Ultra-high Temperature Environments Research Articles

Screw dislocation growth defects enhancing electromagnetic wave absorption performance of GdB6

In this study, a purity of up to 98.36 wt. % GdB6 with screw dislocation growth morphology were successfully fabricated using an in-situ reaction approach. The terraced-like structure of the GdB6 enhanced the interfacial polarization and multiple interface scattering of the electromagnetic waves. As a result, the as-obtained high purity GdB6 powder presented superior electromagnetic wave absorption performance. The minimum reflection loss value can be −49.24 dB at the frequency of 13.12 GHz with a thin matching thickness of 1.44 mm. In addition, the widest effective absorption bandwidth can be up to ∼4 GHz (14–18 GHz) with a thin matching thickness of 1.25 mm. The remarkable electromagnetic wave absorption performance of GdB6 ceramics could be attributed to conductance loss and polarization loss enhanced by the screw dislocation growth defects, as well as synergistic effects with magnetic loss. The as-obtained GdB6 with synergistic dielectric loss and magnetic loss is to be a novel single-phase with excellent electromagnetic wave absorbing material, which will pave the way on the investigation of rare earth hexaborides for the ultra-high temperature environment applications.

Performance experiment of ultra high temperature cementing slurry system

Introduction: The escalating pursuit of oil and gas reserves in China has led to increasingly deep and ultra-deep well drilling, encountering extreme temperatures that challenge the heat resistance capabilities of cement slurries. This study addresses the critical need for high-performance cement slurries capable of withstanding ultra-high temperatures during drilling and completion operations.Methods: A novel ultrahigh temperature conventional density (UHTE) cement slurry was formulated by incorporating high-temperature-resistant additives, namely DRF-1S and DRH-2L. An indoor testing framework was established to assess the slurry’s performance across various parameters: Evaluating the slurry’s ability to maintain uniform consistency over time. Measuring the amount of free water separated from the slurry under simulated downhole conditions. Assessing the slurry’s transition from fluid to solid state over time. Determining the compressive strength and other mechanical attributes after curing at elevated temperatures.Results: The experimental findings revealed the following: An optimal silica sand dosage of 50% was found to enhance the overall performance of the UHTE cement slurry. The developed UHTE cement system, fortified with DRF-1S and DRH-2L, demonstrated effective functionality within a temperature range of 180°C to 210°C, representing a significant advancement in high-temperature resistance. The slurry maintained API water loss below 100 mL, ensuring minimal fluid loss during placement. Adjusted thickening time allowed for adequate pumping and placement without premature setting. Settlement stability was maintained below 0.04 g/cm3, indicating excellent homogeneity and stability. Incorporation of the anti-decay material DRB-3S ensured a 28-day compressive strength exceeding 50 MPa at 210°C, signifying robust structural integrity under extreme thermal conditions.Discussion: This research provides a robust foundation for the practical application of UHTE cementing technology in ultra-high temperature environments. The successful development of the UHTE cement slurry system, characterized by its superior temperature resistance, controlled water loss, optimized thickening behavior, and exceptional mechanical properties, paves the way for field trials and further enhancements. Future work will involve testing the effectiveness of the new additive combination under actual downhole conditions and refining the formulation to develop an even more advanced UHTE cementing additive. These advancements will contribute to enhanced wellbore integrity, improved drilling efficiency, and increased safety in deep and ultra-deep oil and gas exploration endeavors in China.

Passivation and Corrosion Behavior of Modified S13Cr Stainless Steel in Ultra-high Temperature Geothermal Fluid

This research aims to investigate the passivation and corrosion behaviour of modified S13Cr stainless steel (SS) in ultra-high temperature geothermal fluids. In this study, S13Cr SS before and after modified were both immersed in a simulated geothermal fluid environment with a temperature of 210°C and CO2 pressure of 3 MPa for 120 h. The results show that the modified S13Cr SS had smaller grain size and lower reverse austenite content, and exhibited higher transpassive potential and lower passive current density in the ultra-high temperature environment. After 120 h of immersion, the passivation film of the modified 13Cr SS was completely dissolved, and a corrosion product film mainly composed of FeCO3 and FeCr2O4 formed with localized corrosion occurring. Moreover, a Ni-rich barrier layer formed at the interface between the inner layer of the product film and the substrate, which hindered the penetration of the corrosive medium. Additionally, the residual MoO2 in the product film played a stabilizing role. Overall, the corrosion resistance of the modified S13Cr SS in ultra-high temperature geothermal fluids is improved.

Ultra-high temperature oxidation resistant refractory high entropy alloys fabricated by laser melting deposition: Al concentration regulation and oxidation mechanism

Poor oxidation resistance is a critical factor limiting the application of metalllic materials at ultra-high temperature environments. In this contribution, Alx(CrMoTaTi)1−x (x = 0.05, 0.1, 0.15) refractory high entropy alloy (RHEA) system was fabricated by laser melting deposition. The as-deposited RHEA was composed of two body-centered-cubic phases (BCC1 and BCC2). It was found that the volume fraction of BCC2 was increased with increasing the Al concentration from 0.05 to 0.15 and, surprisingly Al0.15(CrMoTaTi)0.85 could thermally grow an external Al2O3 scale during oxidation in air at 1300 °C. The insights into the microstructure-based oxidation mechanism of the RHEA were illustrated.

Effect of SiC on the anti-ablation resistance and flexural strength of (Hf-Ta-Zr)C-C/C composites

Recently, much attention has been drawn to the development of high temperature resistance of carbon-based composites due to their increasing demand in various applications. Herein, (Hf-Ta-Zr)C single-phase solid solution and SiC ceramic were incorporated into C/C by polymer infiltration and pyrolysis (PIP), forming (Hf-Ta-Zr)C-SiC-C/C composites. The findings reveal that the high yield of polycarbosilane facilitate enhanced compactness and interfacial debonding between the solid solution ceramic and the matrix. Notably, the composites with a mass ratio of (Hf-Ta-Zr)C: SiC= 3:1 exhibit a pseudo-plastic fracture model with flexural strength of 280.71 ± 7.52 MPa and modulus of 38.92 ± 3.62 GPa. Furthermore, the mass and linear ablation rates with only 0.328 mg/s and − 0.067 µm/s, respectively, are attributed to the sufficient healing defects such as cracks and pores within the inner layer by SiO2, along with enhanced adhesion of the Hf-Ta-Zr-O layer. This research contributes to the development of a rational design strategy for fabricating thermal structure components intended for ultra-high temperature environments.

High-temperature oxidation behavior of laser-cladded refractory Al0.75NbNi0.1Mo0.1Cr0.5Si0.1Wx high-entropy coatings

Refractory High Entropy Alloys (RHEAs) have great potential for ultra-high temperature environments and are one of the potential candidates for high temperature applications. In this work, a series of Al0.75NbNi0.1Mo0.1Cr0.5Si0.1Wx (x = 1, 1.5, 2) refractory high-entropy alloy coatings is prepared by laser cladding technology. The microstructure and oxidation behavior at 1000 °C and effect of changing oxidation temperature on oxidation behavior of the coatings is investigated. The results show that Al0.75NbNi0.1Mo0.1Cr0.5Si0.1Wx RHEA coatings are composed of BCC, W5Si3 and AlNi3 phases. The microstructure of RHEA coatings exhibits dendritic-cellular grain transition with increasing W content. The specific mass gains of coatings due to high temperature oxidation is 65.5 mg/cm2 for x = 1, 8.5 mg/cm2 for x = 1.5 and 14.5 mg/cm2 for x = 2 at 1000 °C for 70 h. After oxidation in 1000 °C for 70 h under air atmosphere, a protective oxide film (such as Al2O3 and SiO2) adhere around NiWO4 on the alloy coatings, which impedes the inward oxygen transport. Moderate addition of W elements is found to be beneficial in enhancing the oxidation resistance of coatings. However, excessive addition of W elements prevents the formation of protective oxides (Al2O3 and SiO2) and reduces the high-temperature oxidation resistance of the coatings. With the increase of oxidation temperature, simple oxides are significantly reduced while compound oxides are increased on the surface of the coatings. The surface appears hill-shaped oxides with the increase of NiWO4.

Bilayer lattice structure integrated with phase change material for innovative thermal protection system design

In recent years, ceramic matrix composite (CMC) lattice structure has become a promising candidate for a new generation of integrated thermal protection systems (ITPSs) used in the ultrahigh-temperature environment. However, the thermal short circuit effect caused by lattice cores limits their application. In this work, we propose a bilayer CMC lattice structure filled with phase change material (PCM) and thermal insulation material for integrated thermal protection systems (ITPSs) to mitigate the thermal short circuit effect. The numerical simulation method is used to verify the effectiveness of the bilayer lattice structure in mitigating the thermal short circuit effect compared with one-layer ITPS. By inserting the middle face sheet, the thermal insulation effect enhances about 16%. Furthermore, the effects of thermal insulation materials, thermal conductivity and thickness of paraffin/expanded graphite composite PCM, and the diameter of the lattice core strut on the thermal insulation performance are discussed. The results show that the thickness of PCM has an optimal solution. Optimizing results show that when the aerogel insulation fiber is used as the thermal insulation material, the thermal conductivity k=0.82 W/(m⋅K) and the thickness t3=10 mm of PCM, the diameter of the core strut d=1.5 mm, the bilayer PCM-ITPS has the best thermal insulation performance. When the ultrahigh-temperature load is continuously loaded, the highest temperature of Top Face Sheet is more than 2300°C, but the highest temperature of Bottom Face Sheet is only 30.12°C, which thermal insulation effect is far better than the traditional ITPS. This work gives a novel scheme to solve the thermal short circuit effect, improving the thermal protection performance and accelerate the application of lattice structure in ITPS.

Temperature-dependent dielectric and wide-temperature-range microwave absorption properties of La0.8Sr0.2MnO3/Al2O3–13%TiO2 coatings

The advancement of absorption materials and coating preparation technology is crucial to address the challenges posed by electromagnetic interference and pollution in high-temperature extreme environments. Here, by using a granulation and plasma spraying strategy, we successfully fabricated a series of La0.8Sr0.2MnO3/Al2O3–13%TiO2 (LSMO/AT13) high-temperature microwave absorption coatings that have excellent dielectric properties and extremely thermal stability. The results showed that the LSMO/AT13 coatings exhibited remarkable oxidation resistance, withstanding high-temperature aerobic environments of up to 1000 °C. Based on the temperature-dependent permittivity of the coatings, the establishment process of polarization and the transformation of loss mechanism were observed and explained. With the increase of temperature, the main dielectric loss mechanism of the coatings transitions from polarization loss to conductive loss. Thanks to the coordinated effects of impedance and loss, the coatings are capable of effectively absorbing microwave over a wide temperature range. When the LSMO content was 30 wt% and the thickness was 1.9 mm, the effective bandwidth ranged from 1.7 GHz to 2.4 GHz at temperatures below 773 K. This study demonstrates the promising application of LSMO/AT13 microwave absorption coatings for ultra-high temperature environment, and provides a reference for the design and optimization of high-temperature microwave absorption coatings.

Thermal insulation characteristics of high-temperature heat seals for hypersonic aero-engines

The high-temperature baseline sealing thermal protection technology is of great significance to realizing hypersonic aero-engines and aircraft. Based on the fact that there are few studies on the high-temperature baseline heat sealing in the ultra-high temperature environment (above 1000 °C), the paper establishes a simulation model to analyze the influence of different characteristic parameters on the thermal protection performance of the heat seal at ultra-high temperature and carried out experiments. Verification, simulation, and experiment error are less than 6%. The research results show that the aluminum silicate fiber has the best thermal insulation effect in the material of the inner thermal insulation layer, and the temperature can be lowered by more than 900 °C under an environment of 1200 °C. It is used to prepare heat seals. In addition, the filling density and thickness of the inner thermal insulation layer have little influence on the thermal insulation effect, and the influence coefficient does not exceed 5%. In the test of the degree of degradation of the thermal insulation performance of the heat seal, it is found that it does not exceed 5%, which meets the requirements for use. This paper further promotes the development of high-temperature thermal protection technology. It can also provide a corresponding technical basis for developing supersonic aero-engines.

Fiber Bragg Grating Temperature Sensor and its Interrogation Techniques

In this comprehensive review, our focus centers novel strategies and methodologies in FBG temperature sensors and their interrogation techniques investigated for sensing in different environments. FBG temperature sensors are investigated for cryogenic, ambient, high-temperature and ultrahigh-temperature environments. Interrogation techniques encompasses optical interferometry, optical edge filtering, time division multiplexing, optical spectrum analysis (OSA) and wavelength division multiplexing (WDM), each possessing distinct characteristics and working principles. The optical interferometry technique offers exceptional sensitivity and high resolution but has a relatively lower temperature sensing range. The optical edge filtering technique provides good temperature sensitivity, enhanced resolution and nominal temperature sensing range which are mainly dependent on the span and slope of the edge of the optical filter. TDM interrogation technique has the multiplexing capability and cost-effectiveness but limitations like the requirement of partial reflective matched FBGs, spatial separ¬¬¬¬ation of the FBGs and the potential cross-talk make it less attractive for commercial applications. OSA and WDM techniques excel in multiplexing capabilities and boast the widest temperature sensing range. However, OSA is limited for research applications only. On the other hand, WDM stands out with its cost-effective per-sensor implementation and extensive usage in commercial interrogation systems. The significance of this review lies in its ability to provide researchers, engineers, and practitioners with a coherent understanding of the evolving FBG temperature sensing landscape. By consolidating and highlighting recent breakthroughs, we aim to inspire further research initiatives and foster the development of optimized FBG temperature sensing systems.

Temperature-Dependent Thermal Parameter Identification of Ceramic Nanorod Aerogels Composite in the Ultrahigh Temperature Environment

The identification of the thermal properties of advanced materials is of great importance in engineering application. In this work, an inverse scheme is proposed to identify the temperature-dependent thermal parameters of ceramic nanorod aerogels (CNRAs) composite in the ultrahigh temperature environment up to 1873 K. The feasibility of the proposed method is successfully tested by an analytical solution for CNRAs with known material properties. Furthermore, the temperature-dependent thermal properties of CNRAs are successfully obtained using the experimental data acquired from the heat conduction experimental testing for a CNRAs plate. Lastly, the obtained thermal properties are used to simulate an arc-heated wind tunnel (AHWT) test of a receiving satellite antenna assembly using the FEM method. The simulated temperature at measured data has a very good agreement with the experimental data. This further demonstrates the strong capability of the proposed inverse method. In summary, the proposed approach provides an important approach for the identification of nonlinear and temperature-dependent thermal properties of advanced materials.

Mechanical model of needle-punched (NP) carbon/carbon (C/C) composites with isogeometric beams-extended springs at mesoscale

The NP C/C composites have strong load-bearing capacity in ultra-high temperature environments, become an indispensable material for aircraft production, which is widely used in aerospace sector. The NP preform transfers the fibers in the XY plane to the Z direction through the NP process, which overcomes the disadvantage of easy delamination of the C/C composites. However, the stiffness and strength in the layers of C/C composites are reduced by introducing defects. In this paper, a mesoscale mechanical model is proposed. Isogeometric circular arc beam element (CABE) is established to characterize the fiber bundles of NP C/C composites, and extended spring element(ESE) is established to characterize the matrix within layers, matrix and chopped fiber felt between layers, and chopped fiber felt at pinhole defects of NP C/C composites. By comparing the tensile, compression and bending tests with the simulation, the correctness of the mechanical model is fully confirmed.

Synergistic reinforcement effects of ZrB2 on the ultra-high temperature stability of Cf/SiC composite fabricated by liquid silicon infiltration

A carbon fiber-reinforced silicon carbide (Cf/SiC) composite was fabricated with ZrB2 via the liquid silicon infiltration (LSI) method. A prepreg was prepared by impregnating the phenolic resin with the ZrB2 powder. The as-LSIed composites were tested for 5 min with an oxyacetylene torch to evaluate their ablation and oxidation properties under an ultra-high temperature environment. The ZrB2 powders and SiC matrix between carbon fiber bundles generated a dense ZrO2-SiO2 layer, which inhibited further oxygen diffusion into the composite and minimized the ablation and oxidation of the carbon fibers. Weight loss and linear ablation rate were further reduced with the addition of ZrB2 to the Cf/SiC composite; moreover, the synergistic effect of ZrB2 and SiC reinforced the ablation properties with increased ZrB2 content. ZrB2 also reduced the amount of residual silicon, which was detrimental to the mechanical properties of Cf/SiC composite.

Carbon-deficient high-entropy (Zr0.17Nb0.2Ta0.2Mo0.2W0.2)C0.89: A potential high temperature and vacuum wear-resistant material

High-entropy carbides are promising materials as sliding structural components in ultra-high temperature environments due to their good phase stability and excellent mechanical properties. However, the tribological behaviors under coupling conditions of high temperature and vacuum environment have not been deeply evaluated. To fill such a gap, the high-temperature tribological properties of carbon-deficient high-entropy (Zr0.17Nb0.2Ta0.2Mo0.2W0.2)C0.89 (HEC0.89) prepared by using five binary carbides (ZrC, NbC, TaC, Mo2C, and WC) as starting materials were investigated. The microhardness and fracture toughness of HEC0.89 were 21.3 ± 0.5 GPa and 4.5 ± 0.2 MPa·m1/2. Most importantly, HEC0.89 exhibited low wear rate (lower than an order of 10-6 mm3/Nm) under vacuum environments from room temperature (RT) to high temperatures. Moreover, the lowest friction coefficient (0.31 ± 0.01) was obtained at 900 °C, which is attributed to the transferring of films consisting of low hardness oxidation products. These results clearly demonstrate the prospective for the application of high-entropy carbides as sliding parts in high-temperature and vacuum environments.

(Hf0.5Ta0.5)C ultra-high temperature ceramic solid solution nanowires

Ultra-high temperature ceramic (UHTC) nanowires are potential reinforcement materials due to it combines the perfect properties of bulk materials and unique geometric properties of one-dimensional (1D) nanostructures. Thus, developing 1D nanomaterials that have excellent morphology and structure retention in ultra-high temperature environments is of prime importance to bring their outstanding performance into full play. Herein, we report the novel solid solution ((Hf0.5Ta0.5)C) ceramic nanowires, which could not only maintain morphological and structural stability at 1900 °C but also exhibit 1D nanostructures under oxyacetylene scouring and ablation at 2300 °C. The morphology evolution of nanowires obeys the Rayleigh instability mechanism, and the internal structure and element distribution of nanowires remain unchanged even if the surface atoms are rearranged. The fascinating nanowires are demonstrated to have great potential as ideal reinforcement materials of composite materials and toughening phases of ceramics that are applied in ultra-high temperature environments, as well as excellent performance enhancement phases of functional materials. Our work may provide new insights into the development of ceramic nanowires and widen their applications.

A novel (Hf1/3Zr1/3Ti1/3)C medium-entropy carbide coating with excellent long-life ablation resistance applied above 2100 °C

Compared to conventional monocarbides, the oxides of medium/high-entropy carbides (M/HECs) expressed excellent antioxidant resistance and high-temperature structural stability, which are great potential to improve the oxidation/ablation resistance of carbon/carbon (C/C) composites. M/HECs ceramics coated C/C composites are ideal long-term ablation-resistant structural materials applied in ultra-high-temperature (above 2100 °C) and oxygen-containing environments. This work reported a novel MEC (Hf1/3Zr1/3Ti1/3)C coating first prepared on SiC-coated C/C composites. The fabricated MEC coating significantly prolonged the anti-ablation time (more than 210 s) above 2100 °C in an oxyacetylene flame ablation environment with a heat flux of 2.4 MW/m2, compared to monocarbide coating (less than 90 s). The ablated surface of MEC coating was composed of amorphous Zr–Hf–Ti–C–O oxycarbide pinned by m-(Hf, Zr, Ti)O2 nanoparticles, forming a unique structure of oxide scale for long-term ablation resistance. This work provides a new way to improve the ablation resistance of monocarbide coatings and develops a great promise for new-generation structural materials at ultra-high temperature environments.

High temperature protection performance of sandwich structure Al2O3/Si3N4/YAlO multilayer films for Pt–Pt10%Rh thin film thermocouples

The composition and microstructure of sandwich structure Al2O3/Si3N4/YAlO multilayer films deposited by magnetron sputtering were investigated. The results of X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) show that α-SiAlON and Y-doped α-SiAlON are formed at the interface of Al2O3/Si3N4 and Si3N4/YAlO respectively after nitrogen annealing at 1300 °C. The thermoelectric properties of S-type (Pt/Pt–10%Rh) thin film thermocouples (TFTCs) with Al2O3 and Al2O3/Si3N4/YAlO protective layers deposited by magnetron sputtering were investigated from 700 °C to 1550 °C. The high temperature static calibration results show that the thermoelectric performance of TFTCs with an Al2O3 protective layer begins to decline at 1350 °C, the drift rate of the TFTCs is 13.27 °C/h, and the TFTCs fail at 1550 °C. However, the drift rate of TFTCs with an Al2O3/Si3N4/YAlO protective layer is only 2.19 °C/h at 1350 °C, and the performance begins to decline significantly at 1550 °C with a drift rate of 82.89 °C/h. The S-type TFTCs with sandwich structure Al2O3/Si3N4/YAlO multilayer provides a good prospect for the application of TFTCs in ultra-high temperature environment.

Dolomitic Marble in a Context of UHT Metamorphism: Possible Signs of Melting, Lenadora Quarry, Sri Lanka

Abstract The Lenadora quarry, located 25 km north of Matale, in central Sri Lanka, exploits dolomitic marble on an artisanal scale. It is located in the Highland Complex but very close to its thrust contact with the Wanni Complex. The rocks have undergone metamorphism to the granulite facies; by analogy with metasedimentary rocks in a similar position south of Kandy, conditions of metamorphism may even have surpassed 900°C and 0.9 GPa. How did dolomitic marble fare in such an ultrahigh-temperature environment? High-resolution large-area image mosaics of imaged polished thin sections were acquired by using both light microscopy and scanning electron microscopy. We focus on fifty areas of interest. As expected, diopside and forsterite porphyroblasts appeared during prograde metamorphism. However, we did not anticipate to see subhedral porphyroblasts of forsterite mimetically replaced by diopside + dolomite. The conversion could have involved a fluid phase or a carbonate melt that had become locally enriched in silica. The presence of a melt accounts for composite calcite + dolomite globules trapped in forsterite. There is no evidence of breakdown products of dolomite, like periclase or brucite. The evidence that a carbonate melt was present is circumstantial; carbonate systems are notorious for erasing telltale evidence of melting. Other minerals encountered in the dolomitic matrix are phlogopite, pargasite, rutile, hydroxylapatite, zirconolite, lakargiite, a magnesiobeltrandoite-like phase, pyrrhotite, and calcite as a minor phase, some of which is of a second generation. Unreplaced relics of forsterite were partially serpentinized at a retrograde stage.

Compressive experimental method and properties of C/C composites under ultra-high temperature environment

Carbon/Carbon (C/C) composites are expected to serve as structural materials over 2800 ℃. Experiments under ultra-high temperatures (UHT) are critical and demanding. In this paper, we established the UHT compressive experiment technique using simultaneous Joule heating and compressive loading fixtures. The specimen was designed and validated to achieve uniform temperature and strain at the gauge section. Compressive strengths and failure behaviors of three-directional (3D) needled, 3D woven, and four-directional (4D) woven C/C composites under UHT up to 3100 ℃ were investigated. The failure modes and mechanism of strength differences were illustrated through mesoscopic surface morphologies. Results showed that the dog-bone-shaped specimen avoided crushing at loading ends and exhibited failure at gauge sections. Temperatures with peak compressive strengths for 3D and 4D woven C/C composites were determined. Differences between the C/C composites were related to heat treatment temperatures. The sublimation phenomenon was observed for 4D woven C/C composites over 3000 ℃, degrading the compressive strengths by over 50%.

Simulation Analysis and Fabrication of a Silicon Carbide-Based Piezoresistive Accelerometer

This paper proposes a Micro Electro Mechanical Systems piezoresistive accelerometer based on a whole SiC substrate. Compared with Si-based sensors, SiC-based sensors have stronger mechanical advantages and unique advantages for applications in ultra-high temperature environments. The characteristics of the accelerometer are designed and numerically simulated, and the accelerometer is evaluated in terms of stress load and working frequency band. An innovative design is carried out to eliminate the stress concentration phenomenon in the corner area of the sensor, which guarantees the working safety of the fragile structure of SiC. After fabrication, packaging and vibration experiment, it is found that the sensor’s working sensitivity can reach 0.21mv/g, and its linearity can reach 98%.