Cobalt-containing silicon oxycarbide glasses derived from poly[methyl(phenyl)]siloxane and cobalt phthalate

Kolář, František; Machovič, Vladimı́r; Svı́tilová, Jaroslava

doi:10.1016/j.jnoncrysol.2006.02.087

Cited by 19 publications

(5 citation statements)

References 16 publications

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“…This enhanced decomposition (decrease in thermal stability) resulted in the release of gaseous byproducts (SiO and CO), similar to what was reported for a or Ni‐containing polysiloxane 22 . A more detailed investigation of the effect of different metal ions on the weight loss of the polysiloxane precursor was, however, outside the scope of the present study 33,35 …”

Section: Resultssupporting

confidence: 81%

“…The ball‐milled batch containing 1 wt% azodicarbonamide (ADA, Sigma‐Aldrich) also, acting as a physical blowing agent was transferred to an oven for foaming and thermal cross linking (5 h at 250°C in air; 2°C/min heating rate). Al foil containers with variable diameters (2–4 cm) were used as a mold for the material during the cross‐linking step; because a highly critical parameter is the homogeneity of the viscous blend during foaming and curing (because the addition of Co affects the cross‐linking characteristics of polysiloxane precursors), 33 mixing with a thin glass spatula was performed just before the foaming, which occurred between 150° and 200°C. The porous monolithic bodies were then pyrolyzed under N 2 or Ar (both 99.999% pure) in an alumina tube furnace (2 h at the selected temperature, in the range 1250°–1400°C in 50°C steps; 2°C/min heating and cooling rate).…”

Section: Methodsmentioning

confidence: 99%

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Growth of One‐Dimensional Nanostructures in Porous Polymer‐Derived Ceramics by Catalyst‐Assisted Pyrolysis. Part II: Cobalt Catalyst

Vakifahmetoğlu

Colombo

Carturan

et al. 2010

Journal of the American Ceramic Society

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Via catalyst-assisted pyrolysis, Si3N4 and SiC nanowires were produced on the cell walls of polymer-derived ceramic foams. The pyrolysis atmosphere and temperature were the main parameters affecting their development: silicon nitride singlecrystal nanowires formed under nitrogen, while silicon carbide ones were produced under argon, and their amount increased with the increasing pyrolysis temperature. Brunauer–Emmett– Teller analysis showed that the presence of the nanowires afforded high specific surface area (SSA) values to the macroporous ceramic foams, ranging from 10 to 110 m2/g. Co-containing samples developed higher SSA values, especially after pyrolysis at 14001C in N2, than samples containing Fe as a catalyst. The differences were explained in terms of morphology (diameter and assemblage), which depended on the processing conditions and the catalyst type (Co or Fe)

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Section: Resultssupporting

confidence: 81%

Section: Methodsmentioning

confidence: 99%

Growth of One‐Dimensional Nanostructures in Porous Polymer‐Derived Ceramics by Catalyst‐Assisted Pyrolysis. Part II: Cobalt Catalyst

Vakifahmetoğlu

Colombo

Carturan

et al. 2010

Journal of the American Ceramic Society

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“…Polysiloxanes have technological relevance in coatings,1–5 membranes,6–16 precursor for ceramics,17–23 among others 5, 23. The incorporation of siloxane units in polyamides,24 polyimides,25–28 epoxy resins,29–31 polyester resins,32 and polyurethanes33 often improves the mechanical properties,26, 28 resistance against corrosion,31, 32 thermal stability,29, 33 and membrane performance27 of these polymers.…”

Section: Introductionmentioning

confidence: 99%

Poly(n‐alkylsilsesquioxane)s: Synthesis, characterization, and modification with poly(dimethylsiloxane)

Prado

Torriani

Yoshida

2010

J. Polym. Sci. A Polym. Chem.

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Self-supported translucent films constituted of poly(n-octylsilsesquioxane) or poly(n-dodecylsilsesquioxane) were obtained from the hydrolysis and condensation of n-octyltriethoxysilane (OTES) or n-dodecyltriethoxysilane (DTES), respectively. Dense films were obtained in the absence of organic solvents, with dibutyltin diacetate as catalyst. These films exhibited good optical transparency and thermal stability. The incorporation of oligomeric dimethylsiloxane units (D Me,Me ) in these materials, derived from silanol-terminated poly(dimethylsiloxane) (PDMS) or 1,1,3,3-tetramethyl-1,3-diethoxydisiloxane (TMDES), was carried out during the hydrolysis and condensation of OTES and DTES and was confirmed by solid-state 29 Si NMR. Poly(n-octylsilsesquioxane) showed a glass-transition temperature at À65 C, due to the increase in the free volume, promoted by the bulky n-octyl groups. The differential scanning calorimetric (DSC) curves of the polymer derived from DTES were characterized by first-order transitions at temperatures ranging from À15.8 to À0.7 C. Further studies of these networks by low-temperature XRD evidenced narrowing of the diffraction halos suggesting a partial order-disorder transition for these materials at lower temperatures. Good thermal stability up to 350 C and the solvent-free production process make these polymers potential candidates for the development of self-supported hydrophobic protective coatings.

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“…Transition metal (eg, Cr, Mn, Fe, Co, Ni, and Cu)‐modified SiOCs have been among the most intensively studied as they have outstanding magnetic, catalytic, and electrical properties . In this paper, we focus on the Ni‐containing SiOCs since it is one of the most promising candidates in catalytic and magnetic areas .…”

Section: Introductionmentioning

confidence: 99%

“…Transition metal (eg, Cr, Mn, Fe, Co, Ni, and Cu)-modified SiOCs have been among the most intensively studied as they have outstanding magnetic, catalytic, and electrical properties. [17][18][19][20][21][22][23] In this paper, we focus on the Ni-containing SiOCs since it is one of the most promising candidates in catalytic and magnetic areas. [24][25][26][27] However, the nonuniform distribution of Ni particles in PDCs through traditional powder mixing compromises desired properties.…”

Section: Introductionmentioning

confidence: 99%

Nickel‐containing magnetoceramics from water vapor‐assisted pyrolysis of polysiloxane and nickel 2,4‐pentanedionate

Yang

Gao

et al. 2019

J Am Ceram Soc

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In this study, novel ferromagnetic Ni‐containing silicon oxycarbide (SiOC–Ni) was successfully fabricated from a base polysiloxane (PSO) with the addition of nickel 2,4‐pentanedionate. The resultant SiOC–Ni nanocomposite consists of in situ formed Ni nanocrystallites with a small amount of NiO uniformly dispersed in the amorphous SiOC matrix, and the corresponding nanocrystallite size increases with the increase of the pyrolysis temperature. The formation of nickel silicides (NixSiy) is completely suppressed by the effect of water vapor during the pyrolysis. The fundamental phase evolution process and mechanisms are explained. In an argon atmosphere, the SiOC–Ni materials pyrolyzed at 900°C are stable up to 1000°C with less than 6 wt% weight loss; they exhibit desirable electrical conductivity up to ~900°C with the highest electrical conductivity at ~247 S/m. This series of SiOC–Ni materials also demonstrates exciting ferromagnetic behaviors. Their new semiconducting behavior with soft ferromagnetism presents promising application potentials for magnetic sensors, transformers, actuators, etc.

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Cobalt-containing silicon oxycarbide glasses derived from poly[methyl(phenyl)]siloxane and cobalt phthalate

Cited by 19 publications

References 16 publications

Growth of One‐Dimensional Nanostructures in Porous Polymer‐Derived Ceramics by Catalyst‐Assisted Pyrolysis. Part II: Cobalt Catalyst

Growth of One‐Dimensional Nanostructures in Porous Polymer‐Derived Ceramics by Catalyst‐Assisted Pyrolysis. Part II: Cobalt Catalyst

Poly(n‐alkylsilsesquioxane)s: Synthesis, characterization, and modification with poly(dimethylsiloxane)

Nickel‐containing magnetoceramics from water vapor‐assisted pyrolysis of polysiloxane and nickel 2,4‐pentanedionate

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