Materials (Basel)
October 2024
The fatigue behavior of metal specimens is influenced by defects, material properties, and loading. This study aims to establish a multi-scale fatigue crack growth model that describes physically short crack (PSC) and long crack (LC) behavior. The model allows the calculation of crack growth rates for uniaxial loading at different stress ratios based on the material properties and specimen geometry.
View Article and Find Full Text PDFFriction as a fundamental physical phenomenon dominates nature and human civilization, among which the achievement of molecular rolling lubrication is desired to bring another breakthrough, like the macroscale design of wheel. Herein, an edge self-curling nanodeformation phenomenon of graphite nanosheets (GNSs) at cryogenic temperature is found, which is then used to promote the formation of graphite nanorollers in friction process towards molecular rolling lubrication. The observation of parallel nanorollers at the friction interface give the experimental evidence for the occurrence of molecular rolling lubrication, and the graphite exhibits abnormal lubrication performance in vacuum with ultra-low friction and wear at macroscale.
View Article and Find Full Text PDFAntimicrobial resistance (AMR) from pathogenic bacterial biofilms has become a global health issue while developing novel antimicrobials is inefficient and costly. Combining existing multiple drugs with enhanced efficacy and/or reduced toxicity may be a promising approach to treat AMR. D-amino acids mixtures coupled with antibiotics can provide new therapies for drug-resistance infection with reduced toxicity by lower drug dosage requirements.
View Article and Find Full Text PDFAntifoulants are the most vital substances in antifouling coatings to prevent marine organisms from colonizing the undersea substrate surfaces. In addition to antibacterial performance, inhibition of biofilm formation is an important criterion for antifouling coatings. In this study, we synthesized pH-responsive matrine@chitosan-D-proline (Mat@CS-Pro) nanocapsules of about 280 nm with antibacterial properties and biofilm dispersibility.
View Article and Find Full Text PDFPolysiloxane/molybdenum disulfide (MoS) composite lubricating coatings that are used in low-earth orbit spacecraft have high resistance to atomic oxygen attack and outstanding vacuum tribological properties. However, their atmospheric environment wear resistance and adaptability under high humidity are poor. In this paper, octa-aminophenyl T8-polyhedral oligomeric silsesquioxane (NH-POSS) was used to enhance their atmospheric wear resistance and environmental adaptability to increase the protection of polysiloxane lubricating coatings for spacecraft.
View Article and Find Full Text PDFNanomaterials (Basel)
April 2022
A new NO nanohybrid of a gas sensor (CTAB-MoS/rGO) was constructed for sensitive room-temperature detection of NO by 3D molybdenum disulfide (MoS) and reduced graphene oxide (rGO), assisted with hexadecyl trimethyl ammonium bromide (CTAB). In comparison with MoS and MoS/rGO, the BET and SEM characterization results depicted the three-dimensional structure of the CTAB-MoS/rGO nanohybrid, which possessed a larger specific surface area to provide more active reaction sites to boost its gas-sensing performance. Observations of the gas-sensing properties indicated that the CTAB-MoS/rGO sensor performed a high response of 45.
View Article and Find Full Text PDFInside a spacecraft, the temperature and humidity, suitable for the human crew onboard, also creates an ideal breeding environment for the proliferation of bacteria and fungi; this can present a hazard to human health and create issues for the safe running of equipment. To address this issue, wear-resistant antimicrobial thin films prepared by magnetron sputtering were developed, with the aim to coat key internal components within spacecrafts. Silver and copper are among the most studied active bactericidal materials, thus this work investigated the antibacterial properties of amorphous carbon coatings, doped with either silver, silver and copper, or with silver clusters.
View Article and Find Full Text PDFJ Phys Chem Lett
October 2021
A hydrogenated amorphous carbon (a-C:H) film shows an ultralow friction coefficient (COF, lower than 0.01); however, its wear life is short in vacuum, and the mechanisms are still not well-understood. This study demonstrates the vacuum tribological behaviors of the a-C:H film can be regulated by interfacial activity.
View Article and Find Full Text PDFStructural design and componential optimization are two primary directions in the study of microwave absorbers. In this study, a novel cobalt ferrite (CoFeO) decorated with -phenylenediamine (PPD) functionalized graphene (PG/CoFeO) binary hybrid with unique hierarchical porous structure was synthesized by a two-step route. The chemical composition, morphology and electromagnetic parameters of the as-prepared sample were investigated successively.
View Article and Find Full Text PDFThe influence of rare earth element (RE) Y on the microstructure and corrosion behavior of extruded AZ91 Mg alloy was surveyed via morphology characterization and corrosion performance measurements. The results indicate the corrosion resistance of the transversal section of AZ91 Mg alloy containing Y was improved compared with AZ91 Mg alloy without Y. The corrosion resistance of the longitudinal section of AZ91 Mg alloy with Y was lower than that of AZ91 Mg alloy without Y.
View Article and Find Full Text PDF"Structural superlubricity" is an important fundamental phenomenon in modern tribology that is expected to greatly diminish friction in mechanical engineering, but now is limited to achieve only at nanoscale and microscale in experiment. A novel principle for broadening the structural superlubricating state based on numberless micro-contact into macroscale superlubricity is demonstrated. The topography of micro-asperities on engineering steel substrates is elaborately constructed to divide the macroscale surface contact into microscale point contacts.
View Article and Find Full Text PDFDirectly dispersing graphene into an electrolyte still remains a crucial difficulty in electrodepositing a graphene enhanced composite coating onto electrical contact materials. Herein, graphene was synthesized electrochemical exfoliation in an ,-dimethylformamide (DMF)/HO solution containing (NH)SO. The electrochemically exfoliated graphene nanosheets (GNs) were directly dispersed by sonication.
View Article and Find Full Text PDFThe influence of dissolved oxygen concentration (DOC) on the microbiologically influenced corrosion (MIC) of Q235 carbon steel in the culture medium of halophilic archaeon was investigated. The increase of DOC from 0.0 to 3.
View Article and Find Full Text PDFStimuli-responsive and biodegradable polymeric carriers are of great importance for safe delivery and efficient release of chemotherapeutic agents. In this work, given the unique advantages of poly(disulfide)s and biodegradable polyphosphoesters, we designed and constructed a reduction-sensitive amphiphilic triblock copolymer poly(ethyl ethylene phosphate)-b-poly(disulfide)-b-poly(ethyl ethylene phosphate) (PEEP-PDS-PEEP) by combining thiol-disulfide polycondensation and ring-opening polymerization (ROP). The thiol-disulfide polycondensation between 1,6-hexanedithiol and 2,2'-dithiodipyridine yielded the linear telechelic pyridyl disulfide-terminated poly(disulfide)s, followed by the treatment with 2-mercaptoethanol to quantitatively produce dihydroxyl-terminated poly(disulfide)s, which was used to initiate the ROP reaction of 2-ethoxy-2-oxo-1,3,2-dioxaphospholane, generating ABA-type amphiphilic triblock copolymers.
View Article and Find Full Text PDFThe dispersion of graphene-based materials in lubricating oil is a prerequisite for improving its friction and wear performance. In this study, polyhedral oligomeric silsesquioxane (POSS) grafted graphene oxide (GO) was synthesized with an aim to improve the dispersibility of graphene in synthetic base oil. The composition and morphology of POSS-GO conjugates were characterized by FTIR, XPS, Raman spectroscopy, TEM and SPM.
View Article and Find Full Text PDFIn this study, a new self-healing shape memory polymer (SMP) coating was prepared to protect the aluminum alloy 2024-T3 from corrosion by the incorporation of dual-function microspheres containing polycaprolactone and the corrosion inhibitor 8-hydroxyquinoline (8HQ). The self-healing properties of the coatings were investigated via scanning electron microscopy, electrochemical impedance spectroscopy, and scanning electrochemical microscopy following the application of different healing conditions. The results demonstrated that the coating possessed a triple-action self-healing ability enabled by the cooperation of the 8HQ inhibitor, the SMP coating matrix, and the melted microspheres.
View Article and Find Full Text PDFIn this work, Co-P coatings were deposited from a chloride-based bath by direct current (DC), pulse current (PC) and pulse reverse current (PRC) methods, respectively. The effects of current modes on the microstructure, composition, microhardness, wear resistance and corrosion resistance of the Co-P coatings were explored. Results showed that the P content in the Co-P coatings increased and the surface roughness decreased in the sequence of DC, PC and PRC methods.
View Article and Find Full Text PDFThermal control ceramic coatings on Mg-Li alloys have been successfully prepared in silicate electrolyte system by plasma electrolytic oxidation (PEO) method. The PEO coatings are mainly composed of crystallized Mg2SiO4 and MgO, which have typical porous structure with some bulges on the surface; OES analysis shows that the plasma temperature, which is influenced by the technique parameters, determines the formation of the coatings with different crystalline phases and morphologies, combined with "quick cooling effect" by the electrolyte; and the electron concentration is constant, which is related to the electric spark breakdown, determined by the nature of the coating and the interface of coating/electrolyte. Technique parameters influence the coating thickness, roughness and surface morphology, but do not change the coating composition in the specific PEO regime, and therefore the absorptance (αS) and emissivity (ε) of the coatings can be adjusted by the technique parameters through changing thickness and roughness in a certain degree.
View Article and Find Full Text PDFCoagulation is a feasible process to reclaim municipal wastewater, however, the role of coagulation in removing effluent organic matter (EfOM) from underutilized wastewater treatment plants (WWTPs) has not been fully explored. We identified the characteristics of the EfOM from a typical underutilized WWTP (i.e.
View Article and Find Full Text PDF© LitMetric 2025. All rights reserved.