Silicon oxycarbide glasses and glass‐ceramics: “All‐Rounder” materials for advanced structural and functional applications

Abstract

Silicon oxycarbides can be considered as being carbon‐containing silicates consisting of glass networks in which oxygen and carbon share bonds with silicon. The carbon‐for‐oxygen substitution in silicate glass networks has been shown to induce significant changes in the network connectivity and consequently strong improvements in the properties of the silicate glass network. For instance, SiOC glasses exhibit Young's moduli, hardness values, glass transition, and crystallization temperatures which are superior to those of vitreous silica. Moreover, the silicon oxycarbide glass network exhibits unique structural features such as reduced mass fractal dimension and nano‐heterogeneity, which significantly affect and/or dictate its properties and behavior. In the present Review, a consideration of the current state of the art concerning the synthesis, processing, and various structural and functional properties of silicon‐oxycarbide‐based glasses and glass‐ceramics is done. Thus, the synthesis of silicon oxycarbides starting from macromolecular precursors such as polysiloxanes or alkoxysilanes‐based sol‐gel systems as well as current advances related to their processing will be critically reviewed. In addition, various structural and functional properties of silicon oxycarbides are presented. Specific emphasis will be put on the intimate correlation between the molecular architecture of the precursors and the structural features and properties of the resulting silicon oxycarbides.

Electromagnetic wave absorbing properties of glucose‐derived carbon‐rich SiOC ceramics annealed at different temperatures

“…Diffraction peaks located at 2θ of 21.6° and 35.2° correspond to the amorphous SiO 2 and SiC phase, respectively, which reveal the crystallization degree of SiO 2 and SiC increase with the increase in temperature and the content of glucose. [21][22][23][24][25] Therefore, the glucose-SiOC nanocomposites can gradually crystallize with the increase in heating temperature and the content of glucose. The crystallization degree of SiC gradually increases with the increase in heat-treatment temperature and the amount of glucose owing to the phase separation as shown in Equation (1).…”

Enhanced electromagnetic wave absorption of Fe‐doped silicon oxycarbide nanocomposites

“…This is different from previous work, in which the graphite covering the SiC phase is observed. Such structure mainly ascribed to the promotion the phase separation by Fe ions according to the following reactions …”

“…Owing to improve the permittivity characteristic, the carbon‐rich PDC‐SiCN composite shows excellent EMI absorbing capability and the RL min reaches −59.60 dB at 12.23 GHz with the thickness of 2.30 mm . In comparison with other PDC‐based materials, SiOC ceramics not only effectively retain the tailoring structure, but also show low cost and good conductivity; thus, they have been widely used in Li ions battery, thermal protection materials, and absorbing materials . Unfavorably, sole SiOC ceramics show poor EMI absorbing capability due to their low dielectric loss .…”

3D Printing of Complex‐type SiOC Ceramics Derived From Liquid Photosensitive Resin

“…Special care must be taken to prevent cracking and to preserve the porous structure upon pyrolysis. The most important factors were the heating rate and the cooling rate . A slow heating/cooling rate can prevent cracking but need to balance the relationship between the material preparation process and the heating/cooling rate.…”