Resistance Properties Research Articles

The microstructure, ablative resistance and mechanical properties of C/C-(Zr, V, Si)C composites after ablation

The microstructure, ablative resistance and mechanical properties of C/C-(Zr, V, Si)C composites after ablation

Color and functionality construction of cellulose towels with biological Monascus pigment based on a nano-suspension system

As a sanitary textile that directly contacts sensitive parts of the human body, such as mouth, nose and eyes, towel is very important for our daily life and health. However, the colored cellulose towels we use daily are dyed with synthetic dyes. This can be a problem for people with sensitive skin, particularly babies. In this research, cellulose towel fabric was dyed using a nano-level Monascus pigment dyeing solution, which eliminated the need for organic solvent to dissolve the pigment, making it an environmentally friendly dyeing scheme. After 90 °C pre-mordanting treatment and 80 °C dyeing for 30 min respectively, the K/S value of towel fabric could reach 9. In addition, the washing fastness of dyed towel fabric was 3–4, the dry/wet friction fastness was 4–5 and 3–4, and the K/S value remained high even after 20 washing times, and also demonstrated a certain level of UV resistance and antibacterial properties. In conclusion, the application of the dyeing method for cellulose towel fabric with biological Monascus pigment based on a nano-suspension system was found to be both efficient and environmentally friendly, which was anticipated to replace certain traditional synthetic dyes in the future.

Cost-effective construction of graphene-based high-temperature electric heating coating with oxidation resistance and high mechanical properties

Cost-effective construction of graphene-based high-temperature electric heating coating with oxidation resistance and high mechanical properties

In-situ synthesis of Yttria-based precipitates and their effects on Fe12Cr6Al in laser powder bed fusion

To advance the suitability of FeCrAl alloys for nuclear applications, radiation damage resistance, creep resistance, corrosion resistance, and mechanical properties enhancement are essential. A promising approach is the introduction of a high density of nitride and oxide nanoprecipitates within the alloy matrix. This study aimed to explore the impact of in-situ formed nitride and oxide precipitates on the properties of Fe12Cr6Al alloy by using a nitrogen-rich atmosphere and incorporating nano-sized Y2O3 (0.45 wt. %) during laser powder bed fusion (LPBF). As a result of adding Y2O3 nanoparticles to the Fe12Cr6Al alloy, the grain size decreased from 70 μm to 40 μm, and the Al-O, Al-N, and Al-N-O precipitates were replaced by Y-O, Y-Al-O, and Y-N precipitates. Additionally, the nitrogen contents increased from 220 ppm to 470 ppm. The sample with Y2O3 exhibited higher mechanical properties, with yield strength, tensile strength, and hardness (HV) increasing by 80 MPa, 112 MPa, and 23 HV, respectively. This study deviates from previous research on Y2O3-containing FeCrAl alloys by investigating the impact of in-situ synthesized Y-N nitrides on Fe12Cr6Al. The objective is to elucidate the combined effects of these precipitates on the properties of Fe12Cr6Al alloy in comparison to literature-reported oxide dispersion-strengthened (ODS) FeCrAl alloys, which were fabricated in an argon (Ar) atmosphere.

Development and validation of a new asphalt mixture to reduce tyre-road contact noise in interurban areas

Road transport is one of the most important sources of noise emissions having a serious impact on human health. Thus, the objective of this study is to develop an innovative asphalt mixture that decreases noise from tyre and pavement interaction on highways with average speeds of about 80 km/h. To achieve this, a series of mechanical and functional tests were conducted both in the laboratory and at the Gustave Eiffel University Accelerated Pavement Testing (APT) facility. The new experimental mixture achieves a balance between high void content and low macro-texture (wavelengths of 5–50 mm), which improves noise reduction while maintaining good mechanical performance. This is achieved thanks to its two-layer structure, with a top layer of reduced maximum aggregate size (4 mm) and a thickness suitable for optimum sound absorption. Various mechanical tests, including the particle loss test and the water sensitivity test, along with functional evaluations focusing on texture, flow resistivity and sound absorption properties, were performed. Measurements on the APT were taken at three different stages of the pavement service lifetime during the testing phase. The outcome was the production of an asphalt mixture that reduced noise up to 6.8 dB in comparison to an asphalt concrete road.

Design, construction and mechanism of highly efficient flame retardant, UV shielding and transparent thermoplastic polyurethanes

The rapid development of 5G communication and new energy poses great challenges to the fire safety, UV resistance, and transparent properties of TPU composites. In this study, a novel and multi-functional flame retardant ((diphenylphosphoryl)azanediyl)bis(ethane-2,1-diyl) bis(diphenylphosphinate) (DPEP) containing multiple flame retardant groups and polyaromatic structure was innovatively designed. The prepared TPU/DPEP composites exhibited excellent fire safety, UV shielding, mechanical and transparent properties. 4 wt% DPEP enabled TPU to pass the UL-94 V-0 rating and improved the LOI to 29.6 %. Compared to pure TPU, the heat release rate and total heat release of TPU/4 wt% DPEP were decreased by 29.06 % and 13.24 %. Meanwhile, TPU/DPEP composites achieved 100 % UV shielding at UV-B wavelengths and up to 68.77 % UV isolation at UV-A wavelengths. Due to the structural similarity and processing meltability, DPEP exhibited good dispersion and compatibility in TPU matrix. TPU/DPEP retained almost the same mechanical and transparent properties as pure TPU. The condensed and gas phase analysis indicated that the flame retardant mode of DPEP was mainly dominated by flame retardant inhibition and the barrier effect of the carbon layer. Compared with the reported flame retardant TPU composites, the TPU/DPEP composites achieved a relatively optimal balance between efficient flame retardant, mechanical, UV shielding, and transparent properties, demonstrating great application prospects in the emerging fields.

Rubber-assisted and modulated epoxy topological network for developing fatigue-resistant, high-strain-cycle high performance shape memory polymer composites

High performance shape memory polymer (HPSMP) has a wide range of application such as smart device, smart mold. In this study, we designed a rigid-flexible shape memory epoxy with flexible chain segment as the main chain and rigid benzene ring as the side group. Meanwhile, carboxyl-terminated nitrile butadiene rubber (CTBN) was accessed into the epoxy main chain as a fatigue-resistant functional filler. The results showed that the flexible backbone plays a major role in improving the ductility. The superior fatigue-resistant shape memory cycling performance was synergistically achieved by modulating the epoxy topological network through altering the disulfide cross-linker prompted by CTBN, and the materials exhibited good high and low-temperature resistant mechanical properties. Comparatively, it is found that disulfide bonding can significantly improve the tensile property and thermal stability for epoxy. The synergistic effect between the elastic chain segments in CTBN and the flexible backbone achieves excellent shape recovery ratio. Therefore, the rational structural design provides an effective way to develop HPSMP, which can expand the application areas for HPSMP.

The Influence of Carbon Fiber on Crystallization and Morphology of Poly(Ether Ketone Ketone) Composites Towards High Rate Thermoplastic Manufacturing Processes

Recent interest in thermoplastic composites for aerospace applications is driven by the need for high-volume manufacturing of materials that display excellent mechanical, thermal, and solvent resistive properties. Specifically, a large component of the composite properties of thermoplastic composites are highly dependent on the crystalline fraction of the semi-crystalline polymer matrix of the reinforced system. This work investigates the melting behavior of poly (ether ketone ketone) (PEKK) and the influence of temperature and fiber on crystallization kinetics and morphology of (PEKK) composites utilizing, differential scanning calorimetry, Velaris-Sefaris modelling, and polarized optical microscopy (POM). Annealing temperatures of 380°C and above were required to fully erase crystalline ordering in the PEKK matrix. Furthermore, carbon fibers accelerated crystallization kinetics in PEKK at a range of temperatures observed via DSC, and Velaris-Sefaris modelling implied a shift from bulk to surface induced nucleation by the addition carbon fiber to the PEKK matrix, reducing activation energy of crystallization events. This nucleation behavior was visually confirmed through POM with observation of transcrystalline domains nucleated from the surface of a single carbon fiber.

Corrosion resistance properties and hydrogen embrittlement protection efficiency of single-layer and multi-layer metal and ceramic films deposited on SS316L substrates

Hydrogen is a promising source of clean energy. However, the tanks used to store hydrogen fuel are prone to hydrogen embrittlement and are thus at risk of stress cracking and catastrophic failure. Accordingly, this study deposited single-layer and double-layer Zr, Al, SiO2, Al2O3, Al@Al2O3, and Al@SiO2 films on 316L stainless steel substrates and examined their feasibility as protective coatings by measuring their anti-corrosion properties and hydrogen permeation currents. The results showed that the single-layer Al2O3 film had a higher corrosion resistance than the single-layer SiO2 film and bare 316L substrate. Among all the coatings, the Al@Al2O3 double-layer coating exhibited the highest protection efficiency of 95%. Moreover, it showed the lowest hydrogen penetration current density (1.08 x 10-3 A/cm2), the longest hydrogen embrittlement time (16000 s), and the lowest hydrogen content (0.008 mol/cm3). In other words, the Al@Al2O3 double-layer coating combined superior corrosion resistance with excellent hydrogen permeation suppression. Consequently, it is a promising material for enhancing the safety and longevity of hydrogen storage tanks in practical applications.

Failure criterion and damage evolution of high-strength geopolymer concrete under compression-shear composite loading after high temperatures

Geopolymer concrete (GPC) holds significant potential for building fire safety design due to its green, low-carbon, and high-temperature resistant properties. In practical applications, concrete structures often face multiaxial composite loads. Therefore, investigating the composite stress performance of high-strength geopolymer concrete (HGPC) after exposure to high temperatures is crucial for assessing structural damage and enhancing fire prevention measures. This paper examines the compressive shear performance of HGPC at various temperatures T (20°C, 200°C, 400°C, 600°C) and stress ratios k (0.15, 0.3, 0.45, 0.6). The study analyzes failure patterns, shear load-displacement curves, shear strengths and their components, and peak shear deformation. Failure criteria are proposed to describe the damage patterns of HGPC under compressive shear loading after high temperatures. Additionally, the damage evolution process is evaluated using the energy method. The results show that HGPC damage surfaces penetrate the coarse aggregate at room temperature under compression-shear composite loading but shift to the aggregate-mortar interface at 600°C. Shear stiffness, peak shear strength, and residual strength increase with higher stress ratios but decrease with rising temperatures. Temperature affects peak shear strength by over 95 %, significantly more than the stress ratio. The shear strength decreases more slowly than compressive strength up to 400°C but more rapidly beyond 400°C. The cohesive strength of HGPC decreases with increasing stress ratio under different temperatures, while contact friction strength exceeds 50 % of peak shear strength. Shear dilation strength generally increases, then decreases, peaking at k = 0.45. The failure criterion based on the modified twin shear unified strength theory aligns best with experimental results. Furthermore, an increased stress ratio retarded the development of damage evolution, which was first accelerated and then slowed with rising temperature.

Sustainable lignin-based powder coatings doped with ZnO displayed excellent UV resistance properties

Sustainable lignin-based powder coatings doped with ZnO displayed excellent UV resistance properties

The Influence of Carbon Fiber on Crystallization and Morphology of Poly(Ether Ketone Ketone) Composites Towards High Rate Thermoplastic Manufacturing Processes

Recent interest in thermoplastic composites for aerospace applications is driven by the need for high-volume manufacturing of materials that display excellent mechanical, thermal, and solvent resistive properties. Specifically, a large component of the composite properties of thermoplastic composites are highly dependent on the crystalline fraction of the semi-crystalline polymer matrix of the reinforced system. This work investigates the melting behavior of poly (ether ketone ketone) (PEKK) and the influence of temperature and fiber on crystallization kinetics and morphology of (PEKK) composites utilizing, differential scanning calorimetry, Velaris-Sefaris modelling, and polarized optical microscopy (POM). Annealing temperatures of 380°C and above were required to fully erase crystalline ordering in the PEKK matrix. Furthermore, carbon fibers accelerated crystallization kinetics in PEKK at a range of temperatures observed via DSC, and Velaris-Sefaris modelling implied a shift from bulk to surface induced nucleation by the addition carbon fiber to the PEKK matrix, reducing activation energy of crystallization events. This nucleation behavior was visually confirmed through POM with observation of transcrystalline domains nucleated from the surface of a single carbon fiber.

BaTiO3 doped PEO coating on pure Mg with enhanced antibacterial, antifouling and corrosion resistance properties

BaTiO3 doped PEO coating on pure Mg with enhanced antibacterial, antifouling and corrosion resistance properties

Effect of Co content on microstructure and properties of TiCN-TiB2 cermets prepared by spark plasma sintering from a TiCN-B4C-Ti-Co system

Series of TiCN-TiB2 cermets were in situ prepared from the TiCN-B4C-Ti-Co system via spark plasma sintering (SPS). The effects of Co content on the densification, microstructure, mechanical properties, and wear resistance of TiCN-TiB2 cermets were investigated. The results showed that the Co addition had little effect on the phase composition of the sintered cermets, but had significant influences on the densification, microstructure and mechanical properties. Appropriate addition of metal Co could enhance densification and promote the grain growth of ceramic phases, but excessive addition resulted in a decrease in hardness and wear resistance. When the Co content was 10 wt.%, the cermet obtained the optimal comprehensive performance (a hardness of 1757 HV and a fracture toughness of 7.02 MPa•m1/2). Meanwhile, the cermets with 10 wt.% Co addition exhibited optimum wear resistance properties due to a good combination of hardness and toughness and moderate grain size. In addition, the formation process and strengthening mechanism in present system were discussed in detail. Results from this work could provide valuable references for the fabrication of TiB2 reinforced TiCN-based cermets.

Polycarbosilane-modified phosphate adhesives for porous Si3N4 ceramic pressure-free bonding at high temperatures

Si3N4 ceramics are widely employed in the aerospace and automotive sectors owing to exceptional mechanical performances, anti-oxidant nature, and corrosion resistance properties. However, their brittleness makes manufacturing complex components challenging, while the intricate nature of welding restricts its use. A Si3N4 ceramic adhesive joint capable of withstanding high-temperature conditions was formed under ambient conditions. Polycarbosilane was introduced into the phosphate adhesive to improve high-temperature thermal matching between the adhesive and substrate, At 600 and 800 ℃, the compressive shear strength increased by 25% and 83%, respectively. After 48h at 1000 ℃, the compressive shear strength was 8.6MPa, indicating excellent oxidation resistance. The adhesive penetrated the matrix pores under capillary action, forming network bonding, and an interfacial reaction generated Si5AlON7, buffering thermal stress. This represents the first phosphate adhesive for bonding Si3N4 ceramics, demonstrating excellent forming capabilities, with bond strengths comparable to that of conventional welds, showing high potential for engineering applications.

Bioresorbable composites based on magnesium and hydroxyapatite for use in bone tissue engineering: focus on controlling and minimizing corrosion activity

A biodegradable matrix with a significant content of bioactive components can be applied for bone tissue replacement, including load-bearing applications in orthopedic surgery. The study outlines the optimized procedure for the production of bioresorbable magnesium-hydroxyapatite (Mg-HA) composites and their corrosion resistance properties. Composites were meticulously crafted by combining pure magnesium with microwave-synthesized hydroxyapatite nanopowder. Sintering occurred via spark plasma sintering technology (SPS). To align the degradation time of the resulting composites with bone remodeling, the corrosion resistance of SPS materials was enhanced through the application of plasma electrolytic oxidation (PEO) and polycaprolactone (PCL) spin-coating methods. The protective properties, morphology dynamics, and composition due to surface treatment and corrosion propagation were investigated using Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP), hydrogen evolution tests, Scanning Electron Microscopy (SEM), Energy-dispersive X-ray (EDX) as well as X-ray diffraction (XRD) analysis. Analytics of the physicochemical properties data of the formed coatings indicate a significant improvement in protective characteristics and deceleration of the corrosive degradation of the samples. The application of polycaprolactone to the PEO coating leads to a decrease in the corrosion current compared to uncoated magnesium composites by more than three orders of magnitude: from 1 10-5 to 2 10-9 A cm-2. During long-term exposure of samples to 0.9 % NaCl solution, it was found that coating reduced the rate of corrosion degradation of samples from 1.5 to 80 times compared to an unprotected Mg-HA composite and sintered magnesium. Mg-HA composites treated with PEO exhibit potential application as bioactive and biodegradable materials for orthopedic implants and fixation devices.

Corrosion-oriented self-healing coating based on ZnMg MOF for efficient corrosion protection of aluminum alloy via in-situ LDH film formation

A corrosion-oriented self-healing coating system relying on metal–organic framework (MOF) based nanofiller is designed for aluminum alloy protection. The nanofiller is comprise of ZnMg MOF nanoparticle as a framework, salicylaldoxime corrosion inhibitors inside the MOF, and a polydopamine layer on the MOF surface. The Al3+ ions generated from the aluminum alloy substrate at the damaged coating area can etch the nanofiller, causing the collapse of the nanofiller and releasing the corrosion inhibitors to suppress the corrosion process in time. Subsequently, Zn2+ and Mg2+ ions from the nanofiller co-precipitate with Al3+ to form a dense AlZnMg layered double hydroxide (LDH) film, which provides further protection performance at the exposed alloy surface. Electrochemical impedance spectroscopy results demonstrate that the intact MOF@S/P coating exhibits a remarkable corrosion resistance property. For the damaged coating, the self-healing performance originated from the formation of LDH layer and the release of corrosion inhibitors gradually took effect, with the |Z|0.01Hz value increasing 2.27 times within 14 days. Moreover, under near-infrared irradiation, the photothermal effect of polydopamine will accelerate the release of corrosion inhibitor, the formation of LDH film, as well as the shape memory effect of coating defect for an efficient recovery of the corrosion resistance property. This novel coating system enables a corrosion-driven and location-specific repair with in-situ deposition of both an inhibitor film and an LDH film. As the first work to fully utilize and consume nanofillers on demand, this approach prevents inadequate use of healing agents, addressing a significant challenge in corrosion-driven self-healing coatings. The self-healing mechanism ensures target-oriented corrosion protection that makes the most efficient use of the healing substances.

Microstructure Evolution and Wear Behavior of Stellite12 Coating Prepared by Laser-Directed Energy Deposition on H13 Steel

Laser-directed energy deposition (LDED) was employed to apply a Stellite12 coating onto an H13 steel substrate. This study explored the effects of processing parameters on the dimensions of the deposited tracks. Comprehensive examinations were conducted on the coatings to assess their phase composition, microstructure, and wear resistance properties. The relationship between microstructural characteristics and thermal field was investigated through a synergy of numerical simulations and experimental analyses. The findings revealed that the Stellite12 coating displayed a heterogeneous microstructure with epitaxial growth and a slight texture across successive layers. The primary phase comprised a γ-Co solid solution and M23C6 carbides, contributing to a significant enhancement in hardness, which was observed to be 2.2 times higher than that of the substrate. The coating demonstrated superior performance in terms of lower friction coefficients and reduced wear rates at both room and elevated temperatures. The predominant wear mechanisms identified were oxidative wear. These results underscore the promising applications of Stellite12 coatings in industrial contexts facilitated by LDED technology.

Effect of ionic soil stabilizer on the properties of lime and fly ash stabilized iron tailings as pavement base

The large use of iron tailings is in urgent need given its huge emissions and pollution to environment. This paper sought to utilize a large quantity of iron tailings with fly ash and lime to prepare road base materials, and use ionic soil stabilizer (ISS) to improve its pavement performance. Different dosage ISS content of was added to the lime-fly ash stabilized iron tailing materials to improve the mechanical strength, frost resistance properties and decrease the dry shrinkage. The results show that the UCS of the specimen with 0.67 % ISS represents enhancement of 195.5 % compared to the control sample at 7 d. After undergoing 15 freeze-thaw cycles, the residual UCS ratio remains at 76.6 %, whereas the control sample exhibits signs of failure. Additionally, the dry shrinkage strain at 30 d was 66.3 % lower than that of the control sample without ISS. The mechanisms underlie that the adsorbed ISS onto iron tailings can reduce the repulsion between total fine particles by lowering the general zeta potential, thus decreasing the porosity of the road base materials. Besides, the ISS can hinder the phase transformation from ettringite (AFt) to monosulfoaluminate (AFm) and its hydrophobic groups can prevent the infiltration and migration of water. The findings reveal that ISS significantly enhances the pavement performance of the stabilized iron tailings, thereby presenting a novel approach for the incorporation of iron tailings in road construction endeavors.

Investigation of photocatalytic and corrosion resistance properties of Zr-Ag doped SnO2 Nanoparticles: The impact of calcination temperature

Investigation of photocatalytic and corrosion resistance properties of Zr-Ag doped SnO2 Nanoparticles: The impact of calcination temperature