A self-organized sandwich structure of chromium nitride for ultra-long lifetime in liquid sodium.

The development of fast neutron reactors with improved efficiency and sustainability, being a tangible solution to the large-scale utilization of nuclear energy, serves as a critical step prior to the commercialization of fusion energy. These reactors use liquid metal coolants, which can weaken the durability of metallic components. Conventional design of protective coatings counts upon thermodynamics, which often overlooks the kinetic factors such as structural evolutions, resulting in deteriorated coating properties.

Charge Density Evolution Governing Interfacial Friction.

It is well-known that the electron nature of a solid in contact plays a predominant role in determining the many properties of the contact systems, but the general rules of electron coupling that govern interfacial friction remain an open issue for the surface/interface community. Here, density functional theory calculations were used to investigate the physical origins of friction of solid interfaces. It was found that interfacial friction can be inherently traced back to the electronic barrier to the change in the contact configuration of the joints in slip due to the resistance of energy level rearrangement leading to electron transfer, which applies for various interface types ranging from van der Waals, metallic, and ionic to covalent joints.

Correction: The corrosion behaviors of multilayer diamond-like carbon coatings: influence of deposition periods and corrosive medium.

[This corrects the article DOI: 10.1039/C6RA05527C.].

Correction: Corrosion and tribocorrosion performance of multilayer diamond-like carbon film in NaCl solution.

[This corrects the article DOI: 10.1039/C5RA21207C.].

Synthesis and Structure of Water-Soluble Sb Quantum Dots and Enhanced Corrosion Inhibition Performance and Mechanisms.

Generally, single organic or inorganic inhibitors could effectively inhibit corrosion for metallic materials; however, there are rarely reports about the hybrid corrosion inhibitors consisting of organic and inorganic inhibitors. Thus, in this work, we synthesize a hybrid environment-friendly water-soluble corrosion inhibitor (Sb quantum dots) containing Sb, SbO, SbO, and carbon using the electrochemical exfoliation method. The inhibition effectiveness in short- and long-term immersion tests is measured using electrochemical methods, weight loss, and surface analysis.

Contrasting Oxygen Reduction Reactions on Zero- and One-Dimensional Defects of MoS for Versatile Applications.

Oxygen reduction reaction (ORR) is a key microscopic process in many electrochemical applications of materials, where the requirements of their ORR performances may vary strikingly, for example, during the uses of MoS as an electrocatalyst and anticorrosion/lubricating coating in aqueous/humid environments, ORR should be activated and inhibited, respectively. To reveal a complete ORR profile of MoS, using first-principles calculations, we examine the stabilities of various possible zero-dimensional point defects on the surface and one-dimensional edge defects and comprehensively explore the ORR activities on pristine MoS surface and those defects in acid/alkaline solutions. It is found that the ORRs on the pristine surface and surfaces with point defects always require large overpotentials (>1.

Novel nitrogen doped carbon dots enhancing the anticorrosive performance of waterborne epoxy coatings.

There are lots of research studies reporting the excellent performances of waterborne epoxy resin coatings to reduce environmental VOC levels. However, it has also been manifested that waterborne epoxy resin coatings do not have high corrosion resistance because of being hydrophilic. Herein, we utilized a kind of N doped carbon dot (N-CD) which has high ethanol solubility and low cytotoxicity to enhance the corrosion resistance of waterborne epoxy resin coatings as a nanofiller.

Thermodynamics and kinetics of an oxygen adatom on pristine and functionalized graphene: insight gained into their anticorrosion properties.

The thermodynamic and kinetic stabilities of an O adatom on graphene are critical factors for the formation of oxide defects in graphene, which leads to the breakdown of a graphene protective coating. To systematically understand various behaviors of an O adatom on graphene under the space conditions, the adsorption energies, diffusion paths and barriers, and penetration paths and barriers of the O adatom on pristine and functionalized graphene (e.g.

Mutual Identification between the Pressure-Induced Superlubricity and the Image Contrast Inversion of Carbon Nanostructures from AFM Technology.

Previous studies predict pressure-induced superlubricity, but that is still undetermined due to the absence of a probing technique. Here, we present unprecedented mutual identification between the superlubricity and atomic-scale image from atomic force microscopy (AFM) measurement by the first-principles simulation of metallic Cu tip scanning on carbon nanostructures. With decreasing tip height, the sliding potential evolves from anticorrugated, to substantially flattened, and eventually to corrugated patterns, inducing superlubricity of the flattened potential at the critical height.

Improvement of anticorrosion ability of epoxy matrix in simulate marine environment by filled with superhydrophobic POSS-GO nanosheets.

Super-hydrophobicity polyhedral oligomeric silsesquioxane-modified graphene oxide (POSS-GO) was synthesized by one-step reaction between graphene oxide (GO) and aminopropylisobutyl polyhedral oligomeric silsesquioxane (POSS-NH). Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra indicated that the POSS were successfully connected to the edge and surface of GO nanosheets. Scanning probe microscope (SPM) and transmission electron microscope (TEM) images demonstrated that the POSS-GO with a thickness of 1.

Tribological properties of synthetic base oil containing polyhedral oligomeric silsesquioxane grafted graphene oxide.

The 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.

Tribological properties of attapulgite/LaO nanocomposite as lubricant additive for a steel/steel contact.

Attapulgite is a layered silicate with good friction-reduction and self-repairing properties. In order to further improve its tribological properties, the present work mainly focuses on the preparation of attapulgite/LaO nanocomposite and study on its tribological behaviors. The tribological properties of mineral lubricating oil (150SN) containing attapulgite/LaO nanocomposite were investigated through an Optimal SRV-IV oscillating friction and wear tester.

Superlubricity Enabled by Pressure-Induced Friction Collapse.

From daily intuitions to sophisticated atomic-scale experiments, friction is usually found to increase with normal load. Using first-principle calculations, here we show that the sliding friction of a graphene/graphene system can decrease with increasing normal load and collapse to nearly zero at a critical point. The unusual collapse of friction is attributed to an abnormal transition of the sliding potential energy surface from corrugated, to substantially flattened, and eventually to counter-corrugated states.

Performance evaluation of mercapto functional hybrid silica sol-gel coating and its synergistic effect with f-GNs for corrosion protection of copper surface.

A nanocomposite coating comprising mercapto functional hybrid silica sol-gel coating and functionalized graphene nanoplates nanocomposite coatings with advanced anticorrosive properties was prepared by a sol-gel method. In this study, graphene oxide (GO) nanoplates were silanized using 3-aminopropyltriethoxysilane (APTES) to obtain functional graphene nanoplates (f-GNs). The f-GNs were characterized by FTIR, XRD, XPS, TEM, AFM and TGA techniques.

Space irradiation-induced damage to graphene films.

Graphene with impressive electrical, optical, chemical and mechanical properties has promising potential applications for photoelectric devices and mechanical components installed on the space facilities, which will probably face hostile environments including high-energy particulate irradiation. Here we explored the effect of simulated space irradiation on the structure and properties of large-area single-layer and multi-layer graphene films (about four layers) including atomic oxygen (AO), electron (EL) and proton (PR). AO with strong oxidizing capacity reacts with carbon atoms of graphene films and generates carbon dioxide, high-energy PR leads to polymorphic atomic defects in graphene through collision and excitation effects.

Multilayer Regulation of Atomic Boron Nitride Films to Improve Oxidation and Corrosion Resistance of Cu.

The boron nitride (BN) monolayer (1L) with high impermeability and resistivity seems to hold promise as a long-term corrosion barrier for Cu under ambient condition, which is supported by recent researches. Here, we perform a complete study of the alternating temperature tests (the sample is exposed in air for 30 days and subsequently heated at 200 °C for 2 h) and electrochemical measurements on 1L and multilayer BN-coated Cu foils. Results imply that the BN-coated Cu foils are less oxidized than uncoated Cu foils after alternating temperature tests, regardless of the layers of BN.

Synergistic effect of hybrid carbon nanotube-graphene oxide as nanoadditive enhancing the frictional properties of ionic liquids in high vacuum.

A remarkable synergetic effect between the graphene oxide (GO) layers and multiwalled carbon nanotubes (MWCNTs) in improving friction and wear on sliding diamond-like carbon (DLC) surfaces under high vacuum condition (10(-5) Pa) and low or high applied load is demonstrated. In tests with sliding DLC surfaces, ionic liquid solution that contains small amounts of GO and MWCNTs exhibited the lowest specific friction coefficient and wear rate under all of the sliding conditions. Optical microscope images of the wear scar of a steel ball showed that GO/MWCNT composites exhibited higher antiwear capability than individual MWCNTs and GO did.

Fabrication of novel graphene-fullerene hybrid lubricating films based on self-assembly for MEMS applications.

The novel graphene-C60 hybrid films have been fabricated successfully on silicon surfaces by a multistep self-assembly process, and showed synergistic effects beyond individual performance in micro/nano-tribological behaviors. It is expected that the graphene-C60 hybrid films may find wide applications as high performance lubricating films in MEMS.

Interface architecture for superthick carbon-based films toward low internal stress and ultrahigh load-bearing capacity.

Superthick diamond-like carbon (DLC) films [(Six-DLC/Siy-DLC)n/DLC] were deposited on 304 stainless steel substrates by using a plane hollow cathode plasma-enhanced chemical vapor deposition method. The structure was investigated by scanning electron microscopy and transmission electron microscopy. Chemical bonding was examined by Raman, Auger electron, and X-ray photoelectron spectroscopy techniques.

Preparation and characterization of ultrathin dual-layer ionic liquid lubrication film assembled on silica surfaces.

A novel ultrathin dual-layer film, which contained both bonded and mobile phases in ionic liquids (ILs) layer, was fabricated successfully on a silicon substrate modified by a self-assembled monolayer (SAM). The formation and surface properties of the films were analyzed using ellipsometer, water contact angle meter, attenuated total reflectance Fourier transform infrared spectroscopy, multi-functional X-ray photoelectron spectroscopy, and atomic force microscope. Meanwhile, the adhesive and nanotribological behaviors of the films were evaluated by a homemade colloidal probe.

Precise positioning of lubricant on a surface using the local anodic oxide method.

This letter describes a new method for the precise positioning of a lubricant on a surface. The nanometer-sized patterns are first fabricated using the atomic force microscopy (AFM)-based local anodic oxide (LAO) method. Multiply alkylated cyclopentanes (MACs) serving as lubricant matrix layers on nanopatterns of silicon dioxide are fabricated.