Thermal Redistribution Research Articles

Task-orientated probabilistic damage model with interdependent degradation behaviors for RUL prediction of traction converter systems

Remaining useful life (RUL) prediction is crucial for the safety and reliability of engineering systems with stringent requirements, like high-speed trains. Previous studies on fixed or phased conditions ignore the effects of time-varying operations on survivability. Additionally, the stochastic dependence among units is often neglected. To address the above problems, a task-oriented probabilistic damage model with interdependent degradation behaviors (TPDM-IDB) and an RUL prediction method based on TPDM-IDB are proposed. The model integrates three relations: the fundamental relation from load to damage, the task-oriented relation from task to load, and the interdependence relation. First, the degradation process and variability of the failure unit are tracked based on failure physics, mapping load to damage. Next, a task-oriented thermal loading translation is proposed to dynamically update load under time-varying operations. Then, to address the underestimation of life caused by interdependent degradation behaviors, the degradation factor is adjusted by thermal load redistribution. Finally, considering the failure stochasticity, a decision simulation method based on structural reliability is employed to predict the RUL. The effectiveness of the proposed method is validated through simulation examples and actual case studies. Notably, the method uses system tasks as inputs, which is more suitable for practical engineering applications.

Thermal redistribution of compressive residual stress introduced by interlayer laser shock peening in hybrid additive manufacturing

The objective of this research was to quantify the change in magnitude and depth of compressive residual stress (CRS) retained in the subsurface by interlayer coldworking when subjected to localized annealing that superimposed tensile stress. The approach was to hybridize additive manufacturing of AlSi10Mg alloy by coupling powder bed fusion (PBF) with laser shock peening (LSP) and characterize the resultant residual stress state by the hole-drilling method. The research found localized annealing from layer deposition formed two distinct regions in the subsurface, which was driven by localized and bulk stress redistribution. The experiments also showed that residual stress redistribution from LSP reached 550 µm into the subsurface, whereas local annealing from the deposition of layers extended only to a depth of 160 µm. Hence, compressive stress imparted by LSP was not entirely canceled by local annealing from PBF. This work provides the first quantification of the stress state response of hybrid additively manufactured parts to thermal loads and is fundamental to improving part performance through increased functional reliability, fatigue life, and corrosion resistance.

Origin of thermal deformation induced crystallization and microstructure formation in additive manufactured FCC, BCC, HCP metals and its alloys

The additive manufacturing (AM) technology has received the widespread attention in the industrial application because of its unique ability to achieve the complex shape and ideal performance. Unfortunately, the impact of the material natural characteristics, such as the crystal structure and alloying, on the microstructure formation at the nanoscale has never been revealed in AM metals. Here, we use large-scale molecular-dynamics simulations to study the rapid thermal deformation processes of additively-manufactured face-centered-cubic (FCC), body-centered-cubic (BCC), hexagonal close-packed (HCP) metals and their alloys (FCC Cu, CuAl0.1, BCC Fe, FeAl0.1, and HCP Mg, MgAl0.1) in the molten pool, in an attempt to elucidate the intrinsic physical mechanisms controlling the crystal nucleation and growth under the complex thermal stress. The results show that the arcuate solid-liquid interface migrates towards the liquid phase until the complete crystallization, in good agreement with the experimental observation. The solidification rate follows a unified slow-to-fast law in the three types of metals, due to the competition between the compressive thermal stress and fast atomic motion. It is noteworthy that the critical radius of the crystal nucleus in the FCC and BCC metals is smaller than that in the HCP metal. The FCC metal exhibits the weak nucleation ability and growth rate, and yet the HCP metal shows the fast growth rate and stable columnar crystal nucleation. Especially, due to the dual regulation of the steep thermal gradient and solute redistribution on the growth driving force, the alloying increases the constitutive supercooling of the solidification front and inhibits the growth of columnar crystals. This trend is particularly prominent in FCC alloys, which is manifested by the obvious amorphous phase and discrete nucleation point in the upper part of the melt pool. The nucleation barrier free energy descends in order of FCC, BCC, and HCP pure metals, but the alloying would increase this energy in the corresponding alloys. The current work gives an insight into the atomic mechanism of the nucleation and growth in AM FCC, BCC, and HCP metals.

Studying the load of composite brake pads under high-temperature impact from the rolling surface of wheels

The object of the research is the processes of thermal stress, perception and redistribution of loads by the brake composite pad during braking of the car in operation. In the current conditions, wedge-dual wear of composite brake pads is observed in the braking systems of freight cars, the feature of which is the deterioration of the braking efficiency of freight trains. With this type of wear, both an increase in the load on the brake pad and an "underuse" of the amount of pressure on it can occur. A comprehensive thermal calculation was carried out for composite brake pads with uniform and wedge-dual wear. The results of the calculation showed that the amount of pressure on an abnormally worn pad is 23.3 % less than that acting on a pad with nominal values. It has been proven that the change in the pressure force on the composite pad with different values of the wear parameters during braking leads to a change in the braking force that occurs between the wheel and the rail during braking. The calculation of the strength of the composite brake pad with wedge-dual wear was carried out. The obtained results will make it possible to develop measures to modernize the elements of the brake lever transmission of freight cars. The field of practical use of the obtained results is car-building enterprises. The conditions for the practical use of the results are the brake lever transmissions of carriages of cars with a gauge of 1520 mm. The conducted studies prove the negative impact of wedge-dual wear not only on braking efficiency, but also on the strength of brake pads. This makes it necessary to create measures aimed at its elimination, which will contribute to increasing the level of train traffic safety and significantly reducing the operational costs of maintaining freight cars

Logarithmic versus Andrade's transient creep: Role of elastic stress redistribution

Creep is defined as time-dependent deformation and rupture processes taking place within a material subjected to constant applied stress smaller than its athermal, time-independent strength. This time dependence is classically attributed to the thermal activation of local deformation events. The phenomenology of creep is characterized by several ubiquitous but empirical rheological and scaling laws. We focus here on primary creep following the onset of loading, for which a power law decay of the strain rate is observed, $\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{\ensuremath{\varepsilon}}\ensuremath{\sim}{t}^{\ensuremath{-}p}$, with the exponent $p$ varying between $\ensuremath{\simeq}0.4$ and 1, this upper bound defining the so-called logarithmic creep. Although this phenomenology is known for more than a century, the physical origin of Andrade-like $(p<1)$ creep remains unclear and debated. Here we show that $p<1$ values arise from the interplay between thermal activation and elastic stress redistribution. The latter stimulates creep dynamics from a shortening of waiting times between successive events, is associated to material damage and, possibly, at high temperature and/or stresses, gives rise to avalanches of deformation events.

Revealing the atmospheres of highly irradiated exoplanets: from ultra-hot Jupiters to rocky worlds

Spectroscopy of transiting exoplanets has revealed a wealth of information about their atmospheric compositions and thermal structures. In particular, studies of highly irradiated exoplanets at temperatures much higher than those found in our solar system have provided detailed information on planetary chemistry and physics because of the high level of precision which can be obtained from such observations. Here we use a variety of techniques to study the atmospheres of highly irradiated transiting exoplanets and address three large, open questions in exoplanet atmosphere spectroscopy. First, we use secondary eclipse and phase curve observations to investigate the thermal structures and heat redistribution of ultra-hot Jupiters, the hottest known exoplanets. We demonstrate how these planets form an unique class of objects influenced by high-temperature chemical effects such as molecular dissociation and H− opacity. Second, we use observations of helium in the upper atmosphere of the exo-Neptune HAT-P-11b to probe atmospheric escape processes. Third, we develop tools to interpret JWST observations of highly irradiated exoplanets, including a data analysis pipeline to perform eclipse mapping of hot Jupiters and a method to infer albedos of and detect atmospheres on hot, terrestrial planets. Finally, we discuss remaining open questions in the field of highly irradiated exoplanets and opportunities to advance our understanding of these unique bodies in the coming years.

The Thermal Behavior of Two Magnetic States in Smart Anticorrosion Coatings

Compounds of nitrilotrimethylenephosphonic acid (NTP) with transition metals are often used as corrosion inhibitors for steels. An FeNTP anticorrosion coating is formed on the steel surface. Doping with certain metals (for example, Zn or Cd) greatly improves anticorrosion properties. Despite the fact that FeNTP, FeZnNTP, and FeCdNTP are completely isostructural compounds, substantial changes in their properties occur upon doping: (i) according to the X-ray electron spectra, Fe atoms in FeNTP are in a high-spin (HS) state, while FeZnNTP and FeCdNTP contain Fe atoms with zero spin (LS); (ii) the difference in the quadrupole splitting of the Mössbauer spectra is specific to the ratio between the HS and LS states. Quan-tum mechanical calculations of the FeNTP system showed two solutions with the properties coincideing with the experimentally found LS and HS states for these systems. In this study, we tested the hypothesis about the coexistence of two states. To study possible thermal redistribution between two magnetic states, the Möss-bauer spectra of FeNTP, FeZnNTP, and FeCdNTP were recorded at various temperatures (77, 300, and 373 K). The Mössbauer data indicate that, with an increase in the temperature, a second component occurs in FeNTP (the ground state is HS; LS occurs already at room temperature and its fraction increases with an increase in the temperature) and FeZnNTP (the ground state is LS; HS occurs at 373 K). At all investigated temperatures, FeCdNTP has only one LS component.

Facet Control and Material Redistribution in GaN Growth on Three-Dimensional Structures

In this work, the influence of temperature and ammonia partial pressure on the GaN shell morphology grown on GaN microfin cores is investigated. We demonstrate that GaN overgrowth on 3D structures above a temperature of 1000 °C is determined by the competition between growth and decomposition that results in the redistribution of material between coexisting surfaces due to their different thermal stabilities. By studying the GaN shell growth under different reactor parameters, we show that decomposition processes, often disregarded during planar growth, strongly influence the vertical-to-lateral distribution of material during GaN growth on 3D structures. We observed that GaN shell growth on a-plane microfins at high temperatures and high ammonia fluxes results in an increase of the decomposition rate of the c-plane surfaces and thus, reduces the growth rate in the vertical direction. On the contrary, the lateral growth rate increases due to the diffusion of material from the less stable c-plane facet to the more stable a-plane facet where it reincorporates. Furthermore, under certain growth conditions, the decomposition of the c-plane outweighed the incorporation, reducing the height of the initial 3D structure during growth, while still gradually growing in the lateral direction, which resulted in the development of inclined facets. These findings highlight the high sensitivity of 3D structures to thermal decomposition processes and redistribution of material. Therefore, the understanding of these mechanisms and their interaction is required for controlling and optimizing growth on these architectures.

Atmospheric heat redistribution effect on emission spectra of Hot-Jupiters

Hot Jupiters are the most studied and easily detectable exoplanets for transit observations. However, the correlation between the atmospheric flow and the emission spectra of such planets is still not understood. Due to huge day–night temperature contrast in hot Jupiter, the thermal redistribution through atmospheric circulation has a significant impact on the vertical temperature–pressure structure and on the emission spectra. In the present work, we aim to study the variation of the temperature–pressure profiles and the emission spectra of such planets due to different amounts of atmospheric heat redistribution. For this purpose, we first derive an analytical relation between the heat redistribution parameter f and the emitted flux from the uppermost atmospheric layers of hot Jupiter. We adopt the three possible values of f under isotropic approximation as 14,12 and 23 for full-redistribution, semi-redistribution and no-redistribution cases respectively and calculate the corresponding temperature–pressure profiles and the emission spectra. Next, we model the emission spectra for different values of f by numerically solving the radiative transfer equations using the discrete space theory formalism. We demonstrate that the atmospheric temperature–pressure profiles and the emission spectra both are susceptible to the values of the heat redistribution function. A reduction in the heat redistribution yields a thermal inversion in the temperature–pressure profiles and hence increases the amount of emission flux. Finally, we revisits the hot Jupiter XO-1b temperature–pressure profile degeneracy case and show that a non-inversion temperature–pressure profile best explains this planet’s observed dayside emission spectra.

Enhanced vapor condensation by thermal redistribution on the evaporation surface in heat-localized solar desalination

• The thermal redistribution method is proposed for improving vapor condensation. • The fabricated 3-dimensional evaporation could achieve high evaporation rate. • The condensation rate could be enhanced 30% by thermal redistribution. • The good performance in seawater enables long-term operation of the system. Due to the abundance and cleanliness, Solar energy has been used for desalination and demonstrated great potential to tackle the grand challenges of freshwater shortage. For more efficient solar evaporation, heat-localized solar evaporation was proposed in 2014, in which heat could be localized at the air–water interface. With the high energy efficiency and simple operation, heat-localized solar evaporation systems have drawn great interest recently, and much progress has been made in exploring new materials and structures for better evaporation performance. Especially, many three-dimensional evaporation structures have been proposed, which enhances the evaporation rate of such systems to be higher than 1.5 kg m -2 h −1 . However, most works focused on improving the evaporation part of such 3-dimensional evaporation systems, while the research on the condensation part are rarely seen, which could be more important for freshwater production. Here, we propose a method of thermal redistribution to improve vapor condensation by increasing the average temperature of generated vapor. We firstly prepared the 3-dimensional triangle-shaped evaporation structures with thermal redistribution, which could be bent at different inclination angles to promote evaporation. The vapor condensation performances were compared between structures with and without thermal redistribution, and results show that thermal redistribution could increase the condensation rate by about 30%. This attributes to the increased average temperature of the generated vapor, while low-temperature vapor could hardly condense in practice. This work presents the method of thermal redistribution, which could be further used to increase freshwater production in heat-localized solar desalination systems.

Different response of stalagmite δ18O and δ13C to millennial-scale events during the last glacial, evidenced from Huangjin Cave, northern China

An anti-phased relationship between Greenland Dansgaard-Oeschger (DO) and Antarctic temperature was revealed by ice core records, and the “bipolar see-saw” mechanism has since been proposed in explanation for the interhemispheric thermal redistribution. However, limited by chronology uncertainties of ice cores, particularly the ice age-gas age differences, the exact phase relationship and triggers for millennial-scale events are still in debate. Searching for proxies that could reflect both boreal and austral signals in one geological archive is therefore, a potential solution for the phase dilemma. Here, high-resolution paleoclimatic records from 55.2 to 36.5 ka BP were reconstructed using 21 230Th/U dates and 647 sets of δ18O and δ13C data by one stalagmite HJ1 from Huangjin Cave, Hebei Province, northern China. Robust millennial-scale fluctuations are found in δ18O and δ13C time series, corresponding to DO events 8 to 14 and Heinrich 4 and 5 events within dating errors. Discrepancies exist in the structures and onsets in δ18O and δ13C records; that is, abrupt DO onsets in δ13C data and gradual onsets in δ18O. Timing of DO onsets in δ13C are prior to (e.g. DO12 and DO14) or synchronous with (e.g. DO8 to DO11) those in δ18O. Comparison of HJ1 δ18O and bipolar ice core records suggests that the East Asian summer monsoon (EASM) is influenced by both hemispheres, but better mimics the Antarctic temperature. This suggests that the EASM is controlled by the cross equatorial airflows, and further indicates an important role of the Atlantic Meridional Overturning Circulation (AMOC) in modulating the inter-hemispheric heat gradient. However, our δ13C profile strongly resembles with the Greenland δ18O record on the millennial timescale, in terms of the “sawtooth” structure and the abrupt transition. This indicates that northern high-latitude climate could modulate hydro-thermal conditions in northern China, possibly via the mid-latitude westerly jet and/or the Silk Road teleconnection, which influences the vegetation/biomass changes and thereby controls stalagmite δ13C values. Therefore, HJ1 δ18O receives climatic signals from the Southern Hemisphere (SH) to a larger extent, while δ13C captures largely the changes in the Northern Hemisphere (NH). Furthermore, comparison between calcite and ice core records shows that during DO14, temperature increases in the NH leads the SH cooling by ∼120 years. However, during short-term DO events, the SH may start cooling ∼150 years before the NH warming. These findings demonstrate two possibilities for the NH-SH phase relationship which are dependent on the trigger location of the AMOC recovery and the “bipolar see-saw” mode is likely controlled by the oceanic processes.

Impacts of Momentum Fluxes Modulated by Surface Waves on Near‐Inertial Motions in Tropical Cyclones

AbstractSurface waves play an essential role in modifying the momentum fluxes across the air‐sea interface, especially under tropical cyclone (TC) conditions. A coupled wave‐ocean circulation model system, taking into consideration the surface wave effects on momentum fluxes, is applied to investigate the generation of near‐inertial motions (NIMs) under TC conditions. When surface waves are ignored, large overestimates in wind power input are obtained, about 10%–40%, occurring in the right and rear TC regions. Surprisingly, the modulation effects of surface waves on the momentum fluxes have impacts on NIMs that reach depths of ∼100 m; the resulting reduction in the near‐inertial velocity can exceed 0.1 m/s (up to 35%) and the reduction in the near‐inertial energy (NIE) is up to 20%. The largest modifications to NIMs are located at two times the radius of the maximum wind speed, relative to the TC center. In the upper ocean, the mixed‐layer NIE reductions due to surface waves are greater in medium‐speed TCs (3–6 m/s) than in rapidly moving TCs, by about ∼10%, because there are more young waves around the TC centers, and better overlapping between the regions with large wind stress changes and ocean current responses. Given that these effects are notable for surface waves impacts on NIMs, and thus on the currents and the resulting thermal redistribution under TCs, the feedbacks of these modified ocean properties must affect TC evolution and should be included in coupled atmosphere‐ocean studies.

Electrically driven transport of photoinduced hot carriers in carbon nanotube fibers.

Hot carriers play a significant role in applications of photovoltaics, photodetection, and photocatalysis. However, effective methods for observing the ultrafast dynamic processes of hot carriers are concentrated on the time domain, on which it is difficult and complex to operate. We propose a novel, to the best of our knowledge, and creative strategy to convert the time-domain dynamic process into a spatially thermal redistribution in suspended carbon nanotube fibers. The large average free path of photoinduced hot holes ensures a prominent offset of temperature distribution. The experimental results confirm the theory about electrically driven transport of hot holes, which has rarely been reported.

Cooperation between Excitation Energy Transfer and Antisynchronously Coupled Vibrations.

The effects of the environment in energy transfer systems have been continuously studied for decades. Here, we investigate how the energy transfer and the emergence of vibrational correlations cooperate with each other based on simulations with a few numerically approximate mixed quantum classical (MQC) methods. By adopting a two-state system with locally coupled underdamped vibrations that are resonant with the electronic energy gap, we observe prominent energy dissipations from the electronic system to the vibrations, rehighlighting the role of underdamped vibrations as a temporal electronic energy buffer. More importantly, this energy dissipation generates specific phase relations between the two vibrations. Namely, the vibrations become anticorrelated right after the initiation of the energy transfer but then synchronized as the transfer completes. These phase relations are interpreted as a selective activation of an anticorrelated motion of the vibrations and a subsequent deactivation by thermal energy redistribution. Furthermore, we show that a single vibration simultaneously coupled to the two electronic states with opposite phases induces a completely equivalent energy transfer dynamics as the two localized vibrations. Finally, we discuss how the vibrational energy dissipation dynamics is affected by the adopted MQC approaches and warn about the increased subtlety toward properly treating dissipation effects over having reliable population dynamics.

Optical and Electronic Properties of Symmetric InAs/(In,Al,Ga)As/InP Quantum Dots Formed by Ripening in Molecular Beam Epitaxy: A Potential System for Broad-Range Single-Photon Telecom Emitters

We present a detailed experimental optical study supported by theoretical modeling of $\mathrm{In}\mathrm{As}$ quantum dots (QDs) embedded in an $(\mathrm{In},\phantom{\rule{-1.5pt}{0ex}}\mathrm{Al},\phantom{\rule{-1.5pt}{0ex}}\mathrm{Ga})\mathrm{As}$ barrier lattice matched to $\mathrm{In}\mathrm{P}$(001) grown with the use of a ripening step in molecular beam epitaxy. The method leads to the growth of in-plane symmetric QDs of low surface density, characterized by a multimodal size distribution resulting in a spectrally broad emission in the range of $1.4$--$2.0\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{m}$, essential for many near-infrared photonic applications. We find that, in contrast to the $\mathrm{In}\mathrm{As}$/$\mathrm{In}\mathrm{P}$ system, the multimodal distribution results here from a two-monolayer difference in QD height between consecutive families of dots. This may stem from the long-range ordering in the quaternary barrier alloy that stabilizes QD nucleation. Measuring the photoluminescence (PL) lifetime of the spectrally broad emission, we find a nearly dispersionless value of $1.3\ifmmode\pm\else\textpm\fi{}0.3$ ns. Finally, we examine the temperature dependence of emission characteristics. We underline the impact of localized states in the wetting layer playing the role of carrier reservoir during thermal carrier redistribution. We determine the hole escape to the $(\mathrm{In},\phantom{\rule{-1.5pt}{0ex}}\mathrm{Al},\phantom{\rule{-1.5pt}{0ex}}\mathrm{Ga})\mathrm{As}$ barrier to be a primary PL quenching mechanism in these QDs.

Effectiveness of thermal redistribution layer in cooling of 3D ICs

AbstractA cooling system composed of a thermal redistribution layer (TRDL) and a thermal through‐silicon via (TTSV) is proposed for three‐dimensional integrated circuits (3D ICs). According to the Fourier heat flow analysis theory, the heat flow model of the proposed cooling system is established and verified by finite element analysis (FEA). It is shown that the maximum error between the heat flow model and FEA is 2.98%, and the maximum temperature of 3D ICs can be reduced by 4.43°C. The established horizontal heat dissipation channel can effectively solve the heat dissipation problem in 3D ICs.

Photovoltaic Response and Charge Redistribution Processes in GaAs/AlGaAs Multiple‐Quantum Wells Structure

The impact of radiative and non‐radiative processes on the photovoltaic response of GaAs/AlGaAs multiple‐quantum wells is investigated by temperature, excitation power, and chopping‐frequency‐dependent surface photovoltage (SPV) measurements. It is shown that a systematic study of SPV amplitude along with phase spectra can provide important information on thermal escape, carrier localization, and spatial redistribution of charge carriers. Characteristic features in SPV‐phase spectra related to quantum well (QW) transitions and their variation under an external perturbation are explained by the electron–electron interaction. It is found that a many‐body interaction inside the QW is responsible for the capture of charges at the heterointerfaces, which builds up an interface electric field and hinders the drift/diffusion of charges. Such an effect becomes dominant under higher excitation powers, causing a sub‐linear enhancement of photovoltage amplitude and an increase in phase delay as a function of photon flux. From the chopping‐frequency‐dependent SPV measurements, it is concluded that carriers during the drift in barrier layers are repeatedly captured by point defects and other QWs, which enhances the effective time response of the photovoltage signal. Results obtained in this study are beneficial in the engineering of quantum structures for high‐efficiency photovoltaics and non‐invasive characterization of electro‐optical processes.

Carrier Dynamics in Al‐Rich AlGaN/AlN Quantum Well Structures Governed by Carrier Localization

The carrier dynamics of Al‐rich AlGaN/AlN quantum well (QW) structures in the presence of strong carrier localization is reported. Excitation density‐dependent photoluminescence (PL) measurements at low temperatures reveal a clear correlation between the onset of efficiency droop and the broadening of the time‐integrated PL spectra. While the droop onset is heavily impacted by the localization strength, the PL emission broadening is observed almost exclusively on the high energy side of the emission spectrum. Spectrally resolved PL decay transient measurements reveal a strong dependency of the carrier lifetimes on the emission photon energy across the spectrum, consistent with a distribution of localized states, as well as on the temperature, depending on the localization strength of the investigated structure. The characteristic “S”‐shaped temperature dependence of the PL emission energy is shown to be directly correlated to the thermal redistribution of carriers between localized states. Based on these findings, the role of carrier localization in the recombination processes in AlGaN QW structures is underlined and its implications for efficiency droop are discussed.

Three-Level Discontinuous PWM for Loss and Thermal Redistribution of T-NPC Inverter at Low Modulation Index

With conventional pulsewidth modulation (PWM) strategies, the switches of a three-level T-type neutral-point-clamped (T-NPC) inverter are not equally utilized at modulation indices lower than 0.5, limiting the inverter power throughput. The inner switches incur more losses than the outer switches. This article investigates a series of space-vector-based discontinuous PWM (DPWM) templates for modulation indices lower than 0.5. The templates relocate the phase current from the inner to the outer switches of a T-NPC inverter. Using them, the device losses are reduced and get redistributed more equally among the inner and outer switches, enabling a higher inverter output current or switching frequency. Confirmatory simulation and experimental results are provided to demonstrate the potential of the three-level DPWM templates in comparison to the conventional PWM templates.

ИССЛЕДОВАНИЕ ВЛИЯНИЯ ПЛАЗМОХИМИЧЕСКОГО МОДИФИЦИРОВАНИЯ НА МАКРО- И МИКРОСТРУКТУРУ ПОВЕРХНОСТНОГО СЛОЯ АВТОКЛАВНЫХ СТЕНОВЫХ МАТЕРИАЛОВ

studies of the high-temperature effect of a plasma torch on the formation of a multilayer structure of the protective and decorative coating of autoclave wall materials are presented. The tasks of the work included studies: a temperature gradient in a multilayer protective-decorative coating; chemical composition of the fused, intermediate and deep layers of the protective and decorative coating; influence of sodium liquid glass on the formation of macro- and microstructures of protective and decorative coatings under the influence of plasma; processes of thermal diffusion and redistribution of oxides in the fused, intermediate and deep layers.
 It was found that when the plasma torch was treated with autoclave wall materials, the surface layer was heated to a depth of 3000 μm, and the maximum surface temperature reached 2000 °C. The pattern of the change in the structure of the fused and intermediate layer is revealed. It is shown that the preliminary impregnation of the surface of silica brick during plasma treatment due to the formation of a low-melting melt eliminates microcracks in its deep layers, and high plasma temperatures promote intensive evaporation of sodium and calcium oxides from the fused layer.