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Materials (Basel, Switzerland) Jun 2024Aiming to solve the problem of thermal decay of resin-based friction materials at high temperatures, rare-earth-lanthanum-oxide-/cerium-oxide-reinforced resin-based...
Aiming to solve the problem of thermal decay of resin-based friction materials at high temperatures, rare-earth-lanthanum-oxide-/cerium-oxide-reinforced resin-based friction plates were prepared using a hot-pressing molding process. The effect of lanthanum/cerium oxide with different contents on the mechanical and tribological properties of the resin-based friction of materials was studied, and its mechanism was explored. The result shows that lanthanum/cerium oxide improves the mechanical and tribological properties of materials so that the coefficient of friction of the specimen is more stable on adding lanthanum/cerium oxide at 5% and 1%. Lanthanum/cerium oxide improves antidegradation properties of resin-based material and reduces the high-temperature wear rate by enhancing the interfacial effect so that the wear form of the specimen changes from predominantly adhesive wear to predominantly abrasive wear.
PubMed: 38930359
DOI: 10.3390/ma17122990 -
Materials (Basel, Switzerland) Jun 2024The presented manuscript focuses on the influence of process parameters of abrasive water jet technology on the creation of non-transient erosive grooves. The processed...
The presented manuscript focuses on the influence of process parameters of abrasive water jet technology on the creation of non-transient erosive grooves. The processed stainless steel SS 316L is additively manufactured using the selective laser melting (SLM) method. Due to the distinct mechanical properties of this material resulting from the production process, the material was machined in two planes according to the direction of the printing layers. The experimental part employed a planned experiment utilizing the DoE (Design of Experiment) method. Experiments aimed at varying process parameters (traverse speed, standoff distance, abrasive mass flow) were conducted at a water pressure of 50 MPa, assessing the parameters' impact on the removed material and the properties of the resulting non-transient erosion groove. The properties of the erosion groove, such as shape and the material removal (area of erosion groove), were evaluated. The influences of process parameters on the observed parameters were assessed using the analysis of variance (ANOVA) method. Experiment preparation and setup were based on a thorough theoretical analysis of the machining process with the abrasive water jet (AWJ) method. The experiment also highlights the diverse properties of the SS 316L material prepared using the SLM method when machined with AWJ technology.
PubMed: 38930333
DOI: 10.3390/ma17122964 -
Materials (Basel, Switzerland) Jun 2024During industrial and laboratory processes involving material grinding, the grinding media endure prolonged high-collision and friction environments, resulting in...
During industrial and laboratory processes involving material grinding, the grinding media endure prolonged high-collision and friction environments, resulting in substantial wear. Consequently, this study adopts the hot-pressing sintering technique in powder metallurgy to prepare SiC-reinforced Fe-based wear-resistant composite grinding media, aiming to increase wear performance. For this purpose, Fe with 10 wt% SiC powders were milled for the fabrication of the composite. Then, sintering was performed by hot press at 1100 °C in a furnace. Scanning electron microscopy (SEM) and X-ray diffraction were employed to investigate the microstructures and phase of SiC-reinforced Fe-based matrix composite. Subsequently, comparative performance evaluations of the newly developed grinding media and traditional chromium-based media were conducted in terms of wear rate and grinding efficiency. The wear resistance tests revealed that the SiC-reinforced composite media displayed significantly superior wear resistance across various abrasives compared to the chromium-containing alternatives. Specifically, the composite media achieved a wear rate reduction of 2.9 times against standard sand over 1 h, and 2.3 and 2.4 times against sandstone and iron slag, respectively. Moreover, extended grinding for 3 hours further enhanced these reductions to 3.1, 2.4, and 2.7 times, respectively. Additionally, efficiency assessments indicated that at a 1:1 material ratio, the composite media outperformed the chromium-containing media in grinding efficiency by 7.5%, 12.5%, and 10.3% for standard sand, sandstone, and iron slag, respectively. Further increasing the material ratio to 3:1 resulted in efficiency improvements of 7.4%, 17.5%, and 11.3%, correspondingly.
PubMed: 38930309
DOI: 10.3390/ma17122940 -
Materials (Basel, Switzerland) Jun 2024The effects of Si addition on the microstructures and properties of CoCrNi medium-entropy alloy (MEA) were systematically investigated. The CrCoNiSi MEA possesses a...
The effects of Si addition on the microstructures and properties of CoCrNi medium-entropy alloy (MEA) were systematically investigated. The CrCoNiSi MEA possesses a single face-centered cubic (FCC) phase when x is less than 0.3 and promotes solution strengthening, while the crystal structure shows a transition to the FCC+σ phase structure when x = 0.4 and the volume fraction of the σ phase increases with a microstructure evolution as the Si content increases. The Orowan mechanism from σ precipitation effectively enhances the strength, hardness, and stain hardening of CrCoNiSi MEA, which also exhibits superior hardness at high temperatures. Furthermore, a large amount of σ phase decreases the wear resistance because of the transformation of the main wear mechanism from abrasion wear for σ-free CrCoNiSi MEA to adhesion wear for σ-contained CrCoNiSi MEA. This work contributes to the understanding of the effect of Si addition on FCC structured alloys and provides guidance for the development of novel Si-doped alloys.
PubMed: 38930262
DOI: 10.3390/ma17122893 -
Materials (Basel, Switzerland) Jun 2024Microstructural heterogeneities of an ASTM A128 grade C steel subjected to heat treatments and their effect on abrasive wear behavior were investigated. The...
Microstructural heterogeneities of an ASTM A128 grade C steel subjected to heat treatments and their effect on abrasive wear behavior were investigated. The heat-treatment process involved different austenization times at 1050 °C and quenching media. To characterize the effects of heat treatment on the material's microstructure and mechanical behavior, two microscopy techniques were used: optical microscopy (OM), and scanning electron microscopy (SEM). The chemical composition of the material was obtained using X-ray fluorescence (XRF) optical emission spectrometry. The variation in carbide composition was evaluated using X-ray Energy Dispersive Spectroscopy (EDS). To characterize the mechanical behavior of the steel, hardness measurements and abrasive wear tests were performed after homogenization annealing and quenching treatments. The results showed that the heat-treated samples developed a heterogeneous microstructure, with the presence of austenitic grains and Martensite around the surface of the samples induced by decarburization in both the protected and unprotected specimens. The specimens with lower decarburization presented less formation of Martensite and precipitated carbides, resulting in lower hardness values and higher abrasion resistance (solution treatment at 1080 °C for 1 h + sand protection + brine quenching).
PubMed: 38930254
DOI: 10.3390/ma17122884 -
Materials (Basel, Switzerland) Jun 2024Braking systems are extremely important in any vehicle. They convert the kinetic energy of motion into thermal energy that is dissipated into the atmosphere. Different...
Braking systems are extremely important in any vehicle. They convert the kinetic energy of motion into thermal energy that is dissipated into the atmosphere. Different vehicle groups have different nominal and maximum speeds and masses, so the amount of thermal energy that needs to be absorbed by the friction pads and then dissipated can vary significantly. Conventional friction materials are composite materials capable of withstanding high temperatures (in the order of 500-600 °C) and high mechanical loads resulting from braking intensity and vehicle weight. In small vehicles traveling at low speeds, where both the amount of thermal energy and its density are limited, the use of slightly weaker friction materials with better ecological properties can be considered. This work proposes a prototype composite friction material using flax fibers as reinforcement instead of the commonly used aramid. A number of samples were prepared and subjected to laboratory tests. The samples were prepared using components of plant origin, specifically flax fibers. This component acted as reinforcement in the composite friction material, replacing aramid commonly used for this purpose. The main tribological characteristics were determined, such as the values of the coefficients of friction and the coefficients of abrasive wear rate. For this purpose, an authorial method using ball-cratering contact was used. The results were analyzed using statistical methods. It was found that the composite material using flax fibers does not differ significantly in its tribological properties from conventional solutions; so, it can be assumed that it can be used in the vehicle's braking system.
PubMed: 38930230
DOI: 10.3390/ma17122861 -
Materials (Basel, Switzerland) Jun 2024This article presents the effect of the conditions of abrasive compounds on the wear of samples made by different methods. The 28MnB5 steel was used, which is intended...
This article presents the effect of the conditions of abrasive compounds on the wear of samples made by different methods. The 28MnB5 steel was used, which is intended for agricultural components, to which two arc and laser coatings were applied. The study included the analysis of microstructure, microhardness, roughness, and tribological experiments on a dedicated stand. The arc coating was found to significantly improve the tribological properties compared to the samples without the coating. Varied wear results were obtained for the laser coating depending on the parameters of the abrasive compound. Studies of the surface roughness of the samples showed that the concentration and pH of the abrasives have a significant effect on the changes in the surface parameters after the tribological tests. The results of the tribological experiments indicated that wear resistance for some of the abrasive mass conditions was improved by the application of heat-applied coatings. In addition, it was found that the power consumption on the stand was the highest for abrasive mass conditions of a 10% moisture content and a pH of 10. For these test conditions, the mass loss was four times higher than for the parameter with W0% and pH7. The energy consumption of the stand was 60 kWh lower for this variant than for the parameter with W10% and pH10. The results of the study have important practical applications that can help in the selection of materials for agricultural machinery components, depending on the abrasive mass conditions.
PubMed: 38930218
DOI: 10.3390/ma17122849 -
Materials (Basel, Switzerland) Jun 2024Ultra-thin 304 stainless steel can be used to flexibly display substrates after they have been subjected to chemical mechanical polishing (CMP). The thickness of the...
Ultra-thin 304 stainless steel can be used to flexibly display substrates after they have been subjected to chemical mechanical polishing (CMP). The thickness of the chemical oxide layer directly affects the polishing efficiency and surface quality of 304 stainless steel. In the study presented in the following paper, the thickness variation of the chemical oxide layer of 304 stainless steel was analyzed following electrochemical corrosion under different oxidant concentration conditions. Furthermore, the impact of the oxidant concentration on the grooves, chips, and scratch depth-displacement-load curves was investigated during a nano-scratching experiment. Through this process, we were able to reveal the chemical reaction mechanism between 304 stainless steel materials and oxidizers. The corrosion rate was found to be faster at 8% oxidant content. The maximum values of the scratch depth and elastic-plastic critical load were determined to be 2153 nm and 58.47 mN, respectively.
PubMed: 38930186
DOI: 10.3390/ma17122816 -
ACS Applied Materials & Interfaces Jun 2024Transparent, hard, and flexible multifunctional coatings have a wide range of applications; however, most of them need organic solvents. Here, we present a solvent-free...
Transparent, hard, and flexible multifunctional coatings have a wide range of applications; however, most of them need organic solvents. Here, we present a solvent-free and UV-cured coating made from fluorinated epoxy MTQ silicone resin combined with branched triepoxy siloxane as the reactive diluent. After UV-initiated ring-opening polymerization in the presence of a triarylsulfonium hexafluoroantimonate catalyst, the resultant cured coating exhibits high transparency (∼92%, 550 nm), pencil hardness (7H), and flexibility (1 mm bending diameter) due to the formed organic-inorganic nanostructures in a highly cross-linked network. The triepoxy siloxane significantly reduces the viscosity before curing and increases cross-link density of the coating. The coating without any volatile content shows a smooth surface with low roughness ( = 0.46 nm) and delivers an anti-smudge ability owing to perfluorinated chains inherited from the MTQ resin. Furthermore, even after 3000 abrasion cycles, the coating still has a water contact angle greater than 90°, displaying excellent wear resistance. Our work provides a promising way to access high-performance multifunctional coatings in a more sustainable manner.
PubMed: 38924769
DOI: 10.1021/acsami.4c03775 -
Journal of Oral Rehabilitation Jun 2024Noncarious cervical lesions (NCCLs) are multifactorial and can be caused by the anatomical structure of the teeth, erosion, abrasion and abnormal occlusion. The aim of...
OBJECTIVES
Noncarious cervical lesions (NCCLs) are multifactorial and can be caused by the anatomical structure of the teeth, erosion, abrasion and abnormal occlusion. The aim of this case-control study was to explore the risk factors for NCCLs.
METHODS
Cone-beam computed tomography was used to determine whether a wedge-shaped defect existed at the cementoenamel junction. We compared 63 participants with NCCLs with 63 controls without NCCLs, matched for sex, age (±1 year) and toothbrushing-related factors (e.g., type of bristle and brushing patterns, frequency and strength). All participants were asked to complete a questionnaire about self-administered daily diet habits and health condition. Univariate and multivariate logistic regression analyses were conducted to determine the risk factors for NCCLs.
RESULTS
Significant variables in the univariate analysis (i.e., p < .2) included frequency of carbonated beverage consumption, sella-nasion-point B angle (SNB) and Frankfort-mandibular plane angle (FMA). Multivariate logistic regression demonstrated that the consumption frequency of carbonated beverages (odds ratio [OR] = 3.147; 95% confidence interval [CI], 1.039-9.532), FMA (OR = 1.100; 95% CI, 1.004-1.204) and SNB (OR = 0.896; 95% CI, 0.813-0.988) was independent influencing factors. The area under the receiver operating characteristic curve (AUC) value of regression Model 1 (established with the frequency of carbonated beverage consumption, FMA, SNB and sleep bruxism) was 0.700 (95% CI, 0.607-0.792; p < .001), and that of regression Model 2 (established using the frequency of carbonated beverage consumption, FMA and SNB) was 0.704 (95% CI, 0.612-0.796; p < .001).
CONCLUSIONS
The consumption frequency of carbonated beverages and FMA was risk factors for NCCLs; the higher the frequency of carbonated beverage consumption and FMA, the higher was the probability of NCCLs. SNB was a protective factor for NCCL occurrence; the larger the SNB, the lower was the probability of NCCL occurrence. These findings have further clarified the aetiology of NCCLs and provided clinicians with valuable insights into strategies for preventing the loss of dental tissue.
PubMed: 38924570
DOI: 10.1111/joor.13772