Resistance Properties Research Articles

Mathematical Modeling of the Effect of TiC Nanopowder Particles on the Wear Resistance Properties of Low-Alloy Steel

In this article, the effect of TiC nanopowder particles on the wear resistance of low-alloy steel 35XGCL (analog is JIS G 5111) is mathematically modeled. First of all, the composition for liquefaction in an electric arc furnace was calculated. 5 and 10% TiC nanopowder particles were added to the alloy as a modifier before pouring liquid metal into the ladle. This process was performed before pouring the liquid metal from the furnace into the ladle. 15% of TiC was added in the furnace as a modifier. Lagrangian interpolation polynomial construction was used in this modeling. The amount of wear resistance was calculated by polynomial expression of the function with determination of unknown coefficients. The results obtained on the basis of the developed model were compared with case studies. The results of the analysis are shown by graphs.

Geomechanical and Hydraulic Behavior of Impermeable Layers for Earthworks

Objective: The objective of this study is to investigate the mechanical and hydraulic behavior of fine sandy soil mixtures from the Coastal Plain of Rio Grande do Sul with bentonite, assessing their technical feasibility as an impermeable layer for earthwork projects. Theoretical Framework: El marco teórico explora la impermeabilización de vertederos sanitarios, destacando la eficacia de los liners para contener contaminantes y el uso de bentonita como aditivo para suelos granulares. Estudios previos señalan mejoras en la conductividad hidráulica y la plasticidad de mezclas de suelo-bentonita, especialmente en regiones con escasez de materiales arcillosos de alta calidad. Method: The method includes laboratory tests with natural soil and mixtures containing different bentonite contents. Physical, granulometric, plasticity, compaction, hydraulic conductivity, and mechanical resistance properties were evaluated. Results and Discussion: The natural soil proved unsuitable for use as an impermeable layer. The results show that the addition of bentonite significantly improved the soil's hydraulic conductivity, with 6% by dry weight achieving values suitable for impermeable layers. However, increasing bentonite content reduced the friction angle, indicating a decrease in mechanical strength. Research Implications: The research highlights the potential of soil-bentonite mixtures as a sustainable solution for impermeable layers in earthwork projects, particularly in regions with limited availability of clayey soils. The results provide technical support for the use of local materials, contributing to the feasibility of environmental engineering projects tailored to regional characteristics. Originality/Value: The research is original in exploring soil-bentonite mixtures as a sustainable solution for impermeable layers in coastal plains, a region with scarce suitable clayey soils. Its contribution lies in the technical evaluation of local materials, promoting innovative and environmentally adapted alternatives for engineering projects in challenging contexts.

Thermal and Mechanical Performances Optimization of Plaster–Polystyrene Bio-Composites for Building Applications

Polystyrene is renowned for its excellent thermal insulation due to its closed-cell structure that traps air and reduces heat conduction. This study aims to develop sustainable, energy-efficient building materials by enhancing the thermal and mechanical properties of plaster–polystyrene bio-composites. By incorporating varying amounts of polystyrene (5% to 25%) into plaster, our research investigates changes in thermal conductivity, thermal resistance, and mechanical properties such as Young’s modulus and maximum stress. Meticulous preparation of composite samples ensures consistency, with thermal and mechanical properties assessed using a thermal chamber and four-point bending and tensile tests. The results show that increasing the polystyrene content significantly improved thermal insulation and stiffness, though maximum stress decreased, indicating a trade-off between insulation and mechanical strength.

A Review on the Effect of Synthetic Fibres, Including Macro Fibres, on the Thermal Behaviour of Fibre-Reinforced Concrete

The mechanical properties of concrete degrade rapidly when exposed to elevated temperatures. Adding fibres to concrete can enhance its thermal stability and residual mechanical characteristics under high-temperature conditions. Various types of fibres, including steel, synthetic and natural fibres, are available for this purpose. This paper provides a comprehensive review of the impact of synthetic fibres on the performance of fibre-reinforced concrete at high temperatures. It evaluates conventional synthetic fibres, including polypropylene (PP), polyethylene (PE), and polyvinyl alcohol (PVA) fibres, as well as newly emerging macro fibres that improve concrete’s fire resistance properties. The novelty of this review lies in its focus on macro fibres as a promising alternative to conventional synthetic fibres. The findings reveal that PE fibres significantly influence the residual mechanical properties of fibre-reinforced concrete at high temperatures. Although PVA fibres may reduce compressive strength at elevated temperatures, they help reduce micro-cracking and increase flexibility and flexural strength. Finally, this review demonstrates that while conventional synthetic fibres are effective in limiting fire-induced damage, macro fibres offer enhanced benefits, including improved toughness, energy absorption, durability, corrosion resistance, and post-cracking capacity. This study provides valuable insights for developing fibre-reinforced concrete with superior high-temperature performance. Steel fibres offer superior strength but are prone to corrosion and spalling, while PP fibres effectively reduce explosive spalling but provide limited strength improvement. PE fibres enhance flexural performance, and PVA fibres improve tensile strength and shrinkage control, although their performance decreases at high temperatures. Macro fibres stand out for their post-cracking capacity and toughness, offering a lightweight alternative with better overall durability.

UV Resistance Properties of Lignin Influenced by Its Oxygen-Containing Groups Linked to Aromatic Rings.

The influence of lignin's primary oxygen-containing functional groups, phenolic OH (Ph-OH) and methoxyl (OMe) groups, especially the Ph-OH/OMe ratio, on its UV absorptivity and long-lasting UV blocking remains unclear. In this study, organosolv lignins (OLs) with varying Ph-OH and OMe contents were prepared to evaluate their UV absorptivity and photostability by EPR (electron paramagnetic resonance). As the Ph-OH contents increased from 0.32 to 6.09 mmol/g, lignin with a higher Ph-OH content displayed better absorptivity with a strong correlation (Pearson's r = 0.95). However, an excessive Ph-OH content (>5.5 mmol/g) reduced the spin content of lignin, negatively affecting its photostability. Taking Ph-OH and OMe groups as the cofactor, OLs with Ph-OH/OMe ratios between 0.44 and 0.64 showed more favorable UV-blocking performance both in the initial state and after UV irradiation. Moreover, lignin-based sunscreens exhibited increasing SPF value even after 8 h of UV exposure, confirming lignin's long-lasting UV-blocking property.

Preparing Al2O3/TiO2 nano-multilayers on the surface of FeAl/Al2O3 coating as tritium permeation barrier

Abstract Preparing tritium permeation barrier (TPB) coating on the surface of structural materials can effectively alleviate tritium permeation in fusion reactor system. However, due to the existence of inevitable certain number of defects in TPB, there is still a gap between the commonly prepared TPB coatings and the requirements proposed by fusion reactors. In this work, composite coatings with Al2O3/TiO2 nano-multilayers (NMLs) covering on the surface of FeAl/Al2O3 coating were prepared as TPB. The FeAl/Al2O3 TPB coating on the surface of 316L stainless steel was prepared by electrochemical deposition of Al, aluminization and in-situ oxidation. Due to the aggregation of Cr, there are micro sized defects in the Al2O3 layer. The presence of defects seriously reduces its hydrogen isotopes permeation resistance. The atomic layer deposition was then adopted to prepare Al2O3/TiO2 NMLs with period thickness of 15, 7.5 and 3 nm on the surface of Al2O3 layer, which not only cover the defects, but also utilize interfaces to suppress hydrogen isotopes permeation. The composite coating sample with the period thickness of 3 nm showed great enhancement of two orders of magnitude in deuterium permeation resistance property compared to the original FeAl/Al2O3 TPB coating at 500 °C, and the permeation reduction factor reaches a high value of 5 × 105, which far above the requirements of future fusion reactors.

Laser Cladding In Situ Carbide-Reinforced Iron-Based Alloy Coating: A Review

Laser cladding, as an advanced surface modification technology, has the advantages of a high energy density, controlled dilution rate and good metallurgical bonding between the coating and the substrate. Its rapid heating and cooling properties help to form a dense and fine coating structure on the surface of the substrate, thus enhancing wear and corrosion resistance. In recent years, the in situ generation of carbide-reinforced iron-based composite coatings has gradually become a research hotspot because it combines the high hardness values of carbide with the high toughness values of iron-based alloys, which significantly improves the comprehensive performance of the coatings. This paper reviews the research progress of laser cladding in situ carbide-reinforced iron-based alloy coatings and explores the role of different types of in situ synthesized carbides (TiC, NbC, WC, etc.) in the coatings and their effects on their wear resistance and mechanical properties. The distribution of carbides in the coatings and their morphological characteristics are also discussed, and the effects of laser power, scanning speed and auxiliary treatments (ultrasonic vibration, induction heating, etc.) on the microstructure and properties of the coatings are analyzed. Finally, the problems and future directions of development in this field are envisioned.

Comparative study on the ablation resistance and mechanical properties of 2.5D C/C composites reinforced with CFMP and CFPAN

Comparative study on the ablation resistance and mechanical properties of 2.5D C/C composites reinforced with CFMP and CFPAN

Evaluating the Economic Efficiency of Fuel Reduction Treatments in Sagebrush Ecosystems That Vary in Ecological Resilience and Invasion Resistance

The concepts of resilience and resistance (R&R) have been used to improve wildland fuel treatment outcomes by identifying parts of the landscape that are more likely to respond well to treatment. This study examined how the economic benefits and costs of fuel treatments in sagebrush (Artemisia spp.) ecosystems varied with the resilience and resistance properties of the treatment site. Generalized ecological models were developed for the economic analysis of fuel treatments that integrated ecological succession, annual grass invasion, pinyon–juniper expansion, and wildfire to simulate ecosystem dynamics over time. The models incorporated resilience and resistance by varying model parameters related to each plant community’s ability to resist annual grass invasion and recover post-disturbance. Simulations produced estimates of the expected (ex ante) benefit–cost ratio for each treatment. The approach also considered the benefits associated with the system remaining in an ecologically favorable condition, allowing us to report a more holistic measure of the net economic benefits of fuel treatments. The results from the simulations indicated fuel treatment was economically efficient in late-successional sagebrush and early-successional juniper in mountain big sagebrush associations. For sagebrush associations where treatment was economically efficient, higher R&R status sites had higher benefit–cost ratios. The results suggested that treatment costs were more determinative of economic efficiency than treatment benefits.

Characterization of Ti-48Al-2Cr fabricated by multi-wire arc additive manufacturing: Microstructure, mechanical, and oxidation resistance properties

Utilizing a multi-wire arc additive manufacturing process applied with high-frequency induction heating wire technology (MWAAM-HF) proposed in this study, Ti-48Al-2Cr alloy straight-walled component was fabricated. During the MWAAM-HF process, three types of wires melt simultaneously and transfer smoothly into the weld pool to form satisfactory component without discernible cracks. The upper and lower regions have higher hardness compared to the middle region in both Z and Y direction. Along the Y direction, the upper region exhibited the highest UTS and YS, while the minimum values were observed along the Z direction. Superior wear resistance was observed in the upper and lower regions. Distinct regions exhibited different levels of high-temperature oxidation resistance and the upper region has superior high-temperature oxidation resistance.

Study on pulse anodizing of 6061 aluminum alloy and its corrosion resistance and mechanical property

Study on pulse anodizing of 6061 aluminum alloy and its corrosion resistance and mechanical property

Enhanced Interfacial Properties of Carbon Fiber/Polymerization of Monomers Reactants Method Polyimide Composite by Polyimide Sizing.

Carbon fiber (CF)-reinforced polyimide (PI) resin matrix composites have great application potential in areas such as rail transport, medical devices, and aerospace due to their excellent thermal stability, dielectric properties, solvent resistance, and mechanical properties. However, the epoxy sizing agent used for traditional carbon fiber cannot withstand the processing temperature of polyimide resin, of up to 350 °C, resulting in the formation of pores or defects at the interface between the fiber and the resin matrix, leading to the degradation of the overall composite properties. To overcome this problem, in this study, a low-molecular-weight thermosetting polyimide sizing agent was prepared and the processability of the sized carbon fiber was optimized by a thermoplastic polyimide. Compared with the unsized carbon fiber polyimide composites, the interfacial properties of the composites after the polyimide sizing treatment were significantly improved, with the interfacial shear strength (IFSS) increasing from 82.08 MPa to 136.27 MPa, the interlaminar shear strength (ILSS) increasing from 103.7 to 124.9 MPa, and the bending strength increasing from 2262.2 MPa to 2562.1 MPa. The sizing agent acts as a bridge between the carbon fiber and polyimide resin, with anchorage and bonding at the interface between the fiber and resin, which are beneficial for enhancing the interface performance of composites.

Preliminary Evaluation of Nickel Silicide (NiSi12-wt%) Laser Cladding for Enhancing Microhardness and Corrosion Resistance of S355 Steel

S355 construction steel, a commonly used mild steel due to its exceptional strength, is prone to environmental degradation, especially pitting corrosion in highly corrosive marine environments. To address this vulnerability, applying a surface layer of nickel silicide (NiSi) cladding on such components could offer a solution, given that NiSi-based alloys are known for their high corrosion resistance and exceptional mechanical properties. Thus, the present study has investigated the corrosion resistance and microhardness of the NiSi12-wt% cladding deposited onto substrates of S355 steel using laser metal deposition. An accelerated ASTM G48 corrosion test and a Vickers microhardness test were conducted in a solution of 6% ferric chloride (FeCl3) solution at room and elevated temperatures to represent marine environments, with uncladded sheet substrates exposed to the same test environments as a reference. All exposed S355 steel samples, with and without cladding, underwent microhardness testing and were characterized using light optical microscopy (LOM) and low-voltage field emission scanning electron microscopy (LVFESEM). The findings indicate that the NiSi12-wt% cladding significantly enhances the corrosion resistance and mechanical properties of the S355 steel samples, showcasing its potential for use in marine and industrial environments where corrosion and mechanical wear are expected.

Scalable Nickel Catalysts for Carbonylative Terpolymerization of Ethylene/α-Olefin with High Efficiency.

The carbonylative polymerization of olefin yields aliphatic polyketones, which are used as engineering plastics in the market due to their excellent mechanical strength, chemical resistance, and surface and barrier properties. However, the usage of precious palladium catalysts has restricted their extensive application as commodity materials. Herein, we present a series of phosphine-sulfonate Ni catalysts with a wide spectrum of electronic and steric substituents on the phosphorus moiety for the carbonylative polymerization of ethylene. Such efficient nickel-catalyzed copolymerization shows the on-demand transformation of ethylene/CO gas to polyketones with quantitative yield and product specificity. A remarkable productivity of up to 20 kg PK (g Ni)-1 was obtained during ethylene/propylene/CO terpolymerization, and the polymerization productivity is independent of the type and feeding amount of α-olefin. The resulting terpolymers show comparable crystallinity, thermal stability, and tensile properties with commercial POKETONE products from Hyosung. The nickel catalyst also features the advantages of using cheap raw material sources and simple synthetic procedures that can be scaled up easily, which enables it to be a promising candidate for industrial application.

Design and simulation of CsPb.625Zn.375IBr2-based perovskite solar cells with different charge transport layers for efficiency enhancement

In this work, CsPb.625Zn.375IBr2-based perovskite solar cells (PSCs) are numerically simulated and optimized under ideal lighting conditions using the SCAPS-1D simulator. We investigate how various hole transport layers (HTL) including Zn3P2, PTAA, MoS2, MoO3, MEH-PPV, GaAs, CuAlO2, Cu2Te, ZnTe, MoTe2, CMTS, CNTS, CZTS, CZTSe and electron transport layers (ETL) such as CdS, SnS2, ZnSe, PC60BM interact with the devices’ functionality. Following HTL material optimization, a maximum power conversion efficiency (PCE) of 16.59% was observed for the FTO/SnS2/CsPb.625Zn.375IBr2/MoS2/Au structure, with MoS2 proving to be a more economical option. The remainder of the investigation is done following the HTL optimization. We study how the performance of the PSC is affected by varying the materials of the ETL and to improve the PCE of the device, we finally optimized the thickness, charge carrier densities, and defect densities of the absorber, ETL, and HTL. In the end, the optimized arrangement produced a VOC of 0.583 V, a JSC of 43.95 mA/cm2, an FF of 82.17%, and a PCE of 21.05% for the FTO/ZnSe/CsPb.625Zn.375IBr2/MoS2/Au structure. We also examine the effects of temperature, shunt resistance, series resistance, generation rate, recombination rate, current-voltage (JV) curve, and quantum efficiency (QE) properties to learn more about the performance of the optimized device. At 300 K, the optimized device provides the highest thermal stability. Our research shows the promise of CsPb.625Zn.375IBr2-based PSCs and offers insightful information for further development and improvement.

The Effect of p-Toluenesulfonic Acid and Phosphoric Acid (V) Content on the Heat Resistance and Thermal Properties of Phenol Resin and Phenol-Carbon Composite

This work presents the results of research on the influence of the amount of p-toluenesulfonic acid and phosphoric acid (V) added to the phenol-formaldehyde resin (pH 7.3–7.8) on its thermal properties and on the phenol-formaldehyde-carbon composite produced on its basis. This material undergoes pyrolysis under high temperature. The addition of a catalyst to the phenol-formaldehyde resin affects its curing rate and degree of cross-linking, but how it affects the thermal properties of the resin depending on the temperature is the subject of this work. This article presents the results of thermal tests for phenol-formaldehyde resin and phenol-formaldehyde-carbon composite. It was examined how the content of the catalyst used during the production process affects the individual thermal parameters of the mentioned materials. The results include experimental tests of thermal diffusivity with uncertainty (±3%), specific heat capacity (±2.5%), thermal expansion with resolution 2 nm analyzed in the temperature range −40–115 °C and thermogravimetric TG/DTA analysis with resolution 0.03 µg in the temperature range from room temperature (RT = 23 °C) to 550 °C. Individual thermal tests showed changes in the thermal properties caused by changes in the catalyst content of the tested materials and the influence of the addition of carbon fibers on the properties of the composite compared to the pure phenol-formaldehyde resin. It was found that there is a certain maximum level of catalyst weight fraction at which the greatest decrease in thermal diffusivity occurs. In the case of phenolic-formaldehyde-carbon composite at −40 °C, an increase in catalyst weight fraction from 2 to 4 wt% caused a decrease in thermal diffusivity by 18.2%, and for phenol-formaldehyde resin, it was 2.8% with an increase in catalyst fraction from 4 to 10 wt%.

Mechanical Properties and Fire Resistance of 3D-Printed Cementitious Composites with Plastic Waste

The study focuses on the development of cementitious composites using 3D printing and plastic waste as a sustainable aggregate substitute. This study involves experimenting with various percentages of plastic waste as a partial substitute for ground granulated blast furnace slag (GGBFS) in a control mix. The study examines the anisotropy of the 3D printing process, comparing it with properties of mold-cast samples. In addition, it assesses the fire resistance and mechanical properties of samples at elevated temperatures (100 °C, 300 °C, and 600 °C). Key mechanical properties, including 28-day compressive stress and flexural strength, are determined through experimental testing using a standard compression test and three-point bending test. The study also considers the modulus of elasticity (MOE) in compressive tests to evaluate a sample’s ability to deform elastically and the flexural toughness index to assess energy absorption and crack resistance of flexural samples. Following the experimental testing, the study’s key findings suggest that significant mass loss occurred at 300 °C and above, with plastic samples demonstrating increased mass loss at 600 °C. At 600 °C, plastic degradation led to the formation of voids and cracks within samples due to heightened internal pressure. Anisotropy was evident in 3D-printed samples, with loads parallel to the layer direction resulting in greater compressive strength and MOE. Furthermore, layer direction parallel to the longitudinal axis of flexural samples yielded higher flexural strength and flexural toughness. Mold-cast samples displayed superior compressive strength and stiffer behavior, with higher MOE compared to 3D-printed samples. However, 3D-printed plastic samples exhibited superior flexural strength compared to mold-cast samples, attributed to the alignment of plastic within the samples. The study also observed a reduction in compressive strength with the addition of plastic, explained by the poor bonding of plastic with cement due to its hydrophobic nature. Despite this, flexural strength generally improved with plastic addition, except at 600 °C, where plastic samples showed significant degradation in both compressive and flexural strength due to plastic degradation within the samples.

Lightweight, thermally insulating SiBCN/Al2O3 ceramic aerogel with enhanced high-temperature resistance and electromagnetic wave absorption performance

Owing to tunable dielectric properties, light weight and high porosity, polymer-derived SiBCN ceramic aerogels possess significant application prospects in electromagnetic wave (EMW) absorption and thermal insulation. However, due to inadequate oxidation resistance, the structural collapse and performance deterioration of SiBCN aerogels will easily occur in high-temperature aerobic environments, limiting their application. Herein, to address this issue, a novel and straightforward strategy based on typical polymer-derived-ceramic (PDC) aerogel method and impregnation with boehmite sol was proposed for synthesizing SiBCN/Al2O3 composite ceramic aerogels. The microstructure, phase composition, thermal insulation, oxidation resistance and EMW absorption properties of SiBCN/Al2O3 ceramic aerogels were investigated. The resulting SiBCN/Al2O3 composite aerogel demonstrates superior high-temperature structural stability, exhibiting an ultra-low linear shrinkage of only 6.5 % following heat treatment at 1200 °C for 2 h in air. Additionally, the composite aerogel shows a low thermal conductivity of 0.039 W/mK and a low density of 0.112 g/cm3. The SiBCN/Al2O3 composite aerogel, composed of dielectric SiBCN, conductive free carbon, and insulating alumina, demonstrates outstanding EMW absorption properties with a minimum reflection loss of −48.6 dB and an effective bandwidth of 5.8 GHz. The enhanced microwave absorption performance is mainly attributed to the improved impedance matching, multiple reflection, and enhanced interfacial polarization resulting from the introduction of Al2O3. Given prominent oxidation resistance, thermal insulation and EMW absorption properties, the SiBCN/Al2O3 composite aerogel paves the way for developing microwave absorption and thermal insulation integrated material in high-speed vehicles.

Highly electrically conductive polyether composites with modified graphene

Abstract With the continuous improvement in the voltage, power, and capacity levels of high-voltage transmission and substation equipment, the problems of power loss and equipment failure caused by the abnormal heating of electrical contact parts are becoming increasingly severe. In the present study, to address this problem, graphite was exfoliated into thin layers of graphene using liquid-phase mechanical exfoliation, ultrasonic dispersion, and spray-drying techniques and incorporated into polyether composites to increase its electrical conductivity. The effects of the graphene content on the electrical conductivity, high-temperature resistance, wear reduction, and antiwear properties of the polyether composites were investigated. The results indicated that when 4 wt% graphene was added, the high-temperature resistance of the graphene–polyether composite (GPC) increased to 330 °C, and the volume resistivity decreased to 6.5 × 103 Ω·cm. Moreover, the contact-resistance coefficient of the GPC was reduced to 0.87 and 0.73 after it was coated on Cu and Al rows, respectively, which significantly increased the electrical conductivity of the electrical contact area. The most significant improvements in friction-reduction and antiwear properties were obtained for the polyether composites from this formulation. GPC has excellent electrical conductivity, high-temperature resistance, wear reduction, and antiwear properties and thus can substantially improve the quality of electrical connections when applied to electrical contact tips.

Highly corrosion-resistant and photocatalytic hybrid coating on AZ31 Mg alloy via plasma electrolytic oxidation with organic-inorganic integration

This study explores the development of an organic-inorganic hybrid coating to enhance the corrosion resistance and photocatalytic properties of AZ31 Mg alloy modified by plasma electrolytic oxidation (PEO). The PEO process typically generates a porous oxide layer, which can reduce corrosion protection by allowing corrosive agents to penetrate the substrate. To address this limitation, phenopyridine (PHEN) and 2-methylimidazole (2-IMD) were incorporated into the PEO surface to form a robust organic layer on the Mg alloy. Potassium hydroxide (KOH) was used to adjust the pH, improving the interaction and solubility between the organic molecules and the PEO coating. The hybrid coating exhibited unique twig-like surface structures that contributed to forming a multifunctional coating with high corrosion resistance and superior photocatalytic activity. The PEO-PHEN-2IMD sample on the Mg alloy demonstrated exceptional corrosion resistance, with the lowest corrosion current density (Icorr) of 1.92 × 10-¹⁰ A/cm², a high corrosion potential (Ecorr), and the highest top layer resistance (Rtop) of 2.57 × 106 Ω·cm², indicating excellent barrier properties. Additionally, the coating achieved complete (100%) degradation of methylene blue (MB) within 30 min under visible light. Density Functional Theory (DFT) calculations provide deeper insights into the bonding mechanisms and interaction stability between PHEN, 2-IMD, and the PEO layer on the Mg alloy and MB dye. These findings confirmed the enhanced performance of the hybrid coating in both corrosion resistance and photocatalytic applications.