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Light alloys are being increasingly investigated as alternatives to ferrous-based engineering components, based on weight considerations. However, in-service applications of such light alloy components often require a surface modification step to enhance their wear and corrosion responses for improved functionality. Thermally sprayed cermet coatings offer an enhanced resistance to wear and corrosion. This work investigates WC-CoCr coatings deposited using two different feedstocks comprising fine and coarse powder size distributions on aluminum alloy and steel substrates using high-velocity air-fuel (HVAF) and high-velocity oxy-fuel (HVOF) spray techniques. The WC-CoCr coatings were HVAF sprayed at various parameters to investigate the relationship between the processing conditions, microstructure, and performance. Microindentation, dry sliding wear, dry sand abrasion, cavitation erosion, and corrosion tests were conducted to assess the performance of the coatings. Despite the qualitative similarities in the microstructures of the coatings, the measured microindentation hardness values were observed to vary, and coatings deposited with higher particle impact velocities showed the highest microhardness between 1400 and 1600 HV0.3. For the three categories of wear investigated, the HVAF coatings showed better resistance than the HVOF coating investigated in this study. The estimated average specific wear rate (SWR) due to sliding wear of the HVOF coating was ~ 16.7 ± 4.0 × 10 −8  mm 3 /Nm compared to that of the most resistant HVAF coating, which exhibited a SWR of ~ 1.7 ± 0.6 × 10 −8  mm 3 /Nm. The cumulative mass loss rate due to the abrasive wear on the HVOF coating reached ~ 1.11 mg/min compared to ~ 0.76 mg/min of the most abrasion-resistant HVAF coating. All coatings showed similar corrosion resistances under the investigated conditions. The combination of wear and corrosion performance of the respective coatings could provide insight into the coating selection for intended applications.

Four FeCrCoMn high-entropy alloy coatings with different preset body sizes are prepared on the surface of 45 steel substrates by laser cladding technology, and the effect of preset body size on the corrosion performance of the coatings is analyzed. The results show that the phase composition of samples with various preset body sizes are all FCC and HCP solid solution structures. However, the microstructure and morphology of the coating are transformed from equiaxial crystals to columnar dendritic crystals with the increase in the preset body size and the size of more than 10-mm grains coarsen obviously, which results in the gradual decrease in hardness and aggravation of the abrasion. The corrosion mechanism of the coating is mainly pitting, and the wear mechanism is mainly abrasive wear, adhesive wear and corrosive oxidative wear. With the increase in the preset body size, the corrosion and abrasion resistance of the coating increases first and then decreases. When the preset body size is 15 mm, the coating has high corrosion protection efficiency due to the dense structure of the coating and few solidification defects, which makes the coating show excellent corrosion and abrasion resistance.

The aim of this study was to evaluate the susceptibility of dentin to brushing abrasion using four different toothbrushes (rotating-oscillating, sonic and two types of manual toothbrushes) with the same brushing forces. Dentin samples (n = 72) were selected from 72 impacted third molars. Half of the surface of dentin samples was covered with an adhesive tape, creating a protected and a freely exposed area in the same specimen. Brushing was performed with either a: sonic (Sonicare PowerUp, Philips GmbH, Hamburg, Germany), b: oscillating-rotating (Oral B Vitality Precisions Clean, Procter & Gamble, Schwalbach am Taunus, Germany) or two different manual toothbrushes c: flat trim brush head toothbrush (Dr. Best: Original, Glaxo-Smith-Kline, Bühl, Germany) and d: rippled-shaped brush head toothbrush (Blend-a-Dent, Complete V-Interdental, Blend-a-med, Schwalbach, Germany) in a custom made automatic brushing machine. The brushing force was set to 2 N and a whitening toothpaste (RDA = 150) was used. The simulation period was performed over a calculated period to mimic a brushing behavior of two times a day brushing for eight years and six months. Dentin loss was quantitatively determined by profilometry and statistically analyzed by Wilcoxon and Mann-Whitney-U Test (p < 0.05). The mean (standard deviation) surface loss was 21.03 (±1.26) μm for the sonic toothbrush, 15.71 (±0.85) μm for the oscillating-rotating toothbrush, 6.13 (±1.24) μm for the manual toothbrush with flat trim brush head and 2.50 (±0.43) μm for the manual toothbrush with rippled-shaped brush head. Differences between all groups were statistically significant at p<0.05. Using the same brushing force and a highly abrasive toothpaste, manual toothbrushes are significantly less abrasive compared to power toothbrushes for an 8.5-year simulation.

The effects of alumina particle size and jet pressure on the bond strength of polyetheretherketone (PEEK) were examined to determine the airborne particle abrasion parameters with minimal effects on PEEK and to achieve optimal bond strength, as a reference for future clinical use. An alumina particle with four particle sizes and three jet pressures was used to air-abrade PEEK. Surface roughness (Ra), morphology, chemical structure, and wettability were analyzed using a stylus profilometer, scanning electron microscope, X-ray diffractometer, and contact angle analyzer, respectively. The shear bond strength (SBS) of PEEK and dental resin cement was analyzed using a universal testing machine (n = 10). The failure modes and debonded fracture surfaces were observed using optical microscopy. Airborne particle abrasion increased the Ra and hydrophobicity of PEEK and deposited alumina residues. The SBS generally decreased after thermal cycling. A large particle size damaged the PEEK surface. The effects of different particle sizes and jet pressures on the SBS were only significant in certain groups. Adhesive failure was the main mode for all groups. Within the limitations of this study, 110 μm grain-sized alumina particles combined with a jet pressure of 2 bar prevented damage to PEEK, providing sufficient SBS and bonding durability between PEEK and dental resin cement.

AISI1045 steel is widely used in mechanical engineering. In spite of the favorable toughness and strength, the surface properties of AISI1045 steel, such as hardness, wear resistance and corrosion resistance, are not ideal. Therefore, surface modification of AISI1045 is necessary, especially for the parts suffering severe work condition. Laser cladding is a promising surface modification technology. In this work, the AlCoCrFeNiTi high-entropy alloy (HEA) coatings were prepared on the AISI1045 steel to improve its surface properties. Metallurgical bonding is obtained between the coating and the substrate. The microstructure and surface properties of the coating were characterized by scanning electron microscope, energy-dispersive spectrometry, x-ray diffraction, electrochemical workstation, microhardness tester and pin-on-ring wear tester. The microstructure of the coating produced by laser cladding is dendritic. The AlCoCrFeNiTi HEA coating is mainly composed of disordered body-centered cubic phase (Fe-Cr), ordered B2 phase (AlNi) and intermetallic phase (Ti-rich). The coating shows excellent abrasion resistance and corrosion resistance in comparison with the substrate. The maximum microhardness of the coating reaches approximately 865 HV, which is 4.5 times of AISI1045 steel.

Tooth wear is a commonly reported finding globally; however, many patients are unaware of having tooth wear. Identifying early signs of erosion, abrasion or attrition and determining the risk factors contributing to a patient's tooth wear may help to prevent further loss of enamel and dentine in the future. Appropriate prevention should be instigated, or appropriate referral made to other health professionals, when conditions such as gastroesophageal reflux or eating disorders are suspected. This paper presents the epidemiology and aetiological factors for tooth wear, as well as identifying the common clinical presentations of tooth wear. Patient perspectives on tooth wear and preventive techniques that can be utilised are also discussed.Key pointsThis paper summarises the clinical presentation of erosion, attrition and abrasion.Prevalence of tooth wear and aetiological factors are discussed in detail.Strategies for prevention of tooth wear are described.

This study compares nickel-aluminum (Ni-Al) and 3Cr13 steel coatings deposited on carbon steel substrates by arc spraying. The objective is to select a coating that will improve the corrosion and abrasion wear resistance of boiler heat exchanger pipes. This comparison involves the study of the microstructure, phase composition, microhardness, wear and erosion, and corrosion resistance of the coatings. The corrosion resistance was evaluated based on seawater immersion, electrochemical impedance, polarization, and galvanic corrosion tests. The results showed that the Ni-Al coating had a porosity of 6.3%, while the 3Cr13 coating had a porosity of 5.2%. The average surface roughness of the 3Cr13, Ni-Al coatings, and polished substrate were 11, 14.4, and 0.13 μm, respectively. The 3Cr13 lamellar structure coating was mainly composed of the α -Fe phase and a small amount of the CrO phase, and the Ni-16wt%Al coating included a solid solution phase and a small amount of the NiO phase. During the wear tests, the Cr13 steel coating had the highest microhardness and the best abrasion resistance at room temperature at the initial stage of friction. However, its abrasion resistance was lower than that of the Ni-Al coating after a 10-min friction test. The friction coefficients of the two coatings were almost the same at 300 °C. The corrosion resistance of the Ni-Al coating was better than that of the 3Cr13 steel coating. The current density of galvanic corrosion of the 3Cr13 coating was 108 μA m -2 and that of the Ni-Al coating was 37 μA cm -2 , indicating that galvanic corrosion occurred between the substrate and the coating. This comparison showed that the Ni-Al coating could provide better high-temperature abrasion resistance and anti-corrosion performance for boiler heat exchanger piping compared with the 3Cr13 steel coating.

Sediment Bypass Tunnels (SBTs) effectively mitigate reservoir sedimentation by diverting flood-laden flows, but they face significant challenges due to hydroabrasive erosion, which compromises their sustainability. Predicting this abrasion is complex due to the intricate interactions between flow hydraulics and sediment transport, along with limited high-quality data. In this study, we explore, for the first time, the potential of using the XGBoost machine learning algorithm to predict the spatial abrasion of SBTs. The Koshibu SBT in Japan, extending approximately 4 km, was selected as the case study. Three experimental scenarios were evaluated: the entire tunnel, the straight section, and the curved section. A spatial abrasion topography was measured using laser scanning tools with a spatial resolution of 2 cm. The controlling factors for abrasion were developed based on geometric and hydraulic features. The abrasion inventory map, consisting of over 1 million data points indicating damaged and non-damaged sites, was divided equally for training and testing the XGBoost algorithm. Results indicate that the XGBoost model effectively predicts 2D spatial abrasions in SBTs, achieving an overall accuracy of 0.864, exceeding 0.9 in some sections. The developed abrasion map accurately captures various complex patterns throughout the tunnel but has some limitations in areas with small wave-like patterns. Overall, this study demonstrates the potential of machine learning algorithms for predicting tunnel abrasion in SBTs. Paper highlights This study introduces a validated 2D model for tunnel abrasion based on field data, contributing to improved sediment management in SBTs. ASM Model efficiently predicts abrasion mapping in SBT, achieving 86.4% overall accuracy. High sensitivity and specificity in distinguishing abraded and non-abraded areas. Captures four complex abrasion patterns in straight and curved sections but is limited to relatively small wave-like patterns. Geometric and hydraulic parameters, particularly the elongated distance and flow velocity, exhibit significant impacts in the ASM model.

In this study, multi-element nitride coatings composed of (Ti, Cr, Cu, Al, Si)N were synthesized on H13 tool steel using cathodic arc deposition (CAD) technology. The N2/Ar flow ratio varied from 0 to 2 as the experimental parameter, and two targets, Ti-Cr-Cu and Al-Si alloys, were utilized simultaneously. The impact of the gas flow ratio on the coatings’ abrasion properties was investigated, focusing on aspects, such as chemical composition, adhesion, hardness, and wear behavior. The experimental findings indicate that the coated specimens with a nitrogen reaction exhibit superior hardness and abrasion resistance compared to those without nitrogen use. While the surface roughness of the specimens tends to increase slightly with a higher N2/Ar ratio, the coating demonstrates improved hardness, adhesion, and abrasion resistance performance. In summary, the wear-resistant characteristics of H13 tool steel can be significantly enhanced when applying a CAD-(Ti, Cr, Cu, Al, Si)N film with a flow ratio of N2/Ar = 2.