Crystallization and oxidation resistance properties of boron modified silicon oxycarbides derived from polymeric precursors by sol–gel method

Muralidharan, M. N.; Pramanik, Nimai Chand; Abraham, P.A.; Jacob, Karl; Panicker, N. Rani

doi:10.1016/j.matlet.2007.12.044

Cited by 14 publications

(21 citation statements)

References 21 publications

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“…35 The presence of boria in borosilicate glasses hinders silica crystallization at high temperature. 34 The pyrolyzed borosilicate glasses in this present study, which were previously shown to be amorphous, 19 are expected to also have remained amorphous following the isothermal TGA exposures. The exothermic peaks present in the DSC thermograms shown in Figure 5A-C are not ascribed to crystallization.…”

Section: Structurementioning

confidence: 64%

“…A few studies on the stability of sol-gel-derived borosilicate glasses to high-temperature exposures in oxidizing gas environments, namely air, are available. [32][33][34][35] A study by Klonczinski et al exposed SiBOC glasses to air at 1300, 1400, and 1500°C for 20 hours, but characterization of the glasses post-exposure was limited to phase analysis by X-ray diffraction (XRD) and electrical resistance. 35 The other studies were limited by isothermal exposures for short times of 1 hour at a single temperature, such as 800, 32 1000, 33 or 1500°C.…”

Section: Mcfarland and Opilamentioning

confidence: 99%

“…The other studies were limited by isothermal exposures for short times of 1 hour at a single temperature, such as 800, 32 1000, 33 or 1500°C 34 . TGA characterization of the SiBOC glasses showed the weight loss to be minor, ascribed to carbon oxidation, 32,34 and less than that of a sol‐gel‐derived silica glass, which was postulated to be due to increased stability of B–C bonds over carbon‐carbon (C–C) bonds in the free carbon phase 32 . These studies suggest that interactions of B with C are strong, even in high‐temperature conditions where some of the carbon is oxidized.…”

Section: Introductionmentioning

confidence: 99%

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Investigations into the thermal stability of sol‐gel‐derived glasses as models for thermally grown oxides

McFarland

Opila

2020

J Am Ceram Soc

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The thermal stability of sol-gel-derived silica and borosilicate glasses exposed to dry O 2 at 800 and 1200°C for 100 hours was characterized by weight change, thermal transitions, morphology, structure, and composition to investigate suitability as models for thermally grown oxides. Rapid weight loss was observed in the first few hours of isothermal exposure for borosilicate glasses, followed by constant weight loss at a low rate for the balance of the exposure. Weight loss resulted from loss of residual hydroxyl species retained from the sol-gel synthesis, and from oxidation of carbon retained from thermal decomposition of the organic precursors by pyrolysis. Characterization of the sol-gel-derived glasses showed structural similarities to silica and binary borosilicate glasses synthesized by melt or vapor deposition methods, and to thermally grown oxides. Oxygen transport mechanisms through the sol-gel-derived glasses is not thought to be affected by the retained carbon. However, a silicaenriched glass surface resulting from boria volatility, observed from a borosilicate glass exposed dry O 2 at 1200°C, will slow O 2 transport rates. The results show that sol-gel-derived silica and borosilicate glasses can be used as models for thermally grown oxides.

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Section: Structurementioning

confidence: 64%

Section: Mcfarland and Opilamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigations into the thermal stability of sol‐gel‐derived glasses as models for thermally grown oxides

McFarland

Opila

2020

J Am Ceram Soc

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“…Soraru et al [24] discovered for the first time in 1997 that during the process of ceramics preparation by the precursor transition method, the addition of boron in SiCO gels could prominently improve the ceramic productivity, and in the follow-up studies, researchers prepared varieties of SiBCO materials by changing raw materials and the experimental procedure. The studies carried out by Muralidharan et al [25] indicated that the crystallization of material has a tendency to decrease after heating at 1773 K, as the content of trimethyl borate (TMB) increases in the porous ceramic preparation process. Tamayo et al [26] prepared the SiBCO glass fiber using MTES, DMDES and boronic acid as raw materials and found that the addition of boron element can enhance the thermal stability of materials.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Properties of SiBCO Aerogel and Its Composites

Feng

Yin³

et al. 2018

Nanomaterials

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To obtain new high-temperature resistant composites that can meet the requirements of aircraft development for thermal insulation and mechanical properties, SiBCO aerogel composites were prepared by sol-gel, supercritical drying and high-temperature pyrolysis with trimethyl borate (TMB) or phenylboronic acid (PBA) as the boron source and mullite fiber as reinforcement. The structure and composition of the SiBCO aerogel and its composites were characterized with SEM, FT-IR, ICP and nitrogen adsorption tests. The specific surface area of the SiBCO aerogel is 293.22 m2/g, and the pore size is concentrated in the range of 10–150 nm. The mechanical properties, the thermal insulation properties and the temperature resistance were also studied. Due to the introduction of boron, the temperature resistance of SiBCO aerogel composites is improved greatly, and the service temperature of composites reached 1773 K. When n (TMB)/n (TEOS) = 1/1, the temperature resistance of the composites is the best. After heating in air at 1773 K for 30 min, the shrinkage of SiBCO aerogel composites is only 2.45%, and the thermal conductivity of the composites is 0.138 W/(m·K) at 1773 K. In addition, the type and amount of catalyst also have certain effects on the mechanical properties and temperature resistance of the composites.

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“…1)4) This is the case of boron incorporation in SiOC glasses, that may increase their thermal stability concerning decomposition, 5) or the SiBCN materials, that possess an improved thermal stability against crystallization compared to SiCN or Si 3 N 4 materials. 6) The enhanced thermal stability of solgel derived SiBCO glasses finds its origin on a phase separation occurring during thermolysis, that may promote the crystallization of ¢-SiC and the growth of thick nanocrystalline and highly graphitized carbon clusters.…”

Section: Introductionmentioning

confidence: 99%

Combined pyrolysis-ammonolysis treatment to retain C during nitridation of SiBOCN ceramics

Tamayo

Peña-Alonso

Mazo

et al. 2016

J. Ceram. Soc. Japan

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Two sets of solgel derived glass materials have been prepared and subjected to different thermal treatments. Pyrolysis in inert atmosphere lead to the formation of amorphous Si(B)CO ceramics whereas if the inert atmosphere is changed to NH 3 once the carbon substituents of the preceramic hybrid material transform to a glassy network, the nitrogen is incorporated efficiently while the carbon is retained into the structure, as revealed by 29 Si NMR analysis. Raman spectra show a less graphitized structure in the case of B-rich materials because of the reduced mobility of the C atoms due to the formation of mixed (B)CN bonds.

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Crystallization and oxidation resistance properties of boron modified silicon oxycarbides derived from polymeric precursors by sol–gel method

Cited by 14 publications

References 21 publications

Investigations into the thermal stability of sol‐gel‐derived glasses as models for thermally grown oxides

Investigations into the thermal stability of sol‐gel‐derived glasses as models for thermally grown oxides

Preparation and Properties of SiBCO Aerogel and Its Composites

Combined pyrolysis-ammonolysis treatment to retain C during nitridation of SiBOCN ceramics

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