Polymer to Ceramic Transformation: Processing of Ceramic Bodies and Thin Films

Sorarii, G. D.; Colombo, Paolo

doi:10.1002/9783527618217.ch15

Cited by 4 publications

(5 citation statements)

References 66 publications

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“…Very limited research, however, has been dedicated to the production of Sialon ceramics from preceramic polymers. Previous studies dealt with chemically modified polymeric precursors, whereas more recent investigation were dedicated to polymers containing micro‐ and nano‐sized filler particles . In the present study we present further developments in the preceramic polymers filled with oxide nano‐particles approach, which constitutes a variation to previous published work on the introduction of active fillers in preceramic polymers .…”

Section: Introductionmentioning

confidence: 89%

Optimization of Phase Purity of β′‐Sialon Ceramics Produced from Silazanes and Nano‐Sized Alumina

2012

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The use of preceramic polymers in the synthesis of Sialon ceramics has been scarcely discussed in the literature. In this article we report the production of virtually phase-pure β′-Sialon ceramics from a mixture of commercially available polysilazanes and γ-Al2O3 nanopowder, pyrolized in N2 atmosphere in the 1300°C–1600°C range. This approach combines the advantage of embedding nano-sized fillers in preceramic polymers, in terms of their reactivity towards the Si–N based ceramic pyrolysis residue, with the complex interactions with residual carbon, also present as a secondary phase in the same ceramic residue. Starting from a polymer (PSZ20) yielding a SiCN amorphous ceramic after pyrolysis, the Sialon phase purity is greatly affected by the residual C content: for an optimized polymer/filler ratio (PSZ20/Al2O3 = 2), β′-Sialon can be produced possesing only small quantities of quasi-amorphous SiC as a secondary phase. Additional improvements based on the partial replacement of PSZ20 with a polymer (PHPS) not containing C in the backbone, lead to the production of pure nanocrystalline β′-Sialon powders (average grain size of 100–200 nm)

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Section: Introductionmentioning

confidence: 89%

Optimization of Phase Purity of β′‐Sialon Ceramics Produced from Silazanes and Nano‐Sized Alumina

2012

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“…Soraru et al 26 studied the structure of SiC ceramics pyrolyzed from PCS, and fabricated alumina containing SiC (SiAlC) ceramics from Al-modified PCS via cold pressing and pyrolysis. 27 In the present work, we have fabricated bulk Si(O)C ceramics from PCS through the process of thermal oxidation, warm compacting, and pyrolysis. Warm pressing was applied in the compaction of the preoxidized PCS in order to enhance the densities of the resultant ceramics via pyrolysis.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structures, and Properties of Bulk Si(O)C Ceramics from Polycarbosilane

Fan

et al. 2009

Journal of the American Ceramic Society

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Bulk Si(O)C ceramics are fabricated from polycarbosilane (PCS) by bulk pyrolysis along the route of cross linking, warm‐pressing, and pyrolysis. The PCS was thermally oxidized for cross linking at various temperatures as a critical step toward the bulk transformation of PCS into bulk Si(O)C ceramics. The degree of cross linking of PSC affects the densities and bonding qualities of the warm‐pressed powder compacts and, hence, the resultant ceramics. Under optimized processing conditions, crack‐free bulk Si(O)C ceramics are obtained with a bulk density attaining 2.2 g/cm3. Despite the existence of a considerable amount of oxygen in the ceramics (16.08 wt%), resulting from the thermal oxidation processing, the ceramics show the characteristics of structures and properties of SiC‐based ceramics. 29Si‐solid state nuclear magnetic resonance spectra (NMR) reveal that the as‐pyrolyzed X‐ray amorphous Si(O)C phase consists mainly of SiC4 coordination units in the ceramic network, with the remainder being silicon‐coordinated carbon and oxygen. Microhardness tests show that the as‐pyrolyzed amorphous Si(O)C ceramics have a high hardness, attaining 24.91 GPa at a load of 2 N, and 19.82 GPa at a load of 10 N. Upon annealing at 1300°C in argon, the amorphous ceramics crystallized into nanophase β‐SiC ceramics, and the ceramics kept the bulk nature of the amorphous ceramics with an increased density. The 29Si‐solid state NMR spectrum indicates that the nanophase β‐SiC ceramics consist of SiC4 units together with some mixed coordination units, namely SiO2C2 and SiOC3. The hardness of the crystallized nanophase Si(O)C ceramics attains 23.20 GPa at a load of 10 N. The present study demonstrates the possibility of fabricating bulk Si(O)C ceramics via the polymer‐processing route, resulting in ceramics with promising structural and mechanical properties.

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“…These two reactions result in cross‐linked PCS with a degree of mechanical strength withstanding the inner tension generated from anisotropy cooling. Obvious C = O bonds also appear at 1630 and 1710 cm −1 in PCS treated at 200°C for 1 h, which can be attributed to the oxidation of Si–CH 3 group . A minor C–O bond located at 1200 cm −1 is also observed and can be ascribed to the oxidation of Si–CH 3 group as well.…”

Section: Resultsmentioning

confidence: 99%

“…Obvious C = O bonds also appear at 1630 and 1710 cm À1 in PCS treated at 200°C for 1 h, which can be attributed to the oxidation of Si-CH 3 group. 30 A minor C-O bond located at 1200 cm À1 is also observed and can be ascribed to the oxidation of Si-CH 3 group as well.…”

Section: May 2012mentioning

confidence: 95%

Preparation of Refined SiC Patterns from Imprinting of Partially Cross‐Linked Solid Polycarbosilane

Zhang

Nakayama

et al. 2012

J. Am. Ceram. Soc.

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Bulky SiC composites with refined patterns were successfully fabricated from an imprinting lithography process using solid polycarbosilane (PCS) as the ceramic precursor. Structures of the master molds were integrally imprinted to PCS pellets by warm‐pressing of nanoimprinter. Total cracking is effectively prevented by precuring of PCS under air condition. The partially cross‐linked PCS exhibits a degree of thermoplasticity, which facilitates embossing of master molds onto the PCS pellets with pattern sizes ranging from 50 μm to 300 nm. The embossed samples were pyrolyzed up to 1300°C for polymer‐conversion and the prepared patterns can be maintained after the precursor transforms to resultant nanocrystalline SiC composite. Meanwhile, this facile imprinting lithography route is supposed to be capable for the synthesis of SiC patterns with nanosized structures.

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Polymer to Ceramic Transformation: Processing of Ceramic Bodies and Thin Films

Cited by 4 publications

References 66 publications

Optimization of Phase Purity of β′‐Sialon Ceramics Produced from Silazanes and Nano‐Sized Alumina

Optimization of Phase Purity of β′‐Sialon Ceramics Produced from Silazanes and Nano‐Sized Alumina

Synthesis, Structures, and Properties of Bulk Si(O)C Ceramics from Polycarbosilane

Preparation of Refined SiC Patterns from Imprinting of Partially Cross‐Linked Solid Polycarbosilane

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