Elaboration of low shrinkage mullite by active filler controlled pyrolysis of siloxanes

Michalet, Thibaut; Parlier, M.; béclin, franck; Duclos, R.; Crampon, J.

doi:10.1016/s0955-2219(01)00251-5

Cited by 33 publications

(41 citation statements)

References 25 publications

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“…This method consists of the impregnation of a polymeric foam with a ceramic slurry followed by a burnout of the organic material and the sintering of the ceramic skeleton. The resulting material is a negative replica of the foam with fully open porosity 5,12,13 . The composite materials obtained by this technique have low shrinkage, good properties and homogeneous microstructure 6,7 .…”

Section: Introductionmentioning

confidence: 99%

Using lithium glass infiltration to enhance the properties of alumina bodies

Acchar

Queiroz

2008

Mat. Res.

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The use of an infiltration process to improve the properties of sintered materials has been widely investigated. This work describes the research carried out in the manufacturing of lithium glass-infiltrated alumina. The infiltration material consisted of a mixture of elements such as Li 2 O, ZrO 2 , SiO 2 Al 2 O 3, CaO and La 2 O 3 . Alumina specimens were sintered in air at 1400 °C for 2 hours. A number of samples were then submitted to the infiltration process at 1400 °C for 15 minutes. Sintered and infiltrated specimens were characterized by X ray diffraction, apparent density, open porosity, flexural strengths and scanning electron microscopy. The results showed that the infiltration process considerably improves the properties of alumina bodies.

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Section: Introductionmentioning

confidence: 99%

Using lithium glass infiltration to enhance the properties of alumina bodies

Acchar

Queiroz

2008

Mat. Res.

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“…By pyrolysis of preceramic precursors such as polysiloxanes, silicon oxycarbide (SiOC) glasses, that contain silicon atoms bonded to oxygen and carbon randomly, can be produced. 7,12,13 Polysiloxane-derived silicon oxycarbide glasses have random three dimensional arrangement of tetrahedral silicon atoms bonded to carbon and oxygen. Thermomechanical properties of the silica glasses can be improved with the replacement of divalent oxygen atoms by tetravalent carbon atoms in silica structure.…”

Section: Introductionmentioning

confidence: 99%

“…To compensate these effects and to control shrinkage, crack and pore formation, a relatively new concept, active filler controlled polymer pyrolysis process (AFCOP) has been developed by several researchers. [4][5][6][7][8][9]13 In this method, the polymer is partially filled with inert or active particles in order to reduce the shrinkage and to allow the fabrication of bulk, crack free ceramics. By incorporation of the active fillers, reactions between the active particles and the precursor occur, which typically result in a volume expansion of the reaction product, as compared to the starting compounds.…”

Section: Introductionmentioning

confidence: 99%

“…Suitable active fillers are elements or compounds such as Al, B, Si, Ti, CrSi 2 , and MoSi 2 to obtain carbide, nitride, or oxide reaction products. 4,6,7,13 In the present work, phenyl and methyl containing polysiloxanes were pyrolyzed by the addition of active Ti particles to develop SiOC-based CMCs. CMC composite monoliths were fabricated with the addition of 60-80 wt.% of Ti fillers by warm pressing under 15 MPa pressure and pyrolysis at elevated temperatures between 900 and 1500 • C under inert argon and reactive nitrogen atmospheres.…”

Section: Introductionmentioning

confidence: 99%

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Silicon oxycarbide-based composites produced from pyrolysis of polysiloxanes with active Ti filler

Akkaş

Öveçoğlu

Tanoğlu

2006

Journal of the European Ceramic Society

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Phenyl (PPS) and methyl (PMS) containing polysiloxanes were pyrolyzed at elevated temperatures (900-1500• C) under argon atmosphere to investigate the phase developments within the polymers. It was found that pyrolysis of the polymers under inert atmosphere up to 1300• C leads to amorphous silicon oxycarbide (SiO x C y ) ceramics. Conversions at higher temperatures results in the transformations into the crystalline ␤-SiC phases. Ceramic matrix composites (CMCs) were developed based on the active filler controlled pyrolysis (AFCOP) of polysiloxanes with active Ti filler additions. CMC monoliths were prepared with 60-80 wt.% of active Ti particulates blended into polymer precursors. Green bodies of the composites were made by warm pressing under 15 MPa pressure and ceramics were obtained by pyrolysis at elevated temperatures between 900 and 1500• C under argon atmosphere. The results showed that due to the incorporation of active Ti fillers, formation of crystalline phases such as TiC, TiSi, and TiO occured within the amorphous matrix due to the reactions between the Ti and the polymer decomposition products. The microstructural and mechanical characterization results of the composites are presented within the paper.

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“…Sicontaining polymers such as polycarbosilane and polysiloxane have been used for this purpose, however, bulk ceramic manufacturing is limited due to an inherent density increase and shrinkage during pyrolytic conversion [1,2]. To compensate this effect and to obtain near-net shapes with complex geometry, the concept of active filler controlled polymer pyrolysis process (AFCOP) has been developed recently [1,3,4]. In this concept, the reactive filler particles such as B, Si, Ti, CrSi 2 incorporated into the polymer reacts with the decomposition products of the polymer such as solid carbon or gaseous CH 4 , C 6 H 6 to form new carbide, nitride or oxide phases.…”

Section: Introductionmentioning

confidence: 99%

Development of Si-O-C Based Ceramic Matrix Composites Produced via Pyrolysis of a Polysiloxane

Akkaş

Öveçoğlu

Tanoğlu³

2004

KEM

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Abstract. Pyrolytic conversion of a preceramic polymer, poly(phenyl)siloxane has been investigated to develop ceramic matrix composites (CMCs) at low temperatures with high dimensional stability. Furthermore, the thermal transformation of the polymer precursor under inert atmosphere was monitored. For this purpose, poly(phenyl)siloxanes were cured at about 200 °C for 2 hours under air and pyrolysed at various temperatures in the range of 900 -1500 °C for 1 hour under inert argon atmosphere. The products of the pyrolytic conversion were analyzed using X-ray diffraction (XRD), thermal analysis (TG and DTA) and scanning electron microscopy (SEM) coupled with EDX analyzer. It was found that pyrolysis under inert atmosphere up to 1300 °C led to amorphous silicon oxycarbide (SiO x C y ) ceramics. Conversions at higher temperatures caused the transformation into the crystalline β-SiC phases. Moreover, to obtain composite monoliths inert Al 2 O 3 and active Ti and Si particulates were incorporated into the polymer as fillers employing compressive moulding at moderate temperatures. During pyrolysis, cross-linked green compacts of the particulate/polymer system were converted into ceramic body and the microstructural parameters and the effects of the filler type on the microstructure were investigated.

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Elaboration of low shrinkage mullite by active filler controlled pyrolysis of siloxanes

Cited by 33 publications

References 25 publications

Using lithium glass infiltration to enhance the properties of alumina bodies

Using lithium glass infiltration to enhance the properties of alumina bodies

Silicon oxycarbide-based composites produced from pyrolysis of polysiloxanes with active Ti filler

Development of Si-O-C Based Ceramic Matrix Composites Produced via Pyrolysis of a Polysiloxane

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