Harsh Environment Applications Research Articles

Investigating the Corrosion Resistance of Different SiC Crystal Types: From Energy Sectors to Advanced Applications.

Silicon carbide, as a third-generation semiconductor material, plays a pivotal role in various advanced technological applications. Its exceptional stability under extreme conditions has garnered a significant amount of attention. These superior characteristics make silicon carbide an ideal candidate material for high-frequency, high-power electronic devices and applications in harsh environments. In particular, corrosion resistance in natural or artificially acidic and alkaline environments limits the practical application of many other materials. In fields such as chemical engineering, energy conversion, and environmental engineering, materials often face severe chemical erosion, necessitating materials with excellent chemical stability as foundational materials, carriers, or reaction media. Silicon carbide exhibits outstanding performance under these conditions, demonstrating significant resistance to corrosive substances such as hydrochloric acid, sulfuric acid, nitric acid, and alkaline substances such as potassium hydroxide and sodium hydroxide. Despite the well-known chemical stability of silicon carbide, the stability conditions of its different types (such as 3C-, 4H-, and 6H-SiC polycrystals) in acidic and alkaline environments, as well as the specific corrosion mechanisms and differences, warrant further investigation. This Review not only delves deeply into the detailed studies related to this topic but also highlights the current applications of different silicon carbide polycrystals in chemical reaction systems, energy conversion equipment, and recycling processes. Through a comprehensive analysis, this Review aims to bridge research gaps, offering a comparative analysis of the advantages and disadvantages between different polymorphs. It provides material scientists, engineers, and developers with a thorough understanding of silicon carbide's behavior in various chemical environments. This work will propel the research and development of silicon carbide materials under extreme conditions, especially in areas where chemical stability is crucial for device performance and durability. It lays a solid foundation for ultra-high-power, high-integration, high-reliability module architectures, supercomputing chips, and highly safe long-life batteries.

Solmers: Versatile hybrid resins for nanometric 3D printing of silica-based photonic components

Owning to their intrinsic properties, silica-based glasses are widely used in various technological fields, especially in photonics. However, high degree of flexibility is yet challenging in realization of next-generation miniaturized optical components. In this work, we develop an approach based on ‶Solmers″ hybrid resins allowing versatile two-photon polymerization 3D printing of silica glasses with 23 nm resolution, doping with Germanium and/or rare-earths elements. Other dopants such as gold nanoparticles were also incorporated for localized metallization. After 3D printing and sintering (1100–1300 °C), high optical quality glasses with low surface roughness (<0.2 nm) were obtained. Structural analyses confirmed the amorphous structure of silica glasses. Various mono- or multi-materials microstructures were successfully fabricated on fused silica substrates. Besides, this approach was extended to the functionalization of optical fibers for optical sensing applications in harsh environment (1000 °C). Compared to organic or organic-inorganic materials, these dense silica-based glasses with enhanced optical and structural properties will open new avenues for the development of emerging advanced optical components.

Experimental Examination of Additively Manufactured Patterns on Structural Nuclear Materials for Digital Image Correlation Strain Measurements

Abstract Background There are a limited number of commercially available sensors for monitoring the deformation of materials in-situ during harsh environment applications, such as those found in the nuclear and aerospace industries. Such sensing devices, including weldable strain gauges, extensometers, and linear variable differential transformers, can be destructive to material surfaces being investigated and typically require relatively large surface areas to attach (&gt; 10 mm in length). Digital image correlation (DIC) is a viable, non-contact alternative to in-situ strain deformation. However, it often requires implementing artificial patterns using splattering techniques, which are difficult to reproduce. Objective Additive manufacturing capabilities offer consistent patterns using programmable fabrication methods. Methods In this work, a variety of small-scale periodic patterns with different geometries were printed directly on structural nuclear materials (i.e., stainless steel and aluminum tensile specimens) using an aerosol jet printer (AJP). Unlike other additive manufacturing techniques, AJP offers the advantage of materials selection. DIC was used to track and correlate strain to alternative measurement methods during cyclic loading, and tensile tests (up to 1100 µɛ) at room temperature. Results The results confirmed AJP has better control of pattern parameters for small fields of view and facilitate the ability of DIC algorithms to adequately process patterns with periodicity. More specifically, the printed 100 μm spaced dot and 150 μm spaced line patterns provided accurate measurements with a maximum error of less than 2% and 4% on aluminum samples when compared to an extensometer and commercially available strain gauges. Conclusion Our results highlight a new pattern fabrication technique that is form factor friendly for digital image correlation in nuclear applications.

High-temperature dielectric with excellent capacitive performance enabled by rationally designed traps in blends

Polymer dielectrics with excellent capacitive performance are urgently needed in advanced electrical and electronic systems. However, due to the dramatic increase in the conduction loss, the energy density and efficiency of polymers degrade severely at elevated temperatures, limiting their application in harsh environments up to 150 °C. Herein, an all-organic polyurea (PU)/polyetherimide (PEI) blend film is designed to prepare high-temperature polymer dielectric. It is found that carrier traps can be introduced by blending, and the hydrogen bond between PU and PEI increases the trap depth, leading to suppressed leakage current and enhanced breakdown strength, thus improving the energy storage performance. PU/30%PEI exhibits a high discharged energy density of ∼3.74 J/cm3 with an efficiency higher than 90% at 150 °C, which is 78% and 70% higher than pristine PU and PEI, respectively. This work provides a facile strategy to improve the energy storage performance of polymer dielectrics by introducing deep traps through blending.

Mechanical and electrochemical properties of (MoNbTaTiZr)1-xNx high-entropy nitride coatings

High-entropy materials possess high hardness and strong wear resistance, yet the key bottleneck for their practical applications is the poor corrosion resistance in harsh environments. In this work, the high-entropy nitride (HEN) coatings of (MoNbTaTiZr)1-xNx (x = 0–0.47) were fabricated using a hybrid direct current magnetron sputtering technique. The research focus was dedicated to the effect of nitrogen content on the microstructure, mechanical and electrochemical properties. The results showed that the as-deposited coatings exhibited a typical body-centered cubic (BCC) structure without nitrogen, while the amorphous matrix with face-centered cubic (FCC) nanocrystalline grain was observed at x = 0.17. Further increasing x in the range of 0.35–0.47 caused the appearance of polycrystalline FCC phase in structure. Compared with the MoNbTaTiZr metallic coating, the coating containing nitrogen favored the high hardness around 13.7–32.4 GPa, accompanied by excellent tolerance both against elastic and plastic deformation. Furthermore, such N-containing coatings yielded a low corrosion current density of about 10−8–10−7 A/cm2 and high electrochemical impedance of 106 Ω·cm2 in 3.5 wt.% NaCl solution, indicating the superior corrosion resistance. The reason for the enhanced electrochemical behavior could be ascribed to the spontaneous formation of protective passive layers over the coating surface, which consisted of the dominated multi-elemental oxides in chemical stability. Particularly, noted that the (MoNbTaTiZr)0.83N0.17 coating displayed the highest hardness of 32.4 ± 2.6 GPa and H/E ratio at 0.09, together with remarkable corrosion resistance, proposing the strongest capability for harsh-environmental applications required both good anti-wear and anti-corrosion performance.

Near-zero thermal expansion ZrW2O8/SiO2f wave-transparent composites: Interfacial anti-debonding structures based on polymeric films

The thermal stability of fiber-optic gyroscopes (FOGs) limits their application in harsh environments. This work utilized the unique water-retention properties of hyaluronic acid and the low-temperature cold sintering process combined to fabricate near-zero thermal expansion ZrW2O8/SiO2f composites with thermal resistance. Based on this novel process, the interface debonding of the composites is effectively suppressed and the mechanical and thermal properties of the composites are significantly improved (flexural strength increased by 69.47 %). Moreover, the interface anti-debonding structure reduces the interfacial polarization and reflection loss of the composites, and enhances the wave-transparent properties in the 2–18 GHz frequency range, with a minimum reflection loss of −0.21 dB. Furthermore, the interface anti-debonding structure of the composite provides creep resistance with enhanced sintering densities (increased by 13.61 %). Simultaneously, the composites achieve a controllable coefficient of thermal expansion (CTE) by regulating the liquid phase content and reach near-zero CTE (−0.246 × 10−6 °C−1 [30–300 °C]). Finally, finite element analysis and thermal shock experiments show that the anti-debonding interfacial structure has excellent thermal resistance, and the densest ZrW2O8/SiO2f composites exhibit the best thermal resistance due to minimal thermal strain during thermal shock, which is expected to meet the requirements of FOGs applications.

Quantum dots may improve space laser communications by tolerating harsh radiation conditions

Bolstering semiconductor laser diodes’ radiation hardness can facilitate their application in harsh environments like space or nuclear power plants.

Experimental Investigation of Producer Gas Effects on Coated Pipelines in Biomass Downdraft Gasifier System

Abstract This research examines the performance of epoxy, ceramic, and graphene coatings on stainless steel 316 in a producer gas environment, focusing on corrosion and erosion resistance. This research aimed to identify the most effective coating for applications in harsh gasification environments. In this research, various analyses, including microstructural examination, hardness and weight measurements, FESEM analysis, and EDAX analysis, were conducted to evaluate the performance of the coatings. The producer gas was passed on to all the coated samples for a period of 100 hours. The significant findings include the superior corrosion and erosion resistance of ceramic-coated stainless steel, as evidenced by low weight fluctuations, maintained hardness levels, and elemental stability. Graphene coatings exhibit high hardness but increased porosity, raising concerns about durability, while epoxy coatings are vulnerable to gas-induced structural alterations. The inclusion rating analysis underscored the ceramic coatings' ability to preserve consistent material properties. Overall, ceramic coatings have emerged as the preferred option for gasification environments due to their structural resilience, inclusion integrity, and elemental stability. Considering the inclusion integrity, mechanical strength, weight stability, and elemental stability, ceramic-coated stainless steel 316 samples exhibit better resistance toward producer gas influence. This research contributes valuable insights for material selection in applications exposed to harsh gasification environments, emphasizing the importance of coating selection for long-term durability and performance.

Experimental characterization of bond between concrete and HDG steel tubes for mixed steel-concrete structures

Bond between concrete and reinforcement material is crucial for the structural behaviour and design of reinforced concrete or mixed steel-concrete structures. When considering applications in harsh environments, such as severe marine exposure or submerged conditions, hot-dip galvanized (HDG) steel seems to be a promising solution, as part of new mixed steel-concrete structural systems. Although it is essential to guarantee an effective composite response, the interaction and bond behaviour between materials is not yet sufficiently well understood. This experimental investigation aimed to study the bond behaviour between concrete and HDG steel tubes, including the influence of adopting concrete pin connectors by creating holes in the tube profile, and also the influence of the galvanic surface state. The impact of bond length on the bond behaviour of the galvanized steel tube embedded in different concrete mixtures was analysed. Pushout tests were conducted to obtain the load end versus slip responses, as well as the failure modes. The results showed that the embedment lengths and the concrete compositions had no relevant effect on the overall shape of the pushout experimental responses, with the exception of the specimens that include the concrete pin connector. However, both variables clearly influenced the bond stress, dissipated energy during pushout until failure, and residual pushout force. The addition of the concrete pin significantly improved the adherence mechanism, while the contamination of the galvanic surface showed to significantly reduce the bond strength.

A Si-Nb co-alloyed AlCrN coating with good mechanical properties, excellent thermal stability and resistance to high temperature oxidation

The thermal properties of AlCrN coatings influence their application in harsh mechanical environments. This paper introduces a Si-Nb co-alloying strategy to prepare AlCrN-based coatings with good mechanical properties, excellent thermal stability and resistance to high temperature oxidation for developing high-performance tool coatings. The results indicate that, benefiting from the synergistic effect of replacing a portion of Si with an appropriate amount of Nb, Al0.59Cr0.31Si0.06Nb0.04N coating exhibits a fine columnar crystal structure different from the featureless dense structure of Al0.60Cr0.32Si0.08N coating. The different microstructure results in the difference of mechanical properties. Therefore, Al0.59Cr0.31Si0.06Nb0.04N has a higher hardness (32.3 ± 0.8 GPa) than Al0.60Cr0.32Si0.08N (28.8 ± 0.8 GPa). Meanwhile, the Al0.59Cr0.31Si0.06Nb0.04N coating get a better thermal stability and a comparable resistance to high temperature oxidation as Al0.6Cr0.32Si0.08N coating. The temperatures of thermal decomposition and oxidation resistance for Al0.59Cr0.31Si0.06Nb0.04N coating are increased by about 125 °C and 175 °C, respectively, compared with Al0.66Cr0.34N coating. In addition, the Si-Nb co-alloyed coatings maintain a better hardness after annealing.

Preparation of superhydrophobic coatings on kraft paper for the protection of important documents

Kraft paper (KP) has the advantages of being biodegradable, recyclable, and environmentally friendly. It has a wide range of applications in paper packaging, food packaging, and other fields. However, the non-waterproof characteristic of KP limits its application in harsh environments or special paper packaging, etc. To solve the problem of poor water resistance of KP, a simple and efficient method is proposed to prepare superhydrophobic coatings on kraft paper (SKP) by spraying method using hydrophobic Nano-calcium carbonate (Nano-CaCO3) particles and rosin (RA) as raw materials. Here, the micro-nano structures are mainly constructed by hydrophobic Nano-CaCO3 particles, and RA is utilized as a binder to improve the adhesion between the nanoparticles and the paper. The results indicated that the water contact angle (WCA) of SKP reached 154.5° and the water sliding angle (WSA) was 3.2°. And after 34 h of immersion in water, the WCA of SKP surface can remain above 150°. It can also withstand 30 times of sandpaper abrasion and 30 times of tape peeling. Overall, SKP shows excellent stability, water resistance, stain resistance and self-cleaning. It is expected to protect important documents in harsh environments.

Device and material investigations of GaN enhancement-mode transistors for Venus and harsh environments

This Letter reports the device and material investigations of enhancement-mode p-GaN-gate AlGaN/GaN high electron mobility transistors (HEMTs) for Venus exploration and other harsh environment applications. The GaN transistor in this work was subjected to prolonged exposure (11 days) in a simulated Venus environment (460 °C, 94 bar, complete chemical environment including CO2/N2/SO2). The mechanisms affecting the transistor performance and structural integrity in harsh environment were analyzed using a variety of experimental, simulation, and modeling techniques, including in situ electrical measurement (e.g., burn-in) and advanced microscopy (e.g., structural deformation). Through transistor, Transmission Line Method (TLM), and Hall-effect measurements vs temperature, it is revealed that the mobility decrease is the primary cause of reduction of on-state performance of this GaN transistor at high temperature. Material analysis of the device under test (DUT) confirmed the absence of foreign elements from the Venus atmosphere. No inter-diffusion of the elements (including the gate metal) was observed. The insights of this work are broadly applicable to the future design, fabrication, and deployment of robust III-N devices for harsh environment operation.

Rational Design of Amorphous Carbon-Coated Laminar-Structured Wood for Integrating Repeatable Early Fire Detection and High-Temperature Affordable Flexible Pressure Sensing in One System.

High-temperature affordable flexible polymer-based pressure sensors integrated with repeatable early fire warning service are strongly desired for harsh environmental applications, yet their creation remains challenging. This work proposed an approach for preparing such advanced integrated sensors based on silver nanoparticles and an ammonium polyphosphate (APP)-modified laminar-structured bulk wood sponge (APP/Ag@WS). Such integrated sensors demonstrated excellent fire warning performance, including a short response time (minimum of 0.44 s), a long-lasting alarm time (>750 s), and reliable repeatability. Moreover, it achieved high-temperature affordable flexible pressure sensing that exhibited an almost unimpaired working range of 0-7.5 kPa and a higher sensitivity (in the low-pressure range, maximum to 226.03 kPa-1) after fire. The high stability was attributed to reliable structural elasticity, and the wood-derived amorphous carbon is capable of repeatable fire warnings. Finally, a Ag@APP/WS-based wireless fire alarm system that realized reliable house fire accident detection was demonstrated, showing great promise for smart firefighting application.

Fully‐Recyclable Green and Fire‐Resistant Triboelectric Elastomer via Geometrical Synergistic Fillers and Its Applications for Smart Firefighting Boots

AbstractWearable sensors for high temperatures (WSHT) applications pose a significant challenge in the electronics field due to the inherent inability of most electronics to function in harsh environments. Triboelectric nanogenerators (TENG) present a substantial potential for applications in such challenging conditions. Herein, a fully‐recyclable flame‐retardant triboelectric elastomer is developed, which exhibits superior charge stability under high temperature conditions and proposes the specially designed synergistic fillers that play a dual role by trapping more charges into the interface and stabilizing the char layers via layer‐ball‐layer structure. An efficient flame‐retardant system is presented, which exhibits a 31% lower fire growth index than the individual components. The maximum surface charge density of this triboelectric elastomer can reach 361 µC m−2, while this surface charge density can be preserved to 70.9% after 16 s of combustion (≈520 °C) and to 37.9% by continuously working at 130 °C. At last, utilizing this flame‐retardant triboelectric elastomer, smart firemen's boots featuring gait analysis for identification and second level early warning systems have been developed. This work paves the way for the development of triboelectric materials and intelligent wearable devices suitable for applications in harsh environments.

Fabrication of hierarchical superhydrophobic structures by silane enriched with nanomaterials for enhancing permeability and freeze-thaw resistance

In this paper, the method of dehydration condensation reaction was used to establish a superhydrophobic cement mortar surface with the contact angle of 159.3° and the slide angle of 6.1° by using organosilane and inorganic nanomaterials. The nanoparticles built roughness and the silane provided low surface energy, which in combination achieved self-cleaning, waterproof and durability improvement. The superhydrophobic coating with good penetration depth is able to show superhydrophobicity after simply brushing and curing at room temperature for 24 hours and maintain hydrophobicity after surface abrasion. A variety of liquid droplets can roll freely from the surface of superhydrophobic cement mortar and carry contaminants rolling down to show self-cleaning performance. In terms of durability, the coating appears good adhesion to the surface of cement mortar, which retained its hydrophobic property after tape-peeling tests and outdoor simulation tests. In addition, compared with ordinary cement mortar, the superhydrophobic cement mortar demonstrates excellent waterproof ability and freeze-thaw resistance through low water absorption and slow quality reduction after multiple freeze-thaw cycles. These key characteristics provide advantages for concrete protection applications in harsh environments.

Shape memory polyimide/carbon nanotube composite aerogels with physical and chemical crosslinking architectures for thermal insulating applications

The development of lightweight smart materials with exceptional shape memory and thermal insulation properties is highly important in the aerospace industry. The reported shape memory polymer aerogels (SMPAs) are restricted to harsh environments because of their poor high-temperature resistance and large volume shrinkage at elevated temperatures. Herein, shape memory polyimide (PI) composite aerogels with superior thermal insulation were fabricated by combining molecularly designed PI chains with amino-functionalized carbon nanotubes (NH2-CNTs) through freezing gelation and subsequent thermal imidization. Because shape memory behavior was thermally triggered, the thermal conductivity associated with the shape memory mechanisms of the aerogels was comprehensively explored. The presence of CNTs promoted heat transfer in the aerogel skeleton, facilitating the shape recovery response. Benefiting from chemical-crosslinked and physical-crosslinked structures, the fabricated PI composite aerogels demonstrated desirable thermo-mechanical properties, exceptional shape memory and superior thermal insulation performance. This study may provide guidelines for designing shape memory PI composite aerogels for harsh environment applications in aerospace engineering.

Ultra-flexible inorganic coating realized by scale-like nanosheets

Rapid development of foldable devices poses a challenging requirement on functional inorganic coatings with high flexibility. However, the inherent brittleness often renders inorganic coatings incompatible with flexibility. How to make flexible inorganic coatings remains challenging. Here, inspired by the scale structure of animal skins, we realize ultra-flexible scale-like coatings on polyimide (PI) film with layered double hydroxide (LDH) nanosheets. The adhesion is enhanced without peeling due to the bonding of polyimide with amino group attached to nanosheets. LDH nanosheets parallel to the substrate form scale-like structure that absorbs and releases stress to prevent coatings from cracking. And the coatings exhibit ultra-flexibility by surviving from 20,000 cycles of bending fatigue test. We apply the LDH-coated PI for atomic oxygen protection, which has important applications in aerospace industry. The coatings are designed as this special scale-like structure to release stress while possessing protection ability. Due to the barrier and adsorption of this flexible LDH coating, the erosion yield of the PI under an exposure of ~5 × 1021 atoms/cm2 is decreased by about 4 orders of magnitude to 0.015 % (~5 × 10−28 cm3/atom), which can satisfy the requirement for applications in harsh space environment of low earth orbit. Our work provides a general solution for simultaneously realizing high mechanical strength and flexibility in the coating technology, which may find applications in other areas, such as flexible electronics.

Source–drain switching characteristics when coupled with a gate-controlled DBD in a microplasma switch

Microplasma switches have attracted considerable attention in harsh environment applications, such as satellites, space exploration, nuclear reactors, and oil drilling, because of their inherent characteristics. A microplasma switch is generally constructed from a source, drain, and gate electrodes, and current conduction is generated between the drain and source (DS), and modulated by the gate. In this work, to improve the gate lifespan and device stability, a microplasma switch with a gate dielectric barrier structure is fabricated due to the even and stable discharge of a dielectric barrier discharge (DBD), and a parameterized nanosecond pulse voltage signal is applied to the gate. Under the effect of the DS voltage, a pulsed DS current is triggered by the gate pulse since a large number of charged particles are generated by the gate DBD, which shows that the DS switching behavior is triggered by the gate pulse. The microplasma switch operates stably (with an average delay jitter of less than 50 ps) at the repetition frequencies (up to 80 kHz). Moreover, the influence of experimental conditions on the switching performance is systematically investigated. The conduction current and delay, which are related to the discharge intensity and speed, are influenced by the electric-field strength of the channel (determined from the pulse amplitude and DS voltage) and its variation rate (determined from the rising and falling edge time of the pulse). In addition, the device performance is influenced by varying the breakdown voltage of the DS (determined from the gas pressure multiplied by DS spacing), which can result in variation of the working coefficient. It is also influenced by varying the wall voltage (decided by pulse width and frequency), which can result in the decrease in the total voltage of the channel.

Exploring the impact of multivalent substitution on high-temperature electrical conductivity in doped lanthanum chromite perovskites: An experimental and ab-initio study

Doped LaCrO3 perovskites hold promise as robust materials for electrical interconnects and sensor applications in harsh environments. In this work, we investigated the high-temperature behavior of La1–xSrxCrO3, La1–xCaxCrO3 and La0.8Sr0.2Cr1-x MnxO3 (0.1 ≤ x ≤ 0.4) through a combination of computational modeling and physical characterization up to 1500 °C. Crystalline structural properties were determined and compared with ab-initio calculations, which demonstrated excellent agreement with experimental findings. High-temperature electrical conductivity measurements were performed under different atmospheres. Calcium and strontium/manganese co-doped lanthanum chromites exhibited typical semiconductor exponential trends and conductivity showed proportional correlation with substitutions levels up to 30%. The DFT modelling was completed up to 1500 °C, including low and high temperature chromite phases and oxygen vacancies insertion. Calculations were correlated with experimental electrical properties. This work expands the understanding of doped lanthanum chromites and paves the way for the development of materials suitable for demanding high-temperature applications.

A toroidal SAW gyroscope with focused IDTs for sensitivity enhancement

A surface acoustic wave (SAW) gyroscope measures the rate of rotational angular velocity by exploiting a phenomenon known as the SAW gyroscope effect. Such a gyroscope is a great candidate for application in harsh environments because of the simplification of the suspension vibration mechanism necessary for traditional microelectromechanical system (MEMS) gyroscopes. Here, for the first time, we propose a novel toroidal standing-wave-mode SAW gyroscope using focused interdigitated transducers (FIDTs). Unlike traditional SAW gyroscopes that use linear IDTs to generate surface acoustic waves, which cause beam deflection and result in energy dissipation, this study uses FIDTs to concentrate the SAW energy based on structural features, resulting in better focusing performance and increased SAW amplitude. The experimental results reveal that the sensitivity of the structure is 1.51 µV/(°/s), and the bias instability is 0.77°/s, which are improved by an order of magnitude compared to those of a traditional SAW gyroscope. Thus, the FIDT component can enhance the performance of the SAW gyroscope, demonstrating its superiority for angular velocity measurements. This work provides new insights into improving the sensitivity and performance of SAW gyroscopes.