Thermal Durability Research Articles

Liquid Metal‐MXene‐Based Hierarchical Aerogel with Radar‐Infrared Compatible Camouflage

AbstractAs military power advances in the realm of information warfare, stealth technology has become a critical area of research for its effectiveness to evade detection. However, achieving high performance of compatible stealth across different functional mode bands remains a significant challenge. In this study, drawing inspiration from plant bionics, concepts of the directional freezing process are applied to develop a liquid metal‐MXene‐based hierarchical aerogel with radar‐infrared compatible camouflage. With a density of only 4.4 mg cm−3, the maximum reflection loss can reach −73.2 dB, and the absorption bandwidth can be adjusted up to 7 GHz. Following a thermal camouflage durability test, the sample successfully lowers the target's temperature from 400 to ≈160 °C. Remarkably, this temperature remains stable even after 180 days of exposure. Additionally, the material's ease of machining enables shape‐shifting camouflage capabilities, allowing objects to transform and resemble harmless items, thereby blending seamlessly with their surroundings. This breakthrough in compatibility performance signifies a substantial leap forward in multifunctional stealth technology development. It not only introduces innovative concepts, but also provides technical support, catalyzing further advancement in this field.

Bio-inspired structural coloration of carbon fiber based on thin film interference: Synergistically enhancing thermal durability, tensile strength and interface properties of colored fiber

Carbon fiber (CF) is inert to dyes or pigments, thus its products usually exhibit a drab black and unexciting look. The bio-inspired structural coloration may provide a dye-free method to color CF. Herein, inspired by the interference colors of the insect's wing, a dye-free structural coloration method is proposed to color CF. A layer of poly(cyclotriphosphazene-co-4,4′-oxydianiline) film is assembled on the CF surface by in situ polymerization under a mild reaction condition, creating vivid colors based on thin film interference. Moreover, the structural color shows excellent thermal durability due to the good thermo‑oxygen stability of NP heterocycles and cross-linked networks in coloration film. Furthermore, the tensile strength of colored CF and the interfacial adhesion between colored CF and resin are also synergistically improved by 17.1% and 48.7%, respectively, because of the sturdiness and surface chemical activity of coloration film. In brief, the colored CF may have potential in designing and preparing new structural and functional composites.

Thermal stability and durability of solar salt-based nanofluids in concentrated solar power thermal energy storage: An approach from the effect of diverse metal alloys corrosion

Concentrated Solar Power (CSP) technology has witnessed substantial growth, with forecasts predicting an increase of 3.4 GW between 2019 and 2024. This expansion necessitates the installation of energy storage systems to meet the growing demand. Solar molten salts, specifically a mixture of 60 % NaNO3 and 40 % KNO3, have emerged as the primary thermal energy storage (TES) medium in commercial CSP plants. However, a significant challenge lies in the corrosive nature of molten salt at high temperatures, which poses limitations in TES applications. The literature has explored a promising solution: reducing corrosion rates by incorporating nanoparticles into molten salts, creating nanofluids. To assess the viability of nanofluids for CSP, it is essential to understand how they perform under working conditions, especially regarding their thermal stability and durability. This study presents further evidence of nanofluid interactions with component materials under static working conditions. Specifically, focus on the impact of corrosion products precipitated during corrosion tests on the physical and thermal properties of Solar Salt-based silica dioxide nanofluids. In this research, nanofluids in contact with stainless steel, nickel‑chromium alloy, and carbon steel were examined before and after subjecting them to a 90-day thermal exposure at 500 °C. These findings provide valuable data on key thermo-physical properties during service, contributing to the design of more precise TES systems and enhancing their overall efficiency and effectiveness.

A Decadal Review and Understanding of Light Weight Concrete (LWC) - Its Mechanical Properties, Temperature Effect and Durability Studies

The idea of Light Weight Concrete (LWC) in the construction industry and its technological development is not entirely a new age methodology, it has been a very old technique with enhanced features. This review paper focuses on the evolution of LWC as a mere construction in ship building to bridges and to other forms of construction components. With its wide range of applications, LWC almost fits in a number of challenging construction projects. This review is based on the last decade especially focussing on the materials and the wastes used in the construction industry providing new arena to explore in LWC. Most of the important studies carried out are carefully taken into consideration. There might be number of challenges involved in practical experience especially while handling different LWC in the field. Some of them are discussed on the paper before dwelling to the studies of mechanical properties of LWC, their thermal properties and durability studies when different materials are used to create LWC.

Review: chitosan-based biopolymers for anion-exchange membrane fuel cell application.

Chitosan (CS)-based anion exchange membranes (AEMs) have gained significant attention in fuel cell applications owing to their numerous benefits, such as environmental friendliness, flexibility for structural alteration, and improved mechanical, thermal and chemical durability. This study aims to enhance the cell performance of CS-based AEMs by addressing key factors including mechanical stability, ionic conductivity, water absorption and expansion rate. While previous reviews have predominantly focused on CS as a proton-conducting membrane, the present mini-review highlights the advancements of CS-based AEMs. Furthermore, the study investigates the stability of cationic head groups grafted to CS through simulations. Understanding the chemical properties of CS, including the behaviour of grafted head groups, provides valuable insights into the membrane's overall stability and performance. Additionally, the study mentions the potential of modern cellulose membranes for alkaline environments as promising biopolymers. While the primary focus is on CS-based AEMs, the inclusion of cellulose membranes underscores the broader exploration of biopolymer materials for fuel cell applications.

MAX, MXene, or MX: What Are They and Which One Is Better?

The fast ever-growing interest in transition metal carbonitrides (MXenes) for energy and catalysis is undermined by the undesirable multi-surficial terminations, which severely limit their applications. In contrast, considering the intriguing and tunable electronic structure, rich surface active sites, and high thermal durability, termination-free MXene (MX) hosts a huge possibility for catalysis. As such, recent advances in the evolution from MAX to MXene, and then to MX are overviewed and compared briefly, before concentrating on the unique future of MX in multi-heterogeneous catalysis. This work also looks beyond the fundamental properties of MX and discusses the potential of such materials for applications in multi-electron redox reactions. It is convinced that the potential success of MX in future catalysis is promising. Further extension toward high entropy and single-atom modifications will consolidate the leading position of MX in catalysis.

Optimal battery thermal management for electric vehicles with battery degradation minimization

The control of a battery thermal management system (BTMS) is essential for the thermal safety, energy efficiency, and durability of electric vehicles (EVs) in hot weather. To address the battery cooling optimization problem, this paper utilizes dynamic programming (DP) to develop an online rule-based control strategy. Firstly, an electrical–thermal-aging model of the LiFePO4 battery pack is established. A control-oriented onboard BTMS model is proposed and verified under different speed profiles and temperatures. Then in the DP framework, a cost function consisting of battery aging cost and cooling-induced electricity cost is minimized to obtain the optimal compressor power. By exacting three rules ”fast cooling, slow cooling, and temperature-maintaining” from the DP result, a near-optimal rule-based cooling strategy, which uses as much regenerative energy as possible to cool the battery pack, is proposed for online execution. Simulation results show that the proposed online strategy can dramatically improve the driving economy and reduce battery degradation under diverse operation conditions, achieving less than a 2.18% difference in battery loss compared to the offline DP. Recommendations regarding battery cooling under different real-world cases are finally provided.

Characteristics of Cs pollucite synthesized at various Cs loadings for immobilization of radioactive Cs

Radioactive Cs is an important fission product known for the generation of a large amount of heat. Several ceramic matrices have been proposed to effectively immobilize radioactive Cs. Among them, pollucite stands out owing to its exceptional thermal and structural durability, low solubility in water, and high Cs retention. This investigation focused on the preparation and assessment of an appropriate precursor for a waste form tailored to the disposal of Cs-loaded silica–alumina (SA) filters. We synthesized simulated Cs-loaded SA filters and transformed them via calcination into a Cs pollucite (CsAlSi2O6) phase. To investigate the influence of Cs loading, five samples with different ratios of the Cs precursor and matrix were synthesized and subsequently subjected to characterization and chemical durability assessment. Depending on the Cs content, the calcination process led to a phase transformation, resulting in the formation of CsAlSiO4 and/or Cs pollucite (CsAlSi2O6). Following calcination, the degree of crystallinity of the samples increased, and in certain instances, their surfaces were covered with agglomerated particles. Building upon prior research, chemical equations elucidating the phase transformation of both the matrix material and Cs pollucite (CsAlSi2O6) were formulated. The chemical durability of the samples was evaluated via the product consistency test-A method. The lowest Cs leaching rate was 3.86 × 10−4 g/m2·day for the sample comprising a Cs2O/matrix ratio of 0.2 and calcined at 1200°C. The high leaching rates observed in certain P-1200 samples can be attributed to the presence of CsAlSiO4. The leaching behavior of Al resembled that of Cs. The leaching rate of Si remained consistent across the samples heat treated at 1200°C (P-1200), and it was lower than those of samples calcined at 1000°C (P-1000). P-1200 is expected to be a suitable precursor of the waste form tailored to Cs immobilization.

Evaluation of Polyurethane Foam Derived from the Liquefied Driftwood Approaching for Untapped Biomass

Nowadays, climate change has become a serious concern, and more attention has been drawn to utilizing biomass sources instead of fossil sources and how petroleum chemical plastics should be reduced or replaced with bio-based materials. In this study, the optimized condition of liquefaction of driftwood was examined. There was a concern that driftwood might have some decay and chemical change. However, according to the Organic Micro Element Analyzer (CHN analyzer) test and Klason lignin and Wise methods, the results proved that lignin content (37.5%), holocellulose content (66.9%), and CHN compositions were very similar to regular wood. The lowest residue content of bio-polyols was produced using liquefaction conditions of 150 °C, reaction time of 180 min, catalyst content of 10%w/w, and 12.5%w/w driftwood loading. Polyurethane foam (PUF) derived from the liquefaction of driftwood and bio-based cyanate was prepared. The PUF prepared from the liquefaction of the driftwood exhibited slightly decreased thermal durability but was superior in terms of 3-time faster biodegradation and 2.8-time increased water adsorption rate compared to pure petroleum-based PUF. As a result, it was shown that driftwood can be identified as a biomass resource for biodegradable PUF.

A review of the factors that influence aging and degradation in crosslinked polyethylene (XLPE) polyolefin

In today's world, the use of products made of crosslinked polyethylene (XLPE) is critical. The total share of polyethylene accounts for more than 40% of the entire commercial plastics market. Polyethylene is the most widely used because of its low cost and ease of processing. However, at high temperatures, simple polyethylene loses its physical properties, limiting its application. The crosslinking of polyethylene is done to preserve the desired properties of the material while also acquiring new qualities. XLPE is the densest of polyethylene materials and has superior technical and operating properties due to its polymer base and molecular structure. XLPE has several distinct properties, including thermal resistance, durability, chemical resistance, and resistance to stress fracture, low dielectric losses, high resistance to microorganisms, and many others, which have allowed its products to be used in the majority of modern human activities. This study aims to review the performance of crosslinked polyethylene (XLPE) insulation and factors influencing changes in its properties during the service.

Novel Diffusion‐Regulated Layering Methodology to Improve Blend Miscibility and Thermal Stability of Organic Photovoltaics

AbstractExtensive research on bulk‐heterojunction (BHJ) optimization has advanced organic photovoltaics (OPVs). However, the need for research addressing the issue of morphological instability and ensuring long‐term durability remains a priority. Herein, a diffusion‐governed morphological modification methodology via a sequential deposition (SD) process comprising ternary components with low miscibility is demonstrated. Sequential coating of a high glass transition temperature (Tg) material and a host binary blend induces a concentration difference between successively coated layers, allowing for effective blending of immiscible materials during solvent evaporation. The enhanced miscibility of the SD‐processed BHJ layer facilitates molecular interactions between the high Tg material and the host materials, thereby increasing the Tg of the BHJ blend. The SD‐processed OPVs exhibit superior photovoltaic performance and suppressed glass transition under thermal stress compared to reference OPVs fabricated via a conventional method. After 500 h of thermal aging at 85 °C, the SD‐BHJ OPV retains over 80% of its initial efficiency, whereas the reference device shows a drastic drop to below 80% of its initial efficiency after only 80 h. This study provides a step toward efficient, long‐term stable OPVs by overcoming the limitations of blend miscibility and poor thermal durability of conventional BHJ systems via a SD process.

Physicochemical and Biochemical Characterization of Collagen from Stichopus cf. horrens Tissues for Use as Stimuli-Responsive Thin Films.

The mutable collagenous tissue (MCT) of sea cucumber, with its ability to rapidly change its stiffness and extensibility in response to different environmental stress conditions, serves as inspiration for the design of new smart functional biomaterials. Collagen, extracted from the body wall of Stichopus cf. horrens, a species commonly found in the Philippines, was characterized for its suitability as stimuli-responsive films. Protein BLAST search showed the presence of sequences commonly found in type VII and IX collagen, suggesting that Stichopus horrens collagen is heterotypic. The maximum transition temperature recorded was 56.0 ± 2 °C, which is higher than those of other known sources of marine collagen. This suggests that S. horrens collagen has better thermal stability and durability. Collagen-based thin films were then prepared, and atomic force microscopy (AFM) imaging showed the visible collagen network comprising the films. The thin films were subjected to thermomechanical analysis with degradation starting at >175 °C. At 100-150 °C, the collagen-based films apparently lose their translucency due to the removal of moisture. Upon exposure to ambient temperature, instead of degrading, the films were able to revert to the original state due to the readsorption of moisture. This study is a demonstration of a smart biomaterial developed from S. cf. horrens collagen with potential applications in food, pharmaceutical, biomedical, and other collagen-based research.

Thermochromic microencapsulated phase change materials for cold energy storage application in vaccine refrigerator

The development of pharmaceutical cold chain logistics calls for thermochromic microencapsulated phase change materials (TC-MPCMs) to fit the demand of temperature indication and low temperature (2–8 °C) cold storage. In this study, TC-MPCMs for low temperature were constructed by encapsulating crystal violet lactone (CVL), bisphenol A (BPA) and n-tetradecane & n-dodecanol (aliphatic compound) binary system into melamine-formaldehyde (MF) resin. The effects of emulsifier type, n-dodecanol content, and core/shell ratio on the performance of TC-MPCMs were investigated. Results indicate that TC-MPCMs with SMA: gelatin ratio of 2:1 exhibit the best morphology and uniform dispersion, with particle size distribution between 4.5 μm and 19.5 μm. TC-MPCMs with 25 wt% 12OH and core/shell of 1.85 demonstrate excellent property in terms of the encapsulation efficiency, melting enthalpy and color difference, which are 67.80 %, 169.90 J/g and 23.39, respectively. Synthesized TC-MPCMs present outstanding thermal durability during 100 thermal cycles and have an appreciable thermal stability at temperature not exceeding 96 °C. The vaccine refrigerator was designed which can maintain a low temperature (2–8 °C) for 12.8 min.

Flux-Assisted Synthesis of Y2 Ti2 O5 S2 for Photocatalytic Hydrogen and Oxygen Evolution Reactions.

Photocatalytic water splitting is an ideal means of producing hydrogen in a sustainable manner, and developing highly efficient photocatalysts is a vital aspect of realizing this process. The photocatalyst Y2 Ti2 O5 S2 (YTOS) is capable of absorbing at wavelengths up to 650 nm and exhibits outstanding thermal and chemical durability compared with other oxysulfides. However, the photocatalytic performance of YTOS synthesized using the conventional solid-state reaction (SSR) process is limited owing to the large particle sizes and structural defects associated with this synthetic method. Herein, we report the synthesis of YTOS particles by a flux-assisted technique. The enhanced mass transfer efficiency in the flux significantly reduced the preparation time compared with the SSR method. In addition, the resulting YTOS showed improved photocatalytic H2 and O2 evolution activity when loaded with Rh and Co3 O4 co-catalysts, respectively. These improvements are attributed to the reduced particle size and enhanced crystallinity of the material as well as the slower decay of photogenerated carriers on a nanosecond to sub-microsecond time range. Further optimization of this flux-assisted method together with suitable surface modification is expected to produce high-quality YTOS crystals with superior photocatalytic activity.

Flux‐Assisted Synthesis of Y2Ti2O5S2 for Photocatalytic Hydrogen and Oxygen Evolution Reactions

AbstractPhotocatalytic water splitting is an ideal means of producing hydrogen in a sustainable manner, and developing highly efficient photocatalysts is a vital aspect of realizing this process. The photocatalyst Y2Ti2O5S2 (YTOS) is capable of absorbing at wavelengths up to 650 nm and exhibits outstanding thermal and chemical durability compared with other oxysulfides. However, the photocatalytic performance of YTOS synthesized using the conventional solid‐state reaction (SSR) process is limited owing to the large particle sizes and structural defects associated with this synthetic method. Herein, we report the synthesis of YTOS particles by a flux‐assisted technique. The enhanced mass transfer efficiency in the flux significantly reduced the preparation time compared with the SSR method. In addition, the resulting YTOS showed improved photocatalytic H2 and O2 evolution activity when loaded with Rh and Co3O4 co‐catalysts, respectively. These improvements are attributed to the reduced particle size and enhanced crystallinity of the material as well as the slower decay of photogenerated carriers on a nanosecond to sub‐microsecond time range. Further optimization of this flux‐assisted method together with suitable surface modification is expected to produce high‐quality YTOS crystals with superior photocatalytic activity.

Thermal and durability characteristics of optimized green concrete developed using slag powder and pond ash

Due to the vast development in the infrastructure section, the production of cement-based concrete is a major driving source for the increased global warming and extensive deployment of natural resources such as river sand. To reduce and mitigate these adverse effects, industrial by-products can be effectively used either in partial or complete levels to replace conventional materials such as cement, river sand, etc without compromising the strength and durability characteristics of concrete. This research work focuses on the experimental investigation of the thermal properties, strength, durability and microstructure analysis of optimized green concrete with pond ash and ground granulated blast-furnace slag (GGBS). The novelty of the proposed work lies in the investigation of the thermal and durability characteristics of sustainable green concrete with GGBS and pond ash as a partial replacement for cement and fine aggregate respectively. An optimum mix ratio obtained from the material characterization of 16 trail mixes was tested for mechanical properties, durability and thermal characterization. Moreover, the microstructure analysis of the optimized mix was performed using Scanning Electron Microscope (SEM) to overview the chemical constituents, bonding of molecules at the interfacial transition zone (ITZ), the effect of elevated temperature, etc Results from the trail mixes revealed that the replacement of 30% GGBS and 20% pond ash increased the compressive strength by 8% at 28 days of curing when compared to the control mix. In addition, a detailed multilinear regression analysis was performed and a new equation was proposed to determine the compressive strength of concrete with GGBS and pond ash. The predictions obtained from the proposed equation showed a good match with the benchmark experiments.

TC@MF phase change microcapsules with reversibly thermochromic property for temperature response and thermoregulation

A series of reversibly thermochromic phase-change microcapsules (TC@MF), demonstrating excellent energy storage and release properties, were synthesized using melamine formaldehyde resin (MF) encapsulated ternary complex consisting of crystal violet lactone (CVL), 2,2-Di-(4-hydroxyphenyl) propane (BPA), and n-hexadecanol. The microstructure, chemical composition, thermal storage capacity, thermal cycling durability, discoloration effect, and thermal regulation performance of TC@MF with different core contents were investigated in detail. With core contents gradually increasing, the chromatic aberration values (ΔE) value of TC@MF increased from 38.23 to 71.69, the melting enthalpy (ΔHm) gradually increased from 180.2 J/g to 218.6 J/g while the leak-proof performance decreased gradually. The TC@MF-2 with the best comprehensive performance has exhibited superior latent heat storage (ΔHm = 192.2 J/g), high chromatic aberration values (ΔE = 57.31), and well leak-proof properties (5.61 %). Furthermore, the thermal performance, morphology, and reversible color reliability of TC@MF-2 remained stable through 100 thermal heating and cooling cycles, demonstrating excellent thermal cycling stability. In summary, such multifunctional microcapsules can directly reflect the energy saturation and depletion states in phase change material applications through color changes. That might be conducive to expanding the value of its practical application in the field of latent heat energy storage, including smart fabrics or fibers, commodity packaging, thermal sensors, reversible thermochromic coatings and solar energy storage, and so on.

Optimization of Segmented Thermal Barrier Coatings (s-TBCs) for High-Temperature Applications

AbstractHot section components of stationary gas turbines, such as turbine blades and vanes, are coated with thermal barrier coatings (TBCs) to increase the component life. TBCs provide thermal insulation to the metallic components from hot gas in the gas turbines. The TBCs represent high-performance ceramics and are mainly composed of yttria-stabilized zirconia (YSZ) to fulfill the thermal insulation function. The microstructure of the TBCs should be porous to decrease heat conduction. Besides the porous TBCs, the subsequently developed vertically segmented thermal barrier coatings (s-TBCs) feature outstanding thermal durability. For the formation of this segmented coating microstructure, the YSZ should be deposited under high thermal tensile stress during the coating process. Therefore, substrates are heated just before the coating by plasma or in an oven in recent research. In this work, the development of process parameters for s-TBCs produced by atmospheric plasma spray (APS) without pre-heating is presented. Within the experiments, the relevant process parameters, such as plasma gases, powder feed rate, surface speed, and pathway strategy, have been optimized to achieve the segmented coating microstructure with high deposition efficiency by a conventional plasma torch. Furthermore, YSZ powders used in this study are characterized, and the effect of powder characteristics on the coating microstructure is investigated. The coating microstructure in this work aims to achieve the formation of a high number of vertical cracks with a combination of low internal residual stress and high adhesive tensile strength for the s-TBCs.

Thermally Stable Apatite-type La10Si5CoO27−δ Catalyst for Toluene Combustion

Abstract A noble metal-free apatite-type La10Si5CoO27−δ catalyst with high thermal durability for toluene combustion has been prepared via coprecipitation followed by calcination at 1000 °C. It completely oxidized toluene at 310 °C, which was comparable to that of 0.1 wt % Pt/Al2O3 calcined at 1000 °C (290 °C). Furthermore, La10Si5CoO27−δ exhibited high catalytic activity even after calcination at 1400 °C via a solid-state reaction route, and the complete oxidation of toluene was realized at 330 °C, lower than that of 0.1 wt % Pt/Al2O3 calcined at 1400 °C (380 °C).

Sintering of Protonic Ceramics for Tubular Solid Oxide Fuel Cells

Protonic ceramics are considered to be the most promising candidates for intermediate-temperature solid oxide fuel cells (SOFCs) owing to their high proton conductivity and competitive electrochemical performance at intermediate temperatures (typically 500–700 °C). However, the fabrication of proton-conducting SOFCs has been challenging mainly due to the poor sinterability of common proton-conducting electrolyte materials. Significantly high sintering temperatures (1500–1600 °C) and long sintering times (up to 24 h) have been reported for obtaining dense, gas-tight proton-conducting electrolytes. These sintering conditions may lead to undesirable interfacial reactions and dense electrode microstructures, thereby limiting the cell performance. The present work focuses on optimizing the co-sintering temperature of tubular SOFCs with a traditional Ni–yttria-stabilized zirconia (YSZ) anode support and proton-conducting functional layers. BaZr0.3Ce0.5Y0.2O3 (BZCY), Ni–BZCY, and BZCY–BaCo0.4Fe0.4Ce0.1Y0.1O3 were used as the electrolyte, anode functional layer, and cathode, respectively. Various approaches to lowering the co-sintering temperature and resulting cell performances will be discussed. We will also examine the thermal cycling behavior and durability of the fabricated protonic SOFCs.