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High-Temperature Materials Open Access

ISSN: 3006-9971 (Online)

3006-9963 (Print)

An Official Journal of State Key Laboratory of Advanced Refractories, Wuhan University of Science and Technology

High-Temperature Materials is a peer-reviewed and open-access journal publishing original, high-quality research on all aspects of materials relating to high-temperature processing in science and technology and high-temperature applications in the energy generation, aerospace, metallurgy, chemical and other process industries. It is published quarterly online by SCIE Publishing Ltd. View full Aims&Scope

High-Temperature Materials

Guide for Authors Submit to HTM

Editors-in-Chief Editorial Board

Articles (58) All Articles

Open Access

Article

24 September 2026

Influence of Mo on Microstructure and High-Temperature Mechanical Properties of Fire-Resistant Steels

The long-term fire safety of steel structures necessitates fire-resistant (FR) steels with superior strength retention after prolonged exposure to elevated temperatures. This study investigates two FR steels with Mo contents of 0.25 wt.% and 0.50 wt.% (correspondingly adjusted Cr contents to maintain a nearly constant total Mo + Cr alloy level) after thermal exposure at 600 °C for up to 6 h. Both steels exhibit a polygonal ferrite (PF) and granular bainite (GB) microstructure, but with different phase fractions. Increasing Mo to 0.5 wt.% promotes bainite formation, resulting in a predominantly granular bainitic microstructure (88% GB and 12% PF). A multi-scale characterization reveals that the higher-Mo/lower-Cr design not only increases the fraction of GB but also dramatically enhances its thermal stability. Importantly, Mo suppresses the premature precipitation of coarse (Nb, Ti)(C, N) in the parent austenite, thereby retaining solutes for the subsequent precipitation of a high number density of fine carbides within the bainitic ferrite laths during thermal exposure. The combination of a high-density dislocation substructure within the stable GB and the strong precipitation strengthening from these dispersed nano-carbides is primarily responsible for the superior strength retention in the higher-Mo/lower-Cr FR3 steel. This steel maintains a high yield strength of 440 MPa after 6 h at 600 °C, which is 158 MPa higher than its 0.25 wt.% Mo counterpart and satisfies the international fire-resistance criterion (YS600 °C/YSRT > 2/3). This work provides a mechanistic basis for optimizing Mo–Cr alloy design to achieve exceptional long-term high-temperature performance in FR steels.

Lijuan Zhu
Chun Feng*
Xiaolu Gui
Qi Ji
Guhui Gao*
High-Temp. Mater.
2026,
3
(4), 10023; 
DOI: 10.70322/htm.2026.10023
Open Access

Article

20 September 2026

Fabrication of Gradient Structured (Ta0.2Nb0.2Ti0.2Zr0.2Hf0.2)C-SiC Composites and Their High-Temperature Ablation Behavior

Porous high-entropy carbide ceramics (PHECs) exhibit excellent high-temperature stability and are considered promising candidates for thermal-protection applications. However, their interconnected pore structure facilitates oxygen ingress during ablation, resulting in accelerated oxidation and structural degradation. In this work, a gradient SiC-rich dense surface layer was constructed on porous (Ta0.2Nb0.2Ti0.2Zr0.2Hf0.2)C ceramics through phenolic-resin infiltration, carbonization, and reactive melt infiltration (RMI) of silicon. The resulting composites exhibited a hierarchical architecture consisting of a dense SiC-rich surface layer and a porous interior. The initial pore structure strongly influenced molten-Si infiltration and reaction behavior, leading to an increase in the thickness of the SiC-rich dense layer from 33.3 to 121.2 μm with increasing porosity. During ablation, oxidation of SiC generated SiO2, which interacted with refractory transition-metal oxides to form a SiO2-rich composite oxide layer that effectively suppressed oxygen diffusion and enhanced oxidation resistance. Consequently, the oxide-layer thickness decreased from 121.4 to 35.2 μm, accompanied by a significant reduction in the mass ablation rate. Among all samples, HEC-SiC5 exhibited the best ablation resistance, with a mass ablation rate as low as 0.23 mg/s. This work establishes a direct correlation between substrate pore architecture, molten-Si infiltration behavior, dense-layer evolution, and ablation resistance, providing a practical strategy for the design of lightweight porous HEC-based thermal-protection materials.

Xinnuo Wang
Cuiyan Li*
Haibo Ouyang*
Qian Yang
Tianzhan Shen
High-Temp. Mater.
2026,
3
(3), 10022; 
DOI: 10.70322/htm.2026.10022
Open Access

Article

17 September 2026

Transformation Characteristics of Gucheng Quartzite and Assessment of Its Application Prospects

With the aim to well understand the relationship between the composition and properties of quartzite in Gucheng, three types of quartzite from a mining area in Gucheng have been investigated. This paper focused on the phase composition evolution and thermal expansion behavior of them under different thermal histories in the temperature range of 1200 °C to 1500 °C, and subsequently, the true density and microstructure were also measured and analyzed. In addition, inclusion analysis was conducted. The results indicate that black quartzite has a higher Fe content, white quartzite has relatively higher Al and K contents, and gray quartzite has a higher Ca content. Furthermore, all three types of quartzite almost completely transform into cristobalite after heat treatment at 1500 °C, although the transformation rates vary slightly with increasing temperature. The thermal expansion of the three types of quartzite exhibits similar trends, but gray quartzite exhibits greater residual expansion. It is believed that the phase transformation plays a dominant role in the total expansion, together with the sintering effect accelerated by the glass phase. At the same time, the microstructure of quartzite was also significantly influenced by the phase transformation process. The gas/liquid inclusion analysis revealed that all three types of quartzite have high inclusion content. The black quartzite contained only 5% transparent particles, the lowest among the three specimens, none of the three quartzite types are suitable for direct use in high-purity quartz applications.

Qian Xu
Bing Fan*
Defeng Zhang
Yucheng Yin*
Shengli Jin
High-Temp. Mater.
2026,
3
(3), 10021; 
DOI: 10.70322/htm.2026.10021
Open Access

Review

15 September 2026

A Review of Heat-Resistant Al Alloys: Strengthening Strategies and Processing Technologies

The rapid advancement of aerospace and transportation technologies toward weight reduction and harsh thermal environments has imposed a stringent demand for Al alloys that can sustain excellent performance at 200–400 °C. Heat-resistant Al alloys have thus garnered strategic significance as a premier class of lightweight structural materials for elevated-temperature applications. This review critically assesses the current state of heat-resistant Al alloys from the perspectives of strengthening strategies and processing technologies. Three representative strengthening strategies have been summarized, including multi-element microalloying, incorporation of nanoparticles, and formation of nano-eutectic skeleton. Meanwhile, a systematic comparative analysis has been conducted on microstructural regulations and mechanical properties of alloys manufactured by permanent mold casting (PMC), powder metallurgy (PM), and laser powder bed fusion (LPBF), with particular emphasis on the processing-structure-property correlations unique to each route. On this basis, the principal technical bottlenecks currently constraining the further advancement of high-performance heat-resistant Al alloys have been identified and critically discussed, thereby outlining prospective research directions to overcome these limitations.

Yi-Nan Piao
Hai-Long Jia*
Tian-Yue Li
Jia-Wang Song
He Wei
Min Zha*
High-Temp. Mater.
2026,
3
(3), 10020; 
DOI: 10.70322/htm.2026.10020
Open Access

Article

09 September 2026

Microstructure, Mechanical and Ablation Properties of Csf Reinforced C-ZrC-CuNi Composites

This study employs short-cut carbon fibers of varying contents as the reinforcing phase and prepares Csf/C-ZrC-CuNi composites via spark plasma sintering. The effects of short-cut carbon fiber content on the microstructure, mechanical properties, and ablation resistance of the composites are systematically investigated, and the fiber toughening and synergistic protection mechanisms are analyzed. The results indicate that the introduction of carbon fibers significantly suppresses the cracking tendency of the composites after ablation and promotes the formation of Cu2O and NiO, both of which act as sintering aids to densify the ZrO2 oxide layer, thereby synergistically enhancing the ablation resistance of the composites. At a carbon fiber content of 10 wt.%, the composites exhibit optimal comprehensive performance: the lowest ablation center temperature (2268 °C), a mass ablation rate of 2.00 mg/s, a linear ablation rate of −3.20 μm/s, and a flexural strength of 53.1 MPa. This study provides experimental evidence for the compositional design and performance optimization of ceramic composite high-temperature thermal protection materials.

Haibo Ouyang*
Yumiao Xing
Cuiyan Li*
Siyi Qi
Tianzhan Shen
Yanlei Li
Xiaoyue Sun
Shuai Zhang
Xinnuo Wang
Xilin Wang
Xinge Niu
High-Temp. Mater.
2026,
3
(3), 10019; 
DOI: 10.70322/htm.2026.10019
Open Access

Article

07 September 2026

Simultaneous Fabrication of Ti–Si Alloy and CA–CA2 Based Tailing Slag Cement via Aluminothermic Reduction of Ferrotitanium Slag

Al2O3–TiO2–CaO-based ferrotitanium slag is a waste slag generated during ferrotitanium-alloy smelting. At present, the TiO2 resource (about 15 wt.%) in ferrotitanium slag has not been effectively utilized. In this study, aluminothermic reduction was used to extract Ti and prepare a Ti–Si alloy, while the low-density Al2O3–CaO-based molten tailing slag floating on the Ti–Si melt was separated to fabricate CA–CA2 tailing-slag cement. The TiO2 content decreased from 14.42 wt.% in the ferrotitanium slag to 1.63 wt.% in the tailing slag. The Ti–Si alloy was mainly composed of Ti5Si3 and Ti5Si4. The mineral composition and hydration behavior of the CA–CA2 tailing-slag cement were similar to those of commercial calcium aluminate cement Secar71. Under the adopted preparation and testing conditions, the mechanical strength of the tailing-slag cement paste reached approximately 85% of that of Secar71, indicating its potential as an alternative refractory binder. The co-production of Ti–Si alloy and CA–CA2 tailing-slag cement provides a potential route for the value-added utilization of ferrotitanium slag.

Xifei Zhang
Tu Long
Ding Chen*
Huazhi Gu
Ao Huang
Lvping Fu
Yongshun Zou
Shenghao Li
Xin Xiao
High-Temp. Mater.
2026,
3
(3), 10018; 
DOI: 10.70322/htm.2026.10018
Open Access

Review

04 September 2026

Friction and Contact Mechanics of Nuclear Graphite in High-Temperature Gas-Cooled Reactors: A Review

The high-temperature gas-cooled reactor (HTGR), as a preferred reactor type for Generation IV nuclear energy systems, widely employs nuclear-grade graphite in its core as the moderator, structural material, and matrix of fuel elements. The friction coefficient between graphite components and the contact stiffness of spherical fuel elements directly affect the structural integrity of the core, the flow characteristics of the pebble bed, and the design of the fuel handling system, serving as critical mechanical parameters for ensuring reactor safety and economic operation. This paper systematically reviews the preparation processes and multi-scale microstructural features of nuclear graphite for HTGRs and summarizes the current research status in two directions: the friction coefficient and the contact stiffness of nuclear graphite. In the field of tribology, the influencing mechanisms of intrinsic factors such as grain size and porosity, as well as extrinsic factors such as ambient atmosphere, temperature, load, and sliding velocity, on the friction behavior of graphite are analyzed with emphasis. The controversies and applicable conditions of the surface energy mechanism and the dangling bond mechanism are discussed. In terms of contact mechanics, the development of asperity models from the Hertz contact and Abbott-Firestone (AF) model to the Kogut-Etsion finite-element based fitting is summarized, along with the evolution from the Greenwood-Williamson (GW) statistical model to the Majumdar-Bhushan (MB) fractal contact model. Experimental methods for measuring stiffness coefficients—namely, the interface displacement method, the impact method, and the acoustic method—are reviewed. On this basis, the severe scarcity of nuclear graphite mechanical data under in-core conditions, such as high temperatures and inert atmospheres, is highlighted. Two systematic experimental works dedicated to graphite materials for HTGRs are integrated: the first measurements of the static and dynamic friction coefficients of isostatically pressed nuclear graphite BG80 in a high-purity helium environment from 25 to 1300  °C, revealing a four-stage variation of the friction coefficient with temperature; and the first acquisition of the temperature dependence and irreversible evolution characteristics of the stiffness coefficient of spherical fuel elements in high temperature helium. These works fill the gaps in fundamental data and can provide quantitative parameter inputs and theoretical support for HTGR core design, pebble-bed flow simulations, and safety analyses.

Tiezhong Lu
Nan Gui*
Zeliang Chen
Minghao Si
Shengyao Jiang
High-Temp. Mater.
2026,
3
(3), 10017; 
DOI: 10.70322/htm.2026.10017
Open Access

Article

06 August 2026

Enhancement on Properties of MgO-MgAlON Composite Refractories by Introducing Solid Waste Containing BN and AlN

Driven by the goals of carbon peaking and carbon neutrality, the resource utilization of solid waste has attracted considerable attention due to its scientific importance and environmental benefits. For this purpose, MgO-MgAlON-BN refractories with enhanced thermal shock and slag resistance were designed and successfully fabricated by introducing BN solid waste as an additive. The results indicate that the sample containing BN additives exhibits superior overall performance compared with those without additives. At a BN content of 3.26 wt.%, the cold compressive strength increases by 21.20%, and the contact angle at 1723 K increases by 50.01%. Further analysis reveals that the improved wetting behavior is mainly attributed to the introduction of BN additives, which promote the formation of numerous micro-convex structures. These structural characteristics restrict slag infiltration and inhibit slag penetration into the refractory matrix, thereby enhancing slag resistance. Consequently, a cost-effective and feasible reinforcement strategy for MgO-MgAlON-BN refractories is proposed, providing a promising pathway for the high-value utilization of solid waste resources.

Zhangyan Zhou
Lulu Wang
Chunming Liu
Chang Su
Huawei Yin
Chuanbo Hu
Yongxin Wang
Shuli Sun
Xinming Ren
Guangming Li
Chengcheng Zhang
Yongli Liu
Chengji Deng
Beiyue Ma*
Chao Yu*
High-Temp. Mater.
2026,
3
(3), 10016; 
DOI: 10.70322/htm.2026.10016
Open Access

Article

03 August 2026

Design of Micro/Nano-Lamellar C4AcH11 and Hydrotalcite in Alumina-Spinel Castables: Enhanced High-Temperature Damage Resistance

In the present study, lamellar hydrates were designed via curing regimes and additives. Structural and high-temperature fracture behavior analyses were employed to elucidate the influence of initial lamellar hydrates on microstructural evolution and thermal stress resistance at elevated temperatures. Key findings reveal that: Pure CAC cured at 25 °C for 24 h predominantly forms metastable CAH10 and C2AH8, whereas under the two-step curing regime, the hydration products are granular C3AH6 and lamellar AH3. Incorporating CaCO3 and MgO under two-step curing promotes the simultaneous generation of micro/nano-lamellar C4AcH11 and Mg-Al Hydrotalcite (M-A-H). The enhanced extent of hydration and pore-filling effect of M-A-H refines matrix porosity, increasing the volume fraction of 5–100 nm pores and elevating the fractal dimension (Ds). This microstructural optimization improves bonding strength, as evidenced by an 82% increase in demolding strength in the designed samples compared with the R samples. C4AcH11 and M-A-H serve as reactive CaO and MgO sources, respectively, facilitating the interlocking distribution of in-situ CA6 and MgAl2O4 at 1600 °C and optimizing pore structure. The hierarchical pore structure and refined crystals synergistically enhance thermal stress resistance by increasing crack deflection, dissipating energy, and improving plastic deformation capacity.

Guoping He
Ning Liao*
Wenjing Liu
Shengli Jin
Yawei Li*
High-Temp. Mater.
2026,
3
(3), 10015; 
DOI: 10.70322/htm.2026.10015
Open Access

Article

13 July 2026

Dynamic Mechanics of Carbon Containing Alumina Refractories and the Effect of Carbon Resource and Cyclic Thermal Exposure

Dynamic thermo-mechanical stresses caused by sudden temperature changes and molten steel impact, etc., accelerate the degradation of Al2O3-C refractories during service. To investigate the dynamic degradation behavior, dynamic mechanical tests were conducted using the Split Hopkinson Pressure Bar (SHPB), systematically examining the effects of partial substitution of flake graphite by expanded graphite and thermal degradation. The results show that the Al2O3-C refractories exhibit a significant strain-rate hardening effect, with strength increasing with impact velocity and the failure mode progressively transitioning from crack propagation to pulverization. Cyclic prolonged thermal exposure to 1500 °C contributes to the SiC whiskers formation and densification, and results in the increase strength and brittleness. The phenomenon of specimen after 5 cycles having the optimal impact resistance proves the both the strength and energy dominated failure process. The introduction of expanded graphite effectively suppresses crack propagation and enhances energy dissipation capacity through interlayer sliding and stress buffering related to the myrmekitic texture, which provides a rationale for the development of low-carbon materials.

Zexian Wang
Haodong Wu
Tianbin Zhu
Juan Yang
Shengli Jin
Yawei Li
Yajie Dai*
High-Temp. Mater.
2026,
3
(3), 10014; 
DOI: 10.70322/htm.2026.10014
Open Access

Review

21 February 2025

Cement-Free Binders in Alumina-Magnesia Refractory Castables—A Review

To solve the problem of the accelerated deterioration of calcium aluminate (CAC)-bonded alumina-magnesia refractory castables during the secondary refining process, the development of cement-free binders has emerged as one significant research field of castables. The hydration behavior, curing mechanism, and properties of the most recent research on cement-free binders are compared in this paper. The problems and the modification of each binder of recent research are summarized. High-temperature performance of the castables bonded by traditional hydraulic cement-free binders (ρ-Al2O3 and activated MgO) is outstanding, explosive spalling resistance of the castables bonded by sol binders (silica sol, alumina sol) is good, and the properties of the castables bonded by novel organic hydratable binder (hydratable magnesium citrate) combine the advantages of these two binders above, but the mid-temperature mechanical strength is low. Furthermore, alumina-magnesia castables bonded by organic-composited inorganic cement-free binders are expected to be a future domain.

Luyan Sun
Donghai Ding*
Guoqing Xiao*
Jianjun Chen
Yuan Feng
High-Temp. Mater.
2025,
2
(1), 10002; 
DOI: 10.70322/htm.2025.10002
Open Access

Article

17 April 2024

Thermogravimetric Study of the Oxidation Behavior of the Cantor’s Alloy at 1000 °C and Beyond

A polycrystalline Cantor alloy, equimolar in Co, Cr, Fe, Mn and Ni, was cast. It was subjected to oxidation in a thermo-balance in a flow of synthetic dry air, at 1000, 1050, 1100 and 1150 °C. The mass gain was globally parabolic but rather irregular. The parabolic constants, ranging from 55 to 700 × 10−12·g2·cm−4·s−1, are much higher than for a chromia-forming alloy. They obey an Arrhenius law with an activation energy equal to 270 kJ/mol. The external oxide scales formed are composed of an outer part made of manganese oxide and an inner part made of (Cr, Mn) oxide containing a thin internal layer of chromia. The Mn and Cr-depleted depths and the Mn and Cr masses lost by the alloy increase with the oxidation temperature. Cr-rich acicular particles precipitated in subsurface at 1100 °C and internal oxidation along the grain boundaries are present in the whole thickness of the sample oxidized at 1150 °C. Oxide spallation occurred during the cooling, at temperatures in the 200–350 °C range, only for the alloys oxidized at 1050 and 1100 °C. Not too thick scale (1000 °C) or deep internal oxidation (1150 °C) may be favorable for scale adherence.

Patrice Berthod*
Lionel Aranda
High-Temp. Mater.
2024,
1
(1), 10002; 
DOI: 10.35534/htm.2024.10002
Open Access

Article

31 December 2024

Porous 430L Stainless Steel as a Support Layer for Planar Solid Oxide Cells: Effect of Porosity on Mechanical Properties

Porous 430L stainless steel components fabricated via tape casting underwent mechanical testing for potential in-vehicle application as mechanical supports of solid oxide cells. Tests included three-point bending up to 5% strain to assess flexural strength, yield strength, Young’s modulus, indentation hardness, and microstructural characterization. This study aimed to establish the relationship between pore former size and volume fraction and the resulting yield strength. It also compared sintered material without pore former, focusing on the influence of a wide range of porosity of up to 46.5%. The materials exhibited an inverse relationship for Young’s modulus, hardness and yield strength as a function of porosity. The lowest flexural yield strength obtained was approximately 120 MPa at the highest porosity of 46.5%, meeting the requirement of 59 MPa for the bipolar plates of existing proton-exchange membrane fuel cells.

Yifei Yan
Dhruv Bajaj
Daolun Chen
Olivera Kesler*
High-Temp. Mater.
2024,
1
(2), 10011; 
DOI: 10.70322/htm.2024.10011
Open Access

Review

09 January 2025

Recent Advancements in Alumina-Based High-Temperature Insulating Materials: Properties, Applications, and Future Perspectives

As a high-temperature thermal insulation material with excellent mechanical properties, alumina (Al2O3)-based materials hold significant potential for applications in aerospace, advanced manufacturing, automobiles, industrial furnaces, and other fields. However, the inherent brittleness of alumina poses a limitation to its wider application. Therefore, there is a pressing need to develop alumina-based materials that offer high toughness while retaining superior mechanical properties. This paper begins by exploring the structure of alumina, highlighting its thermal conductivity, insulation, and mechanical properties in high-temperature environments. It then reviews the classification and synthesis methods of alumina-based materials, along with the latest advances in design strategies. Notably, the rational design of alumina composition, structure, and morphology is emphasized as crucial for optimizing material performance, thereby supporting the industrial development and application of these materials in high-tech sectors. Finally, the paper discusses the challenges and evolution of alumina-based materials in real-world industrial applications and suggests potential directions for future development.

Yufei Sun
Suya Li
Qi Zhao
Zihan Cong
Yuguo Xia
Xiuling Jiao
Dairong Chen*
High-Temp. Mater.
2025,
2
(1), 10001; 
DOI: 10.70322/htm.2025.10001
Open Access

Review

11 June 2025

Recent Advances in High-Temperature Properties of High-Entropy Alloys

High-temperature alloys are critical for advanced thermal components in aerospace and energy industries. Conventional alloys, which rely on a single principal element with limited alloying additions, often exhibit insufficient phase stability and rapid oxidation at extreme temperatures. In recent years, high-entropy alloys (HEAs) have emerged as revolutionary candidates for high-temperature applications, overcoming the limitations of conventional alloys through their unique multi-principal element design and exceptional performance. This review systematically examines the latest progress in HEAs’ key high-temperature properties: tensile properties, creep resistance, oxidation resistance, and phase stability. Research demonstrates that HEAs achieve remarkable mechanical properties at elevated temperatures through multiple mechanisms, such as lattice distortion effects, precipitation of ordered L12-structured phases, and refined grain boundary engineering. For instance, refractory HEAs like MoNbTaVW and Hf-Nb-Ti-V systems exhibit superior creep resistance at temperatures exceeding 1600 °C, outperforming traditional nickel-based superalloys. The slow diffusion of oxygen and the formation of multi-component oxide layers enhance the high-temperature oxidation resistance of high-entropy alloys. Additionally, HEAs display excellent phase stability under thermal exposure, driven by high configurational entropy and optimized microstructural designs, including nanoscale lamellar phases and coherent precipitates. Despite these advances, challenges remain in balancing mechanical strength with ductility, ensuring long-term durability under cyclic thermal-mechanical loads, and tailoring compositions for extreme service conditions. Future efforts should integrate machine learning, computational modeling, and high-throughput experiments to accelerate the discovery of novel HEA systems and validate their performance in practical applications. By addressing these challenges, HEAs are poised to revolutionize material solutions for next-generation aerospace engines, nuclear reactors, and high-efficiency energy systems.

Weiming Pan
Daoyuan Huang
Wanlin Wang
Guangyang Dou
Peisheng Lyu*
High-Temp. Mater.
2025,
2
(2), 10011; 
DOI: 10.70322/htm.2025.10011
Open Access

Review

27 August 2024

Strongly Correlated Electrons and High Temperature Superconductivity

It is very important to clarify the mechanism of high-temperature superconductivity in strongly correlated electron systems. The mechanism of superconductivity in high temperature cuprate superconductors has been studied extensively since their discovery. We investigate the properties of correlated electron systems and mechanism of superconductivity by using the optimization quantum variational Monte Carlo method. The many-body wave function is constructed by multiplying by correlation operators of exponential type. We show that d-wave superconducting phase exists in the strongly correlated region where the on-site repulsive interaction is as large as the bandwidth or more than the bandwidth. The d-wave pairing correlation function is shown as a function of lattice sites, showing that the long-range order indeed exists.

Takashi Yanagisawa*
High-Temp. Mater.
2024,
1
(1), 10004; 
DOI: 10.35534/htm.2024.10004
Open Access

Review

13 June 2025

Advances in Sintering Technologies for SiC Ceramics: Mechanisms, Challenges, and Industrial Applications

Silicon carbide (SiC) ceramics have become critical materials for high-temperature engineering applications because of their exceptional mechanical strength, thermal conductivity, and chemical stability. In order to meet the diverse needs of industrial applications, various sintering methods have been developed. These include traditional methods such as pressureless sintering, reaction-bonded sintering, hot pressing, and recrystallization, as well as advanced technologies like spark plasma sintering, oscillatory pressure sintering, and flash sintering. This review provides a systematic analysis of both traditional and advanced sintering techniques for SiC ceramics. It highlights their mechanisms, critical process parameters, and impacts on the final material properties. Key challenges, including high sintering temperatures, additive selection, microstructural control, and scalability, are examined. Strategies for balancing cost-efficiency with performance are also discussed. In addition, recent advancements in SiC-based composite materials for applications ranging from aerospace components to catalytic filtration systems are presented. Finally, future research directions are proposed. These focus on precise additive engineering, microstructure tailoring, and innovative sintering methodologies to speed up the transition of high-performance SiC ceramics from laboratory prototypes to large-scale industrial implementation.

Yufeng Chen
Chao Yu*
Xu Cheng
Ruiting Wang
Chengji Deng
Jun Ding
Zhenglong Liu
Beiyue Ma
Hongxi Zhu
Jiaxun Hu
Chuanqi Tan
High-Temp. Mater.
2025,
2
(3), 10013; 
DOI: 10.70322/htm.2025.10013
Open Access

Review

25 February 2025

Innovations in IN939: From Cast Alloy to Additive Manufacturing

Nickel-based superalloys are the most reliable material choice for the hot sections of turbines. These superalloys are mainly employed in aircraft engines, particularly in the combustor and turbine sections. In this scenario, the growing need for materials that can endure high temperatures while retaining their strength has driven the development of IN939. Although IN939 holds these significant important properties and applications, it has received less attention in recent literature than other superalloys. This review aims to comprehensively analyze the main research on IN939 over the past 50 years. From 1970 to 1980, research primarily focused on the development of IN939 through casting methods. Between 1980 and 1990, the emphasis shifted to studying its oxidation resistance and microstructural stability during service. The period from 1990 to 2000 focused on repairing components after long service time at high temperatures. In recent decades, advances in additive manufacturing techniques have led to growing interest in developing IN939 using methods like laser powder bed fusion (LPBF). Research in the area has demonstrated that the LPBF technique offers a promising approach to manufacturing high-performance IN939 components.

Sgambaro De Lorenzi Mariana
Verner Soh
Delvin Wuu
Si Rong Ng
Desmond Lau
Siyuan Wei
Chee Koon Ng
Wenqi Guo
Pei Wang
Zhongji Sun*
Zhili Dong*
High-Temp. Mater.
2025,
2
(1), 10003; 
DOI: 10.70322/htm.2025.10003
Open Access

Article

14 November 2024

Hardness-Porosity-Grain Size Interrelationship in Conventionally Sintered 3 mol% Yttria Stabilized Zirconia

Considerable research has been done in the past on expensive, <50 nm particle size 3 mol% yttria-stabilized zirconia (3YSZ) using advanced sintering techniques. However, insights are still needed to reveal which factors among grain size and porosity, when both are changing simultaneously, more strongly control the hardness of conventionally sintered, relatively coarse, 250 nm 3YSZ powder, which can be used to make large industrial engineering ceramic parts at a lower cost. This investigation showed that elevating the sintering temperature from 1500 °C to 1650 °C increased the Rockwell hardness from 49.4 HRA to 86.0 HRA, which was concomitant with an increase in grain size and bulk density. A pseudo-inverse Hall-Petch relationship between hardness and grain size was observed given by H (in HRA) = 153.1 − 69.2/$$\small\sqrt{(\mathrm{grain}\,\mathrm{size})}$$ with a somewhat low R2 of 0.95, which was mainly due to the porosity being an additional important variable. Compared to grain size, the impact of open pore fraction (P) on hardness was stronger, inferred from a higher R2 of 0.99 while fitting the data into the well-known exponential decay equation, H = 92.9 exp(−11.1P). Finally, it was observed that the 3YSZ conventionally sintered at 1650 °C for 2 h had 0.8% open porosity, 6.08 g/cm3 bulk density, 960 nm grain size and consisted of only tetragonal ZrO2.

Abhijeet Phatak
Prashant Gupta
Somnath Mandal*
Harshit Agrawal
Om Parkash
Devendra Kumar
High-Temp. Mater.
2024,
1
(2), 10008; 
DOI: 10.70322/htm.2024.10008
Open Access

Article

29 September 2024

Reactions and Phase Transformations at Sintering of Cubic Boron Nitride Based Materials

Superhard cubic boron nitride (cBN) cutting materials with different contents of cBN were investigated. The compositions of cBN-based materials included ceramic and metallic binders. The sintering of materials was performed by high-temperature hot pressing (HPHT) six-anvil apparatus at pressure 4.5 GPa and temperatures 1400–1450 °C. The process of compaction and processing of superhard cBN materials is followed by numerous chemical reactions. The chemical reactions are very important in compaction and sintering. The volume transformations during chemical reactions affect the shrinkage of the materials and may also impact the residual porosity of the finished products. The adhesion between the grains also depends on these chemical reactions. The research analyzed the volume transformations of various reactions during HPHT sintering of cBN materials, which may play a significant role in forming their structure and properties.

Stepan Pavlov
Andrey Yurkov*
Mikhail Andrianov
High-Temp. Mater.
2024,
1
(1), 10006; 
DOI: 10.70322/htm.2024.10006
Open Access

Review

09 January 2025

Recent Advancements in Alumina-Based High-Temperature Insulating Materials: Properties, Applications, and Future Perspectives

As a high-temperature thermal insulation material with excellent mechanical properties, alumina (Al2O3)-based materials hold significant potential for applications in aerospace, advanced manufacturing, automobiles, industrial furnaces, and other fields. However, the inherent brittleness of alumina poses a limitation to its wider application. Therefore, there is a pressing need to develop alumina-based materials that offer high toughness while retaining superior mechanical properties. This paper begins by exploring the structure of alumina, highlighting its thermal conductivity, insulation, and mechanical properties in high-temperature environments. It then reviews the classification and synthesis methods of alumina-based materials, along with the latest advances in design strategies. Notably, the rational design of alumina composition, structure, and morphology is emphasized as crucial for optimizing material performance, thereby supporting the industrial development and application of these materials in high-tech sectors. Finally, the paper discusses the challenges and evolution of alumina-based materials in real-world industrial applications and suggests potential directions for future development.utf-8

Yufei Sun
Suya Li
Qi Zhao
Zihan Cong
Yuguo Xia
Xiuling Jiao
Dairong Chen*
High-Temp. Mater.
2025,
2
(1), 10001; 
DOI: 10.70322/htm.2025.10001
Open Access

Review

21 February 2025

Cement-Free Binders in Alumina-Magnesia Refractory Castables—A Review

To solve the problem of the accelerated deterioration of calcium aluminate (CAC)-bonded alumina-magnesia refractory castables during the secondary refining process, the development of cement-free binders has emerged as one significant research field of castables. The hydration behavior, curing mechanism, and properties of the most recent research on cement-free binders are compared in this paper. The problems and the modification of each binder of recent research are summarized. High-temperature performance of the castables bonded by traditional hydraulic cement-free binders (ρ-Al2O3 and activated MgO) is outstanding, explosive spalling resistance of the castables bonded by sol binders (silica sol, alumina sol) is good, and the properties of the castables bonded by novel organic hydratable binder (hydratable magnesium citrate) combine the advantages of these two binders above, but the mid-temperature mechanical strength is low. Furthermore, alumina-magnesia castables bonded by organic-composited inorganic cement-free binders are expected to be a future domain.utf-8

Luyan Sun
Donghai Ding*
Guoqing Xiao*
Jianjun Chen
Yuan Feng
High-Temp. Mater.
2025,
2
(1), 10002; 
DOI: 10.70322/htm.2025.10002
Open Access

Review

02 September 2024

A Review on the Application of Nanomaterials to Boost the Service Performances of Carbon-Containing Refractories

To meet the high-quality requirements for clean steel production and fully exploit the performance advantages of carbon-containing refractories, nanomaterial has been introduced into the matrix to develop advanced carbon-containing refractories. Nanomaterials, as critical additives, play a crucial role in developing novel refractories. The service performances of carbon-containing refractories are affected not only by their physical and chemical properties but also by their microstructure. This review provides a comprehensive overview of the latest research on oxide-carbon composite refractories containing nanomaterials, categorized by their composition: nanocarbons, nano oxides, and nano non-oxides. Incorporating nanomaterials can enhance the service performances of the refractories, optimizing phase composition and microstructure. Furthermore, future research directions in nanomaterial technology for carbon-containing refractories are discussed.utf-8

Junyi Lv
Haijun Zhang
Haohui Gu
Feng Liang*
High-Temp. Mater.
2024,
1
(1), 10005; 
DOI: 10.70322/htm.2024.10005
Open Access

Review

11 June 2025

Recent Advances in High-Temperature Properties of High-Entropy Alloys

High-temperature alloys are critical for advanced thermal components in aerospace and energy industries. Conventional alloys, which rely on a single principal element with limited alloying additions, often exhibit insufficient phase stability and rapid oxidation at extreme temperatures. In recent years, high-entropy alloys (HEAs) have emerged as revolutionary candidates for high-temperature applications, overcoming the limitations of conventional alloys through their unique multi-principal element design and exceptional performance. This review systematically examines the latest progress in HEAs’ key high-temperature properties: tensile properties, creep resistance, oxidation resistance, and phase stability. Research demonstrates that HEAs achieve remarkable mechanical properties at elevated temperatures through multiple mechanisms, such as lattice distortion effects, precipitation of ordered L12-structured phases, and refined grain boundary engineering. For instance, refractory HEAs like MoNbTaVW and Hf-Nb-Ti-V systems exhibit superior creep resistance at temperatures exceeding 1600 °C, outperforming traditional nickel-based superalloys. The slow diffusion of oxygen and the formation of multi-component oxide layers enhance the high-temperature oxidation resistance of high-entropy alloys. Additionally, HEAs display excellent phase stability under thermal exposure, driven by high configurational entropy and optimized microstructural designs, including nanoscale lamellar phases and coherent precipitates. Despite these advances, challenges remain in balancing mechanical strength with ductility, ensuring long-term durability under cyclic thermal-mechanical loads, and tailoring compositions for extreme service conditions. Future efforts should integrate machine learning, computational modeling, and high-throughput experiments to accelerate the discovery of novel HEA systems and validate their performance in practical applications. By addressing these challenges, HEAs are poised to revolutionize material solutions for next-generation aerospace engines, nuclear reactors, and high-efficiency energy systems.utf-8

Weiming Pan
Daoyuan Huang
Wanlin Wang
Guangyang Dou
Peisheng Lyu*
High-Temp. Mater.
2025,
2
(2), 10011; 
DOI: 10.70322/htm.2025.10011
Open Access

Review

13 June 2025

Advances in Sintering Technologies for SiC Ceramics: Mechanisms, Challenges, and Industrial Applications

Silicon carbide (SiC) ceramics have become critical materials for high-temperature engineering applications because of their exceptional mechanical strength, thermal conductivity, and chemical stability. In order to meet the diverse needs of industrial applications, various sintering methods have been developed. These include traditional methods such as pressureless sintering, reaction-bonded sintering, hot pressing, and recrystallization, as well as advanced technologies like spark plasma sintering, oscillatory pressure sintering, and flash sintering. This review provides a systematic analysis of both traditional and advanced sintering techniques for SiC ceramics. It highlights their mechanisms, critical process parameters, and impacts on the final material properties. Key challenges, including high sintering temperatures, additive selection, microstructural control, and scalability, are examined. Strategies for balancing cost-efficiency with performance are also discussed. In addition, recent advancements in SiC-based composite materials for applications ranging from aerospace components to catalytic filtration systems are presented. Finally, future research directions are proposed. These focus on precise additive engineering, microstructure tailoring, and innovative sintering methodologies to speed up the transition of high-performance SiC ceramics from laboratory prototypes to large-scale industrial implementation.utf-8

Yufeng Chen
Chao Yu*
Xu Cheng
Ruiting Wang
Chengji Deng
Jun Ding
Zhenglong Liu
Beiyue Ma
Hongxi Zhu
Jiaxun Hu
Chuanqi Tan
High-Temp. Mater.
2025,
2
(3), 10013; 
DOI: 10.70322/htm.2025.10013
Open Access

Article

14 November 2024

Hardness-Porosity-Grain Size Interrelationship in Conventionally Sintered 3 mol% Yttria Stabilized Zirconia

Considerable research has been done in the past on expensive, <50 nm particle size 3 mol% yttria-stabilized zirconia (3YSZ) using advanced sintering techniques. However, insights are still needed to reveal which factors among grain size and porosity, when both are changing simultaneously, more strongly control the hardness of conventionally sintered, relatively coarse, 250 nm 3YSZ powder, which can be used to make large industrial engineering ceramic parts at a lower cost. This investigation showed that elevating the sintering temperature from 1500 °C to 1650 °C increased the Rockwell hardness from 49.4 HRA to 86.0 HRA, which was concomitant with an increase in grain size and bulk density. A pseudo-inverse Hall-Petch relationship between hardness and grain size was observed given by H (in HRA) = 153.1 − 69.2/$$\small\sqrt{(\mathrm{grain}\,\mathrm{size})}$$ with a somewhat low R2 of 0.95, which was mainly due to the porosity being an additional important variable. Compared to grain size, the impact of open pore fraction (P) on hardness was stronger, inferred from a higher R2 of 0.99 while fitting the data into the well-known exponential decay equation, H = 92.9 exp(−11.1P). Finally, it was observed that the 3YSZ conventionally sintered at 1650 °C for 2 h had 0.8% open porosity, 6.08 g/cm3 bulk density, 960 nm grain size and consisted of only tetragonal ZrO2.utf-8

Abhijeet Phatak
Prashant Gupta
Somnath Mandal*
Harshit Agrawal
Om Parkash
Devendra Kumar
High-Temp. Mater.
2024,
1
(2), 10008; 
DOI: 10.70322/htm.2024.10008
Open Access

Article

06 June 2025

Effects of Changing the Specific Surface Area in the Ceramic Matrix of CAC-Containing Refractory Castables on the Initial Stiffening and Setting Behaviour

Besides the coarse and medium grain size distribution, the matrix components play a central role in the performance of refractory castables. Practical experience shows that the particle size distribution (PSD) and the specific surface area of the ceramic matrix significantly influence processing, setting, and sintering behaviour. However, there is a lack of systematic studies on how PSD or specific surface area changes affect castable properties. This study aims to address this gap by varying ceramic matrices to create refractory model castables with different matrix surface areas. Three dispersing agents with different mechanisms (electrosteric and steric) were used at graded concentrations. Results show that castables with higher specific surface areas (using (very) finely ground and highly sintered alumina raw materials with high specific surface areas) and different dispersing agents and their concentrations show substantial differences in the initial stiffening and setting behaviour. Higher specific surface areas of the matrix result in an earlier first stiffening, while adding more dispersing agents leads to delayed stiffening. The refractory model castables’ first stiffening and hydration range (with a simultaneous temperature maximum) vary considerably depending on the dispersing agent used and its concentration, caused by completely different mechanisms.utf-8

Florian Holleyn*
Tim Waldstädt
Johannes Kasper
Christian Dannert
Olaf Krause
High-Temp. Mater.
2025,
2
(2), 10009; 
DOI: 10.70322/htm.2025.10009
Open Access

Review

19 June 2025

Research Progress on High-Entropy Fibrous Materials

Due to their lightweight, high strength, and thermal resistance, HEFMs exhibited significant potential in aerospace, energy storage, environmental protection, and defense. This review systematically presented the research progress on high-entropy fibrous materials (HEFMs), covering their fundamental concepts, fabrication methods, crystal structure characteristics, performance advantages, and application fields. The different crystal structure types and fabrication techniques of high-entropy ceramic fibers and high-entropy alloy fibers were discussed. Additionally, the mechanical property advantages of HEFMs and their applications in thermal insulation materials, catalysis, and energy storage were analyzed. Finally, the current challenges in HEFM research and provide an outlook on future development directions.utf-8

Yulong Wang
Xue Shen
Tengyu Du
Zeyu Wang
Zhigang Yang*
Gang Yu
Guoqiang Qin
Shengya He*
Zhi Wang
Lei Wen
High-Temp. Mater.
2025,
2
(3), 10014; 
DOI: 10.70322/htm.2025.10014
Open Access

Article

17 April 2024

Thermogravimetric Study of the Oxidation Behavior of the Cantor’s Alloy at 1000 °C and Beyond

A polycrystalline Cantor alloy, equimolar in Co, Cr, Fe, Mn and Ni, was cast. It was subjected to oxidation in a thermo-balance in a flow of synthetic dry air, at 1000, 1050, 1100 and 1150 °C. The mass gain was globally parabolic but rather irregular. The parabolic constants, ranging from 55 to 700 × 10−12·g2·cm−4·s−1, are much higher than for a chromia-forming alloy. They obey an Arrhenius law with an activation energy equal to 270 kJ/mol. The external oxide scales formed are composed of an outer part made of manganese oxide and an inner part made of (Cr, Mn) oxide containing a thin internal layer of chromia. The Mn and Cr-depleted depths and the Mn and Cr masses lost by the alloy increase with the oxidation temperature. Cr-rich acicular particles precipitated in subsurface at 1100 °C and internal oxidation along the grain boundaries are present in the whole thickness of the sample oxidized at 1150 °C. Oxide spallation occurred during the cooling, at temperatures in the 200–350 °C range, only for the alloys oxidized at 1050 and 1100 °C. Not too thick scale (1000 °C) or deep internal oxidation (1150 °C) may be favorable for scale adherence.utf-8

Patrice Berthod*
Lionel Aranda
High-Temp. Mater.
2024,
1
(1), 10002; 
DOI: 10.35534/htm.2024.10002
Open Access

Review

25 February 2025

Innovations in IN939: From Cast Alloy to Additive Manufacturing

Nickel-based superalloys are the most reliable material choice for the hot sections of turbines. These superalloys are mainly employed in aircraft engines, particularly in the combustor and turbine sections. In this scenario, the growing need for materials that can endure high temperatures while retaining their strength has driven the development of IN939. Although IN939 holds these significant important properties and applications, it has received less attention in recent literature than other superalloys. This review aims to comprehensively analyze the main research on IN939 over the past 50 years. From 1970 to 1980, research primarily focused on the development of IN939 through casting methods. Between 1980 and 1990, the emphasis shifted to studying its oxidation resistance and microstructural stability during service. The period from 1990 to 2000 focused on repairing components after long service time at high temperatures. In recent decades, advances in additive manufacturing techniques have led to growing interest in developing IN939 using methods like laser powder bed fusion (LPBF). Research in the area has demonstrated that the LPBF technique offers a promising approach to manufacturing high-performance IN939 components.utf-8

Sgambaro De Lorenzi Mariana
Verner Soh
Delvin Wuu
Si Rong Ng
Desmond Lau
Siyuan Wei
Chee Koon Ng
Wenqi Guo
Pei Wang
Zhongji Sun*
Zhili Dong*
High-Temp. Mater.
2025,
2
(1), 10003; 
DOI: 10.70322/htm.2025.10003

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