caused by rain droplet erosion to the leading edge of wind turbine blades is extremely severe. To reduce this issue, in this study, hydroxyl-terminated polybutadiene (HTPB) and isophorone diisocyanate (IPDI) were used as the polyurethane (PU) polyol and curing agent, respectively, to prepare a PU coating with a high resistance to water droplet erosion (WDE) for the protection of the leading edge of wind turbine blades. The effect of n (–NCO):n (–OH) (R-value, n is the molar ratio) on the mechanical properties and WDE resistance of PU coatings, the relationship between the two performances, and the influence of the erosion conditions on the WDE behavior were investigated for the first time. The results show the existence of a correlation between the mechanical properties (hardness, impact, flexibility, and tensile strength) and WDE resistance of the coating. While, a better abrasion resistance is found not to result in a better WDE resistance. The PU coating with an R-value of 1.2 shows an optimal WDE resistance in both atomization and jet erosion experiments. In atomized droplet erosion (ADE) experiments, the change in erosion velocity accelerates the incubation period of coating erosion damage and increases the erosion rate. In jet droplet erosion (JDE) experiments, the damage to the coating is closely related to the erosion angle, reaching a maximum at an impact angle of 60°. Furthermore, in the ADE experiments, various erosion morphologies, such as pits, grooves, cracks, and stepped texture, are observed on the damaged coating surface. While, regarding the JDE experiments, holes, grooves, and cracks are observed. Such damage is caused by the combined effects of water hammer pressure, lateral jets, and local permeation.

For effective implementation of smart machine technology, there is a great demand for real-time monitoring of the wear progression of machine components. In this work, the effectiveness of assessing wear by monitoring the airborne wear particles was investigated. Sliding wear tests were performed using different combinations of stainless steel (SUS304) and alumina material pairs while monitoring the size distribution and the number of particles using a particle counter. The results showed that particles less than 2 μm in size accounted for more than 83 % of the total number of airborne particles. However, particles greater than 2 μm account for 95 % of the volume of airborne particles. Additionally, in the case of wear volume, the total wear volume, which is the sum of the plate and the ball wear volumes, should be similar to that of the total airborne particle volume. For the SUS304/SUS304 pair, the total wear volume and the total airborne particle volume were very similar. However, in the case of alumina/SUS304 and alumina/alumina, the total wear volume and total airborne particle volume were not similar, and the total wear volume was significantly higher than the total airborne particle volume. The effectiveness of the airborne particle monitoring technique depended strongly on the material pairs. This was due to the fact that particle dispersion behavior varied with respect to the wear mechanisms of the materials.