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Aerogel composites reinforced by fibers have found extensive applications in the field of thermal insulation and energy conservation. However, the composites are hindered by their high infrared radiation transmittance and weak interface adhesion in practical applications. Herein, we designed and prepared a novel thin composite called 'fiber/whisker/aerogel paper' (SWAP) with a thickness of less than 1 mm. The SWAP integrated SiC nanowhiskers (SiC nw) as opacifiers and ultrafine SiO 2 fibers as reinforcement, fabricated through wet manufacturing and sol-gel process. The 'fiber/aerogel paper' (SAP) and SWAP exhibited low thermal conductivity at room temperature, measuring 0.025 W/(m·K) and 0.033 W/(m·K), respectively. Additionally, they exhibited low densities of 0.195 g/cm3 and 0.225 g/cm3, respectively. Notably, SWAP exhibited excellent high-temperature insulation performance, primarily due to its low infrared transmittance (50% at 3 μm). The incorporation of SiC nw and ultrafine SiO 2 fibers collectively enhanced the interfacial adhesion with the aerogel matrix even amidst rigorous testing (weight loss less than 3%). SWAP also demonstrated flexibility, high thermal stability, hydrophobicity, and flame resistance. Furthermore, a comprehensive investigation into the performance variations and influencing g factors of the material was conducted under different heat treatment conditions. This research provides guidance for the application of such materials under high temperatures. [ABSTRACT FROM AUTHOR]

The ZrO 2 fiber paper exhibits excellent thermal insulation properties, however, its limited mechanical strength and insufficient thermal stability hinder its widespread applications. The composite fiber papers, using mullite fibers possessing a high aspect ratio and exceptional thermal stability combined with ZrO 2 fibers, were fabricated via a vacuum-assisted filtration method. This method involved the successive stacking of composite fibers with alumina sol, using vacuum-induced directed water flow to create a layered structure reminiscent of nacre. The layered structure of the nacre, which demonstrates remarkable strength and hardness, has also served as a source of inspiration for the architectural design of the fiber paper. The tensile strength of pure ZrO 2 fiber paper was significantly enhanced by the addition of 7 wt% mullite fibers, resulting in a remarkable increase to 0.1805 kN/m. The paper exhibited exceptional resistance to bending, maintaining 96 % of its bending strength even after undergoing 100 cycles. The thermal shrinkage of the composite paper, containing 15 wt% mullite fibers, was reduced from 17.75 % observed in pure ZrO 2 fiber paper to a mere 1.32 % after undergoing heat treatment at a temperature of 1300 °C for 2 h. The composite paper, measuring 5 mm in thickness and consisting of 7 wt% compositions, displayed exceptional thermal insulation properties when exposed to a hot side temperature of 1370 °C. It effectively insulated temperatures up to approximately 1000 °C. [ABSTRACT FROM AUTHOR]

The present paper investigates the effect of carbon nanofibers (CNFs) on the microstructure and mechanical properties of Carbon fiber reinforced carbon and silicon carbide binary matrix (C/C–SiC) composite prepared by using the reactive melt infiltration technique. The CNFs used in this paper were generated through in-situ reaction in the pores of C/C preforms using the chemical vapor deposition. Results indicate introducing additional carbon sources in the form of CNFs in the C/C preform can remarkably improve the permeability of molten Si, resulting in higher density and more uniform microstructure of the RMI-deriver C/C–SiC composites. Consequently, the in-situ formation of CNFs reduces the residual Si content by 64.71% and increases the mechanical strength and modulus at room temperature by [22.31% and 17.89%] and after heat treatment at 1500 °C by [35.6% and 47.48%] with respect to no-CNF containing composites due to a lower amount of residual Si content and additional reinforcement effect of the unreacted CNFs. [ABSTRACT FROM AUTHOR]

Carbon-based materials are widely used in electrical heaters, resistors, battery electrodes, and other applications. Membranous electronic components, with light weight, small volume, extraordinary mechanical flexibility, can be used in microelectronic devices and flexible electronic devices. The C/Si 3 N 4 composite film was prepared by circulating 16% sucrose solution on the coating machine for 4 times and heat treating with nitrogen at 850 °C for 60min. The composite film has excellent electrical conductivity, and the resistivity is 15 mΩ cm at normal temperature (20 °C), and the minimum resistivity can be less than 1 mΩ cm at high temperature. In addition, the composite film maintains the inherent flexibility of silicon nitride fiber paper, and the minimum bending radius is as low as 3 mm. Compared with polymer flexible membranes, C/Si 3 N 4 composite membranes show excellent long-term stability at high temperatures, and the preparation process is green, low cost, easy to operate, and suitable for large-scale production. [ABSTRACT FROM AUTHOR]

In this paper we present the results of an investigation of the influence of excess energy applied through ball milling on surface hydration behavior of alumina particles manufactured by three different methods. It is shown that different hydration amount are generated due to the defects and newly generated surfaces introduced during high energy ball milling processes. And the various gibbsite/bayerite ratio of the formed hydrates are attributed to the coordination defects resulting from heat treatment during the manufacturing process. As a result, it is confirmed that the dispersant works more efficiently with particles in which hydrates are formed, and the surfaces with structures closer to gibbsite seem to respond more effectively to dispersant in slurries. [ABSTRACT FROM AUTHOR]

The addition of Cr3+-oxides in a refractory provides unmatched corrosion resistance at high temperatures but generates toxic and water-soluble Cr6+ compounds, particularly in oxygen-rich and alkaline conditions. In this paper, a Cr3+ raw material (chrome-hibonite) was synthesized by the solid oxide reaction route and was used to make different calcium aluminate cement bonded alumina-based refractory castables. The castables (chrome-free and Cr3+ oxides containing) were compared regarding corrosion resistance against municipal waste slag at 1500 °C under air atmosphere. The relative Cr6+ formation within the castables containing Cr3+ oxides (Cr 2 O 3 and Ca(Al,Cr) 12 O 19) upon heat treatment at 500–1500 °C were investigated using X-ray diffraction (XRD), and Cr6+ leaching test, etc. Compared to castables without Cr3+ oxides, the corrosion resistance increases at least 5 times upon Cr3+-oxides addition, irrespective of their forms (Cr 2 O 3 or Ca(Al,Cr) 12 O 19). However, at all the tested temperatures, Ca(Al,Cr) 12 O 19 addition into the castables could suppress the Cr6+ generation significantly (below the standard solid-waste disposal limit of 3 mg/L) compared to Cr 2 O 3 , which was well above the limit. [ABSTRACT FROM AUTHOR]