Application Of High Pressure Research Articles

An axial elastic deformation of ceramets on elastohydrodynamic lubrication of wavy-tilt-dam mechanical face seals

Purpose This paper aims to investigate the lubrication characteristics of siliconized graphite with a wavy-tilt-dam (WTD) pattern applied to the hydrodynamic face seals. Design/methodology/approach It focuses on two friction pairs, carbon graphite versus tungsten carbide (CG-TC) and siliconized graphite versus siliconized graphite (SG-SG), through a three-dimensional elastic hydrodynamic lubrication numerical model that integrates finite difference method and finite element method. The consequence of axial elastic deformation of sealing pair materials on film thickness, film pressure, cavitation and sealing performance for a WTD mechanical face seal under full working conditions of ΔP = 0.8, 5.3 and 15.8 MPa are analyzed theoretically. Findings The nuclear hydrodynamic WTD face seal generates a convergent gap and exhibits a dual-characteristic behavior of hydrodynamic and hydrostatic effects under various ΔP. Compared to the CG-TC, the SG-SG shows a lower minimum film thickness, decreasing by 3.9%, 17.3% and 35.1%. The flow leakage rate decreases by 47.8%, 52.1% and 75.4%. In addition, the film stiffness increases by 46.8%, 49.8% and 97.8%. Thus, the SG-SG better deals with the dynamic tracking problem, and the sealing performance is stable. The strength and hardness of siliconized graphite enhance WTD sealing performance and improve cavitation control in high-pressure applications. Originality/value The lubrication characteristics of the siliconized graphite with a WTD pattern could inform the future design of hydrodynamic shallow groove wavy seals in boiler feedwater engineering implements under high-pressure conditions for the nuclear power industry. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2024-0382/

Ester-Based Lubricant and Anti-Leidenfrost Additive Solutions on Aluminum High-Pressure Die-Casting Applications

The high-pressure die-casting process is growing since it is a cost-effective solution in the production of lightweight parts for a variety of industries. Nevertheless, the harsh working conditions of the die lead to premature failing and poor quality of the produced parts. Lubricants are applied to cooling the die surface and create a protective film to minimize die wear. However, the high temperature of the die during the casting production makes it difficult for the lubricant to reach the die surface due to the Leidenfrost effect. In this study, the effectiveness of newly developed ester-based lubricants designed to address Leidenfrost phenomenon in high-pressure die-casting is evaluated at laboratory and pilot plant scale. The new lubricants are based on the same ester solution; however, one of them includes a specially formulated anti-Leidenfrost additive to optimize performance at the temperature ranges typically encountered in industrial aluminum high-pressure die-casting processes. The results show a correlation between lubricant heat-transfer capability and aluminum adhesion. Additionally, a pilot plant methodology for testing newly formulated lubricants has been established while the experimental methodology developed for assessing heat-transfer capability is validated as a rapid and cost-effective approach for evaluating lubrication alternatives for high-pressure die-casting applications. Finally, the efficiency of environmentally friendly ester-based lubricants for high-temperature applications has been demonstrated.

Design and Analysis of Composite Materials for High-Pressure Environments

Composite materials have proved to be a critical application in high pressure application fields owing to their mechanical characteristics, light weight and flexibility. The current work is aimed at the design and investigation of sophisticated composite materials for high pressure applications and to overcome the drawbacks of metals and alloys. The study also discusses fibers such as carbon fibers or glass fibers, and matrices, with the focus on the best lay-up configurations and size-dependent anisotropic behavior. Several techniques like mechanical testing techniques, and finite element analysis techniques to estimate the mechanical properties like tensile strength, fatigue life and failure modes etc.. The study again stresses the comparative advantage of hybrid composite materials when it comes to stress strength, damage invulnerability, and stability. Suggestions for further studies include the investigation of bio based composites and optimization of the fabrication methodology for sustainability aspect. These outcomes prove useful for aerospace, marine and energy industries firms where high pressure resilience is paramount.

Comparative Analysis of External Gear Machine Performance Considering Deformation and Thermal Effects

The energy efficiency of external gear pumps (EGPs), as in other positive displacement machines for high-pressure applications, is significantly influenced by the power losses occurring in the lubricating interfaces that seal the internal displacement chambers. Therefore, it is crucial to account for these interfaces accurately when developing predictive simulation tools. However, in literature various modeling approaches can be found that consider different assumptions regarding the analysis of these interfaces. This makes it challenging for a designer to determine which physical domains needed to be modelled accurately in order to assess the EGP performance. This paper addresses the above research question by leveraging a comprehensive simulation tool (Multics-HYGESim) developed at the authors’ research team which includes thermal-tribological considerations pertaining to the meshing of the gears, the lubricating films at the tooth tip interfaces, at the journal bearings, and at the lateral interfaces. The tool considers realistic fluid properties, including the effects of cavitation and aeration, mixed lubrication effects, as well as material deformation effects for the gears, lateral bushings and the EGP housing. Additionally, recent advancements to the model, presented for the first time in this work, include coupled thermal analysis of the EGP, including fluid domain, lubricating interface domain and solid domain. The heat transfer evaluation in the solid domain allows predicting the body temperatures along with their thermal deformation. Material deformation effects strongly affect the internal balancing features of an EGP as well as its internal pressurization. All the mutual interaction between the geometrical domain, the body motions and their deformation, the fluid dynamic and the thermal domains make a realistic quantification of these effects difficult in simulation. Using a commercial EGP as a reference, for which experimental results are available concerning volumetric and hydromechanical efficiency, this paper demonstrates how predictions can vary based on different simulation assumptions regarding body and lubricating film behavior. The paper will present simulated predictions starting from a basic rigid body assumption that considers only body motion and analytical formulations of lubricating interfaces, to simulation model cases of progressively increasing in complexity to account for deformations different bodies i.e. the gears, bushings and the housing. The most complex case would include evaluation of thermal behavior along with deformation effects. A detailed distribution of power loss and leakages arising from different sources of hydromechanical and volumetric losses is presented for all cases under consideration. The results will offer valuable insights to EGP designers, enabling them to understand the strengths and limitations of different modeling assumptions on the prediction of EGP behavior, especially regarding the effects of body deformation.

Numerical Simulations of Thermodynamic Processes in the Chamber of a Liquid Piston Compressor for Hydrogen Applications

This paper presents the results of numerical simulations examining the thermodynamic processes during hydraulic hydrogen compression, using COMSOL Multiphysics® 6.0. These simulations focus on the application of hydrogen compression systems, particularly in hydrogen refueling stations. The computational models employ the CFD and heat transfer modules, along with deforming mesh technology, to simulate gas compression and heat transfer dynamics. The superposition method was applied to simplify the analysis of hydrogen and liquid piston interactions within a stainless-steel chamber, accounting for heat exchange between the hydrogen, the oil (working fluid), and the cylinder walls. The study investigates the effects of varying compression stroke durations and initial hydrogen pressures, providing detailed insights into temperature distributions and energy consumption under different conditions. The results reveal that the upper region of the chamber experiences significant heating, highlighting the need for efficient cooling systems. Additionally, the simulations show that longer compression strokes reduce the power requirement for the liquid pump, offering potential for optimizing system design and reducing equipment costs. This study offers crucial data for enhancing the efficiency of hydraulic hydrogen compression systems, paving the way for improved energy consumption and thermal management in high-pressure applications.

Pressure-induced phase transition from monomers to dimers in liquid crystals

ABSTRACT The crystal structures of liquid crystals, particularly various oligomers, have garnered significant attention, laying the groundwork for developing new materials and devices. Here, we demonstrate pressure plays a crucial role in the structure of liquid crystals. High-pressure Raman and photoluminescence spectra were on 5CB (4-cyano-4’−pentylbiphenyl) liquid crystal. Upon compression, the appearance of prominent fluorescence peaks suggests a phase transition. The Raman peaks, reflecting the C–H and C≡N bonds, exhibit splitting at a pressure of 3.2 GPa, further confirming the pressure-induced phase transition. The splitting is consistent with earlier calculations on the stretching vibration of the C≡N bond for various oligomers and indicates a phase transition from monomers to dimers in 5CB liquid crystal. The opposite shifts in Raman modes under pressure, specifically the blue-shift of C–H bonds and the red-shift of C≡N bonds, indicate that pressure enhances intermolecular interactions and leads to conjugation between the electrons on the C≡N bonds and the C–H bonds, resulting in dimer formation. Our findings not only reveal a novel strategy for producing oligomers in liquid crystals through the application of high pressure but also highlight that Raman spectroscopy is a valid, non-contact method for investigating the mechanisms of oligomerization.

Effect of Evaporation and Condensation Temperature on Performance of Organic Rankine System Using R134a, R417A, R422D, R245fa

Organic Rankine Cycles (ORCs) are identified as one of the most promising technologies for generating electricity from low-grade heat sources. Unlike conventional Rankine cycles, ORCs operate at lower temperatures and pressures. This allows them to utilize organic fluids or refrigerants as the working fluid instead of water, which is better suited for high-pressure and high-temperature applications. The performance and design of an ORC system are heavily dependent on the chosen working fluid. Therefore, selecting the right working fluid is crucial for a specific application, such as solar thermal, geothermal, or waste heat recovery. This study analyzed the performance of ORCs using four different working fluids: R-134a, R-245fa, R417A, and R422D. The researchers investigated how variations in condensation and evaporation temperatures affect thermal efficiency, mass flow rate, pump power, and turbine pressure ratio. The Engineering Equation Solver (EES) program was used for analyses. The results demonstrated that condensation and evaporation temperatures significantly influence system performance. The study found that ORC systems using R417A and R422D exhibited higher efficiencies compared to the other working fluids analyzed. Additionally, these fluids required lower mass flow rates per unit of power generation compared to the other fluids.

Modal analysis of laminated composite beams reinforced with randomly oriented fibers for aeronautical engine applications

Turbine blades are integral components of aircraft engines, directly influencing performance, efficiency, and safety. These blades operate under extreme conditions, facing high temperatures, significant mechanical stresses, and corrosive environments. Therefore, the selection of appropriate materials for turbine blades is crucial to ensure their reliability, engine efficiency and longevity. The present paper is focused on modal analysis of the laminate beam in layers’ carbon (mast) / ceramic. In this study, we use the Euler-Bernoulli hypothesis for the fins which considered the fin as a simple beam. The simulation was performed using Ansys software to assess the natural frequencies and mode shapes of the laminated beam under bending loads. The results compared to those of beams made from supper alloys used in aircraft engines. The findings reveal that the laminate composite beam exhibits greater dynamic stability than its alloy counterparts. This enhanced stability suggests that laminated composite materials are particularly suited for high-pressure applications, where performance and reliability are critical. Notably, the composite material with carbon mast (HM) demonstrates superior mechanical properties, including increased rigidity, reduced micro-cracking, improve efficiency and performance of flight engines and increased lifetime. Finally, this study underscores the importance of innovative materials in aeronautical engineering, highlighting the advantages of laminated composites in dynamic applications.

Shelf Life and Organoleptic Attributes of Multifruit Smoothies Treated by Combined Mild Preservation Technologies

The application of high hydrostatic pressure and mild heat treatment represents preservation processes for extending the shelf life of food products without compromising their quality. The combination of these physical methods at lower applied levels represents a promising approach to preserving the quality of treated products. This study aims to investigate the impact of combined treatments on the quality and storage stability of strawberry, banana, almond milk and avocado smoothies. The total colony count, electronic nose and tongue signals, colour, viscosity and sensory properties were examined over a 14-day storage period at 6 °C. The combined treatments were found to be effective in reducing the total colony count. During the sensory analysis, the impact of storage was the most prominent factor. Both the treatments and storage conditions significantly affected the colour characteristics of the samples. The smoothie samples exhibited pseudoplastic flow behaviour. Both applied treatments resulted in enhanced texture stability of the samples during the storage period. The electronic tongue and nose could differentiate between groups of fresh and stored samples, as well as between control and treated samples.

Changes in the microbiota and colour of pork meat batter during refrigerated storage in relation to the application of High Hydrostatic Pressure

The aim of this work was to study the effect of High Hydrostatic Pressures (HHP) on microbial degradation pattern and colour stability of pork meat batters used to produce fresh sausages. Besides treatments at 300 or 600 MPa for 5 min, pH (5.8 vs 5.4) and nitrite addition (100 vs. 0 mg/kg) were considered as variables. A not treated control was also monitored. The different samples were stored at 4°C and periodically analysed for their microbiota and colour. At the end of shelf life (TMC > 6.5 log CFU/g) a metagenomic analysis was also carried out to better clarify the effect of the treatments on microbial spoilage patterns. The results showed that the treatment at 300 MPa slightly affected initial cell load, but slowdown growth kinetics, especially at low pH, while 600 MPa strongly reduced microbial spoilage. The application of HHP was able to prolong shelf life of meat batters, from about two weeks (control) to 40 and 80 days in the case of treatments at 300 and 600 MPa, respectively. Metagenomic analysis revealed different degradation patterns in relation to tested variables: untreated samples showed the prevalence of Brochothrix spp., while the application of HHP determined the presence also of Carnobacterium, Bacillus, and Staphylococcus, depending on the treatment and the meat batter pH. Concerning colour, differences were mainly observed in redness (a*) and were due to the presence of nitrite. These findings suggest that HHP can be a feasible strategy to stabilize fresh sausages, although further studies are needed to assess their safety.

STRESS ANALYSIS OF THE MAIN COMPONENTS OF IMPROVED GATE VALVE CONSTRUCTION

This study explores the stress resistance of an improved valve design under high-pressure conditions, focusing on stress distribution across both the sealing element and the valve body. A 2D model of the valve was created in AutoCAD and analyzed using Python’s Matplotlib, simulating performance under pressures up to 75 MPa, 5 MPa above the operational limit. Results reveal critical stress patterns, with stress concentrations reaching up to 325 MPa along the inner radius of the sealing element and valve body. Radial, longitudinal, and circumferential stresses were evaluated, showing a gradual decrease in compressive forces from the inner to outer surfaces. The contact areas between the sealing element and valve body emerged as critical zones, with high-pressure exposure raising the risk of early material fatigue and functional degradation. Overall, the improved valve design exhibits significant resilience under high-pressure conditions. However, sustaining this performance over time will require proactive inspection and maintenance to prevent premature wear and material fatigue. This research provides valuable insights for enhancing valve designs and improving durability in high-pressure applications within the oil and gas industry. The analysis demonstrates that the improved valve design can withstand high pressures effectively, but highlights the importance of routine inspection and maintenance to prevent premature failure due to material fatigue. Continuous monitoring, particularly around the inner radius and critical contact areas, is recommended to ensure operational longevity and reliability under fluctuating pressure conditions. Keywords: Linear motion valve, body, finite element analysis, wear, seal.

Squeezing Out Nanoparticles from Perovskites: Controlling Exsolution with Pressure.

Nanoparticle exsolution has emerged as a versatile method to functionalize oxides with robust metallic nanoparticles for catalytic and energy applications. By modifying certain external parameters during thermal reduction (temperature, time, reducing gas), some morphological and/or compositional properties of the exsolved nanoparticles can be tuned. Here, it is shown how the application of high pressure (<100bar H2) enables the control of the exsolution of ternary FeCoNi alloyed nanoparticles from a double perovskite. H2 pressure affects the lattice expansion and the nanoparticle characteristics (size, population, and composition). The composition of the alloyed nanoparticles could be controlled, showing a reversal of the expected thermodynamic trend at 10 and 50bar, where Fe becomes the main component instead of Ni. In addition, pressure drastically lowers the exsolution temperature to 300°C, resulting in unprecedented highly-dispersed and small-sized nanoparticles with a similar composition to those obtained at 600°C and 10bar. The mechanisms behind the effects of pressure on exsolution are discussed, involving kinetic, surface thermodynamics, and lattice-strain factors. A volcano-like trend of the exsolution extent suggests that competing pressure-dependent mechanisms govern the process. Pressure emerges as a new design tool for metallic nanoparticle exsolution enabling novel nanocatalysts and surface-functionalized materials.

Electrical Conductivity and Sound Velocities of Talc Under High Pressure and High Temperature Conditions and Application to the Subducting Cocos Plate

AbstractTalc is expected to be an important water carrier in Earth's upper mantle, and understanding its electrical and seismic properties under high pressure and temperature conditions is required to detect possible talc‐rich regions in subduction zones imaged using geophysical observations. We conducted acoustic and electrical experiments on natural talc aggregates at relevant pressure‐temperature conditions. Compressional wave velocity (Vp) was measured using ultrasonic interferometry in a Paris‐Edinburgh press at pressures up to 3.4 GPa and temperatures up to 873 K. Similar Vp values are obtained regardless of the initial crystallographic preferred orientation of the samples, which can be explained by talc grain reorientation during the experiment, with the (001) plane becoming perpendicular to the uniaxial compression axis. Electrical conductivity of the same starting material was determined using impedance spectroscopy in a multi‐anvil press up to 6 GPa and 1263 K. Two conductivity jumps are observed, at ∼860–1025 K and ∼940–1080 K, depending on pressure, and interpreted as talc dehydroxylation and decomposition, respectively. Electrical anisotropy is observed at low temperature and decreases with increasing pressure (∼10 at 1.5 GPa and ∼2 at 3.5 GPa). Comparison of acoustic and electrical results with geophysical observations in central Mexico supports the presence of a talc‐bearing layer atop the subducted Cocos plate.

Interrogating the Role of Stack Pressure in Transport‐Reaction Interaction in the Solid‐State Battery Cathode

AbstractAs solid‐state batteries (SSBs) emerge as leading contenders for next‐generation energy storage, chemo‐mechanical challenges and instabilities at solid‐solid interfaces remain a critical bottleneck. Ensuring sufficient interfacial contact within composite cathode architectures often requires the application of high stack pressures, posing a significant hurdle in the development of viable, large‐scale SSBs. In this work, the impact of stack pressure is investigated on the performance of solid‐state composite cathodes comprised of single‐crystal LiNi0.5Mn0.3Co0.2O2 (SC‐NMC532) active material particles and a Li6PS5Cl (LPSCl) solid electrolyte phase. By unraveling the complex interplay between stack pressure and microstructure‐dependent mechanisms, the profound influence on interfacial resistances, cathode utilization dynamics, current constriction effects, and lithiation heterogeneities are revealed. Through a comprehensive examination of coupled reaction kinetics and transport interactions at the electrode and particle length scales, the implications of stack pressure at different C‐rates and microstructural arrangements are elucidated, thereby delineating the limiting mechanisms that are prevalent at low stack pressures. This work underscores the critical role of optimizing the cathode microstructure to mitigate the chemo‐mechanical challenges associated with SSB operation at low stack pressures, offering valuable insights and design guidelines for the development of high‐performance SSBs.

Pressure-controlled luminescence in fast-response barium fluoride crystals

Cross-luminescence (CL) in a barium fluoride (BaF2) scintillator arising from the recombination of a valence band electron and a core band hole results in a fast picosecond decay time. However, the CL emission wavelength in the vacuum ultraviolet region is difficult to detect, and intrinsically intense and slow nanosecond self-trapped exciton (STE) luminescence occurs. Herein, we report a redshift in the CL emission wavelength with high-pressure application. The wavelength of the CL emission shifted from 221 nm to 240 nm when 5.0 GPa was applied via a sapphire anvil cell. Increasing the pressure decreases the core-valence bandgap due to the downward expansion of the valence band, resulting in a decrease in the valence band minimum. The onset of a phase transition from a cubic crystal structure to an orthorhombic crystal structure at 3.7 GPa inhibited the recombination of conduction band electrons and self-trapped holes, leading to the disappearance of the STE emission. Manipulating the band structure of BaF2 by high-pressure application enables control of its luminescence emission, providing a pathway toward solving the problems inherent in this leading fast-response scintillator.

Effects of acoustic shock waves on the structural and optical properties of cadmium borate

Cadmium borate (CdB₂O₄), an inorganic compound combining transition metals and non-metals, has a broad range of optical applications. In this study, CdB₂O₄ was subjected to acoustic transient pressure using a semi-automatic Reddy tube, with shock pulses applied at counts of 100, 200, 300, and 400 at a Mach number of 1.5, corresponding to a transient pressure of 0.59 MPa and a temperature of 520 K. Control and shock-treated samples were analyzed using XRD, Raman, FTIR, SEM, UV-DRS, and photoluminescence spectroscopy to investigate shock wave effects. The XRD analysis revealed peak disappearance, the formation of new peaks, increased crystallinity, and instability in crystallite size. Raman spectroscopy showed peak disappearance, shifts, and broadening of lattice modes. SEM indicated increased particle size and agglomeration under shock conditions, consistent with changes in crystallinity. UV-DRS analysis shows a slight change in their band gap. Photoluminescence exhibited fluctuating trends in luminescent properties after the shock treatment. The findings reveal that CdB₂O₄'s structural and optical properties are sensitive to acoustic pressure, suggesting its potential for tailored optical behavior in specific applications. These results enhance our understanding of how acoustic pressure affects CdB₂O₄ and open new possibilities for optimizing its use in high-pressure applications.

Kinetics of Hydrolytic Depolymerization of Textile Waste Containing Polyester

Textile products comprise approximately 10% of the total global carbon footprint. Standard practice is to discard apparel textile waste after use, which pollutes the environment. There are professional collectors, charity organizations, and municipalities that collect used apparel and either resell or donate them. Non-reusable apparel is partially recycled, mainly through incineration or processed as solid waste during landfilling. More than 60 million tons of textiles are burnt or disposed of in landfills annually. The main aim of this paper is to model the heterogeneous kinetics of hydrolysis of multicomponent textile waste containing polyester (polyethylene terephthalate (PET) fibers), by using water without special catalytic agents or hazardous and costly chemicals. This study aims to contribute to the use of closed-loop technology in this field, which will reduce the associated negative environmental impact. The polyester part of waste is depolymerized into primary materials, namely monomers and intermediates. Reaction kinetic models are developed for two mechanisms: (i) the surface reaction rate controlling the hydrolysis and (ii) the penetrant in terms of the solid phase rate controlling the hydrolysis. A suitable kinetic model for mono- and multicomponent fibrous blends hydrolyzed in neutral and acidic conditions is chosen by using a regression approach. This approach can also be useful for the separation of cotton/polyester or wool/polyester blends in textile waste using the acid hydrolysis reaction, as well as the application of high pressure and the neutral hydrolysis of polyester to recover primary monomeric constituents.

Isolation of valuable substances from berry seeds and pomace by the green high-pressure methods, their evaluation and application in cosmetic creams

Berry seeds and pomace generated as a by-product of fruit processing contain valuable nutrients and bioactive compounds; however, nowadays it is inefficiently recycled or even discarded as a waste. Valorisation of such by-products for the development of higher value ingredients would substantially increase the sustainability of the sector. For this purpose, green extraction methods with supercritical CO2 (SFE-CO2) and pressurized liquid (PLE) extraction with hydro-ethanol were consecutively applied to strawberry, blackberry and elderberry seeds and rowanberry pomace for the isolation of lipophilic and higher polarity substances. SFE-CO2 extracts were rich in unsaturated fatty acids (oleic, 10.76 − 23.25 %; linoleic, 39.11 −59.74 %; linolenic, 1.32 − 43.83 %), tocopherols (31 – 637 μg/g), phytosterols (1992 – 3775 μg/g), carotenoids (65.06 – 2147 μg β-carotene/g) and chlorophylls (27.95 – 130.4 μg/g). Anthocyanins (22.7 – 697.6 mg cyanidin-3-O-glucoside equivalents/100 g), flavonoids (2.75 – 7.43 mg quercetin eqv./g), proanthocyanidins (122.2 – 199.4 catechin monohydrate eqv./g), antioxidant and antibacterial properties were evaluated for the PLE extracts. The extracts were tested in cosmetic creams at 2 % concentrations and strawberry seed extracts were selected for the evaluation of cream properties. In general, PLE extract addition had slight effect on antioxidant properties and sun protection factor of creams. However, considering the presence of high value constituents both in the lipophilic and hydrophilic extracts and the studies showing the benefits of the use of these constituents in cosmetic products, it may be expected that the extracts may be promising ingredients in developing new natural cosmetic products, including cosmeceuticals. In addition, the extracts may be promising ingredients in the formulation of nutraceuticals.

Insulating Material with Scale Components for High-Temperature and High-Pressure Water Applications.

Accurately measuring water holdup in horizontal wells is crucial for effectively using heavy oil reservoirs. The capacitance method is among the most widely used and accurate techniques. However, the absence of suitable insulating materials at high temperatures and pressures limits the effectiveness of capacitive water holdup measurement in heavy oil thermal recovery. This study introduces a new composite material based on an aviation-grade, special glass glaze as the insulating medium doped with inorganic components (CaSO4, MgSO4, Ca(OH)2, and SiO2). This new composite material demonstrates outstanding insulating performance under high-temperature and high-pressure conditions in water. A water environment with a high temperature of 350 °C and a pressure of 12 MPa considerably enhances the composite material's insulation. After 72 h of continuous use, the insulation performance remains 0.3 MΩ. The layers exhibit improved insulation and stability, maintaining integrity through five consecutive temperature shocks in 500 °C air and 20 °C water. XRD, IR, SEM, and TEM analyses reveal that the new composite material is amorphous after firing and that the addition of inorganic components improves the bonding between the glass glaze components and contributes to a denser structure. Simultaneously, SEM and TEM analyses indicate that adding inorganic components results in a smoother, crack-free, and more compact surface of the special glass glaze. This enhancement is crucial for the material's long-term stability in high-temperature and high-pressure water environments.

The structural mechanisms of pressure-induced phase transitions in the Carpy-Galy phase layered perovskites

In layered perovskites with the Carpy-Galy structural type, similar structural phase transitions occur under high pressure. These structural changes, which are crucial for the pressure-induced phase transition in layered perovskite, were analyzed based on experimental X-ray diffraction data. The tilting of the Ti-O6 octahedra and the distortion of the arrangement of rare-earth atoms were studied in detail. Changes in these structural features in layered perovskite serve as common indicators of the phase transition to the monoclinic phase that occurs under high pressure application.