High Temperature Atmosphere Research Articles

Study of black glaze and sauce glaze porcelains from Dangyangyu kiln during the Song and Jin Dynasties, China

In the Song and Yuan Dynasties of China, numerous renowned kilns simultaneously employed black glaze and sauce glaze porcelain; however, limited research has been conducted on the differentiation of process systems and the potential existence of a transforming relationship between these two types of porcelains from the same kiln. In this study, the black glaze, sauce glaze and flambé (窑变, Yaobian) glaze porcelain from Dangyangyu kiln during the Song and Jin Dynasties were selected to compare their optical characteristics, firing and formula process via OM, LRS, SEM-EDS, XPS, DIL and EDXRF methods. The research reveals that notable distinctions exist in the glazing process between black glaze and sauce glaze porcelain; while the former demonstrates thicker glazing techniques, the latter showcases thinner glazing techniques. Sauce glaze porcelains undergo firing at high temperatures within strong reducing atmospheres and differs from black glaze in terms of their formulation processes. The sauce glaze is composed of high Al clay with a low flux content, making it a calcium-alkali glaze. On the other hand, the black glaze has a higher flux content and falls under the category of high calcium glazes. Through the investigation of flambé glaze, it was observed that despite a thicker black glaze layer does not promote Fe enrichment on the glaze surface, however, when the flux content in the glaze is lower, meanwhile accompanied by a high temperature and strong reducing atmosphere firing process, the glaze exhibits a dynamic tendency towards the formation of sauce coloration.

Solvent-free Simplistic Synthesis of Bis(indolyl) Methanes Using Tulsion®-8052 MP Resin

Abstract: Tulsion®-8052 MP cation resin catalyst accelerates chemical reaction by creating a suitable environment for the aldehyde and indole reactants to interact and form desired product bis(indolyl) methanes in solvent-free room temperature conditions. The uniqueness of this catalytic method is that it is eco-friendly, recyclable, selective, and operates on a variety of functional groups with good to excellent yield at room temperature conditions without the use of any hazardous solvents, high temperature, and inert atmosphere.

Fretting fatigue crack initiation and propagation behaviours of Ti6Al4V alloy coated by functionally graded material

Fretting fatigue pertains to the behaviour of engineering components undergoing cyclic loading while in contact with each other. This intricate contact-related phenomenon often results in premature failure compared to conventional fatigue issues. Moreover, when these components operate in high-temperature atmospheres and experience high wear conditions, such as the heat transfer tubes in the nuclear reactor, the application of Functionally Graded Material (FGM) coatings becomes essential. Consequently, it is imperative to investigate how FGM coatings influence the initiation and propagation behaviour of fretting fatigue cracks. This paper employs the Critical Plane (CP) method to calculate the damage parameter. Additionally, Linear Elastic Fracture Mechanics (LEFM), specifically the Extended Maximum Tangential Stress (E-MTS) criterion, is utilized to examine how FGM coatings affect the paths of fatigue crack propagation in the presence of fretting conditions. Meanwhile, due to the unavailability of material properties of FGM coatings, the damage parameter and stress intensity factors are utilized to indirectly assess the effect of FGM coatings on crack initiation and propagation lifetimes. The FGM coating significantly influences tangential stress, thereby affecting the length of the stick zone, while having minimal impact on the distribution of normal stress along the contact surface. Furthermore, it is observed that adjusting the variation in composition of FGM coatings and the elastic modulus of the first FGM coating layer provides a potential technique for enhancing both crack initiation and propagation lifetimes.

Microstructure and mechanical properties evolution of 310S and GH3536 in hydrogen metallurgy service

The evolution of microstructure and mechanical properties of 310S austenitic stainless steel and GH3536 nickel-based alloy in hydrogen metallurgy service condition is investigated by conducting heat treatment under high temperature and hydrogen atmosphere. As the annealing time increases at 750 °C, carbide precipitate phases of the σ and μ brittle phases appear in the materials. At 900 °C, the dissolution of carbides induces the dispersion of brittle phases, while the hydrogen content reaching its peak. These brittle phases are still present at defects like grain boundaries at 1050 °C, with the surface of precipitates showing corrosion pits. Materials exhibit increasing strength and hardness initially with temperature and annealing time, followed by a decrease. Meanwhile, fracture elongation shows a positive correlation with temperature but a negative correlation with time. After annealing at 1050 °C for 500 h, GH3536 retains its high-temperature softening behavior and elongation at fracture, demonstrating excellent plastic stability. Furthermore, the mechanism of high temperature and hydrogen affecting metals is expounded, providing reference for the selection and optimization of materials which service in high temperature and hydrogen.

Physico-chemical analysis of the properties and stability of CdS and CdS:O to be applied in thin-film solar cells

Oxygenated cadmium sulfide (CdS:O) has emerged as a promising photovoltaic material, improving the CdTe solar cell spectra response and due to its potential, it could be applied in different kinds of thin-film solar cells. However, despite CdS:O benefits, its stability and its interface with CdTe have not been widely studied. This work study the physico-chemical properties of CdS and CdS:O films are studied, in addition a window layer is proposed consisting of CdS/CdS:O (bi-layer). Analyzing these samples in three stages: 1) as-deposited, 2) annealed, and 3) after CdTe deposit in order to determine its stability.The results showed that high temperature and reactive atmosphere generates a structural rearrangement and secondary phase formation in the window layer. Chemical composition was analyzed by XPS deep profile, suggesting a homogenous element distribution into film. The implementation of the bilayer in CdTe/bi-layer/glass structure helped to control the oxygen interdiffusion towards to absorber layer; this improves the stability at the cell junction, thereby increasing the electrical properties in the solar cell.

Transport cross sections and collision integrals for N(4S)–O(3P) and N(4S)–O(1D) interactions in high-temperature air plasmas

Collisions between nitrogen (N) and oxygen (O) play a crucial role in determining transport coefficients in high-temperature atmospheres of Earth and planetary. In this study, the momentum transfer, viscosity, third-moment, and fourth-moment transport cross sections for the N(4S)–O(3P) and N(4S)–O(1D) interactions are reported in the collision energy range of 10−6–10 Hartree based on the classical and semiclassical methods. The new and accurate potential energy curves for N–O interactions, which are used to provide the input for calculations of the cross sections, are calculated based on the state-of-the-art ab initio method. The classical and semiclassical collision integrals are provided at 300–50 000 K, and the results support the calculation of transport coefficients in a third-order approximation. In particular, the collision data for the N(4S)–O(1D) interaction based on ab initio points are reported for the first time. The calculated transport cross sections and collision integrals are helpful for studies of modeling the high-temperature air plasmas.

High-Temperature Steam and Atmospheric Oxidation Characteristic of a Heat-Resistant SP2215 Steel

The high-temperature oxidation performance of SP2215 has become an important issue when they were used as superheaters and reheaters exposed to two different high-temperature environments. In this study, the oxidation behavior of SP2215 steel was investigated under steam and an atmosphere of 650–800 °C for 240 h. The microstructural and chemical characterization of the samples were performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), a glow discharge optical emission spectrometer (GD-OES), and atomic force microscope (AFM). The kinetic curves of oxidation revealed excellent oxidation resistance under both environments, but significant different oxidation characteristics, oxide film composition, and structure were obvious. In the steam experiment, selective intergranular oxidation was evident at relatively low temperatures, which was attributed to the preference absorption of supercritical water molecules at the grain boundary. Conversely, a double-layer structure of outer Fe2O3 and a small amount of Fe3O4 and inner Cr2O3 was formed uniformly at 800 °C. In the high-temperature atmosphere experiment, a protective chromium film was dominant at 650–700 °C, and a loose multicomponent oxide film was formed at 750–800 °C, primarily consisting of Cr2O3, spinel FeCr2O4, and CuO.

Oxidation Behavior of Atmospheric Plasma Sprayed NiAl Coating at High Pressure Oxygen Atmosphere

The high-temperature and high-pressure oxygen-rich combustion gases often cause the high temperature gas conduit in rocket engine to suffer severe oxidation, resulting in a reduced service life. The present study deposited a dense NiAl coating on GH4202 superalloy using atmospheric plasma spraying and investigated its oxidation behavior in a high temperature and high-pressure oxygen atmosphere. The results showed that the NiAl coating presented excellent bonding with the superalloy substrate throughout tests. The uncoated GH4202 substrate was severely oxidized during high pressure oxygen atmosphere. It was found that only a continuous very thin Al2O3 oxide scale evolved on the NiAl coating surface and no oxidation was observed at the interface between the NiAl coating and GH4202 substrate. Moreover, no significant inner oxidation occurred to NiAl coating. Therefore, the present APS NiAl coating can provide effective protection of superalloy from oxidation at high pressure oxygen combustion gas atmosphere.

Enhanced efficiency and long-term stability of all inorganic CsPbBr3 perovskite solar cells via regulation of charge separation and extraction by band engineered-Co3O4 nanocrystals as a hole transport material layer

Insertion of an inorganic HTM intermediate at the CsPbBr3/Carbon interface can significantly improve photo-generated holes extraction efficiency without sacrificing advantages in device stability. Herein, low-cost and eco-friendly Co3O4 nanocrystals were synthesized by precipitation method and utilized as efficient inorganic HTM for CsPbBr3 PSCs. By regulating the hole quasi-fermi level (Ef, HTL) of the perovskite film with Co3O4 nanocrystals possessing a lower conduction band (CB), the built-in electric field (BEF) inside the CsPbBr3 can be reinforced, for which the Co3O4-induced energy level reconstruction facilitates fast charge separation and extraction because of the intensified driving force. In addition, the charge recombination behavior can be effectively inhibited. Finally, all inorganic CsPbBr3 PSCs with an architecture of FTO/c-TiO2/m-TiO2/CsPbBr3/Co3O4/carbon PSC realizes efficiency of 8.92% with an open-circuit voltage (Voc) of 1.531 V. Furthermore, the unencapsulated Co3O4-based PSC exhibits excellent stability in ambient air, keeping 98% of its initial efficiency after 90 days in 80% high humidity condition, and 97% of initial efficiency after 40 days in a high-temperature atmosphere of ∼80 °C.

High-temperature high-cycle fatigue performance and machine learning-based fatigue life prediction of additively manufactured Hastelloy X

Uncertainties in fatigue life of laser powder bed fusion (L-PBF) additively manufactured parts arise from microstructural heterogeneities and randomly dispersed defects generated during the L-PBF. Stress-controlled fatigue performances of L-PBF-built Hastelloy X were examined in 400 °C and 600 °C high-temperature atmospheres. Given the inherent anisotropy of the L-PBF-built Hastelloy X, the fatigue tests were performed on the samples with distinct building orientations. Fatigue-induced damage evolution characteristics were meticulously analyzed after drawing the S-N curves with a 0.1 stress ratio, a 20 Hz loading frequency and varied stress amplitudes. We established a database of the fatigue test results with material properties of the L-PBF-built Hastelloy X to build a machine learning (ML) framework for fatigue life prediction, skipping the traditional fatigue-life mathematical models that are less applicable to L-PBF-built metals. For capturing the intricate influence of diverse factors on the fatigue life accurately, deep neural network (DNN) and support vector machine (SVM) were utilized and optimized within the ML-based framework. By comparing our ML-based approach with traditional methods for life prediction, it is indicated that ML techniques can transcend the physical limitations associated with the fatigue processes while simultaneously offering a unified depiction thereof.

Unveiling the failure mechanism on creep response of a casting Ni-based superalloy in thin-wall thickness

With the improvement of thermal efficiency and the lightweight tendency of engine blades, Ni-based superalloy is widely used owing to its excellent performance in high-temperature atmospheres. This work studied the effects of surface oxidation, internal environmental attack, and matrix damage on the failure mechanism in a thin-walled casting Ni-based superalloy at 980 °C/160 Mpa. At the edge of the fracture, the sample suffered a severe environmental attack, resulting in the oxidation-affected zone forms. However, the loss of effective bear area induced by surface damage could not be the main reason for the sample's failure. At the interior of the matrix, voids were preferably initiated at the interface of MC carbides. As the increase of creep deformation, dynamic recrystallization (DRX) occurred at the tip of the voids, which increased the transverse grain boundaries and promoted crack propagation. Moreover, the DRX provided a short penetration path for the nitrogen, causing internal nitridation with AlN and Ti(Ta)N to precipitate. EBSD analysis confirmed that nitrides induced significant dislocations to accumulate at the boundaries of nitrides/γ, accelerating the failure of the sample.

Nonlinear ultrasonic techniques to quantify oxidation damage in carbon/carbon composite material

This research applies linear and nonlinear ultrasonic (NLU) techniques to quantify oxidation damage in a carbon/carbon (C/C) composite material cut from an automotive friction disc ring. The oxidation as a result of gasification of carbon at high temperatures (T >∼ 500 °C) is a major degradation mechanism in C/C composites. This is the first research to successfully use a dry-contact mediator wedge setup for nonlinear ultrasonic applications, enabling repeatable in-situ Rayleigh wave measurements on slow wave velocity materials where submersion is impractical. The samples are subjected to thermal damage by exposure to a high temperature atmosphere over multiple holding times, and the oxidation damage is visualized using scanning electron microscopy (SEM). The sample mass is recorded and both linear (velocity and attenuation) and nonlinear (β′) ultrasonic measurements are performed after each holding time. Superior sensitivity to early stage oxidation affirms the suitability of nonlinear Rayleigh wave measurements for the quantification of thermally induced oxidation damage in C/C composites, while the double mediator wedge setup is well suited for high attenuation, slow wave velocity materials, demonstrating potential applicability for in-situ condition monitoring. The results show that a systematic oxidation starts after 3 min of exposure to the temperature in this C/C composite. The oxidation induced fiber–matrix debonding, matrix defects (appearing to be microcracking), and void growth are consistently detected by the Rayleigh wave velocity and acoustic nonlinearity. In addition to the higher sensitivity, the nonlinearity parameter has the capability of selectively measuring the strength related damage such as the observed fiber–matrix debonding, while the wave velocity can detect the oxidation voids. A combined use of these two parameters can provide useful information on the microstructural evolution in C/C composites subjected to high temperatures.

Wireless Sensor Network Based Early Fire Detection System

Every year millions of hectares of forest are devastated by fire. Forest fires may occur due to Natural causes or Man-made causes. Natural causes include lightning which set trees on fire, High atmospheric temperatures and dryness (low humidity). Man-made causes include naked flame, cigarette or bidi, electric spark or any source of ignition that comes into contact with inflammable material. Reason could be any, but important is forest fire causes huge damage to forest and nature. Infact, fires on large scales cause air pollution, mar quality of stream water, threaten biodiversity and spoil the aesthetics of an area. Forest fire causes imbalances in nature and endangers biodiversity by reducing faunal and floral wealth. Therefore, there is a need to develop methods for timely detection of forest fire so that damage is minimum. Existed methods for forest monitoring and fire detection are traditional and based on human observation, satellite imaging, use of digital cameras. There are several drawbacks associated with them such as inefficiency, power consumption, latency, accuracy and implementation costs. Therefore, to address these problems the deployment of automatic fire detection system is necessary to allow early and fast fire extinction. In this paper we present an early fire detection system based on Wireless Sensor Network.

The impact of anthropogenic activity on the heat resistance and condition of green spaces in the Central and Kirovsky Districts of Volgograd

This paper examines the impact of anthropogenic activity on the heat resistance and condition of green spaces in the Central and Kirovsky Districts of Volgograd. The method of the analyzed diagnostics of the state of green spaces used in the experiment is described the determination of heat resistance by the degree of damage to chlorophyll-bearing tissues according to F.F. Matskov. The role of the impact of motor transport on the degree of endurance by green spaces of high atmospheric temperatures is considered. The paper presents the results of a study of the heat resistance and state of trees under conditions of various levels of anthropogenic load. The study of the negative human impact on the state and degree of resistance to the action of high temperatures was carried out in the Central and Kirovsky Districts of the city of Volgograd. The studied territories belonged to a residential or park area, as well as transport. The experiments have shown that the indicators of the stability of tree plantations located near the highway and the residential area differ in terms of indicators. Exhaust gases from vehicles reduce the heat resistance of vegetation and their productivity. The obtained materials can serve as a basis for further monitoring of the state of green spaces in Volgograd and carrying out further measures of greening the city.

AUBERT & DUVAL NY690

Abstract Aubert & Duval NY690 (NiCr30Fe alloy) is a high-chromium nickel alloy that has excellent resistance to many corrosive aqueous media and high temperature atmospheres. In addition to its corrosion resistance, Aubert & Duval NY690 has high strength, good metallurgical stability, and favorable fabrication characteristics. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming and heat treating. Filing Code: Ni-783. Producer or source: Aubert & Duval S.A.

High-performance diatom co-doped Ti3C2Tx electrode material based on guanidine salt

The co-doping of a variety of heteroatoms can enhance the chemical reactivity and electron transport capacity of the composites. However, the doping process of Ti3C2Tx is usually carried out under harsh reaction conditions such as high temperature and protective atmosphere, which is easy to destroy the two-dimensional structure of Ti3C2Tx. Therefore, it is necessary to create doping conditions with reducing environment. In this work, Sulfur-nitrogen and phosphorus-nitrogen diatomic co-doped Ti3C2Tx ((S, N)-Ti3C2Tx and (P, N)-Ti3C2Tx) are first prepared using two weakly reducing guanidine salts, and the corresponding electrodes are prepared. The electrochemical test results show that at 1 A g−1, the Cm of (S, N)-Ti3C2Tx and (P, N)-Ti3C2Tx is 269.3 F/g and 168.3 F/g, which are 2.03 times and 1.27 times that of Ti3C2Tx (132.6 F/g), respectively. In addition, guanidine salt doping also gives Ti3C2Tx improves cycle stability. These results show that (S, N)-Ti3C2Tx and (P, N)-Ti3C2Tx can be used as excellent electrode materials for high-performance supercapacitors. Guanidine salt is a new heteroatomic source, and its processing operation provides a broader and more convenient experimental idea for heteroatomic doping.

Investigation of the early stage corrosion characteristics of molten (nitrate) salt – oxide – metal interfaces, and the links to interfacial thermo-mechanical stress

This paper investigates the early-stage corrosion behaviour of 4 alloys in solar-salt under air and argon at elevated temperatures for 7 days. The multi-layered interfacial corrosion oxides were observed to consist of an inner Cr-rich oxide and an outer Na/Fe-rich oxide. The inner tensile stress between the interfacial oxide layers were observed to correlate to the spallation of the porous outer Na/Fe-rich oxide layer. The combination of chemical aggression of molten salt, high temperature and argon atmospheres, acts in synergy to increase the kinetics of formation of Na/Fe–rich outer oxide layer, and it’s tendency to degrade by spallation due to an inner tensile stress.

Spatially Heterogeneous Chemistry Observed using NIRTI on SOFC Anodes

Solid oxide fuel cells (SOFCs) are high temperature electrochemical conversion devices which are challenging to study due to their high operating temperature and dual atmosphere requirements. Traditional tools to study SOFCs are unable to resolve any spatial dependent chemistry which may be occurring on the cell. This study used Near Infrared Thermal Imaging (NIRTI) to identify spatially varying temperature changes indicative of heterogeneous chemistry occurred during C remediation reactions using gas phase oxidants and electrochemical oxidation on anode-supported SOFCs. The spatial dependences observed are probably due to kinetics and transport of the oxidizing species involved, which may provide insight for modeling SOFC kinetics and operation.

Mechanically Robust Nanoporous Polyimide/Silica Aerogels for Thermal Superinsulation of Aircraft

Polyimide aerogels (PIAs) are thermally insulating materials that possess various advantages, such as exceptionally high temperature resistance and low thermal conductivity, which make them great potential candidate materials to be applied in the area of thermal protection. However, under harsh mechanical stresses, the macro- and microscopic structural stability of PIAs may be compromised due to shrinkage/collapse, leading to performance degradation. Herein, we propose a homogeneous organic/inorganic hybrid formation strategy for constructing nanoporous polyimide/silica aerogels (PIAs-A) with exceptional mechanical strength and ultralow thermal conductivity. The results obtained indicate that PIAs-A have an optimal three-dimensional nanoporous network structure with a pore size distribution mainly within the range of 10–20 nm. Monitoring the temperature evolution of the material’s cold surface showed that it remained at a low temperature of 37.5 °C even when the material was placed against a hot surface of 150 °C. The residual mechanical strengths of the aerogels remained at a superior level (with strength degradation being less than 9%) after exposure to ultralow and high-temperature atmospheres. Furthermore, compressive stress values at 3% strain exceeded previously reported values for PIAs by 625 and 733% at −50 and 100 °C, respectively. Meanwhile, our aerogels displayed flame resistance even when exposed to a heat source of approximately 1200 °C, possessed favorable hydrophobic properties, and maintained dimensional stability up to 504 °C. The robust mechanical and thermal insulation properties of PIAs-A make them a promising substitute material for thermal superinsulation in aircraft.

Mesospheric and Upper Stratospheric Temperatures From OMPS‐LP

AbstractWe report the development of a temperature profile data set from the Ozone Mapping and Profiler Suite Limb Profiler (OMPS‐LP) instrument on the Suomi NPP satellite. The data set covers a roughly 10 year period from 2012 to 2022, and temperatures are provided in the altitude range between 35 and 70 km. The algorithm uses daytime Rayleigh scattered radiation near 350 nm to estimate atmospheric density profiles, which are vertically integrated using the hydrostatic equation to estimate atmospheric pressure. Temperature profiles are then derived using the ideal gas law. Spectral structures in the OMPS‐LP radiances are a source of systematic errors that limit the absolute accuracy to ±2 K. However, since the systematic errors do not change significantly over time, the relative accuracy is better than ±1 K. Our temperature data set has been designed to supplement global temperature maps produced by assimilation of data from traditional meteorological sensors, including GNSS radio occultation sensors, that provide high quality atmospheric temperature profiles up to 40–55 km. We show comparisons to other co‐located temperature datasets to validate our product.