Harsh Environment Applications Research Articles

Superhydrophobic anti-icing/de-icing SR/CNTs surfaces hot-embossed with femtosecond laser machined mold

Anti-icing/de-icing surfaces are dispensable in reducing accidents and economic losses caused by accumulated ice and frost on outdoor facilities in cold and humid environments. In this work, a low-cost, reproducible process was presented to fabricate superhydrophobic anti-icing/de-icing surfaces. For this purpose, concave micro-structures were firstly created on the mold steel surface using femtosecond laser machining, and then the corresponding convex micro-structures were prepared on the surface of a silicone rubber (SR) composite mixed with multi-wall carbon nanotubes (CNTs) using hot embossing. Thanks to the presence of unique micro-scale peak-ridge structures, the as-prepared SR/CNTs surfaces possess superhydrophobic characteristic. Long icing delay time was endowed by the large volume of air pockets inside micro-structures, and the icing time was significantly extended from 67 to 416 s, which is ascribed to the greatly inhibited heat transfer between the droplet and the surface. Moreover, the SR/CNTs surface had excellent photothermal conversion capability with the presence of photothermal particles CNTs, and the temperature of the surface increased rapidly from 21.6 to 86.1 °C in 5 min under a standard sunlight irradiation. In addition, the SR/CNTs surface also possesses superior photothermal defrosting and de-icing performance as the ice and frost on the surface can be quickly melted under a standard sunlight intensity irradiation and the de-icing rate is up to 0.92 mg/s. Finally, the good reusability of the mold steel and the resistance to mechanical wear and chemical corrosion of superhydrophobic SR/CNTs surface found in this work make the proposed approach promising for industrial mass production and anti-icing/de-icing applications in harsh environments.

Two-dimensional photonic crystal acetylcholinesterase hydrogel and organohydrogel sensors for efficient detection of organophosphorus compounds

Sensors capable of detecting organophosphorus (OP) compounds have attracted the most attention owing to severe OP contamination worldwide. Despite many years of research, the developed OP sensors mainly focused on detecting water-soluble OPs in proper environments and the exploration of OP sensors suitable in resource-limited areas is extremely challenging. Here, a simple two-dimensional photonic crystal (2D PC) hydrogel featuring capabilities of effectively quantitative determination of OP compounds is facilely constructed by immobilizing the enzyme acetylcholinesterase (AChE) onto a bovine serum albumin (BSA) protein hydrogel. Owing to the specific interaction between AChE and OP compounds, the OP compounds are easily bound to the hydrogel, triggering volume phase transition and resulting in apparent Debye diffraction ring variations. The resulting hydrogel sensors show a limit of detection (LoD) of 2.23 nM for trichlorfon and 0.07 nM for diethyl methylphosphonate (DMPP), respectively. On the basis of the hydrogel, a responsive organohydrogel is facilely fabricated utilizing a solvent exchange strategy to meet the requirements of applications in harsh environments and detection of the non-water-soluble OP compounds. The organohydrogel sensors, however, demonstrated a LoD of 0.70 μM for trichlorfon and 4.46 μM for DMPP, respectively. This work provides new light on the development of next-generation stable, low-cost, and portable field sensing devices.

A Scalable Fully Printed Organic Thermoelectric Generator for Harsh Environments Enabled by a Stable n‐type Polymer

AbstractAffordable and versatile power sources become crucial as miniaturized electronics and sensors become more widespread. Organic thermoelectric generators (TEGs), capable of tapping into wasted heat sustainably and economically, are viewed as key enablers for powering the sensor networks of the future. Until recently, the performance of n‐type organic thermoelectric materials has severely lagged behind their p‐type counterparts. However, reports of a stable and highly conductive n‐type polymer, poly(benzodifurandione) (PBFDO), are changing this notion. Nonetheless, validation of PBFDO as a suitable ink for scalable fabrication processes and integration of the material into a scalable organic TEG have yet to be demonstrated. This work presents the development, characterization, and optimization of a PBFDO ink for use in a scalable inkjet printing process. The n‐type ink is then integrated into a screen‐printed origami‐inspired architecture, resulting in a 21‐leg PEDOT:PSS/PBFDO organic TEG capable of delivering a record‐high normalized power density among reported polymer‐based TEGs of 0.718 nW cm−2 K−2. Moreover, the module ambient stability is demonstrated for up to 90 d, while its use for potential applications in harsh environments is validated for a temperature range of ‐8 °C to 200 °C and up to 90% relative humidity, a first for organic TEGs.

Multiscale textured solar absorber coatings for next-generation concentrating solar power

A high-temperature stable solar absorber is crucial for next-generation (Gen3) concentrating solar power (CSP) plants, to enable high temperature operation, maximize power generation efficiency, and thereby reduce the levelized cost of energy. This study presents novel, fractal-textured solar absorber coatings whose multiscale feature scales effectively match the visible region of the solar spectrum, leading to superb absorptive properties. Single and bimetallic oxide coatings of copper, cobalt and manganese were prepared on Inconel 625 substrates using electrodeposition. The effect of electrodeposition parameters and annealing temperature are systematically studied to optimize the morphology and properties of the oxide coatings. Multiscale textured bimetallic coatings of copper manganese oxide and copper cobalt oxide demonstrate a superior absorptance of 0.985, a remarkably low emittance <0.45 and an exceptional optical efficiency of ∼96 % under Gen3 CSP operating conditions, surpassing previously reported values in the literature by about 5 %. Durability tests confirmed the coatings’ steadfast endurance of mechanical and environmental stress, making them suitable for long-term application in harsh CSP environments.

Improved wear and corrosion resistance of additively manufactured SS316L by laser remelting process

Directed energy deposition is an efficient and flexible additive manufacturing technique that has broad application prospects due to its ability to fabricate intricate structures with heterogeneous properties. In this study, the laser-based directed energy deposition (L-DED) technique is employed to deposit an austenitic stainless steel 316L powder at a significantly high deposition rate. In recent developments, laser remelting (LR) has been explored as a superior alternative for enhancing the surface integrity of the components produced by L-DED. This study endeavours to examine the impacts of LR, emphasizing the improvement of wear and corrosion resistance. The grain refinement is achieved through laser remelting, which eventually leads to a 34 % improvement in micro–hardness over the as-deposited sample; as a result of increased micro–hardness, wear resistance improved by 66 % when compared to the as-deposited specimen. Furthermore, the corrosion resistance performance of the laser-remelted samples is compared with as-deposited samples by electrochemical impedance spectroscopy (EIS) in a solution of 3.5 % NaCl solution. The remelted sample showed improved corrosion resistance, which is attributed to the grain refinement due to rapid solidification in LR. This study demonstrates that laser remelting can be an effective way to improve the wear and corrosion resistance of SS316L, which enlarges its application in harsh environments.

3D-printed redox-active polymer electrode with high-mass loading for ultra-low temperature proton pseudocapacitor

The stable operation of supercapacitors at extremely low temperatures is crucial for applications in harsh environments. Unfortunately, conventional inorganic electrodes suffer from sluggish diffusion kinetics and poor cycling stability for proton pseudocapacitors. Here, a redox-active polymer poly(1,5-diaminonaphthalene) is developed and synthesized as an ultrafast, high-mass loading, and durable pseudocapacitive anode. The charge storage of poly(1,5-diaminonaphthalene) depends on the reversible coordination reaction of the C=N group with H+, which enables fast kinetics associated with surface-controlled reactions. The 3D-printed organic electrode delivers a remarkable areal capacitance (8.43 F cm–2 at 30.78 mg cm−2) and thickness-independent rate performance. Furthermore, the 3D-printed proton pseudocapacitor exhibits great low-temperature tolerance and delivers a high energy density of 0.44 mWh cm−2 at −60 °C, as well as operates well even at −80 °C. This work signifies that combining organic material design with 3D hierarchical network electrode construction can provide a promising solution for low-temperature-resistant supercapacitors.

Effect of non-static pre-oxidation treatment on the cyclic ablation behavior of SiC-ZrC/SiC multilayer coated graphite

SiC-ZrC based ceramics have caught much attention as coatings for graphite materials. However, the coefficient of thermal expansion (CTE) mismatch between coatings and matrix severely limits their application in harsh environments. Herein, we proposed a non-static pre-oxidation treatment under an air pressure of 0.05 MPa to increase the surface roughness of graphite matrix to 18.054 μm and then prepared the SiC-ZrC/SiC multilayer coating on the pre-oxidized graphite. The results demonstrate that a firm interlocking structure was formed between SiC-ZrC/SiC multilayer coating and graphite matrix, which effectively improved the bonding strength and enhanced the cyclic ablation resistance of coatings. The bonding strength of SiC-ZrC/SiC multilayer coated on graphite pre-oxidized under negative pressure was 5.70±0.42 MPa, which was 54.89% higher than that on graphite pre-oxidized under atmospheric pressure (3.68±0.08 MPa). After the plasma ablation for 360 s (60 s × 6), the linear and mass ablation rates of SiC-ZrC/SiC multilayer coated graphite which was pre-oxidized under negative pressure were -0.083 μm/s and 0.101 mg/s, respectively.

Synthesis-in-place of V2O5 nanobelts for wide range humidity detection

Resistive type humidity sensors offer advantages in simplicity, low cost, compact size, and remote operation. Due to the benefits, they have great potential for use in a variety of environments and future applications, including the Internet of Everything (IoE). However, resistive humidity sensors have limitations in detecting extreme humidity levels below 10 % or above 90 % relative humidity (RH) and are also vulnerable to high temperatures, which hinders their use in harsh environments applications. For broader applications, humidity sensors with reliable performance across the full range of humidity levels and high stability at elevated temperatures need to be developed. Here, we report high performance resistive humidity sensors based on V2O5 nanobelts operating at high temperatures. The V2O5 nanobelts are directly deposited between Pt electrodes by O2-assisted physical vapor transport (PVT) method. The V2O5 nanobelt humidity sensor exhibits reliable humidity sensing properties over a wide range from 1 % to 100 % RH. Furthermore, long-term stability and reproducibility of V2O5 nanobelts are demonstrated through 25 consecutive humid air pulses and measurements obtained after 4 months of storage. The high performance of the V2O5 nanobelt humidity sensor is advantageous for practical use in applications ranging from IoE environments to harsh industrial conditions.

Architecturing ultra-stable multi-dimensional MXene/MAX self-supporting electrode anchored with Low-Pt for efficient hydrogen evolution reaction in harsh environments

The design of self-supporting structure is particularly important to improve the stability and electrochemical performance of hydrogen evolution reaction electrode. Here, a facile strategy for building novel ultra-stable 0D-2D-3D integrated self-supporting electrode with high conductivity, sufficient diffusion channels and large reactive surface area was proposed. In the heterostructure, 2D Ti3C2Tx flakes in-situ synthesized on 3D network porous Ti3AlC2 surface which provides the multiple reactive surface areas and aggregation resistance to facilitating 0D ultrafine Pt nanoparticles uniform anchorage. Combined with structural characterization and first-principles calculations revealed that, the highly dispersed ultrafine Pt synergistically coupling strong metal-support interactions creates a unique multifunctional catalytic interface with high stability and atomic utilization efficiency of Pt to promote the HER in acidic and seawater. The resultant self-supporting electrode (support 0.48 wt% Pt) exhibits much superior activity to 10 % commercial Pt/C (loaded on foam nickel) in 0.5 M H2SO4 (55 mV@10 mA cm−2) and simulate seawater (196 mV@10 mA cm−2) while reducing the Pt usage by 15 times. Meanwhile, the electrode also illustrates outstanding stability under high current densities (100 h@100 mA cm−2). This study provides a new design idea for developing integrated self-supporting catalytic electrodes to meet the durability of hydrogen evolution reaction applications in harsh environments.

Tb-doped borosilicate glass scintillators with high thermal stability for high-resolution X-ray imaging

Scintillators with high thermal stability and excellent spatial resolution are desirable for X-ray imaging applications in harsh environments. Here, Tb3+-doped borosilicate glass scintillators were prepared using conventional melt-quenching method. The optimized Tb3+-doped borosilicate glass (G-15Tb) scintillator exhibited a significantly higher X-ray excited luminescence intensity (147 % of Bi4Ge3O12). Furthermore, it possessed a remarkable imaging spatial resolution of 20 lp/mm, surpassing the standard requirement for X-ray imaging and medical computed tomography scans (2 lp/mm). Moreover, the X-ray excited luminescence intensity of G-15Tb glass sample remained unchanged even after being submerged in water for 30 days, indicating exceptional water resistance. Additionally, the integral intensity of photoluminescence at 573 K is 96.7 % of its initial value. Most importantly, the G-15Tb glass scintillator remains high-quality X-ray images even at elevated operating temperatures. Therefore, the Tb3+-doped borosilicate glass scintillator holds immense potential for high-resolution X-ray imaging in harsh environments.

Dual bioinspired superhydrophobicity and magnetically-induced self-healing ferrofluid-based SLIPS to inhibit corrosion of copper

Copper has extensive industrial applications. However, the susceptibility to corrosion makes it vulnerable in harsh environments. Bioinspired coating presents a novel approach to address copper corrosion. Bioinspired from lotus leaves and pitcher plants, this research endeavors to create superhydrophobic and ferrofluid-infused surfaces (FIS) on copper substrate. Firstly, a one-step electrodeposition method is employed to fabricate superhydrophobic surface on copper. Secondly, Fe3O4 nanoparticles are sequentially modified with dopamine hydrochloride and dodecanethiol to endow surface hydrophobicity. Then, the modified Fe3O4 is dispersed in oil to create a magnetic fluid, which is finally infused onto the superhydrophobic matrix, forming the FIS coating. Electrochemical testing confirms the high protective effect of the bio-inspired superhydrophobic and magnetic fluid composite coating against corrosion. The FIS coating exhibits a prominent low-frequency impedance modulus (7.73 × 106 Ω·cm²) even after immersion in NaCl solution for 60 d. Furthermore, the coating demonstrates an outstanding magnetic-driven self-healing capability, as evidenced by the minimal decrease in the |Z|0.01 Hz value (remaining as high as 109 Ω·cm²) even after undergoing six cycles of scratching and self-healing process. This corrosion resistance can be attributed to the combined effects of the accommodating effect of superhydrophobic matrix and the self-healing property of the magnetic fluid under the magnetic field. This dually bio-inspired coating technology offers significant advantages for copper applications in harsh environments.

Tolerance of Corundum‐Structured Tin‐Doped Indium Oxide Thin Films to Gamma‐ray Irradiation

Corundum‐structured Sn‐doped indium oxide (rh‐ITO) is investigated as a novel transparent conductive oxide. Herein, its gamma‐ray tolerance up to a total dose of 77 kGy is examined for potential applications in harsh environments, such as space. The investigations are conducted on rh‐ITO with Sn concentrations of 0 and 5 at%. X‐ray diffraction 2θ‐ω scan analysis reveals that no phase separation occurs due to gamma‐ray irradiation. The carrier concentration in undoped rh‐In2O3 increases after irradiation, indicating that the gamma rays displace the oxygen atoms and form oxygen defects that generate donors. The high visible light transparency of rh‐In2O3 and rh‐ITO is maintained after irradiation. This study demonstrates the high stability of rh‐ITO to gamma‐ray irradiation until 77 kGy dose. This work contributes to the application of rh‐ITO as an electrode in high‐radiation environments.

Effect of compositional undulation on the mechanical behavior of atomic-scale planar-faulted Ni-Mo-W films

Ni exhibits exceptional resistance to heat and corrosion, making it a sought-after material for harsh environment applications. The introduction of low interfacial energy planar defects (e.g., nanotwins and stacking faults) can greatly enhance the mechanical properties of Ni at elevated temperatures, but this strategy generally remains difficult due to Ni's high stacking fault energy (120–130 mJ/m2). Here, we apply HRSTEM, APT characterization, and DFT calculation to discover that inhomogeneous distribution of Mo atoms can facilitate the nucleation and stabilization of atomic-scale stacking faults in Ni-Mo-W thin films, in addition to the increase in global concentration. Micro-tensile experiments confirm the exceptionally high tensile strength up to 3 GPa. Post-mortem TEM analysis reveals that de-faulting followed by selective activation of dislocation emission and glide are the strength-limiting deformation mechanism. This work provides a practical strategy for designing ultrahigh strength, stable nanostructured materials by local chemical undulation.

Complex precipitation behavior in a Co-free high entropy alloy during aging

High entropy alloys (HEAs) demonstrate high strength, thermal stability, and irradiation resistance, making them desirable for applications in nuclear reactors and other harsh environments. Many existing HEAs contain cobalt (Co), which makes them unsuitable for nuclear applications due to the long-term activation of Co. A previously studied Co-free alloy, (Fe0.3Ni0.3Mn0.3Cr0.1)88Ti4Al8, exhibits high strength but compromised ductility due to its network of brittle precipitates upon aging. This work investigates the formation mechanism and evolution of the precipitates, including L12 (Ni3Ti type, ordered face-centered cubic structure), B2 (NiAl type, ordered body-centered cubic structure), and Chi (FeCr-rich ordered α-Mn structure), in this alloy at 650 °C, the aging temperature that yields the alloy’s peak strength after 120 hours. Using ex-situ scanning electron microscopy, transmission electron microscopy, and atom probe tomography, the precipitates were characterized in terms of their composition, morphology, and crystal structure at various aging times. In addition, synchrotron-based, in-situ X-ray diffraction was used to probe the evolution of precipitates in the bulk during key phases of in-situ aging. The L12 precipitates exhibit complex growth and coarsening behavior – their coarsening starts after just 24 hours, and competition between the L12 and B2 phases arises after 72 hours leading to a decrease in L12 volume fraction. Conversely, B2 and Chi precipitates exhibit delayed nucleation and growth, and do not form in observable quantities until after 24 hours. Once formed, however, these precipitates quickly dominate the microstructure, with >50 % volume fraction after 120 hours, leading to the previously observed mechanical properties. This study provides a foundational understanding of the evolution of multi-precipitate structures in HEAs and guides future alloy development and optimization by tailoring the precipitates.

GA-BP-Based Low-Noise FBG Hydroacoustic Monitoring System with Reference Sensor.

To address the issue of harsh marine background noise impacting the monitoring signal of fiber-optic hydrophones, we propose a low-noise fiber Bragg grating (FBG) hydroacoustic monitoring system with a reference sensor based on genetic algorithm backpropagation (GA-BP). Through theoretical analysis, we deduce the noise suppression steps of the GA-BP algorithm based on the reference sensor and construct train and test sets based on the data from the reference sensor and monitoring sensor at different times, optimizing the GA-BP algorithm to find the best fitting results and thereby obtaining the low-noise monitoring signal. Experimental results from the anechoic tank show that the proposed method can suppress background noise interference on effective signals and that the suppression effect improves as the background noise increases. The sound pressure sensitivity ranges from -173.76 dB to -171.33 dB at frequencies of 8 kHz to 12 kHz, with a response flatness of less than 2.43 dB. The noise suppression effect is obvious under the condition of poor signal-to-noise ratio (SNR), which can reach more than 18.3 dB. The advantages of the proposed algorithm in array signal processing are further demonstrated by the directivity experiment, which proves that the algorithm has a great potential for engineering applications in harsh marine environment.

A flexible, thermal-insulating, and fire‐resistant bagasse-derived cellulose aerogel prepared via a refrigerator freezing combined ambient pressure drying technique

Cellulose aerogel is a most promising alternative to the plastic foam owing to its low thermal conductivity, eco-friendliness and renewability, which however suffers from the complex preparation process, poor mechanical property and flammability. Herein, we develop a flexible, thermal-insulating, and fire-resistant cellulose aerogel by a facile refrigerator freezing and ambient pressure drying process, using bagasse and inorganic minerals as the main raw materials. The as-obtained bagasse-derived cellulose (BC) aerogel exhibited a high porosity of 92 %, an acceptable thermal conductivity of 51.5 mW/(m·K) and an excellent compressible cyclability. Furthermore, an inorganic mineral-reinforced bagasse-derived cellulose aerogel (IMr-BC) with improved fire-resistant property was prepared via the same method. The inorganic minerals endowed the original BC aerogel with a superior flame retardancy, which was able to withstand a continuous burning of butane gun at 1300 °C for over 20 min, and its thermal insulation application could be extended to a temperature as high as 1100 °C. These aerogels prepared in this work are expected to be used for thermal management applications in harsh environments.

Effect of titanium dioxide nanoparticles on the dielectric, thermal, and corrosion resistance properties of polyimide (PI) nanocomposites

In the present study, the effect of varying titanium dioxide (TiO2) nanoparticles on the dielectric, thermal, and corrosion characteristics of PI-based composites prepared by spark plasma sintering was investigated. The results obtained revealed that the TiO2 nanoparticles were uniformly dispersed within the PI matrix. Addition of TiO2 into the neat PI markedly reduced its dielectric constant and electrical conductivity by 72.7% and 82.3%, respectively, as well as enhancing its breakdown strength by 16.7% at 8 wt% TiO2 loading. The nanocomposites depict better thermal stability and heat-resistance index characteristics when compared to the PI. Additionally, the produced nanocomposites exhibit improved corrosion resistance than that of the neat PI. The remarkable improvement in the dielectric, thermal stability, and corrosion resistance of the nanocomposites is achieved by better dispersion of the TiO2 particles in the polymer matrix. The enhancement in properties suggests TiO2/PI-based nanocomposites potential for a variety of applications in electrical insulation, thermal management, and harsh environment.

Performance enhancement of a semi-active flapping foil energy harvester via airfoil with modified trailing edge and jet flap

This paper aims to numerically study effectiveness of the use of a suitable combination of an airfoil with modified trailing edge and jet flap in enhancing the energy harvesting performance of a semi-active flapping foil. The configuration of the proposed airfoil is created by referring to the method of generating a blunt trailing edge airfoil. The most promising airfoil profile is obtained by only thickening the rear part of the original airfoil to reach a thickness of 2% chord, which can apparently promote the energy capturing capability of a semi-active flapping foil when compared with its conventional counterpart with a sharp trailing edge airfoil. Furthermore, a jet flap, an active flow control technique, is then applied on the aft portion of the modified airfoil and the effectiveness of this combination is assessed by a comparison with that of the passive flow control device, Gurney flap. The present findings suggest that this combination can be much more effective than a Gurney flap in significantly increasing the energy harvesting efficiency of the semi-active flapping foil over a wide range of operating conditions, and also has the advantage of structural integrity, which make it more suitable for harsh environment applications.

Spark plasma sintering of TiC with TiAly as sintering aid: Mechanisms and microstructures

TiC features an interesting combination of mechanical properties, high-temperature resistance, and lightness, making it an excellent candidate for several applications in harsh environments. However, its sintering to obtain bulk components is extremely challenging. Herein, we show that titanium aluminide is a promising sintering aid for TiC (5, 10, and 20 vol% were investigated). The aluminide allows the formation of a nearly fully dense component at 1350 °C by spark plasma sintering under 80 MPa. The aluminide forms a grain boundary secondary phase that promotes the Ti diffusion: Ti from TiC can be dissolved within the TiAly at the neck center and precipitate at the neck surface, while C can easily diffuse through the TiC lattice. Higher temperatures cause the extrusion of the aluminide out of the SPS die and its reaction with oxygen impurities. The final microstructure is constituted by nearly pure TiC with isolated alumina pockets at the triple points.

In-situ deposition modification of hydrophilic polytetrafluoroethylene (PTFE) membranes using surfactants as anchoring points for long-term stability

Polytetrafluoroethylene (PTFE) membranes are renowned for their excellent thermal stability, resistance to strong acids and alkalis, and superior mechanical stability. However, its inherent strong hydrophobicity significantly limits its use in water treatment. In this study, a SiO2 coating was successfully deposited in-situ on the surface of PTFE membranes using a hydrolyzed solution of tetraethyl orthosilicate (TEOS) compounded with the commercial fluorinated polyoxyethylene ether surfactant FS-31 (C6F13CH2CH2O(CH2CH2O)nH). The modification mechanism involves using the low surface energy nonionic fluorocarbon surfactant FS-31, which interacts hydrophobically with the PTFE substrate, serving as an “anchor” point around which the TEOS hydrolyzes and condenses around the fibers and nodes of the PTFE membrane, forming a complete and stable chemical network structure. The results show that the initial water contact angle of the modified membrane dropped to 36.5°, and the water flux reached 537.9 L m−2 h−1. After being continuously immersed in strong acid (5 wt% HCl), strong alkali (4 wt% NaOH), and oxidizing agent (5 wt% NaClO) for one week, the membrane maintained excellent hydrophilicity and stability. This study proposes a mild and efficient modification method to prepare durable hydrophilic PTFE membranes, portending great potential for applications in harsh environments.