Ceramic Fibers Research Articles

Advancements in Thermal Insulation through Ceramic Micro-Nanofiber Materials

Ceramic fibers have the advantages of high temperature resistance, light weight, favorable chemical stability and superior mechanical vibration resistance, which make them widely used in aerospace, energy, metallurgy, construction, personal protection and other thermal protection fields. Further refinement of the diameter of conventional ceramic fibers to microns or nanometers could further improve their thermal insulation performance and realize the transition from brittleness to flexibility. Processing traditional two-dimensional (2D) ceramic fiber membranes into three-dimensional (3D) ceramic fiber aerogels could further increase porosity, reduce bulk density, and reduce solid heat conduction, thereby improving thermal insulation performance and expanding application areas. Here, a comprehensive review of the newly emerging 2D ceramic micro-nanofiber membranes and 3D ceramic micro-nanofiber aerogels is demonstrated, starting from the presentation of the thermal insulation mechanism of ceramic fibers, followed by the summary of 2D ceramic micro-nanofiber membranes according to different types, and then the generalization of the construction strategies for 3D ceramic micro-nanofiber aerogels. Finally, the current challenges, possible solutions, and future prospects of ceramic micro-nanofiber materials are comprehensively discussed. We anticipate that this review could provide some valuable insights for the future development of ceramic micro-nanofiber materials for high temperature thermal insulation.

Ceramic Fiber-Reinforced Polyimide Aerogel Composites with Improved Shape Stability against Shrinkage

Polyimide (PI) aerogels, renowned for their nano-porous structure and exceptional performance across a spectrum of applications, often encounter significant challenges during fabrication, primarily due to severe shrinkage. In this study, we innovatively incorporated ceramic fibers of varying diameters into the PI aerogel matrix to enhance the shape stability against shrinkage. Thestructure of the resulting ceramic fiber-reinforced PI (CF-PI) aerogel composites as well as their performance in thermal decomposition, thermal insulation, and compression resistance were characterized. The results revealed that the CF-PI aerogel composites dried by supercritical ethanol achieved greatly reduced shrinkage as low as 5.0 vol.% and low thermal conductivity ranging from 31.2 mW·m−1·K−1 to 35.3 mW·m−1·K−1, showcasing their excellent performance in shape stability and thermal insulation. These composites also inherited the superior residue-forming ability of ceramic fibers and the robust mechanical attributes of PI, thereby exhibiting enhanced thermal stability and compression resistance. Besides, the effects of different drying conditions on the structure and properties of CF-PI aerogels were also discussed. The coupling use of supercritical ethanol drying with the addition of ceramic fibers is preferred. This preferred condition gives birth to low-shrinkage CF-PI aerogel composites, which also stand out for their integrated advantages include high thermal stability, low thermal conductivity, and high mechanical strength. These advantages attribute to CF-PI aerogel composites substantial potential for a wide range of applications, particularly as high-performance thermal insulation materials for extreme conditions.

Electrospinning Nonspinnable Sols to Ceramic Fibers and Springs.

Electrospinning has been applied to produce ceramic fibers using sol gel-based spinning solutions consisting of ceramic precursors, a solvent, and a polymer to control the viscosity of the solution. However, the addition of polymers to the spinning solution makes the process more complex, increases the processing time, and results in porous mechanically weak ceramic fibers. Herein, we develop a coelectrospinning technique, where a nonspinnable sol (<10 mPa s) consisting of only the ceramic precursor(s) and solvent(s) is encapsulated inside a polymeric shell, forming core-shell precursor fibers that are further calcined into ceramic fibers with reduced porosity, decreased surface defects, uniform crystal packing, and controlled diameters. We demonstrate the versatility of this method by applying it to a series of nonspinnable sols and creating high-quality ceramic fibers containing TiO2, ZrO2, SiO2, and Al2O3. The polycrystalline TiO2 fibers possess excellent flexibility and a high Young's modulus reaching 54.3 MPa, solving the extreme brittleness problem of the previously reported TiO2 fibers. The single-component ZrO2 fibers exhibit a Young's modulus and toughness of 130.5 MPa and 11.9 KJ/m3, respectively, significantly superior to the counterparts prepared by conventional sol-gel electrospinning. We also report the creation of ceramic fibers in micro- and nanospring morphologies and examine the formation mechanisms using thermomechanical simulations. The fiber assemblies constructed by the helical fibers exhibit a density-normalized toughness of 3.5-5 times that of the straight fibers due to improved fracture strain. This work expands the selection of the electrospinning solution and enables the development of ceramic fibers with more attractive properties.

(Ca0.25La0.5Dy0.25)CrO3 Ceramic Fiber@Biomass-Derived Carbon Aerogel with Enhanced Solute Transport Channels for Highly Efficient Solar Interface Evaporation

The use of solar interface evaporation for seawater desalination or sewage treatment is an environmentally friendly and sustainable approach; however, achieving efficient solar energy utilization and ensuring the long-term stability of the evaporation devices are two major challenges for practical application. To address these issues, we developed a novel ceramic fiber@bioderived carbon composite aerogel with a continuous through-hole structure via electrospinning and freeze-casting methods. Specifically, an aerogel was prepared by incorporating perovskite oxide (Ca0.25La0.5Dy0.25)CrO3 ceramic fibers (CCFs) and amylopectin-derived carbon (ADC). The CCFs exhibited remarkable photothermal conversion efficiencies, and the ADC served as a connecting agent and imparted hydrophilicity to the aerogel due to its abundant oxygen-containing functional groups. After optimizing the composition and microstructure, the (Ca0.25La0.5Dy0.25)CrO3 ceramic fiber@biomass-derived carbon aerogel demonstrated remarkable properties, including efficient light absorption and rapid transport of water and solutes. Under 1 kW m−2 light intensity irradiation, this novel material exhibited a high temperature (48.3 °C), high evaporation rate (1.68 kg m−2 h−1), and impressive solar vapor conversion efficiency (91.6%). Moreover, it exhibited long-term stability in water evaporation even with highly concentrated salt solutions (25 wt%). Therefore, the (Ca0.25La0.5Dy0.25)CrO3 ceramic fiber@biomass-derived carbon aerogel holds great promise for various applications of solar interface evaporation.

Unlocking the superior flexibility and enhanced catalytic oxidation performance of CoTiO3 nanofibrous membranes through zirconium doping

The development of continuous CoTiO3 (CTO) fibers with prominent catalytic oxidation activity, tunable fibrous structures, and improved recyclability is appealing for application in efficient organic wastewater treatment; however, inescapable flaws remain, such as their inherent brittleness and adverse operability. Herein, a facile and effective strategy is proposed for the fabrication of flexible and mechanically robust CTO nanofibrous membranes through a combination of element doping and sol–gel-assisted electrospinning. Compared with pristine CTO fibers, the resulting zirconium-doped CoTiO3 (ZCTO) nanofibrous membranes displayed remarkably enhanced flexibility and tensile mechanics, which were attributed to their lower crystallinity, smaller grain size, and fewer fiber surface defects. The developed ZCTO fibrous membrane demonstrated exceptional resistance to bending fatigue, retaining a polymer-like bending rigidity of approximately 25 mN even after undergoing 200 reciprocating bending cycles. Furthermore, the incorporation of zirconium into CTO clearly had an advantageous effect on the formation of oxygen vacancies, thereby enhancing the surface adsorption of peroxymonosulfate (PMS), accelerating the electron transfer process, and weakening the peroxy bonds. The tetracycline degradation efficiency of the ZCTO fibers remained at 81.4% within 10 min after 5 continuous cycles. Benefiting from their robust mechanical properties and excellent catalytic activity, the fabricated membranes demonstrated outstanding dynamic catalytic performance under gravity-driven conditions. More importantly, the reported strategy might be adopted and extended to develop a wide range of ceramic fibers with enhanced flexibility and mechanics for catalytic oxidation.

High performance Ce0.8Nd0.2O2-δ-carbonate hollow fiber membrane for high-temperature CO2 separation

Ceramic-carbonate dual phase (CCDP) membrane consisting of oxygen ionic conductor and molten carbonate has potential applications in clean energy delivery as it enabling the direct CO2 separation or capture at the elevated temperatures. The performance of previous CCDP membranes is not ideal either with a low CO2 flux or with a poor operational stability. In the present work, we looked at the CeO2-based oxygen ionic conductor (neodymium doped cerium (NDC)) as the porous ceramic hollow fiber support to form NDC-carbonate hollow fiber membranes. The NDC hollow fiber was fabricated by the combined phase inversion and sintering techniques and the preparation conditions were optimized to better accommodate the carbonate phase and maintain the mechanical stability. The NDC hollow fibers possessed good bending strength, reaching 91.5 MPa upon sintering at 1500 °C. The effects of feed gas composition and sweep flow rates on the CO2 separation performance were carefully investigated. The resultant dual phase hollow fiber membranes exhibited appreciably high CO2 permeation fluxes at temperatures exceeding 800 °C, which was required to activate both conductions of oxygen and carbonate ions. The achieved maximum CO2 flux of the optimized NDC-carbonate hollow fiber membranes was up to 5.08 mL min−1 cm−2 with 50%CO2–50%N2 as the feed gas at 900 °C. At 700 °C, the membrane exhibited a relatively stable CO2 permeation behavior over 120 h and the spent membrane maintained a stable structure. The high flux and good operational stability of the developed membrane make a huge step towards practical applications.

Review on preparation technology of carbide resistant ultra-high temperature ceramic fiber

The rapid development of hyper-sonic vehicles has put forward an urgent demand for ultra-high temperature resistance ceramic fibers ceramic matrix composites. The properties of ultrahigh-temperature ceramic matrix composites made of carbon-based ultra-high temperature resistance ceramic fibers are excellent. Therefore, the preparation processes of several commonly used carbide-resistant ultrahigh-temperature ceramic fibers are described in detail. This review compares the advantages and disadvantages of five common methods (Molten-salt synthesis method, Chemical Vapor Reaction Method, Chemical Vapor Deposited method, Sol-Gel Method &amp; Polymer-Derived method) for preparing ceramic fibers, summarizes the preparation methods that should be used in the face of different preparation requirements, and evaluates the improvement and prospect of each method. Among them, the polymer-derived method, as the most difficult and effective preparation method, has been given great hope by material scientists.

Strength and thermal insulation properties of foam-formed ceramic fiber paper with different reinforcement methods

Abstract Foam-forming technique imparts ceramic fiber paper with excellent uniformity, low density, and high porosity, but its strength loss must be compensated. Herein, a flexible and rigid foam-formed ceramic fiber network was manufactured by using different strength improvement methods and simultaneously investigated their strength and thermal insulation properties. Sufficient strength (1136 kPa) was achieved by combining Polyvinyl alcohol (PVA) 2 % and Polyester (PET) 3 %. However, the tensile strength of fiber networks would decrease under the contribution of inter-fiber bonding area reduced when the fiber length was longer than 24 mm. Benefiting from the developed flocculation system (aluminum sol-anionic polyacrylamide-carboxymethylcellulose), the strength of the foam-formed ceramic fiber network was 20 kPa, the retention rate increased from 75 % to 88 %, and the average aggregation factor of fillers in the Z direction was 0.67. By adjusting the ratio and Z-directional distribution of functional fillers, the sintered foam-formed paper with a tensile strength of 1300 kPa and compressive strength of 1000 kPa could be obtained. The thermal insulation performance (thermal conductivity 0.03252 W/(m·K)) was similar to the quartz fiber paper reinforced silica airgel, and the flame resistance was better than the commercialized aluminum silicate wool board.

Impact of Ceramic Micropillar Array and Fiber Layer Composite Structure on Kinematic and Heat Transfer Characteristics of Single Droplet Impacting a Wall.

The well-known limitations of spray cooling on high-temperature solids at the Leidenfrost temperature point have been significantly improved by a composite structure of steel micropillar arrays and insulating thin films. However, the physical mechanism of a single droplet impact on the walls of high-temperature composite structures in spray cooling remains elusive. We have experimentally studied and quantified the kinematic and thermal transfer characteristics of a single droplet impacting high-temperature micropillar arrays with fiber membrane composite structures. In particular, micropillar arrays of ceramic materials of different shapes (rectangular and cylindrical) used in this study were made using the more flexible PμSL technique, for which precision reaches the micron level. The results show that the presence and different layouts (embedded or placed on top) of the fiber layer significantly affect the spreading coefficient and thermal transfer efficiency of the droplets after impact. In terms of kinematic characteristics, unrelated to the structure of micropillar arrays, compared to structures without film, the maximum spreading coefficient of droplets significantly increased by more than 40% (43% for rectangular, 46% for cylindrical) when the fiber film was placed on top, and increased by more than 20% (20% for rectangular, 33% for cylindrical) when the fiber film was embedded. In terms of thermal transfer characteristics, at a temperature of 200 °C, the presence of the fiber layer changed the wettability of the surface of the micropillar structure, leading to a certain extension of the total evaporation time of the droplets compared to the surface of the micropillar structure without film.

Constructing Robust LiF‐Enriched Interfaces in High‐Voltage Solid‐State Lithium Batteries Utilizing Tailored Oriented Ceramic Fiber Electrolytes

AbstractThe pursuit of high‐performance energy storage devices has fueled significant advancements in the all‐solid‐state lithium batteries (ASSLBs). One of the strategies to enhance the performance of ASSLBs, especially concerning high‐voltage cathodes, is optimizing the structure of composite polymer electrolytes (CPEs). This study fabricates a high‐oriented framework of Li6.4La3Zr2Al0.2O12 (o‐LLZO) ceramic nanofibers, meticulously addressing challenges in both the Li metal anode and the high‐voltage LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode. The as‐constructed electrolyte features a highly efficient Li+ transport and robust mechanical network, enhancing both electron and ion transport, ensuring uniform current density distribution, and stress distribution, and effectively suppressing Li dendrite growth. Remarkably, the Li symmetric cells exhibit outstanding long‐term lifespan of 9800 h at 0.1 mA cm−2 and operate effectively over 800 h even at 1.0 mA cm−2 under 30 °C. The CPEs design results from the formation of a gradient LiF‐riched SEI and CEI film at the Li/electrolyte/NCM811 dual interfaces, enhancing ion conduction and maintaining electrode integrity. The coin‐cells and pouch cells demonstrate prolonged cycling stability and superior capacity retention. This study sets a notable precedent in advancing high‐energy ASSLBs.

Catalytic systems on a ceramic fiber carrier with deposited metals in the process of carbon monoxide oxidation

Catalytic systems on a ceramic fiber carrier with deposited metals in the process of carbon monoxide oxidation

Microstructure and mechanical properties of continuous carbon fiber-reinforced SiC ceramic composite fabricated by direct ink writing

The direct ink writing (DIW) technique is considered efficient for manufacturing complex-shaped Cf/SiC composites. However, the SiC slurry with high load has poor flow ability and covering-fibers properties, resulting in numerous gaps between the ceramic matrix and fibers. This study utilized DIW to manufacture Cf/SiC composites and improved the slurry's printing ability by adjusting the binder content. Moreover, the printing parameters, such as the angle between the fiber nozzle and slurry nozzle and the slurry nozzle size, were optimized to enhance the accuracy of the body structure and the filling effect of the slurry on the fiber gaps. The results showed that a binder content of 0.4 wt% produced excellent thixotropic, viscoelastic, and shear thinning behavior in the slurry. By using a fiber nozzle angle of 60° and a nozzle diameter of 1.55 mm, the slurry effectively filled the gaps between the fiber bundle and matrix, reducing the number and size of pores in the SiC matrix. These improvements greatly enhance the density, strength, and fracture toughness of the Cf/SiC composites. Therefore, this research demonstrated that optimizing the printing parameters not only improved the structural accuracy of the printed bodies but also greatly enhanced the properties of the ceramic matrix composites.

UV assisted 3D fabrication of hollow ceramic with single-channel direct ink writing

The inherent brittleness of ceramics poses significant challenges in the fabrication of hollow ceramic fibers, severely constraining their practical applications. In this study, a novel method for creating three-dimensional hollow fiber ceramic structures using UV-assisted single-channel direct ink writing was demonstrated. A concentric single-channel nozzle featuring shell/core structure was devised through the coaxial embedding method, and this specially designed nozzle was manufactured using digital light processing technology. During the UV-assisted direct ink writing process, the photosensitive ceramic slurry can be rapidly cured in place under the irradiation of UV light, ensuring high fidelity of the printed components. The hollow fiber structure produced in this study has a circular, pentagram, triangular and quadrilateral inner core, which can be adjusted according to the designed nozzle structure. This approach facilitates a straightforward and expedited creation of scaffolds featuring small-diameter hollow fiber structures, broadening the scope of potential applications for direct ink writing.

Structural, morphological, mechanical, and thermal insulation properties of multiple-phase magnesium silicate ceramic fibers electrospun from dual-precursor sols

As the research for advanced materials suitable for high-temperature uses continues, the need for oxide ceramic micro-nanofibers with outstanding mechanical and thermal properties becomes increasingly important. By incorporating two types of magnesium sources, specifically Mg(CH3COO)2·4H2O and MgCl2·6H2O, into the precursor, a range of fibers made of magnesium silicate ceramics was produced through electrospinning. X-ray diffraction (XRD) analysis verified that the resulting multiple phases included MgO, MgSiO3, Mg2SiO4, and amorphous SiO2, with the phase composition being affected by the diffusion reaction of Mg ions. The fibers produced using the dual-precursor method maintained a stable morphology with a uniform and compact structure after undergoing high-temperature treatments ranging from 1000 to 1200 °C. This study is the first to report the tensile strength of magnesium silicate fibrous membranes, which was found to be 1.54 ± 0.27 MPa and 1.21 ± 0.73 MPa after heat treatment at 800 °C and 1000 °C, respectively. Furthermore, these fibrous membranes demonstrated dependable thermal insulation properties within the testing range of 500–1000 °C, along with a low thermal conductivity at room temperature of 0.0301–0.0306 W m−1·K−1. Characterized by their impressive mechanical strength and high temperature stability, magnesium silicate ceramic micro-nanofibers show significant potential for various applications in the targeted field.

Use of ceramic fiber modified with ferrites for the cleaning of flue gases of graphitization furnaces

Use of ceramic fiber modified with ferrites for the cleaning of flue gases of graphitization furnaces

Hierarchical MFI Zeolite Membranes for Superior Xylene Separation

AbstractThe separation of p‐xylene from its xylene isomers (o‐xylene, m‐xylene) is a significant concern in the petrochemical industry. MFI zeolite membranes offer great potential for energy‐efficient and high‐selective xylene separation. Synthesizing ultrathin (&lt; 1 µm) MFI zeolite membrane for high‐flux separation is highly desired but remains challenging. Herein, a novel and facile strategy for synthesizing hierarchical MFI zeolite membranes on ceramic hollow fibers from multi‐dimensionally assembled (2D@0D) seed layers is demonstrated. Owing to the rapid growth of 0D MFI seeds and the voids‐preserved growth of stacked 2D MFI seeds, the hierarchical MFI membrane synthesized for 2 h yielded an ultrathin skin layer (≈255 nm thick) and many macro‐voids within the sublayer (void fraction: 14.86%), which facilitated molecular permeation and simultaneously maintained high separation selectivity of zeolitic pores. The membrane exhibited over sevenfold higher p‐xylene permeance (2.81 × 10−7 mol m−2 s−1 Pa−1) and over threefold improved p‐/o‐xylene separation factor (1228) than the conventional MFI membrane.

Comparative investigation on fire resistance of different fire prevention schemes for 1670 MPa steel wires used in bridge cables

This paper mainly investigated the fire resistance of different fire prevention schemes for 1670 MPa steel wires used in bridge cables. The fire resistance tests on bridge cables under different fire protection schemes were carried out. The failure modes and the varied patterns of temperature at different positions of the cables was studied, and the optimal design scheme of fire protection for bridge cables was also obtained. Furthermore, the tensile test of steel wire after fire was carried out to study the degradation law of mechanical properties of steel wire. The results showed that the cables undergo varying degrees of bending deformation after the fire, mainly due to the poor fire protection effect. The wrapping process of the fire protection scheme was a key factor affecting the protective effect. When the premature invalidation of the wrapping mode failed to occur, the aerogel material would have better thermal insulation behavior than the basalt fiber. The temperature rising rate of Schemes D (6 mm ceramic fiber aerogel tape), E (10 mm high silica glass aerogel tape) and F (10 mm nano thermal isolation felt-ceramic fiber aerogel) was relatively gentle, and the temperature of most measuring points within 4500s was not more than 300 °C. Based on the failure mode and the temperature of the cables, it could be judged that Schemes E and F were better than Schemes C (4 mm composite fiber fire-resistant isolation tape) and D while schemes A (4 mm basalt fiber needled felt) and B (4 mm aerogel tape) had the worst fire protection effect. Due to the surface temperature, the fracture morphology of steel wires after fire varied greatly, mainly divided into brittle fracture and ductile fracture. With the increase of temperature, the yield and ultimate strength of steel wire of Schemes A, B, C, D and E decreased greatly after fire, and along with a maximum decrease of 73.78% and 69.02% respectively.

Printable, flexible ceramic fiber paper based on electrospinning

Printable, flexible ceramic fiber paper based on electrospinning

Sintering simulations for ceramic multilayer laminates with paper-derived ceramics: From sintering dilatometry to anisotropic sintering simulation

Alumina-based multilayer laminates with layers of varied porosities and ceramic fiber reinforcements, which can be achieved by including paper-derived ceramic layers, are interesting candidates for chemically stable and thermal shock resistant materials. In order to investigate the complex sintering behavior of these laminates, the sintering of each alumina layer contained within a laminate, each one with its individual sintering anisotropy and sintering shrinkage, has to be considered separately. For this purpose, sintering curves are determined by dilatometry measurements, serving a consecutive examination by an analytical model. Modeling parameters specific to each layer, are applied in finite-element-type sintering simulations for symmetrical multilayer laminates. Differences in the sintering shrinkages may cause internal stresses at layer interfaces and, in turn, may influence the thermal and mechanical properties of multilayer laminates after sintering. Accordingly, the prediction of developing internal stresses within alumina-based multilayer laminates by the presented sintering simulations is a key aspect of this study.

Study of online tensile properties for continuous ceramic fibers under high‐temperature loads

AbstractIn this study, a self‐developed online test platform for high‐temperature mechanical properties was utilized to test the tensile properties of three continuous ceramic fibers from room temperature to 1 000°C. It was observed that the tensile strength of all tested continuous ceramic fibers decreased significantly with increasing temperature. Specifically, significant peeling of the surface organic coating from room temperature to 400°C, inherent and newly formed defects exposed from 600°C to 1 000°C contributed to the decrease in tensile strength. More importantly, compared with room temperature, the strength of the silicon carbide fibers and the alumina fibers remained 29.7% and 20.2% respectively when stretched online at 1 000°C, while the quartz fibers dropped to 4.3% dramatically. These findings contribute valuable data for the potential application of ceramic fiber filaments as flexible thermal protection materials.