Wear Volume Research Articles

Enhancing wear resistance of inconel 601 through pack alumunizing coating and advanced lubrication environments

Inconel 601 alloy is a material widely used at high temperatures. One of the most important mechanical properties to consider for some of the materials used in these areas is wear. Wear that occurs at the contact points between parts both causes material loss and reduces material performance. For this reason, coatings and new lubricants are used on material surfaces to reduce wear. In this study, nanoparticle and cryogenic lubricants with different viscosities were prepared to reduce the wear of Inconel 601. Additionally, the surface is hardened by the pack aluminizing. With the 100 µm thick NiCrAl intermetallic coating layer formed on the surface by the aluminizing process, an improvement was achieved in the hardness (2.9 times) and elasticity modulus values (15%) of the surface. The wear behavior of Inconel 601 was investigated under different loads (15 N, 25 N, 35 N) and using different lubricants (Dry, Nano-MQL-Mix, Cryo-MQL, Cryo-Nano-MQL) in a ball-on-flat wear device. In the studies conducted, the lowest volume loss, friction coefficient and wear depth were achieved in Cryo-Nano-MQL conditions and aluminized samples, while the highest values occurred in a dry environment. When the volume loss results are examined, the average volume loss in the as received samples occurred in a dry environment with 2.76 mm3. When switching from dry environment to Cryo-Nano-MQL at a load of 35 N, a decrease of 96.85% is observed. In alumination samples, the average volume loss occurred in a dry environment with 1.74 mm3. When switching from dry environment to Cryo-Nano-MQL at a load of 35 N, a decrease of 97.70% is observed. Tribological performance was improved by increasing the viscosity of the lubricants used and by using the pack aluminization method.

Scratch-Induced Deformation Behavior of Wire-Arc Directed Energy Deposited α-Titanium

This study investigates the scratch response of α-phase commercially pure titanium (cp-Ti) produced via wire arc directed energy deposition (WDED), focusing on the thermal history and directional effects. Progressive scratch tests (1–50 N) revealed heterogeneous wear properties between the top and bottom layers, with the top layer exhibiting higher material recovery (58 ± 5%) and wear volume (5.02 × 10−3 mm3) compared to the bottom layer (42 ± 5% recovery, 4.46 × 10−3 mm3), attributed to slower cooling rates and coarser grains enhancing ductility. The variation in the properties stems from the thermal gradient generated during WDED. Electron backscatter diffraction analysis showed higher kernel average misorientation (KAM) in the bottom layer (0.84° ± 0.49° vs. 0.51° ± 0.44°), affecting plasticity by reducing dislocation and twin boundary mobility. No significant differences were observed between longitudinal and transverse orientations, with coefficients of friction averaging 0.80 ± 0.12 and 0.79 ± 0.13, respectively. Abrasive wear dominated as the primary mechanism, accompanied by subsurface plastic deformation. These findings highlight the significant influence of WDED thermal history in governing scratch resistance and deformation behavior, providing valuable insights for optimizing cp-Ti components for high-performance applications.

Research on the Microstructure and Properties of Arc-Sprayed Austenitic Stainless Steel and Nickel-Based Alloy Composite Coatings with Different Spraying Distances

1Cr18Ni9Ti and Monel composite metal coatings with five different spraying distances were prepared by arc spraying technology. The density, hardness, friction, and wear properties and acid corrosion rate of the coatings with different spraying distances were studied by X-ray diffraction, scanning electron microscopy, Rockwell hardness test, and friction and wear test. Research shows that the spraying distance has a significant effect on the density, hardness, porosity, friction, and wear properties and corrosion rate of the coating. When the spraying distance is 250 mm, the coating has the maximum density and hardness, the minimum porosity and corrosion rate, and the minimum friction coefficient and wear volume. Cu3.8ni and cr0.19fe0.7ni0.11 compounds in the coating have significant effects on the friction, wear, and hardness of the coating. The results show that too-high or too-low spraying distance will lead to pores and large particle agglomeration in the coating, which will affect the surface physical properties of the coating.

Exploring the Effect of Ti on Mechanical and Tribological Properties of an AlCrFe2Ni2Tix High-Entropy Alloy

Low friction and wear constitute a challenge for metallic materials under dry sliding conditions. In the current study, we successfully prepared an AlCrFe2Ni2Tix (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) high-entropy alloy (HEA) consisting of a body-centered cubic (BCC) phase and an AlNi2Ti phase that exhibited an outstanding combination of a compression strength of above 3 GPa and a ductility degree of 26% at room temperature. Under a 20 N load, the dry friction tests showed that AlCrFe2Ni2Ti0.4 HEA had the lowest wear volume (1.498 mm3), with a coefficient of friction of 0.3929. It is related to the volume fraction of AlNi2Ti precipitate increasing with increasing Ti content, thus resulting in better wear resistance. Through the strengthening mechanism analysis, it is crucial to manipulate the composition of the AlNi2Ti precipitate to obtain desirable mechanical properties in the AlCrFe2Ni2Tix HEA. The main mechanism of wear friction is identified as adhesion wear. Therefore, the addition of Ti into AlCrFe2Ni2 HEA can effectively improve its mechanical and wear resistance due to the significant improvement in hardness and its inherent solution strengthening. Our study provides a new strategy for designing new BCC HEAs with a combination of high hardness, yield strength, and excellent wear.

Catalytic and Tribological Performances of a Novel Bi-Functional Ionic Liquid in Lubricating Ester Oil

To address the detrimental effects of the residue of catalysts on the tribological performances of ester lubricants, a novel and efficient bi-functional ionic liquid 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-methylimidazole di(2-ethylhexyl) phosphate ([(BHT-1)MIM][DEHP]) was prepared. The catalyst not only facilitates the synthesis of pentaerythritol tetra-hexanoate (PETH) through the catalytic esterification reaction—achieving up to 96% conversion with a 94% yield—but also enhances the tribological performance of ester oil PETH when used as a lubricant additive. The tribological property has been improved remarkably: the mean friction coefficient for PETH + [(BHT-1)MIM][DEHP] is notably lower, at 0.110, compared to the PETH, which has a coefficient of 0.180. Meanwhile, the wear scar diameter of the steel ball, when lubricated with PETH + [(BHT-1)MIM][DEHP], is notably smaller than that of a steel ball lubricated solely with PETH. Especially, the reduction in the wear volume at 100 °C is up to 81.46% compared with the base oil PETH. [(BHT-1)MIM][DEHP], PETH + [(BHT-1)MIM][DEHP], and the worn track of the upper running ball and lower disc were systematically characterized by using Nuclear Magnetic Resonance (NMR) spectra, a Fourier Transform Infrared Spectrometer (FT-IR), a field emission scanning electron microscope (FESEM), Thermal gravity analysis (TG), X-ray photoelectron spectroscopy (XPS), and an optical microscope (OM). The wear mechanism of the tailored lubricant oil was discussed in terms of the chemical composition of the worn surface.

Tribological performance of carbon nanospheres as lubricant additives: insights from molecular dynamics simulation and experimental analysis

Abstract To investigate the lubrication mechanism of carbon nanospheres and compare their tribological performance with carbon powder, this study presented a comprehensive analysis of their potential as lubricant additives through both experimental testing and molecular dynamics simulations. Carbon nanospheres were synthesized using the hydrothermal method. Extensive comparisons were conducted between carbon powder and carbon nanospheres, focusing on material characterization, dispersion stability, antifriction performance, and antiwear capability. Findings revealed that carbon nanospheres outperformed carbon powder as lubricant additives in PAO 10 owing to their smaller particle size and spherical shape. Specifically, at a concentration of 1wt%, a load of 50 N, a disk speed of 10 rpm, and a temperature of 25 °C, the addition of carbon nanospheres reduced the friction coefficient by 34% and wear volume by 35%. The improved tribological performance was linked to the ability of carbon nanospheres to fill the pits, improving the interface smoothness. Molecular dynamics simulation of carbon nanospheres effectively reflected substrate roughness in the bulk region and further confirmed that this filling effects increased the lubricant's load-bearing capacity, which contributed to the reduction of friction and wear. This study provided significant insights into the development of innovative high-performance lubricant additives for oil-based lubrication in metal friction pairs.

Measurement of volumetric wear of printed polymer resin and milled polymer infused ceramic network definitive restorative materials.

Currently there is no regulatory requirement or international standard for the wear resistance of dental materials and therefore no need to test prior to market launch. The purpose of this in vitro study was to evaluate and compare the total volumetric wear characteristics of milled polymer infiltrated ceramic network (MPICN) and printed polymer resin (PPR) as substrates opposing five antagonists, human enamel (EN), lithium disilicate (LD), zirconia (ZR), MPICN, and PPR, and to evaluate and compare the volumetric wear of these same materials as antagonists. Ten of each antagonist for a total of 50 EN, LD (IPS e.max CAD), ZR (IPS e.max ZirCAD MT), MPICN (Crystal Ultra), and PPR (Crowntec for NextDent) were shaped into spherical heads and were tested against 2 disk-shaped substrates, MPICN (Crystal Ultra) and PPR (Crowntec for NextDent). Specimens were tested in a wear machine with a third-body food substitute and loaded with a force of 20 to 70N at 1Hz for 100 000 cycles. The total wear volume was digitally measured by comparing scans before and after cycling. The area of the wear facet of the antagonists was measured in a similar way and used to estimate the total volume loss of the antagonists. Data were analyzed using 2-way and 1-way ANOVA followed by the Tukey multiple comparisons post hoc test (α=.05). Antagonist type was found to significantly affect the total volume wear of the substrate (P=.022). EN was found to cause significantly more wear in opposing substrates than ZR and PPR. Substrate material did not significantly affect the wear rate of the substrates (P=.345) nor did the interaction between substrate and antagonist type (P=.150). Antagonist wear was significantly affected by antagonist type (P<.001), with ZR showing no visible signs of wear and MPICN showing the most wear overall; substrate type (P=.002), with antagonists opposing MPICN showing more wear than PPR; and their interaction (P=.031). Differences in the wear resistance of milled polymer infiltrated ceramic network and printed polymer resin definitive restorative materials were found but varied depending on the opposing material. No material showed superior wear resistance across all tests. Overall, printed polymer resins created less wear in opposing antagonists than milled polymer infiltrated ceramic network materials.

Enhancing Reciprocating Wear Resistance of Co37Cr28Ni31Al2Ti2 Spark Plasma Sintered Medium-Entropy Alloy via TiC Addition.

The aim of this paper is to investigate the effect of TiC addition on the microstructure, microhardness, and wear resistance of the medium-entropy alloy Co37Cr28Ni31Al2Ti2, which is suitable for applications in aerospace, automotive, and energy industries due to its high strength and wear resistance. The samples containing 0, 10, 20, and 40 wt.% of TiC were synthesized. The alloy's microstructure changes significantly with the addition of TiC particles: they are uniformly dispersed in the FCC matrix, effectively increasing the Vickers hardness from 439 HV for the base alloy to 615 HV for the 40% TiC alloy. The four alloys were subjected to reciprocating dry sliding friction tests at loads of 2 N, 5 N, and 10 N. The wear volumes of the base alloy at these loads were 2.7 × 107, 4.6 × 107, and 1.1 × 108 μm3, respectively. The experimental results indicate that adding TiC greatly improves the wear resistance of the alloy by increasing the hardness and forming an oxide protective film. This study highlights the potential for developing alloys with excellent tribological properties for demanding application scenarios.

Damage response analysis combined with machine learning to investigate the effect of frequency on the impact-sliding fretting corrosion behavior of Inconel 690 alloy

Abstract Inconel 690 alloys have been widely applied in the manufacturing of steam generator tubes for pressurized water reactors at nuclear power station. However, complicated impact-sliding fretting corrosion behavior always accompanies its entire service period. This study, which is based on experimental research and numerical analysis methods, investigates the effect of impact frequency on the impact-sliding fretting corrosion behavior of Inconel 690 alloy tubes. Then, machine learning is applied to predict the evolution law of the degree of damage. The results show that different impact frequencies do not affect the damage failure mechanism of the impact-sliding fretted alloy tube surface. However, an increase in impact frequency will lead to a more severe degree of damage. The corresponding maximum wear depths of the 5, 10, and 15 Hz impact frequencies caused by the impact-sliding fretting wear scars were approximately 6.630, 11.105, and 14.485 µm, respectively. The corresponding wear volume increased from approximately 3.626×104 µm3 to 6.325×104 µm3 and 8.395×104 µm3. Furthermore, machine learning modeling demonstrates perfect robustness and precision in predicting the damage evolution rule of the impact-sliding fretting corrosion behavior of an alloy tube.

Ionic liquid functionalized binary montmorillonite nanomaterials as water-based lubricant additives for steel/steel contact.

Two-dimensional (2D) nanomaterials have attracted much attention for the lubrication enhancement of water. Stably dispersing nanosheets in water for an extended period is a challenging task. 2D montmorillonite (MMT) nanosheets are modified with protonic ionic liquids (PILs) with the assistance of simple and efficient mechanochemical synthesis, which can stably disperse in water. With the help of TEM, FTIR, and XPS characterization, it is further demonstrated that the one-step mechanochemical stirring synthesis method can introduce the anions and cations of PILs into the MMT interlayer simultaneously, which gives the binary-modified MMT nanosheets some of the advantages of PILs, such as designability and functionalization. The successful intercalation and grafting of ionic liquids between the MMT nanosheets made it possible to obtain ultra-thin thickness and micro-nano size of the binary MMT nanosheets, and the synergistic effect of the 2D MMT nanosheets and the PIL laid a good foundation for the realization of the excellent lubricity, the easy-sliding interlayer structure, and the adsorption of the film more easily. Using the modified MMT nanosheets, the coefficient of friction and wear volume can be reduced by 76% and 94% at a high frequency and high load, respectively. The successful intercalation of PILs endows the MMT nanomaterial with better thermal stability and extreme pressure properties, with the maximum bite-free load (PB) being nearly 17 times higher than water. The friction mechanism shows that the enhancement of the lubrication and anti-wear performance is attributed to the boundary adsorbed tribofilm of MMT nanosheets achieving a repairing effect of the friction interfaces, which provides effective lubrication for steel/steel contact, thus preventing further wear of the friction pair surface. This work provides green, economical guidance for developing natural water-based lubricant additives and has great potential in sustainable lubrication.

Biodegradation and mechanical performance of Silane-chitosan-graphene oxide composite coating on AZ31 magnesium alloys for biomedical applications.

Biodegradable magnesium alloy medical implants have attracted considerable interest thanks to their remarkable biocompatibility and mechanical properties. However, the rapid corrosion rate of magnesium alloys in physiological environments presents a major challenge to their practical application. Therefore, this study attempted to design a silane/chitosan /graphene oxide composite coating that reduces the corrosion and enhances the biodegradation of magnesium alloys used in temporary implants. The composite fabrication process adopted a cost-effective spin-coating technique providing a uniform coating of magnesium alloy substrates. Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) results showed a dense and compact silane/chitosan/graphene oxide (Silane/CS/GO) coating on the magnesium coated alloy surface. The mechanical properties of the fabricated silane/chitosan/graphene oxide composite were also investigated by microindentation and scratch tests. The hardness of the magnesium alloy increased from ~268HV ±13.4 to ~644.13HV±32.2 upon the application of the coating. Moreover, the results showed that the cohesive critical load (LC) of the ternary composite was greater than LC~3.02±0.15N. In addition, compared to uncoated AZ31 alloys, the friction coefficient and wear volume of the ternary composite decreased from ~0.13±0.02 to ~0.07±0.004 and from ~18 to ~0.04 (106μm3), respectively. Finally, the corrosion of the composite coating was assessed in simulated body fluid (SBF) in vitro at 37°C. Hydrogen evolution results revealed that graphene oxide seemed to delay the diffusion of corrosive ions into the Mg matrix, while Silane prevented the coupling of GO graphene oxide sheets to the metal surface. Consequently, silane / chitosan /graphene oxide composite coatings could be a very useful material for coating magnesium implant devices. It contributed to reduce the corrosion of the substrate and alleviate the cost and discomfort of implants.

Behavior of M2 steel with CrN/TiN thin films by cathodic arc PVD method

The objective of this project is to obtain results on the films generated on M2 highspeed steel substrates, used in cutting applications and wear resistance. These samples were coated with CrN as the base layer and TiN as the film, using the PVD cathodic arc method. The project was carried out in collaboration with SADOSA S.A. de C.V., a company specialized in industrial coatings for high-speed cutting tools.The methodology included microstructural characterization through scanning electron microscopy (SEM) and composition analysis (SEM-EDS), along with topographical analysis using optical profilometry. The film thickness was determined using the calotest method, and tribological analysis was conducted with the pin-on-disk technique, obtaining wear tracks, volume loss, and specific wear rate according to ASTM G99 standards. The adhesion of the films was also evaluated using VDI 3198 standards to assess the adhesion quality of the samples. Finally, the data were collected for the analysis of the obtained results.

A predictive system based on experimental study of lubricant blended with composite additives

Friction &amp; wear are main reasons for mechanical failures of heavy loaded gearboxes. However, reformed lubricant can be used to control this. This study investigates the tribological behavior of composite Nano size particles with ZDDP as add-on in EP gearbox oil for various concentrations of composite additive - 0.005, 0.01, 0.02 wt.%. All tests have conducted under variable loads (60 N, 80 N &amp; 100N) &amp; sliding velocities (0.65m/s, 1.05 m/s &amp; 1.50 m/s). The experimental reading on antiwear &amp; antifriction parameters for gear EP oil has been tested on pin on disc instrument. The response surface approach was used to build the experiment's design (DOE), which examined the ideal friction coefficient &amp; wear volume loss in EP 220 Lubricant. Outcomes from the experimental study have been compared for two gear EP oils to indicate influence of various parameters like nanoparticles blend %, load and sliding velocity. It is found that the blending of gear EP oil with composite additives &amp; ZDDP diminishes the wear &amp; COF by 11.98 % and 9.81 % individually under various load &amp; speed working conditions.

The Influence of Load and Ball on the Sliding Wear Characteristics of HVOF-Sprayed WC-12Co Composite Coating

This study examines the impact of various abrasive balls and sliding loads on WC-12Co coatings. For this purpose, 4 N, 8 N, and 12 N loads were applied to the WC-12Co composite coatings with Al2O3 and Si3N4 balls. WC-12 Co composite was deposited by the high-velocity oxygen fuel method on the AISI 304 substrate. The wear tests were conducted in accordance with ASTM G99 on a ball-on-disc tribometer at room temperature. In order to study the results of the coating tests, wear volume loss was measured against each counter body. Surface roughness and microstructure changes before and after wear were examined by electron microscopy. The resulting wear tracks were examined with an optical profilometer and the wear amount was calculated. When comparing the Al2O3 ball with the Si3N4 ball, the Al2O3 ball corrodes WC-12Co coatings more and is most susceptible to abrasive grooving, brittle cracking, and spalling. Wear rates rose by 77%, 58%, and 67% when the Si3N4 abrasive sample and the samples with Al2O3 coating were subjected to 4 N, 8 N, and 12 N loads, respectively. WC-12Co coating layers and powders were subjected to X-ray diffraction analyses, which revealed that coarse WC-12Co powder underwent less decarburization due to HVOF spraying.

The effect of load on the fretting wear behavior of TC4 alloy treated by SMAT in artificial seawater

The TC4 alloy has become an ideal material for marine engineering due to its excellent corrosion resistance, high specific strength and light weight in seawater. However, components made from TC4 alloys often come into contact with parts such as propellers and turbine engine blades, leading to severe fretting wear during operation and significantly reducing their service life. In this study, the untreated TC4 alloy samples were used as the control group, and the samples after 240 min of surface mechanical attrition treatment (SMAT) were selected to investigate the fretting wear behavior under different load conditions in artificial seawater environment. The results show that the friction coefficient of TC4 alloy remains relatively unaffected by load variations, both before and after SMAT treatment. With the increase of load, the fretting regime gradually changed from gross slip to partial slip, and the wear depth, volume and wear rate increased. Under the same load, the wear volume of TC4 alloy after SMAT treatment is significantly reduced, indicating that its wear performance has been improved.

Biocompatible TA4 and TC4ELI with excellent mechanical properties and corrosion resistance via multiple ECAP.

Titanium (Ti), characterized by its exceptional mechanical properties, commendable corrosion resistance and biocompatibility, has emerged as the principal functional materials for implants in biomedical and clinical applications. However, the Ti-6Al-4V (TC4ELI) alloy has cytotoxicity risks, whereas the strength of the existing industrially pure titanium TA4 is marginally inadequate and will significantly limit the scenarios of medical implants. Herein, we prepared ultrafine-grained industrial-grade pure titanium TA4 and titanium alloy TC4ELI via the equal channel angular pressing method, in which the TA4-1 sample has ultrahigh strength of 1.1 GPa and elongation of 26%. In comparison with the micrometer-crystalline Ti-based materials, it showed a 35% reduction in wear depth and more than 10% reduction in wear volume, while the difference in the corrosion potential of the simulated body fluids was not significant (only ∼20 mV). XRD, electron backscatter diffraction, and transmission electron microscope characterization confirms that their superior strengths are mainly due to grain refinement strengthening.

Performance optimization and compatibility of FeCoNiCrMo0.2 high-entropy alloy coatings laser-cladded onto 4Cr5MoSiV1 steel surfaces

4Cr5MoSiV1 steel, known for its excellent toughness, thermal stability, and high hardenability, finds widespread application in areas such as hot extrusion dies, forging molds, and die-casting molds. However, its operational performance and service life are significantly impacted by limitations in surface hardness, wear resistance, and corrosion resistance. This study focuses on the optimization of laser cladding processes, preparing a FeCoNiCrMo0.2 high-entropy alloy cladding layer on the surface of 4Cr5MoSiV1 steel through laser cladding, and conducts an examination and validation of the microstructure and mechanical properties of the cladding layer. The experiments employed a laser power of 2.5 kW, a beam diameter of 3mm, a scanning speed of 5 mms−1, a gas flow rate of 1.5 Lmin−1, and a powder feed rate of 30g min−1. The results reveal that the top of the cladding layer is dominated by fine and dense equiaxed crystals, the middle by dendritic crystals with secondary dendrite arms, and the bottom by cellular crystals. The cladding layer is primarily composed of a face-centered cubic (FCC) phase structure, with the precipitation of particulate hard σ phases within and between the crystals. The average microhardness of the cladding layer is 360 HV0.2, approximately 63.6% higher than that of the base material. The average coefficient of friction for the cladding layer is 0.6609, with a wear volume of about 27 mg, representing an improvement of approximately 18% over the base material; the wear volume is about 81% of that of the base material. In a 3.5% NaCl solution, the self-corrosion current density of the cladding layer is measured at 9.98 × 10−9 A/cm2, with a self-corrosion potential of −368.3 mV. Compared to the base material, it achieves an enhancement in electrochemical corrosion capability while maintaining relative compatibility. The process and research provide a theoretical foundation and methodological reference for the surface modification of 4Cr5MoSiV1 steel.

Wear resistance of 3D printed, milled, and prefabricated methacrylate-based resin materials: An in vitro study.

Three-dimensional (3D) printing and milling technologies have been increasingly used in prosthodontic practice for fabricating digital prostheses. Nevertheless, evidence relating to the wear resistance of denture teeth fabricated using these methods is lacking. The purpose of this in vitro study was to compare the wear resistance exhibited by denture teeth fabricated using 3D printing and milling technologies with prefabricated denture teeth. Fifty specimens of resin denture teeth from 3 types of manufacturing processes were prepared and divided into 5 groups: 1 group of 3D printed denture teeth (NextDent C&B MFH), 2 groups of milled denture teeth (Ivotion Dent and VIPI Block), and 2 groups of prefabricated denture teeth (Major Dent and Cosmo HXL). Each group of specimens was occluded with a zirconia antagonist under a 49-N load with thermocycling conditions for 120 000 cycles. The antagonist was horizontally displaced back and forth at a 2-mm distance and a frequency of 1.6Hz. The quantification of the volume loss and the maximal wear depth of the worn specimens were recorded, while the wear characteristics were assessed with a scanning electron microscope (SEM). Data were analyzed using the Kruskal-Wallis test followed by pairwise comparison tests (α=.05). Significantly different wear depths and volume losses were found among groups (P<.05). The highest wear depth and volume loss were observed in the VIPI Block (0.513 ±0.147 mm and 3.094 ±0.790 mm³), followed by Cosmo HXL group (0.312 ±0.020 mm and 1.446 ±0.134 mm³), Major Dent (0.261 ±0.034 mm and 1.219 ±0.196 mm³), Ivotion Dent (0.253 ±0.021 mm and 1.082 ±0.089 mm³), and NextDent C&B MFH (0.208 ±0.059 mm and 0.843 ±0.372 mm³). Based on the analysis of the SEM images, distinct groups of specimens exhibited varying degrees of crack formation. Furthermore, their worn surfaces showed diverse characteristics in terms of wear patterns and roughness attributes. The manufacturing methods for fabricating 3D printed, milled, and prefabricated denture teeth exhibit comparable wear resistance, with 3D printed denture teeth demonstrating the highest level of wear resistance.

Perspective of Tribological Mechanisms for α-Alkene Molecules with Different Chain Lengths from Interface Behavior.

Three α-alkene lubricants, differentiated by chain length, were selected as model compounds to investigate the influence of chain length on tribological properties. The novelty of this study lies in setting chain length as the sole variable to explore its impact on surface and adsorption energy. Based on the above findings, the study provides a unique explanation of the intrinsic relationship between chain length and tribological performance. The tribological properties of the three α-alkenes were compared, and subsequent characterization methods elucidated the wear mechanisms and explored tribochemical reactions. The study employed the Owens-Wendt-Rabel-Kaelble (OWRK) method and density functional theory (DFT) to investigate each compound's surface energy and adsorption energy. Experimental results revealed that the average friction coefficients (abridged as COF) for 1-decene, 1-tetradecene, and 1-octadecene decreased sequentially to 0.125, 0.099, and 0.075, respectively. The wear volume of 1-tetradecene decreased by 53.2% and that of 1-octadecene decreased by 64.0% compared to 1-decene. This can be attributed to the simultaneous enhancement of the surface energy and adsorption energy with increasing chain length. On the one hand, the increase in surface energy facilitates tribochemical reactions positively influencing the formation of tribofilms. On the other hand, the increase in adsorption energy enhances the adsorption of lubricants on the substrate surface. The synergy of these two effects allows 1-octadecene and 1-tetradecene (long-chain α-alkenes) to exhibit superior tribological performance compared to that of 1-decene (short-chain α-alkenes). Ultimately, this study offers unique insights into understanding lubrication mechanisms.

Retrievability of Fractured Abutment Screws and Damage to Implant–Abutment Connections: An In Vitro Comparative Analysis of Conventional vs. Drilling Techniques

This study aimed to evaluate the retrievability and potential damage to implant–abutment connections caused by fractured abutment screw removal using conventional and drilling techniques. A total of forty abutment screws were randomly inserted into forty dental implants, and then they were fractured and extracted using different removal methods: Group A employed a conventional approach utilizing an exploration probe and an ultrasonic device without irrigation (n = 10) (conventional); Group B used the Phibo drilling removal system without irrigation (n = 10) (Phibo); Group C utilized the Rhein83® drilling removal system without irrigation (n = 10) (Rhein83); and Group D implemented the Sanhigia® drilling removal system without irrigation (n = 10) (Sanhigia). Pre- and postoperative micro-computed tomography (micro-CT) scans were performed on the dental implants, and Standard Tessellation Language (STL) digital files were generated for morphometric analysis to measure the wear volume. ANOVA was used to assess the volumetric differences (mm3) and percentage ratios of the internal thread volumes of the implant–abutment connections before and after the procedures. Results: This study found no statistically significant differences in the volumetric and percentage ratios of internal threads among the implant groups (Phibo, Rhein83, Sanhigia, and conventional). However, the success rate for retrieving fractured abutment screws was higher (90%) with the drilling systems compared to the conventional technique (50%). These results suggest that drilling systems are more effective for the retrieval of damaged screws. Although drilling techniques without irrigation demonstrated higher removal efficiency compared to the conventional method, both approaches resulted in similar wear volumes at the implant–abutment connections when used to extract fractured screws.