International Journal of Applied Ceramic Technology

This research targets to produce new composites from a highly reactive metakaolin‐based geopolymer matrix reinforced with natural particles for use in sustainable ceramics, building and construction. Commercial waterglass and added mineral particles were optimized for geopolymer composites to provide higher strength, stability, and durability. The design method implicated higher flexural strength of one type of commercial metakaolin, one commercial waterglass formulation, a single‐low‐energy geopolymer processing, and seven types of added mineral particles. The particulate reinforcement formulations added to the geopolymer matrix were: (1) 20 wt% chamotte and 40 wt% Prairie fine sand; (2) 20 wt% chamotte and 40 wt% Quikrete medium sand; (3) 20 wt% chamotte and 40 wt% Quikrete fine sand; (4) 20 wt% ball‐milled fine sand; (5) 20 wt% ball‐milled fine sand and 40 wt% Quikrete fine sand; (6) 20 wt% ball‐milled fine sand and 40 wt% Prairie fine sand; (7) 10 wt% ball‐milled fine sand and 50 wt% Prairie fine sand. Potassium metasilicate Kasolv 16 with 11 M of water, Metamax metakaolin, reinforced with 20 wt% ball‐milled fine sand, and 40 wt% Prairie fine sand (BF20PF40) resulted in the highest strength geopolymer composite. BF20PF40 also yielded lower mass loss, higher packing density, and better thermal stability.

Although BaLiF3 ceramic has a high quality‐factor at microwave frequencies (Q × f value = ∼83000 GHz) coupled with a low sintering temperature (750°C/2 h), its high negative temperature coefficient of resonant frequency (τf = ∼ −70 ppm/°C) prevents practical applications. In the present paper, we employed SrTiO3 as a second phase (7 mol%) to tune the negative τf value to near zero (∼2.5 ppm/°C) and added a small amount of LiF (4 mol%) to reduce the sintering temperature to ∼800°C. Sintering in the N2 atmosphere has a beneficial effect on the density, while it has a detrimental impact on the Q × f value of the sintered body due to the partial reduction of Ti⁴⁺ in the SrTiO3 (SrTi⁴⁺1‐xTi³⁺xO3‐xFx) and F‐vacancies in the BaLiF3 (BaLiF3‐x). The 0.93BaLiF3 +0.07SrTiO3 composite with 4 mol% LiF addition exhibits excellent combined microwave dielectric properties (εr = 14, Q × f = 55 000 GHz, and τf = −3 ppm/°C), coupled with low sintering temperature (785°C/3 h) and good cofiring chemical compatibility with silver, which is a promising candidate for LTCC applications.

This study explores the feasibility of producing cost‐effective zircon–basalt composite ceramics using slip casting method. Zircon is effectively stabilized by basalt up to 1550°C, preventing its decomposition; however, challenges such as gas release and partial melting during sintering result in increased porosity and reduced mechanical strength. Thermal analysis, including thermogravimetric and differential thermal measurements, identified a stepwise mass loss in basalt beginning 600°C, attributed to the sublimation of chlorine‐ or fluorine‐containing compounds. Visual thermal analysis determined a melting point of 1300°C ± 50°C for basalt. Scanning electron microscopy revealed pore formation from gas release and the presence of zircon grains within an anorthite matrix. Microhardness increased with both basalt content and sintering temperature, while flexural strength showed an inverse relationship, highlighting the negative impact of porosity. These findings demonstrate the complex interaction between composition, processing parameters, and microstructure in determining the mechanical properties of zircon–basalt composites. To mitigate the challenges of gas release and porosity, further optimization could involve refining the sintering parameters, such as lowering the heating rate or introducing additional additives to trap volatile species, thereby improving the material's densification and mechanical integrity.

Alumina titania slag (It is an industrial waste generated during the preparation of iron titanium alloys by aluminum thermal reduction method.) and light‐burned magnesia were used as raw materials to prepare MgAl2O4 spinel at 1400–1600°C. Particularly, the effect of the mass ratio of alumina titania slag and light‐burned magnesia on the synthesis and densification of MgAl2O4 spinel was studied. The mass ratio of alumina titania slag and light‐burned magnesia was adjusted to 100:29, 100:35, 100:41, and 100:47. Alumina titania slag was mixed with light‐burned magnesia according to above mass ratio, respectively, and pressed into billets diameter of 20 mm and height of 15 mm. The green‐body billets then were sintered at 1400–1600°C in an air atmosphere. Bulk density, apparent porosity, phase composition, and microstructure of final sintered products were analyzed. The results indicated that MgAl2O4 spinel could be prepared by solid reaction of alumina titania slag and light‐burned magnesia. With the increasing magnesia content, the bulk density of samples and lattice parameters of MgAl2O4 spinel increased, while apparent porosity of samples decreased. At the same time, the higher magnesia content, the more MgAl2O4 spinel particles with obvious structure appeared and grew large.

The diffusion of solute atoms at grain boundaries significantly impacts material properties. This study employed magnetron sputtering to prepare CrAlN‐Ag coatings on silicon nitride substrates. Comprehensive characterization was conducted on the surface and cross‐sectional morphologies of the coatings, as well as the concentration distribution of Ag elements along the coating depth direction. The diffusion mechanism of Ag atoms at the Σ5(012)[100] grain boundary and CrAlN(100) surface was analyzed using ab initio calculations. Based on this understanding, the distribution of Ag elements in the coatings was regulated. The results indicate that the Ag nanoparticles on the coating surface originate from the migration of Ag atoms from within a 260 nm depth range of the coating. The energy barrier for Ag atoms migrating along grain boundaries is .98 eV, suggesting that grain boundaries serve as rapid pathways for Ag atoms migrating toward the surface. Additionally, vacancy defects at grain boundaries and surfaces create energy traps that restrict the free diffusion of Ag atoms. Based on this mechanism, the stoichiometric deviation of N elements in the coatings was regulated. For the coatings after regulation, the size of surface Ag particles decreased, and the mechanical properties and wear resistance were improved.

The reaction bonding technique offers a promising approach for controlling matrix sintering shrinkage in oxide/oxide ceramic matrix composites (OCMCs), thereby reducing the sintering cracks and enhancing mechanical properties. In this study, aluminum nitride (AlN) was used as an alumina precursor to fabricate OCMCs via reaction bonding. The results indicated that the mechanical properties of the OCMCs could be greatly improved due to the volume expansion induced by AlN oxidation, which reduced sintering cracks, and the high sintering activity of AlN, which enhanced the particle bonding strength in the matrix. However, the strong bonding between the matrix and fibers, attributed to the high sintering activity of AlN, resulted in the decrease of toughness. These findings confirm that the reaction bonding can effectively improve the mechanical properties of OCMCs, but careful control of matrix‐fiber bonding is essential to optimize overall performance.

The effects of cold isostatic pressing (CIP) pressure on the sintering densification, the mechanical and insulation performances of a 95.5 wt% alumina ceramic are investigated. The density of sintered ceramic increases with the increase of CIP pressure, and tends to level off when the CIP pressure is higher than a suitable pressure (120 MPa). This is attributed to the effect of CIP pressure on the pore size. The fracture strengths of green body and sintered ceramic both increases linearly with the increase of densities, which can be explained by the weakest‐link assumption of fracture that initiates from pores. For the sintered ceramics, the direct current (DC) dielectric breakdown strength (DBS) increases exponentially with density, while the alternating current (AC) DBS prepared under different pressures have no noticeable difference, and this may be attributed to it that the large pores can discharge under DC while cannot discharge under AC. This work can contribute to fabricating ceramics with excellent performances on the premise of reducing costs.

High‐entropy boride (HEB) ceramics demonstrate significant potential for cutting tool applications, yet conventional synthesis methods face challenges in achieving full densification and optimal mechanical performance. (Mo0.2Zr0.2Ta0.2Nb0.2Ti0.2)B2 HEB ceramics were prepared using the spark plasma sintering‐high‐frequency (SPS‐HF) dual sintering method. The optimal mechanical properties of the HEB ceramic cutting tool materials were achieved at a sintering temperature of 1750°C. Compared with the HEB ceramic tool material without Al2O3 (HEB0), the HEB ceramic tool material containing 3 wt% Al2O3 (HEB3A) exhibited improved mechanical properties. The Vickers hardness and flexural strength of HEB3A were 20.07 GPa and 492.85 MPa, representing increases of 2.87% and 17.28%, respectively, compared to HEB0. The HEB3A tool achieved a cutting distance of 1000 m and a coefficient of friction of 0.62 during dry cutting tests on 45 steel, representing a 66.67% increase and an 11.29% reduction, respectively, compared to the HEB0 tool. The results indicate that the addition of Al2O3 improves the cutting performance of HEB ceramic tools. This work shows that the HEB‐based ceramics with high hardness, high toughness, and high flexural strength have potential applications in the field of cutting tools.

This study presents a simulation methodology to choose the optimal material combination before constructing a ceramic‒metal composite joint. Two types of joint assemblies/structures designed with and without pores and eight material combinations are tested. The finite element discretization of the model is implemented using Abaqus. The effect of thermal stress is functionally evaluated by Von Mises Stress (VMS) and average volumetric stress as a decision parameter. The joint assembly with Al2O3/Ag‒Cu‒Ti/Kovar composite material is found to have a relatively larger limit to get fractured. The thermal strain rate for optimal material combination is 3.77 × 10⁻⁶ K‒1 (with pores) and 6.11 × 10⁻⁶ K‒1 (without pores), respectively. The porous joint structure's average thermal stress is (∼30%‒50%) lower than the non‐porous joint structure. The analysis concludes that pores do not always deteriorate joint performance. An empirically fit equation is derived to estimate the VMS value for any pore's shape, size, location, porosity, and material properties. The equation can be used to predict the VMS value for any ceramic‒metal composite material combinations. An empirical linear equation is also derived to predict effective coefficient of thermal expansion as a function of microstructure (shape, size, location, and porosity) and material type (effective molecular mass).

The economically unfeasible electrochemical breakdown of water is linked to the production of materials with low overpotential using a simple method. The study demonstrates the fabrication and use of samarium oxide (Sm2O3) on carbon nanotubes (CNTs) as an effective and long‐lasting electrocatalyst for oxygen evolution reaction (OER). X‐ray diffraction analysis confirms fabrication of Sm2O3 embedded CNTs (Sm2O3/CNTs) phases with 0.052 nm lattice strain, while scanning electron microscopy structural analysis shows a ball‐like shape with 78 nm average particle size. The synthesized catalyst performs well, attaining a current density of 10 mA cm⁻² and having an onset potential of 1.33 V versus reversible hydrogen electrode (RHE). In contrast to Sm2O3 and CNT, which exhibit higher overpotentials of 311 and 342 mV with corresponding Tafel slopes of 62 and 83 mV dec⁻¹, respectively, Sm2O3‒CNT has a low Tafel slope of 38 mV dec⁻¹ and a lower overpotential of 276 mV. With a current density of more than 50 mA cm⁻², the catalyst demonstrated remarkable stability over 180 h. The electrochemical impedance spectroscopy analysis attributed the robust ionic conductivity of K⁺ ions, their small hydration sphere, and reduced electrode impedance to their Rct value of 3.4 Ω. The composite potential of CNTs and Sm2O3 as a long‐term and effective OER electrocatalysis substitute has been demonstrated through promising results.

In this study, it is attempted to improve the fracture toughness of 3/2‐mullite (3Al2O3 2SiO2 or Al6Si2O13) by precipitating α‐cristobalite. All specimens were prepared from raw‐alumina (Al2O3) and raw‐silica (SiO2) powders using spark plasma sintering. Excess raw‐silica over the ideal composition of 3/2‐mullite was added to the powders to produce α‐cristobalite precipitated in the 3/2‐mullite matrix. The fracture toughness increased to a maximum of 2.60 MPa m0.5 with 31 vol% α‐cristobalite. The precipitation reinforcement can be explained by an analogy to the residual stress effect based on the conventional crack‐tip shielding model in particle‐dispersed composite. This finding reinforces the fracture toughness based on the precipitated phase in the composite rather than using conventional additives.

High‐entropy design is an attractive strategy to improve the comprehensive performances of RE2SiO5 as next‐generation thermal/environmental barrier coating (T/EBC) materials for protecting SiC‐based ceramic composites (SiC‐CMCs) in the hot section of gas turbine engines. Herein, we designed a novel high‐entropy RE monosilicate ((6RE1/6)2SiO5) by co‐doping the Sc, Yb, Tm, Er, Y, and Dy elements to synergistically improve thermophysical properties and molten calcium–magnesium–alumina–silicate (CMAS) corrosion resistance. The results revealed that as‐prepared (6RE1/6)2SiO5 had an ultra‐low thermal conductivity (1.22–1.74 W·m⁻¹·K⁻¹), and a matched coefficient of thermal expansion ((4.57–5.05) × 10⁻⁶ K⁻¹) with SiC‐CMCs in the testing temperature range. Moreover, it showed an excellent ability against CMAS corrosion at 1300°C and 1500°C. The thicknesses of reaction product layer were about 44 and 102 µm after CMAS corrosion at 1300°C for 48 h and 1500°C for 24 h, respectively. All of the above results identify that as‐prepared (6RE1/6)2SiO5 will be a suitable candidate as next‐generation T/EBC for protecting SiC‐CMCs.

Glass fiber(GF)‐reinforced polymers can cause vigorous wear for the screws and barrels in the plasticizing units of injection molding machines. The three types of WC composite coatings were selected to spray on 42CrMo steel by high‐velocity oxygen fuel spraying process. The designed PPS‐40%GF pins were used to simulate the tribological system. Against PPS‐40%GF pins, the wear rates of WC‐12Co, WC‐20Cr3C2‐7Ni, and WC‐10Co‐4Cr coatings were 0.014 × 10⁻⁹, 0.053× 10⁻⁹, and 0.097 × 10⁻⁹ mg/mm, respectively. The corresponding wear rates for PPS‐40%GF tribo‐pairs were 0.119 × 10⁻⁹, 0.102 × 10⁻⁹, and 0.079 × 10⁻⁹ mg/mm, respectively. The wear resistance of the coatings was ordered of WC‐12Co > WC‐20Cr3C2‐7Ni > WC‐10Co‐4Cr coatings. The wear mechanisms of the coatings were studied and addressed.

This study investigates the thermal insulation performance of CeO2 and Y2O3 co‐doped ZrO2 solid solutions cerium‐yttria co‐doped stabilized zirconia (CYZ), prepared via the solid‐state reaction method. A comparative assessment was conducted between CYZ and Y2O3‐ZrO2 solid solutions yttria‐stabilized zirconia (YSZ) under 10 GPa pressure conditions. The results reveal that the temperature change efficiency of CYZ is significantly enhanced, compared to YSZ. Under equivalent heating power conditions, the maximum temperature differential within the cavity for CYZ (with 25 wt.% CeO2 doping) reached 300°C, marking a 20% improvement over YSZ. This implies that employing CYZ as an insulation material could reduce heating energy consumption by approximately 20%. The notable lattice distortion induced by CeO2 incorporation enhances phonon scattering under high‐pressure high‐temperature conditions, effectively reducing heat transfer. Furthermore, the Debye temperature of CYZ was determined to be approximately 800°C under 10 GPa compression. Above this temperature, CYZ exhibits a characteristic 1/T dependence, with its thermal insulation performance improving as temperature increases, whereas YSZ demonstrates minimal variation in its insulation characteristics. And leveraging the excellent high‐temperature thermal insulation properties of CYZ, it is expected to achieve cavity temperatures exceeding 2500°C under 10 GPa pressure.

Owing to their superior mechanical properties and low thermal conductivity, oxide ceramic fabrics (OCFs) containing an amorphous phase exhibit significant potential as thermal insulation material. However, the amorphous component is metastable, necessitating an investigation into the thermal stability of OCFs. Here, we comparatively investigated the microstructure and mechanical properties of two OCFs after thermal treatments. One OCF was composed of a ternary Al2O3‐SiO2‐B2O3 glass, while the other binary OCF comprised Al2O3 nanocrystallites embedded within a SiO2 glass matrix. Results demonstrated that the crystallization of Al4B2O9 occurred during the thermal treatment of the ternary OCFs, subsequently transforming into Al18B4O33. The SiO2 persisted as a glass matrix up to 1300°C. In contrast, the binary OCF retained its microstructure up to 1100°C. After being treated at 1300°C, the binary OCF predominantly consisted of mullite micrograins, without the presence of amorphous phase. The flexural strength of the two OCFs decreased as the treatment temperature increased, and they lost their bendability due to the formation of a substantial number of crystallites. This study underscores the significant impacts of thermal treatment on the microstructure and mechanical properties of OCFs with amorphous component.

To enhance the thermal shock resistance of low‐carbon MgO–C refractories, SiC nanowires incorporated SiC/MgAl2O4 composite reinforcer were introduced. The effect of SiC/MgAl2O4 on the mechanical properties, thermal shock resistance, oxidation resistance and slag resistance of low‐carbon MgO–C refractories was explored. The results showed that the low‐carbon MgO–C sample incorporated with 9 wt.% SiC/MgAl2O4 (M9) displayed optimal overall properties, with 28% higher residual strength ratio, 59% lower oxidation index, and 18% reduced corrosion area compared to the reference sample M0. The increased residual strength ratio is mainly attributed to the synergistic effect of SiC nanowires and rod‐shaped MgAl2O4, which facilitate crack deflection and branching, and energy dissipation through bridging and pull‐out mechanisms, collectively contributing to matrix toughening. Besides, M9 (3 wt.% graphite) demonstrates better mechanical strength, oxidation resistance, and slag resistance compared to high‐graphite samples (10 wt.% graphite), highlighting the significant potential of SiC/MgAl2O4 composite reinforcer in developing sustainable low‐carbon refractories.

An ionic nickel complex was utilized to synthesize an adsorptive mesoporous MFI zeolite membrane for the removal of heavy metal ions from water. The synthesis conditions (synthesis temperature = 185°C, synthesis duration = 96 h, and molar ratio of NaOH to silica was set to 1) resulted in the highest nickel content (3.5 wt%) within the zeolite structure. The incorporation of nickel into the zeolite structure requires high energy and sufficient time. The template used simultaneously incorporates nickel into the structure and creates a mesoporous structure. Water permeation tests conducted on the membrane demonstrated that a 20‐h heat treatment yielded the highest water flux. The presence of nickel ions in the feed solution reduced the membrane blocking (water flux declined from 40 to 15 L m⁻² h⁻¹ over 1 week) by forming stable nickel complexes with some of the anions in water and hydrophilic surface modification effect, while water flux reduction occurred within 6 h in the absence of nickel ions. Analysis of nickel ion concentrations indicated that the membrane functions effectively as an adsorptive zeolite membrane.

Lightweight geopolymers are well‐suited for construction applications, including thermal and acoustic insulation panels and fire‐resistant barriers. Their porous microstructure can be tailored by incorporating gas bubbles into the fresh ceramic mixture. Several factors—such as geopolymer composition, mixing and curing conditions, and the setting behavior of the paste—play a crucial role in bubble retention within the consolidated specimens. This study investigated the processing of porous metakaolin‐based geopolymers prepared with the addition of 5, 7.5, and 10 wt.% of a preformed liquid foam stabilized with xanthan gum. The addition of 0.45 wt.% xanthan gum improved foam stability, ensuring uniform pore distribution and minimizing bubble collapse during processing. This approach enabled the fabrication of specimens with low densities (0.87–1.46 g/cm³) and high porosity (39.49%–64.78%), significant air permeability, and well‐controlled microstructural characteristics, with average pore sizes varying from 99 to 137 µm. Based on the findings, the geopolymeric binder containing 7.5 wt.% foam demonstrated a balance of strength, low density, reduced water absorption, and engineered porosity, making it a promising candidate for sealing components or thermal insulation materials. The direct foaming method and processing conditions effectively enhanced the properties of porous geopolymers, highlighting their potential for advanced construction applications.

To enhance the electrochemical performance of NiMn‐LDHs electrode materials, this study explores metal Co doping and synthesizes nano‐onion‐like NiCoMn‐LDHs composites. By examining the effects of various heat treatment temperatures (100°C, 110°C, 120°C, 130°C, and 140°C), we identified that NiCoMn‐LDHs prepared at 130°C exhibited superior performance. The results reveal that Co doping significantly increases the specific capacitance compared with undoped NiMn‐LDHs. The 130°C NiCoMn‐LDHs achieved a specific capacitance of 4413 F g¹ at 1 A g⁻¹ and maintained 3055 F g⁻¹ at 10 A g⁻¹, demonstrating excellent rate performance. These findings highlight the benefits of Co doping and optimized heat treatment for improving NiMn‐LDHs in supercapacitor applications, providing a strong foundation for their use in high‐performance energy storage devices.

The ceramic‐glaze for polished glazed porcelain stoneware tile is directly linked in determining the quality of the final product, as its characteristics significantly influence surface properties after polishing, including stain resistance, abrasion resistance, and chemical resistance. In this study, the effect of incorporating nanomaterials of alumina and silica into a glaze formulation for polished glazed porcelain stoneware tile was evaluated, with the goal of enhancing stain resistance by reducing surface porosity. Initially, the nanomaterials and the standard glaze formulation (STD) were characterized to assess the individual behavior of each material. Later, ten glaze formulations were developed—in a simplex centroid system—each subjected to postpolishing analysis, with the primary selection criterion being improved stain resistance. Optical microscopy analysis of surface porosity revealed that the addition of nanosilica (nano‐SiO2) reduced glaze surface porosity by up to 67%, thereby significantly improving the stain resistance of the final product. Conversely, the addition of nanoalumina (nano‐Al2O3) increased surface porosity, negatively affecting stain resistance. The reduction in porosity observed with nano‐SiO2 is attributed to enhanced particle packing and an increase in relative density within the glaze matrix. Finally, formulations with the lowest surface porosity were selected for further testing for comparison to STD. These tests included X‐ray diffraction, differential scanning calorimetry, thermogravimetric and differential analysis, dilatometry, and scanning electron microscopy. Thermal expansion and hemispherical temperature tests allowed the theoretical viscosity to be calculated using the Vogel–Fulcher–Tammann equation, revealing that formulations containing nano‐SiO2 exhibited lower temperatures for dilatometric softening, Littleton softening, and flow point. SEM analysis confirmed a reduction in porosity and a decrease in pore diameter in the nano‐SiO2 formulations.

Silica fumes are investigated as a strengthening agent for grade 30 concrete in this study. Silica fume was added in weight proportions of 4, 8, and 12 wt.%. The slump test, ultrasonic pulse velocity, total water absorption, compressive strength, and embodied CO2 emissions of the newly developed concrete mix were determined. The results of this study indicate that silica fumes positively affect concrete's mechanical characteristics, durability, and microstructure, as well as its embodied CO2 emissions. In addition, silica fume concentrations have been shown to enhance concrete's compressive strength. The major compressive strength increment was 37% with a mixture containing 8 wt.% silica fume. This was compared with a silica fume‐free mixture under the same conditions. Additionally, the SEM images of a newly developed concrete mix revealed positive interaction, resulting in a significant reduction in cracks and pores compared to a silica fume‐free sample. Moreover, the results showed a significant decrease in absorption and an increase in ultrasonic pulse velocity as a result of an increase in the proportion of silica fumes. Compared to the mixture without silica, there was a maximum improvement of 6% with an addition of 8 wt.% silica. The optimum reduction in embodied carbon emissions was 37% at 12 wt.% silica addition. On the other hand, silica fume addition negatively affects workability, where workability decreases inversely with this additive.

Conventional, flash, and hybrid sintering (unique combination of conventional and microwave heating) experiments were performed on 10% Ce‐doped zirconolite samples and the results were compared. Ce–zirconolite was prepared using reactive, pressure‐less, field‐assisted hybrid processing directly from the precursor made using commercial chemical agents, viz., CaTiO3, ZrO2, TiO2, and CeO2 at 1350°C/2 h. For comparison, Ce–zirconolite ceramics were produced by the conventional synthesis at 1350°C/72 h and then sintering at 1450°C/10 h based on a literature methodology. The Ce–zirconolite samples were also flash sintered for the first time at 1100°C in just 5 min with the application of an AC field to ∼98% density with a finer grain size. A novel reactive flash synthesis procedure of zirconolite precursors with subsequent flash sintering was also explored. The flash process for both synthesis/sintering needs only ∼15% of the energy (85% savings) and hybrid method requires ∼ 33% (67% savings) of the total energy, respectively, when compared to the values reported for conventional synthesis and sintering processes together for zirconolite manufacturing. Thus, both the field‐assisted processing techniques were found to be highly energy efficient for the fabrication of Ce‐zirconolite ceramics, making them suitable for applications in Plutonium‐based nuclear waste disposal.

To investigate the thermal shock resistance of thermal barrier coating with AlCoCrFeNi high‐entropy alloy as the bond coating, this study prepared the AlCoCrFeNi bond coating on the 316L stainless steel substrate by vacuum plasma spray technique, and the 7YSZ ceramic coating was prepared by atmospheric plasma spray technique. The thermal shock resistance of the AlCoCrFeNi/7YSZ thermal barrier coating system was subsequently characterized by the water‐quenching test at 1000°C. The results showed that longitudinal and transverse cracks appeared inside the 7YSZ coating during the water‐quenching test. The longitudinal cracks mainly extended along the grain boundaries within the YSZ particles. In contrast, the transverse cracks primarily existed between the YSZ particles and the grain boundaries between the columnar grains and the equiaxed grains inside the YSZ particles. During the thermal shock process, the failure of the AlCoCrFeNi/7YSZ thermal barrier coating system was mainly concentrated inside the 7YSZ coating rather than at the interfaces. The thermally grown oxide layer of Al2O3 was generated inside the thermal barrier coating system during the water‐quenching test. However, there was no significant effect on the failure process.

Environmental barrier coatings (EBCs) protect SiC‐based ceramic matrix composites (CMCs) in turbine hot sections from high‐temperature volatilization in combustion gases. The formation of a SiO2 thermally grown oxide (TGO) is expected under the EBC after long‐term operation. The oxidation resistance of the EBC is understood as a life‐limiting factor for the CMC, and this work predicts long‐term oxidation behavior under EBCs through a simple statistical approach. Specimens were exposed to 1350°C isothermal conditions for 100‐h thermal cycles in flowing steam for up to 1000 h. The EBC morphology, SiO2 thickness, and SiO2 cracking behavior were assessed. Using thousands of SiO2 thickness measurements across many millimeters of the interface, a realistic representation of the entire TGO was captured via a lognormal distribution. The lognormal fit parameters were extrapolated out to 25 000 h to assess the degree of SiO2 growth, the spread of SiO2 thicknesses related to the rough oxidizing interface, and percentages of the intermediate bond coating consumed. Local interfacial defects from the coating deposition process are identified as local failure points for EBC—CMC systems.

Al2O3–SiC–C refractory for one‐ladle enterprises technology was prepared using bauxite, SiC, C, pyrophyllite, and corundum as raw materials. The sample composition, phase, structure, and porosity were analyzed at different service degrees. The material exhibited a periodic pattern of destruction during the service process. Carbon oxidation resulted in the formation of a decarburization layer. This led to the formation of a low‐melting phase through combination of slag. This low‐melting phase underwent a reaction and permeation with iron and slag and was then removed through a process of scouring, leaving behind pores and an erosion layer stripped from the material. The formation of a decarburization layer and low‐melting phases reduced the thermal shock resistance of the material, and the structural damage caused by thermal shock accelerated chemical erosion. Furthermore, the penetration of iron into the brick joints contributed to the failure of the material.