Aluminum Silicate Fiber Research Articles

Preparation and properties of lightweight aluminum silicate-based fibrous ceramic membranes with different binder contents for high-temperature dust removal

Fibrous ceramic membranes are widely regarded as ideal hot-gas filtration media due to their unique three-dimensional network structure. In this work, deionized water and sodium lignosulfonate (NaLS) were respectively introduced into the preparation of fibrous ceramic membranes, with aluminum silicate fibers used as the matrix skeleton and silica sol used as the high-temperature binder. Their effects on the binder content, morphology, structural parameters, and mechanical properties were investigated and compared, and then the application performance of the preferred sample was evaluated. The results indicated that the addition of both significantly reduced the binder content, resulting in decreased bulk density and increased apparent porosity. Notably, compared to the addition of water, the addition of NaLS effectively preserved the binder content at the junctions between fibers so that the flexural strength and stiffness were barely affected, which benefits from the decrease in the viscosity of the binder liquid under the action of electrostatic repulsion and steric hindrance. Moreover, the preferred prepared fibrous ceramic membrane exhibited high-performance characteristics, such as superior thermal shock resistance, low pressure drop, and high filtration efficiency and pulse-jet cleaning efficiency, thereby offering considerable prospects for practical applications.

High-Emissivity Double-Layer ZrB2-Modified Coating on Flexible Aluminum Silicate Fiber Fabric with Enhanced Oxidation Resistance and Tensile Strength.

Fibers crystallize and become brittle at high temperatures for a long time, so the surface coating must maintain long-lasting emission performance, which requires superior antioxidant properties of the high-emissivity fillers. To improve the radiation performance of the coating and the tensile strength of the fiber fabric, a double-layer coating with high emissivity was prepared on the surface of flexible aluminum silicate fiber fabric (ASFF) using MoSi2 and SiC as emissive agents. The incorporation of borosilicate glass into the outer coating during high-temperature oxidation of ZrB2 results in superior encapsulation of emitter particles, effectively filling the pores of the coating and significantly reducing the oxidation rate of MoSi2 and SiC. Furthermore, the addition of an intermediate ZrO2 layer enhances the fiber bundle's toughness. The obtained double-coated ASFF exhibits an exceptionally high tensile strength of 57.6 MPa and a high bond strength of 156.2 kPa. After being subjected to a 3 h heating process, the emissivity exhibits a minimal decrease of only 0.032, while still maintaining a high value above 0.9. The thermal insulation composites, consisting of a flexible ASFF matrix and a ZrB2-modified double-layer coating, exhibit significant potential for broad applications in the field of thermal protection.

Pd nanoparticles decorated N-doped holey graphene assembled on aluminum silicate fibers agglomerate for catalytic continuous-flow reduction of nitroarenes

Rational design and preparation of efficient fixed-bed catalysts for continuous-flow system are highly desired but remain daunting challenges. Herein, we report the synthesis of an assembly catalyst consisted of aluminium silicate fibers (ASFs) agglomerate and Pd nanoparticles (PdNP) decorated N-doped holey graphene (NHG) through a facile hydrothermal co-assembling strategy. Due to the interconnect network and porous structure, the as-obtained PdNP/NHG-ASFs assembly is suitable to be utilized as a fixed-bed catalyst for organic reactions in continuous-flow mode. The processing rate is much higher than that of the previously reported fixed-bed systems based on metal-based catalysts. In addition, the catalytic continuous-flow system displays a remarkable durability and good substrate generality to other substituted nitrobenzenes. This work provides rational design concept for efficient fixed-bed catalyst with dual active components and paves a way for the industrial application in organic synthesis.

Thermal insulation characteristics of high-temperature heat seals for hypersonic aero-engines

The high-temperature baseline sealing thermal protection technology is of great significance to realizing hypersonic aero-engines and aircraft. Based on the fact that there are few studies on the high-temperature baseline heat sealing in the ultra-high temperature environment (above 1000 °C), the paper establishes a simulation model to analyze the influence of different characteristic parameters on the thermal protection performance of the heat seal at ultra-high temperature and carried out experiments. Verification, simulation, and experiment error are less than 6%. The research results show that the aluminum silicate fiber has the best thermal insulation effect in the material of the inner thermal insulation layer, and the temperature can be lowered by more than 900 °C under an environment of 1200 °C. It is used to prepare heat seals. In addition, the filling density and thickness of the inner thermal insulation layer have little influence on the thermal insulation effect, and the influence coefficient does not exceed 5%. In the test of the degree of degradation of the thermal insulation performance of the heat seal, it is found that it does not exceed 5%, which meets the requirements for use. This paper further promotes the development of high-temperature thermal protection technology. It can also provide a corresponding technical basis for developing supersonic aero-engines.

High temperature-resistant flexible inorganic coating for aluminium silicate fiber cloth with low solar absorption ratio and high emissivity

To prepare a coating with a high emissivity and low solar absorption ratio on the surface of aluminum silicate fiber cloth, the sol-gel method was used with silica sol as a binder. In this study, the effects of two white fillers, titanium oxide and zirconia, on the substrate and radiation properties of coatings were compared after heat treatment at 800–1200 °C. The ZrO2-based coating had good stability after heat treatment at 800–1200 °C, and maintained its white color, exhibiting solar absorption ratio of approximately 0.14 and emissivity of 0.84. ZrO2-based coatings prevented harmful cracking, as observed for the TiO2-based coatings after heat treatment, because of the ZrO2 phase transformation. The ZrO2-based coating did not have strong bonding with the substrate, and the substrate strength was improved by maintaining a weak bonding interface. Compared with the TiO2-based coatings, which exhibit reduced substrate strength above 1000 °C, the ZrO2-based coating was more suitable for the surface of flexible fiber cloths as a temperature-resistant coating with good development prospects.

Characterization and mechanism analysis of interaction between Inconel 713C superalloy and a novel crucible-shell “integrated” mold

A novel crucible-shell “integrated” mold for rapid preparation of supercharged turbines was quantitatively characterized, and the interaction mechanism between refractory and melt was systematically analyzed. The results show that Inconel 713C superalloy is not easy to react with aluminum silicate fiber crucible, and the interaction between them is physical penetration. At the same time, the slag balls in the crucible are easy to peel off into the alloy and form inclusions. The reaction between Inconel 713C superalloy and shell surface material (ZrSiO4) can be divided into Penetration, Stalling/dissolution, Reaction and Diffusion stages. The interface reaction layer is composed of Nb2O5, Al2O3, ZrO2, Cr2O3 and TiO2. The oxide elements produced by the reaction come from the alloy and ceramic shell. Compared with the traditional preparation of turbocharger turbine under discontinuous vacuum, the use of “integrated” mold to prepare turbine under continuous vacuum environment reduces the oxygen, nitrogen and hydrogen content of castings, and the purity of Inconel 713C superalloy is higher and the preparation time is faster, which is conducive to industrial production, which can shed new lights on choosing alternative refractory material for the rapid preparation of high-purity superalloys.

High emissivity scale structure MoSi2-silicon glass coating on aluminum silicate fiber cloths with excellent flexibility and oxidation resistance below 1000 °C

In order to maintain the strength of flexible substrate while applying the oxidation resistance dense glass coating, a scale structure coating on aluminum silicate fiber cloth was prepared with fused silica powder and silica sol as the binder and MoSi2 as the emissive agent. The scale structure of the coating with large cracks along the braided grain and small random cracks on the fiber bundles allowed the fiber cloth to retain its flexible properties. Due to the block effect of dense SiO2 glass phase on oxygen diffusion, the mass loss was only 0.35% after oxidation at 800 °C for 24 h while the average normal emissivity (2–14 μm) remained about 0.88. The MoSi2-silicon glass coating could avoid the generation of excessively strong interface with the substrate and improve the tensile strength of the sample to 140.52 MPa.

Optimization of SiC–ZrC high emissivity composite flexible coating for thermal protection with high interfacial bond strength and temperature resistance

Aluminum silicate fiber fabric (ASFF) has been widely used in the outer surface of flexible insulation felt on the leeward side of aerospace vehicle. In order to improve the temperature resistance of ASFF, a kind of SiC–ZrC composite coating was prepared on the surface of fiber fabric via spraying method with SiC as emittance agent and ZrC as additive. The surface morphology and mechanical properties of the coating were studied. Compared with the single-component SiC coating, the composite coating could effectively avoid coating spalling and improve the surface integrity at high temperature. After thermal treatment at 1100 °C for 2 h, the interface bond strength of the composite coating/substrate was 52.41% higher than that of SiC coating/substrate. The tensile strength of fiber fabric with SiC–ZrC composite coating could reach 91.75 MPa, which was 101.76% higher than that of raw ASFF. Therefore, the SiC–ZrC coating could greatly improve the temperature resistance of ASFF, and has an attractive application prospect in the field of thermal protection system.

Mechanical properties of reinforced porcelain slabs with mullite whiskers introduced by aluminum silicate fiber

Mullite whiskers (3Al2O3·2SiO2) reinforced porcelain slabs with high bending strength and fracture toughness were successfully prepared by calcining a kaolin-potash feldspar-albite mixture with aluminum silicate fibers (ASF, Al2O3·SiO2). Effects of ASF content on the properties of porcelain slabs were investigated. Bending strength and fracture toughness of the samples reach the peak values, 39% and 19% higher than that of the blank samples when the amount of ASF is 5 wt%. The elongated and needle-like mullite whiskers are obtained in the substrates with ASF fiber addition, differing from the rod-shaped mullite whiskers in the blank ones. During the sintering process, ASF provides growth environment and ingredient for elongated mullite whiskers. The in-situ generated elongated mullite whiskers link the porcelain slabs substrate as a bridge and consume more energy before the fracture occurred. Therefore, mullite whiskers induced by ASF can offer reliable opportunity for preparation of porcelain slabs with good mechanical properties.

Sound Absorption Performance of Aluminum Silicate Fiber for Noise and Vibration Reduction of Distribution Transformer

In view of the low-frequency noise problem in urban substation, the sound absorption (SA) properties of aluminum silicate fibers (ASF) with different materials, unit weight, plate thickness and cavity thickness were tested in this paper. It was found that the high-purity ASF with larger unit weight, plate thickness and cavity thickness had larger low-frequency SA coefficient, which provided technical support for the development of new low-frequency noise reduction materials for substation.

Vanadium-based catalytic fibers for selective reduction of NO by NH3 and their potential use on co-processing of dust and NOx

This work is dedicated to fabrication of catalytic fibers for the process of selective catalytic reduction of NOx by NH3 (NH3-SCR). By employing vanadium-titanium as main catalytic components, we investigated the effect of different inorganic supports (glass fiber, aluminum silicate fiber and quartz fiber), preparation methods (a sol–gel method and a hydrothermal method) and loading weight of V2O5 on the NH3-SCR performance of catalytic fibers. The catalytic aluminum silicate fiber with 5% vanadium/titanium ratio prepared by a sol–gel method (denoted as V5Ti/AF) showed the best SCR and mass transfer performance. Characterization results indicated that a relatively large surface area, strong acidity, well-dispersed catalyst particles, and good redox and desorption properties derived from the interaction between catalytic components and supports all contributed to the good performance of V5Ti/AF. The pressure drop of catalytic fibers were measured, and the total pressure drop of catalytic fibers and de-dust ceramic membranes was much lower than previously prepared catalytic ceramic membranes, indicating their potential use in the co-processing of dust and gaseous pollutants.

Aluminum silicate fibers reinforced wood-plastic composites: A strengthening strategy based on the interfacial interactions between inorganic fibers and organic agricultural wastes

Using the methods of high-speed mixing, screw extrusion, and injection molding, wood-plastic composites (CS-PF-ASFX) with inorganic fibers (aluminum silicate fibers, ASF) and organic agricultural wastes (cotton stalk, CS) as reinforcing fillers were prepared. The effects of different contents of ASF on the properties of wood-plastic composites were analyzed. Materials were characterized by Fourier infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric (TG) analyses. The creep, relaxation, and mechanical behavior were also tested. With the increase of ASF contents, the FT-IR peaks at approximately 1740 cm-1 shifted to lower wavenumber, indicating the potential interactions between ASF and CS. The XRD patterns of the composites implied that the crystal structures of each component were maintained. Moreover, the addition of ASF enhanced the mechanical properties and thermal stabilities of CS-PF-ASFX composites, and the tensile strength and impact strength reached maximum of approximately 39.4 MPa and approximately 3.89 kJ/m2, respectively.

Comparison Thermal Insulation Effects of Different Thermal Insulation Materials for a Roadway Tunnel at Southeast Edge of the Qinghai-Tibet Plateau

In seasonal frost regions, tunnels are affected by frost damage after excavation. At entrance and exit section of tunnels, thermal insulation layer (TIL) is widely used to mitigate this problem. In this study, a moisture-temperature coupled mathematical model was established. Based on field observed air temperature at entrance section of Altun mountain tunnel, the thermal regime of surrounding rocks was investigated. Moreover, a comprehensive evaluation method was established to evaluate the thermal insulation effects of seven thermal insulation materials. The results showed that, with increase in thickness of TIL, maximum frozen depths of surrounding rocks decreased almost linearly. At the vault (H1), arch hance (H2), foot (H3), and inverted arch (H4) of the tunnel, the thermal insulation effect was different. When the thickness of TIL reached to 5 cm, there would be no seasonal freezing process at the four points. Seven types of TIL were considered for the thermal insulation of the tunnel. The optimal thickness of them was 4.2, 11.0, 5.5, 6.3, 10.2, 12.8 and 8.5 cm. To ensure the surrounding rocks do not experience freezing process, rigid polyurethane foam would be the best choice. Considering the cost, dry process aluminum silicate fiber would be a better one.

A fast-ion conducting interface enabled by aluminum silicate fibers for stable Li metal batteries

Lithium (Li) metal anode is attracting more attention because of its ultrahigh theoretical specific capacity and the lowest redox potential. However, the growth of Li dendrites caused by nonuniform Li-ion diffusion and distribution leads to safety hazards and hinders its practical application. Here, a fast-ion conducting interface is constructed on the Li surface to address the above issues by employing aluminum silicate (ASO) fibers. In addition, a stable inorganics-rich solid electrolyte interphase can be formed, which is revealed by cryogenic transmission electron microscopy and X-ray photoelectron spectroscopy. As a result, a stable Li anode with long-term lifespan can be achieved (over 5500 cycles with low overpotential at 3 mA cm−2 in Li/Li symmetric cells). When paired with the LiFePO4 cathode, the cell with ASO can achieve more than 500 cycles with reduced capacity degradation. This work might shed new light on the facile design of fast-ion conducting interface for the Li metal anode and even other alkali-metal anodes.

High emissivity double-layer coating on the flexible aluminum silicate fiber fabric with enhanced interfacial bonding strength and high temperature resistance

A high emissivity double-layer coating with SiC and ZrO2 as emittance agents was prepared on the surface of flexible aluminum silicate fiber fabric (ASFF) to improve the thermal insulation performance of the fiber fabric. The tensile strength and interfacial bonding strength of raw ASFF, ASFF with single-layer ZrO2 coating and ASFF with double-layer SiC-ZrO2 coating were compared and studied. The ASFF with SiC-ZrO2 coating still exhibits a high tensile strength of 75 MPa after heat treated at 1100 °C. The shear bond strength of the coating/substrate interface and the coating/coating interface is 0.08 MPa and 0.18 MPa, respectively. The spectral emissivity of the SiC-ZrO2 coating is as high as 0.93, which is about 1.6 times that of the raw ASFF. The heat-proof and thermal insulation integrated composite consisting of flexible ASFF substrate and double-layer SiC-ZrO2 high emissivity coating demonstrated potential application as large area of thermal protection material.

Aluminum silicate fiber membrane: A cost-effective substitute for fiber glass separator in Li–O2 battery

Currently, glass fiber membrane is widely used as the separator in Li–O2 batteries due to its high ionic conductivity, electrolyte uptake and thermal stability. Unfortunately, its high cost hinders the future commercialization of Li–O2 battery. Herein, a cost-effective aluminum silicate fiber (ASF) membrane was utilized for the first time to replace the conventional glass fiber as the separator in Li–O2 batteries. Thanks to the high ionic conductivity and good electrolyte wettability, batteries with ASF separator exhibit high electrochemical performance, even better than those with commercial glass fiber. In addition, the ASF membrane also shows better thermal stability under extreme conditions. Impressively, the cost of aluminum silicate fiber is less than 1% of the glass fiber (2.3 $/m2 vs. 370.7 $/m2). The combination of excellent performance and low cost promises it to be an ideal substitute for the conventional glass fiber as the separator for Li–O2 batteries.

Thermal insulated and mechanical enhanced silica aerogel nanocomposite with in-situ growth of mullite whisker on the surface of aluminum silicate fiber

Fiber-reinforced silica aerogel composite has attracted increasing attention in thermal insulation area. Nevertheless, the suboptimal mechanical properties from the weak fiber-aerogel interface seriously restricted the development and application of the composite. In this work, mullite whisker was synthesized in-situ on the surface of aluminum silicate fiber to fabricate the fiber/whisker multiscale structure. The needle-like monocrystalline mullite whiskers were uniformly grown on the surface of fiber, with a length of about 15 μm and a diameter of 100–120 nm. Owing to the pinning effect of mullite whiskers, the fiber-aerogel interface was enhanced immensely. The aluminum silicate fiber/mullite whisker/silica aerogel demonstrated a remarkable high compression strength of 2.33 MPa, 9.32 times higher than that of the composite without whiskers, a low density of 0.26 g/cm3, and a low thermal conductivity of 37.3 mW/(m·K). These results indicate that the fiber/whisker/aerogel nanocomposite is a sort of promising thermal insulation material for heat preservation.

Durability and Electrical Conductivity of Carbon Fiber Cloth/Ethylene Propylene Diene Monomer Rubber Composite for Active Deicing and Snow Melting.

To reduce the impact of road ice and snow disaster, it is necessary to adopt low energy consumption and efficient active deicing and snow melting methods. In this article, three functional components are combined into a conductive ethylene propylene diene monomer (EPDM) rubber composite material with good interface bonding. Among them, the mechanical and electrical properties of the composite material are enhanced by using carbon fiber cloth as a heating layer. EPDM rubber plays a mainly protective role. Further, aluminum silicate fiber cloth is used as a thermal insulation layer. The mechanical properties of EPDM rubber composites reinforced by carbon fiber cloth and the thermal behaviors of the composite material in high and low temperature environments were studied. The heat generation and heat transfer effect of the composite were analyzed by electrothermal tests. The results show that the conductive EPDM rubber composite material has good temperature durability, outstanding mechanical stability, and excellent heat production capacity. The feasibility of the material for road active deicing and snow melting is verified. It is a kind of electric heating deicing material with broad application prospects.

In-situ Synthesized Mullite Whiskers on the Surface of Aluminum Silicate Fibrous Felts with Low Thermal Conductivity and High Compression Rebound Performance

In this study, in situ synthesized mullite whiskers on the surface of aluminum silicate fibrous felts was prepared by gas-phase deposition and reaction. Effects of the concentration of impregnation solutions on the density, thermal conductivity, microstructure and the compression rebound performance of the fibrous felts during the in situ synthesized mullite whiskers process were analyzed. The mullite whiskers were generated on the surface of aluminum silicate fibrous felts through gas-phase deposition and reaction of AlOF and SiF4, which proved that the mullite whiskers could form on the aluminum silicate fibers in this process. The results showed that the materials fabricated at the optimum process showed a high compression resilience ratio (94.6%) after compression to a compressive strain of 10%, meanwhile the density and the thermal conductivity of the sample fabricated at the optimum process were 0.1536g/cm3 and 0.04102 W/(m*K), respectively.

Thermal and wear behavior of three inorganic fiber-reinforced wood-plastic composites in simulated soil aging conditions

This study investigated the effects of simulated soil aging on the thermal and wear properties of rice husk fiber/polyvinyl chloride (PVC) composites reinforced with three inorganic fibers (aluminum silicate fiber (AS); basalt fiber (BF) and zirconia fiber (ZF)). The thermal and wear behavior of the composites exhibited a downward trend during the simulated soil aging process; weak interface (pulling out of fiber) resulted in the induction of strength and anti-aging properties. However, the addition of inorganic fibers improved the anti-aging properties of the composites. When the simulated soil aging time was up to 21 d, ZF reinforced composites (ZFRC) exhibited high thermal and wear resistance properties due to superior interfacial adhesion between the fiber and PVC matrix. The average friction coefficient (μ) and specific wear rate (K) of ZFRC were reduced by 12.1% and 40.7%, respectively, compared to the unreinforced composites.