Service Durability Research Articles

Microstructured Self-Healing Flexible Tactile Sensors Inspired by Bamboo Leaves.

Wearable electronic devices with multifunctions such as flexible, integrated, and self-powered play a crucial role in the fields of health monitoring, motion monitoring, and human-computer interaction. However, their core basic components, flexible pressure sensors, face challenges including poor long-term stability and insufficient real-time sensing accuracy. In order to solve the challenges of long-term, stable, and accurate sensing of the sensor, this paper prepares polydimethylsiloxane (SHPDMS) with intrinsic self-healing property and designs a high-sensitivity self-healing capacitive flexible pressure sensor with dual microstructures (grating microstructured electrodes and microporous dielectric layer) as the substrate based on SHPDMS. Specifically speaking, the self-healing of the sensor under mild conditions was realized by introducing reversible imine bonds with low bonding energy into the polydimethylsiloxane (PDMS) flexible substrate, which solved the problem of the material's long-term service durability. A grating-like microstructure was introduced into the flexible electrode by using a spotted bamboo taro leaf as a template, and a dual microstructure sensor was constructed by combining it with a microporous dielectric layer doped with single-walled carbon nanotubes. This way reduces the elastic modulus of the dielectric layer, improves the dielectric constant of the sensor under loading, and thus significantly improves the sensor's sensitivity and extends the measurement accuracy in a low-stress range. The prepared self-healing flexible sensor achieves a sensitivity of 3.6 kPa-1, a minimum detection limit of 5 Pa, a response recovery time of less than 80 ms, and stability over 5000 cycles, which exceeds most previously reported silicone rubber-based capacitive flexible sensors.

Insight into the salt damage mechanism to the asphalt-aggregate interface in recycled asphalt mixtures at different salt environments using molecular dynamics and DFT simulations

In coastal areas, the complex salt environment poses new challenges to the interfacial stability and service durability of hot recycled asphalt pavements. To investigate the influence mechanism of salt environment on the adhesion properties of asphalt-aggregate interface, this study employed molecular dynamics (MD) simulation and density functional theory (DFT) to analyze the interfacial interaction energy, molecular diffusion behavior, component distribution, and molecular electrostatic property at asphalt-aggregate interface. The results show that as the content of aged asphalt increased, the interaction between asphalt and anions (Cl⁻ and SO₄²⁻) is weaker than that with cations (Na⁺, Mg²⁺ and Ca²⁺). H₂O causes the aromatics, saturates and resins to move away from the interface. Cl⁻ causes the saturates to further move away from the interface, while Na⁺ and Mg²⁺ bring the aromatics closer to the interface. Due to the greater polarity of SO₄²⁻, it moves the resins closer to the interface. With increasing aged asphalt content, the number of hydrogen bonds between asphalt and SiO₂ increases from none to some, thus enhancing the interfacial adhesion. However, this adhesion becomes more susceptible to salts. The aging effect redistributes the charge of asphalt molecules, concentrating negative potentials on the carbonyl and sulfoxide functional groups located on the outside of molecules. This increases the polarity of the asphalt molecules, making them more susceptible to salt ion attack. These findings contribute to the understanding of the adhesion properties of recycled asphalt mixtures in extreme salt environments.

Effect of hygrothermal aging on the friction behavior and wear mechanism of the multi-filler reinforced epoxy composites for coated steel

Polymer-based composites for steel structure coating are an effective strategy to improve tribological properties and service durability under hygrothermal aging conditions. In the present paper, epoxy resin was improved by mechanical reinforcement and frictional lubrication fillers, and a kind of multi-filler reinforced epoxy composite (MFREC) was successfully prepared. Water uptake behavior, mechanical and thermal property evolution, friction behavior and wear mechanism as well as micro-topography analysis of MFREC under hygrothermal aging were conducted and discussed in detail. The research results showed that the water uptake curve of MFREC after distilled water and 5 wt% NaCl water solution immersions confirmed the two-stage diffusion model, where the quasi-equilibrium water uptakes were 4.23% and 3.67%, respectively. Additionally, the fundamental reason for the degradation of the mechanical and thermal properties of MFREC was the hydrolysis of the resin and the de-bonding of the fillers/matrix interface. The interface shear strength of MFREC adhesive and steel gradually decreased with the hygrothermal aging, but did not lose the bonding property, because the uniformly dispersed multi-fillers can fill the internal defects of the matrix and prolong the crack propagation path to block the effect. Before hygrothermal aging, MFREC had excellent friction and wear resistance compared to resin matrix, especially under water lubrication conditions. The anti-wear rate of MFREC increased by up to 59.6% compared to the room temperature dry test environment due to the coupling effects of the water lubrication and anti-friction characteristics of modified fillers. Hygrothermal aging had little effect (＜12%) on the friction coefficient of MFREC, but the anti-wear properties decreased significantly, especially the Ws increased by 255.1% under the 60 °C immersion condition. Because the degradation of thermal/mechanical properties was not enough to resist the high shear stress of the steel ball, leading to severe fatigue wear.

Understanding the interface fracture mechanism by composite BFPMPC mortar and cement concrete bending beam

This study aims to utilize basalt fiber-reinforced polymer-modified magnesium phosphate cement (BFPMPC) mortar as an overlay for rapidly repairing surface defects such as raveling and delamination on Portland cement concrete (PCC) pavements, thereby swiftly restoring traffic flow and enhancing pavement service durability. Initially, double layered three-point bending fracture (DLTPB) tests were conducted on composite BFPMPC and PCC specimen with different predetermined crack lengths. The flexural strength was measured, fracture parameters were obtained based on the double-K fracture criterion, and crack propagation paths were determined using digital image correlation (DIC) methods. Subsequently, the fracture behavior of the composite beam was predicted by boundary effect model, and the interface microstructure between BFPMPC and PCC was characterized using nanoindentation, nano-scratch, and SEM/EDS techniques. Finally, by analyzing the fracture characteristics of the composite specimens, the crack propagation model was established and validated by finite element analysis (FEA). The results indicated that BFPMPC mortar overlay can enhance the flexural strength of composite structure. The unstable fracture toughness, cohesive fracture toughness, and fracture energy decreased with increase of crack length-to-height ratio (a0/D), while the initiation fracture toughness increased with increase of a0/D. DIC measurements provided insights into the morphology of the crack tip and the length of the fracture process zone (FPZ). The boundary effect model predictions aligned with the fracture characteristics of the specimens, which were controlled by nonlinear fracture criteria. Nanoindentation tests revealed that the mechanical properties of the interface are influenced by multiple sub-interfaces, with the elastic modulus relationship being ITZ-4 > ITZ-2 > ITZ-3 > ITZ-1. Further analysis of scratch hardness and scratch fracture toughness confirmed that the BFPMPC-PCC interface exhibited high fracture toughness, which was crucial for improving structural resistance to fracture. SEM/EDS observations revealed significant cracks at the interface between BFPMPC and ordinary Portland cement (OPC), while cracks between BFPMPC and coarse aggregates were smaller. Subsequently, the fracture analysis model for composite specimens was proposed to finely reveal interface fracture failure, and the FEA results exhibited a high degree of consistency with experimental results.

Zn doped CeO2 supporting Ni–Pt catalysts toward robust hydrogen generation from hydrous hydrazine

Ni-based bimetallic catalysts with noble metals exhibit high activity and selectivity for hydrogen generation from hydrazine monohydrate. However, their poor service durability remains a critical challenge. This study investigated the use of Zn-doped CeO2 as a support for Ni–Pt catalysts to improve their long-term stability. A series of Ni–Pt/Zn-doped-CeO2 catalysts were prepared via a simple co-precipitation and reduction method. Compared to the pristine Ni50Pt50/CeO2 catalyst, the Zn doping can improve the stability of CeO2 support in the alkaline condition, and the X-ray photoelectron spectroscopy (XPS) analysis clearly indicates that Zn doping leads to a negative shift in the binding energy of connected Ni and thus enhances the stability of the electronic structure in the catalysts. The findings in this work suggest that Zn-modified CeO2 supporting Ni–Pt catalyst offer a promising approach to achieving a better balance between activity and durability for hydrogen generation catalysts.

Anti-icing performance of hydrophobic coatings on stainless steel surfaces

This study aims to prevent ice accumulation on the surface of drilling tools by investigating the effectiveness of hydrophobic coatings, which is one of the most promising methods to solve drilling difficulties in warm ice. Herein, four types of hydrophobic organic coatings that can be used on metal surfaces were tested to evaluate their anti-icing performance, service durability, and friction properties. All of them possess rough surfaces with microstructure characteristics such as pores, stripes, or micropapillae. They also exhibit hydrophobicity, with water contact angles of 101.6°, 100.0°, 103.1°, and 108.5°. They can significantly prolong the required freezing time of water droplets on their surfaces, effectively reduce ice adhesion, and decrease the friction between ice and their surface. The ice adhesion in the axial, tensile, and tangential directions can be reduced by 65.64 %, 56.31 %, and 72.11 %, respectively, for the coating with silicon (Si)-based and fluorine (F)-containin compounds (coating-C) at −30 °C; while it can be reduced by 85.05 %, 73.9 %, and 94.2 %, respectively, for the coatings with Si-based and polytetrafluoroethylene (PTFE) compounds (coating-D). The two coatings mentioned above lose their anti-icing performance after 20 icing and de-icing cycles, and their hydrophobicity after 120 abrasion cycles under a load of 6 N.

A PDMS coating with excellent durability for large-scale deicing

The icing of wind turbine blades leads to a decrease in output power, seriously jeopardizing the economic benefits and operational reliability of wind farms. Conventional deicing techniques require expensive equipment and consume a large amount of energy. Low-interfacial toughness coatings without energy dissipation are believed to be a highly potential passive deicing technology. However, the durability in service is facing challenges. Herein, low-interfacial toughness PDMS coatings were prepared by physical blending. Through the optimization of added plasticizers and SiO2, PDMS coatings with excellent large-scale deicing performance were obtained. The constant deicing force and ice adhesion strength were reduced to 14.69 N/cm and 12.63 kPa, respectively. Moreover, a systematic durability assessment of the PDMS coating was carried out to address the actual operating conditions of wind turbines. Fortunately, the results showed that the PDMS coating could withstand 200 icing/deicing cycles while maintaining constant deicing force and ice adhesion strength of less than 50 N/cm and 30 kPa, respectively. After long-term thermal aging (21 days), UV irradiation (42 days) and salt spray corrosion (20 days), the PDMS coating still retained superior icephobicity and outstanding large-scale deicing performance. This work contributes to the research and development of low-interfacial toughness materials for large-scale deicing applications on wind turbine blades.

Gold-sputtered LPG fiber sensor pulse electroplated with iron-carbon for monitoring passivation and depassivation of carbon steel in concrete pore solutions

Monitoring the passivation and depassivation of reinforcement steel is of significant importance, particularly for certain reinforced concrete structures that define the time of steel rebar depassivation as the end of the durability service life. In this study, a gold-sputtered long-period grating (LPG) optical fiber sensor coated with pulse-electroplated iron-carbon is characterized for continuous monitoring of the surface state of carbon steel from passivation to depassivation in concrete pore solutions. Electrochemical corrosion and optical tests are performed simultaneously using an electrochemical workstation and an optical instrument. A protective passivation film with a thickness of approximately 4.05 nm was formed on the iron-carbon coating after 5 days of immersion in the simulated concrete pore solution, and its thickness is nonlinearly correlated with the wavelength shift of the LPG optical fiber sensor during the passivation process. The resonant wavelength changes in the opposite direction after depassivation, which can be used for the detection of the depassivation time. After depassivation, the wavelength shift and mass loss of the iron-carbon coating can be divided into three phases, and a linear relationship exists in each phase. The gold-sputtered fiber sensor coated with pulse-electroplated iron-carbon investigated in this study, demonstrates better performance than silver-deposited LPG fiber sensors.

Studying the resistance to ultraviolet radiation of products with paintwork in a UV chamber

The research presented in this article is devoted to testing samples of plastic cladding panels with paint coating of different colors, in order to assess its technical characteristics and resistance to climatic conditions. Paint and varnish coatings form a barrier preventing the penetration of moisture and aggressive substances, thereby extending the service life of the equipment. As part of the experiment, two samples of paintwork were provided for further analysis. The test methodology included visual inspection of the objects, roughness measurement and microscopic analysis with further application of Matlab application program package. The experimental results showed that both paintwork samples changed their color. Analysis of the roughness data showed that the white sample performed slightly better, as well as when analyzing the data obtained from the microscope. Additional research and testing can be done to improve the design of the switches and increase their durability in service.

Molecular dynamics simulation of mechanical strengthening properties of SiC substrate covered with multilayer graphene

A large number of practices have shown that under the coupling influence of complex working conditions and frequent reciprocating contact, the surfaces of semiconductor devices in micro/nano electromechanical systems often produce adhesive wear, which is the essential reason resulting in short durability service life and declining contact mechanical properties for microelectronics semiconductor devices. However, graphene can significantly improve the interface properties of mechanical components and electronic components due to its excellent mechanical properties, such as high carrier concentration, good thermal conductivity, and low shear. Thus, the study of mechanical strengthening properties and plastic deformation of SiC material with covered multi-layer graphene in MEMS devices will play a significant role in improving the durability service life of MEMS device, and understanding its strengthening and toughening mechanism. Therefore, this paper studies and discusses the effects of stacking type and extreme service temperature with low and high levels on the contact mechanical properties (maximum load, hardness, Young modulus, contact stiffness), micro-structure evolution, contact mass, fold morphology, and total length of dislocation. The atomic-scale mechanism of enhanced mechanical properties of SiC material with multi-layer graphene is explained. The research shows that the damage to carbon-carbon bond at the maximum indentation depth will lead graphene to lose the excellent in-plane elastic deformation capability when the graphene stacking type is AB stacking, so that the maximum load-bearing capacity of the substrate covered by three layers of graphene will drop linearly. In addition, the mechanical property of SiC material coated with three graphene layers is twice that of pure SiC substrate, and the strengthening mechanism is mainly due to the increase of wrinkle caused by the increase of multilayer graphene loading, which causes the quality of contact between the SiC substrate and the virtual indenter to decrease, thus increasing the interface contact stiffness. The increase of the active temperature will trigger off the increase of the atomic vibration frequency, which will cause the number of interface contact atoms to increase greatly, and the interface contact stiffness will weaken, and finally lead the interface contact quality to improve, This is because the mechanical properties of SiC substrate coated with multilayer graphene will decrease approximately linearly with the extreme service from low temperature to high temperature. In addition, the stress concentration in the subsurface layer of SiC substrate can induce the evolution of its micro-structure, and the increase of the number of graphene layers on the substrate can effectively reduce the stress concentration distribution in the subsurface layer of the substrate.

Effect of MgO on Evolution of Interface Structure between Low‐Basicity Refining Slag and MgO–C Refractory

MgO–C bricks are widely used as a refractory lining in the slag line part of the ladle of a cord steel refining. The dissolution of their main component MgO into the refining slag is one of the main reasons for their shortened service durability. Laboratory experiments are carried out using low‐alkalinity refining slag and unaltered MgO–C bricks by static crucible method. Physicochemical analysis, FactSage thermodynamic calculations, etc., are performed on the specimens, and the dissolution mechanism of magnesia is investigated. When the low‐melting‐point‐phase CaMgSiO4 (CMS) decomposes at high temperatures, the concentration and activity of (MgO) at the local interface between slag and MgO‐C brick increase rapidly, inhibiting the dissolution of magnesia into slag at the CMS in situ. The rapid weakening of the dissolution drive of the slag to the magnesia corrosion occurs when the MgO content in the refining slag approaches saturation. To verify the feasibility of extending the service life of MgO–C bricks at the refining ladle slag line, the study involves controlling the MgO content in the refining slag.

Numerical modeling of chloride diffusion in cement-based materials considering calcium leaching and external sulfate attack

Chloride-induced corrosion of steel bars can shorten the service life of concrete structures in marine environment. Therefore, a numerical model that can accurately characterize the chloride diffusion in marine concrete can help to evaluate the service durability of structures. In this paper, a novel chloride diffusion model considering the coupling effect of calcium leaching and sulfate attack in cement-based materials is proposed. The model can not only simulate the increase of porosity structure and the desorption of bound chloride caused by calcium leaching, but also characterize the competitive antagonism between sulfate and chloride salts in cement-based matrix, which produces expansive products to fill pores and promotes the desorption of bound chloride. The proposed model was further developed in COMSOL, and verified by two groups of literature experimental data. Then, the verified model was applied to investigate the coupling effect of calcium leaching and external sulfate attack on chloride diffusion process in cement-based materials. The results show that the proposed model can effectively reproduce the chloride diffusion process in both groups of tests well. In contrast to the single influencing factor, the coupling effect of calcium leaching-sulfate attack on the chloride diffusion process in cement-based materials shows that there is a phenomenon of inhibiting chloride diffusion in the early stage of erosion, but it shows a promoting effect in the later stage. Compared with sulfate attack, calcium leaching always dominates the influence of chloride diffusion in cement-based matrix. Furthermore, considering the coupled effect of leaching-sulfate attack, the initial corrosion time of reinforced concrete is about 24.5% earlier than that without considering the coupling effect. Increasing the thickness of steel bar cover layer and reducing the initial porosity of matrix can effectively delay the occurrence of steel bar corrosion in cement-based matrix.

Multiscale investigation on bitumen-aggregate interfacial debonding using molecular dynamics and finite element method

Adhesive failure between bitumen and aggregates is the primary cause of cracking in asphalt mixtures and pavement moisture damage. The resulting pavement distress poses a significant challenge to the service durability of the road infrastructure. Previous studies have validated that aggregate mineralogy has a significant influence on the adhesion properties between bitumen and aggregates; however, there is still a lack of a mechanistic understanding of the influence of the mineral constitution and distribution on the interfacial debonding behavior. This study aims to fill this knowledge gap by proposing a multiscale approach based on molecular dynamics (MD) simulations and the finite element method (FEM). First, the MD method was employed to extract the traction-separation curve of the interface between bitumen and minerals at a molecular scale. The obtained traction-separation relationship was then utilized as the input parameter for the zero-thickness cohesive element in the microscale bitumen-aggregate finite element model. The combined simulation results indicate that quartz with bitumen has the best cracking resistance at the molecular scale, followed by albite, mica, pyroxene, and anorthite. Among the three selected aggregates, the greywacke aggregate exhibited the best cracking resistance at the microscale level. Moreover, the distribution microstructure of the minerals was found to affect the cracking path of the bitumen-aggregate interface, and the bitumen-mica interface elements at the junction area with quartz have a late debonding. The proposed research method spearheads the prediction of multiscale bitumen-aggregate interfacial behavior by considering the aggregate mineralogical heterogeneity.

Gibbs Adsorption and Zener Pinning Enable Mechanically Robust High-Performance Bi2 Te3 -Based Thermoelectric Devices.

Bi2 Te3 -based alloys have great market demand in miniaturized thermoelectric (TE) devices for solid-state refrigeration and power generation. However, their poor mechanical properties increase the fabrication cost and decrease the service durability. Here, this work reports on strengthened mechanical robustness in Bi2 Te3 -based alloys due to thermodynamic Gibbs adsorption and kinetic Zener pinning at grain boundaries enabled by MgB2 decomposition. These effects result in much-refined grain size and twofold enhancement of the compressive strength and Vickers hardness in (Bi0.5 Sb1.5 Te3 )0.97 (MgB2 )0.03 compared with that of traditional powder-metallurgy-derived Bi0.5 Sb1.5 Te3 . High mechanical properties enable excellent cutting machinability in the MgB2 -added samples, showing no missing corners or cracks. Moreover, adding MgB2 facilitates the simultaneous optimization of electron and phonon transport for enhancing the TE figure of merit (ZT). By further optimizing the Bi/Sb ratio, the sample (Bi0.4 Sb1.6 Te3 )0.97 (MgB2 )0.03 shows a maximum ZT of ≈1.3 at 350 K and an average ZT of 1.1 within 300-473 K. As a consequence, robust TE devices with an energy conversion efficiency of 4.2% at a temperature difference of 215 K are fabricated. This work paves a new way for enhancing the machinability and durability of TE materials, which is especially promising for miniature devices.

Lubricant-infused iron palmitate surfaces with high durability and stable condensation heat transfer

Slippery liquid-infused porous surfaces are vulnerable to lubricant depletion caused by three major factors encompassing, the evaporation, cloaking, and shearing. Herein, lubricant-infused iron palmitate surfaces (LI-IPSs) are presented addressing the challenges of (1) evaporation-driven lubricant depletion enabled by the immensely clustered micro-/nano-structures of iron palmitate surface (IPS), (2) completely suppressing the wetting ridge even with miscible water-oil combinations enabled by only the handful uptake of oil by IPS. The apparent contact angle θa and sliding angle α of water on LI-IPSs are 98° ± 2° and 3° ± 1°, respectively. Under evaporation-driven lubricant depletion analysis, the shelf-durability of LI-IPSs has been found to last for 10 days in partially open environment at the ambient temperature (25 °C). The heat fluxes and condensate fluxes have been determined. The highest condensate flux on LI-IPSs (14 kgh−1 m−2) is ascribed to the dropwise condensation mode with efficient droplet dynamics. However, the service durability of LI-IPSs has lasted only for 50 ± 5 min under rigorous condensation, which is further addressed by developing a LI-IPS prototype. Based on the excellent wicking capability of IPS, LI-IPS prototype is capable of maintaining the dropwise condensation unless the oil is available in the oil tub. The LI-IPS prototype has been subjected to open environment at ambient temperature for 168 h, and even after that, the stable dropwise condensation has been achieved with the same range of droplet speed as had been observed in the first hour. Meantime, the high condensation heat fluxes at various subcooling temperatures are obtained, justifying the promising ability of LI-IPS.

Study of toughening behavior of SiC whiskers on 8YSZ thermal barrier coatings

The embrittlement of thermal barrier coatings (TBCs) in a high-temperature service environment inhibits the ability of the top-coat to resist crack initiation and propagation, in which the cracks are generated by erosion or wear of particles, limiting the service durability of TBCs. This study was based on the preparation of SiC whiskers (SiCw) / Y2O3 partially stabilized ZrO2 (YSZ) integrated composite powder, and the SiCw/YSZ composite TBCs was prepared through the atmospheric plasma spraying (APS) to improve the toughness of the top-coat. The effects of SiCw on the fracture toughness, tribological properties, erosion resistance and bending strength of the coatings were studied. The results showed that the fracture toughness of the composite coating with a SiCw length-to-diameter ratio (L/D ratio) of 250 was 24.6 % higher than the YSZ coating. Moreover, the composite coating presented excellent performance in wear, erosion, and resistance to crack propagation and spallation. The low amplitude of the Weibull modulus m of hardness distribution of the doped coating proved the stability effect of SiCw on the reinforcement and toughening of the coating.

Influence of Filler Type and Rheological Properties of Asphalt Mastic on the Asphalt Mastic-Aggregate Interaction.

The asphalt mastic-aggregate interaction plays an important role in the overall properties of asphalt mixtures and their durability in service in flexible pavements. This paper aims to study the influence of the physico-chemical features of fillers and the rheological properties of asphalt mastics on the bonding behavior between asphalt and aggregate, and the interfacial deterioration mechanism when subjected to static water immersion and pressured water immersion. It was found that the filler type (limestone powder, basalt powder, and granite powder) had a certain influence on the complex modulus of asphalt mastics, and its pore volume and specific surface area had significant effects on the phase angles and permeability of asphalt mastics. The effect of water pressure can accelerate the deterioration of bond strength of the asphalt mastic-aggregate interface in the short term, indicating that the dynamic water pressure generated by the driving load promotes the water damage process in asphalt pavements. In comparison, the residual bond strength ratio of the granite-asphalt mastic aggregate was the highest, while its bond strength was lower than that of the interface between limestone-asphalt mastics and limestone aggregate. This demonstrated that a low asphalt mastic complex modulus and a high phase angle are helpful in improving the durability of asphalt mixtures subjected to static and pressured water immersion conditions.

Water-borne, durable and multicolor silicon nanoparticles/sodium alginate inks for anticounterfeiting applications

Recently, water-borne fluorescent inks have attracted extensive attention in anti-counterfeiting applications due to their convenient implementation and eco-friendliness. However, due to poor service durability, the latent authorization information from the inks is easily damaged, and even disappears when encountering water. Moreover, most of the existing fluorescent inks are monochromic, toxic, and allergic to skin, thus are unsuitable for their sustainability during real-life applications. Herein, this work presents environment-friendly, durable, and multicolor fluorescent anti-counterfeiting silicon nanoparticles (SiNPs)/sodium alginate (SA) inks. The multicolor SiNPs are synthesized by a one-pot method with defined morphologies and optical properties. Subsequently, SA is employed as the binder to prepare the fluorescent inks with optimized rheological properties. Practicability results show that the SiNPs/SA inks not only exhibit excellent printability, but also impart authentic information with superior covert performance. More notably, spraying solution of calcium dichloride can further improve fluorescent fastnesses of the SiNPs/SA inks by ionic crosslinking.

Recent advances in zinc-ion hybrid energy storage: Coloring high-power capacitors with battery-level energy

Zinc-ion hybrid capacitors (ZICs) are considered as newly-emerging and competitive candidates for energy storage devices due to the integration of characteristic capacitor-level power and complementary battery-level energy. The practical application of rising ZICs still faces the specific capacity and dynamics mismatch between the two electrodes with different energy storage mechanisms, which cannot meet the ever-growing indicator demand for portable electronic displays and public traffic facilities. Focusing on these unresolved issues, this mini-review presents recent advances in ZICs referring to the hybrid energy storage mechanism, design strategies of both capacitor-type and battery-type electrode materials, and electrolyte research toward advanced performances (e.g., high operational potential, wide adaptive temperature). Finally, current challenges and future outlook have been proposed to guide further exploration of next-generation ZICs with a combination of high-power delivery, high-energy output and high-quality service durability.

On the durability of zirconia-reinforced lithium silicate and lithium disilicate dental ceramics under severe contact

Zirconia-reinforced lithium silicates (ZLS) are a novel generation of aesthetic, lithium-based ceramics intended for use in dental restorations at high loads due to their enhanced fracture strength compared to the previous lithium disilicate (LS2) materials. However, under severe dental conditions, material durability in service may be limited by wear from repetitive, frictional contacts. Here, a comparison is made between commercial ZLS and LS2 dental ceramics of their severe wear behavior under sliding contact against hard zirconia antagonists by means of in-vitro pin-on-disk tests. Specific wear rates greater than 10−6 mm3/N⋅m are obtained. The mechanisms responsible for material removal are a combination of deformation and fracture. Results are discussed in terms of the materials’ microstructure and mechanical properties. In combination with analytical modelling, ZLS dental ceramics are estimated to be up to 5 times less durable than LS2 under conditions modelling heavy chewing/bruxism. Finally, implications for the microstructural design of novel lithium silicate/disilicate materials with improved durability are considered.