Nanosized Si&lt;sub&gt;3&lt;/sub&gt;N&lt;sub&gt;4&lt;/sub&gt;/SiC-Powders by Polysilazane/Polycarbosilane-Pyrolsysis

Boden, G.; Keuthen, M.

doi:10.4028/www.scientific.net/kem.89-91.107

Cited by 4 publications

(5 citation statements)

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“…18 Intimate mixtures of Si 3 N 4 /SiC nanosized powders have been produced by pyrolysis of polysilazane/poly(carbosilane) mixtures, and the initial Si-N and Si-C bonds in the precursor were retained. 19 As a general rule, carbon removal from the organic substituents on silicon is not complete and SiC/Si 3 N 4 mixtures are usually obtained. To minimize the amount of residual carbon, pyrolyses have been performed under ammonia, and silicon nitride and oxynitrides have been produced from carbon-containing precursors.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Investigation of the Synthesis of Thin Silicon Nitride Films on Silicon Single-Crystal Wafers via Ammonia-Assisted Pyrolysis of Organosilicon Polymers

et al. 2001

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Thin layers of a-Si3N4 were synthesized by the pyrolysis of thin films of poly(methylsilane) (PMS) and poly(dimethylsilane) (PDMS) spin-coated on silicon single-crystal wafers and via deposition of the volatile species resulting from the thermal cracking of the bulk precursor in the presence of ammonia. The process was monitored by FT-IR spectroscopy. The reaction between NH3 and PMS begins at 200 °C with the slow production of a slightly cross-linked product involving Si3N knots. Extensive amination of PMS occurs on pyrolysis at 300 °C, under 5−10 Torr NH3 overpressure. The product exhibits IR bands characteristic of both a silazane and an aminosilane species, which are presumably formed by Si−H and N−H heterodehydrocoupling. Between 200 and 450 °C, this cross dehydrocoupling reaction competes very effectively with the Kumada rearrangement. Significant loss of carbon occurs from the resulting poly(carbosilazane) between 500 and 600 °C. Prolonged curing under NH3 at 300 °C, to remove all Si−H groups and to give a densely cross-linked polysilazane, suppresses the Kumada rearrangement, and negligible carbon loss occurs on raising the pyrolysis temperature to 700 °C. Although the main product is still a-SI3N4, there is an increased amount of residual carbon.

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Section: Introductionmentioning

confidence: 99%

Spectroscopic Investigation of the Synthesis of Thin Silicon Nitride Films on Silicon Single-Crystal Wafers via Ammonia-Assisted Pyrolysis of Organosilicon Polymers

et al. 2001

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“…Si-N-C powder was prepared by polysilazane/polycarbosilazane-pyrolysis (described elsewhere [11]): The powder analysis is given in Table I. Si-N-C powder was prepared by polysilazane/polycarbosilazane-pyrolysis (described elsewhere [11]): The powder analysis is given in Table I.…”

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confidence: 99%

Structural development and properties of SiC-Si3N4 nano/microcomposites

et al. 1996

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“…Phases present were not identified and changes in microstructure brought about by the two-stage hot pressing were not discussed. However, other work 25,30 has shown that crystallization of amorphous Si-C-N takes place to form α-Si 3 N 4 and β-SiC at temperatures > 1400 • C and it is likely that the first stage at 1500 • C allowed this to occur before proceeding to the higher HP temperature. RT strengths of the Si 3 N 4 and nanocomposites increased with the highest flexural strength of 1550 MPa achieved for the nanocomposite containing 25 vol.% SiC, similar to the strength reported for the Al 2 O 3 -free nanocomposites (see Table 1).…”

Section: Silicon Nitride-sic Nanocomposites Prepared From Amorphous S...mentioning

confidence: 98%

“…The HT‐bending strength was also improved by the carbon coating method 18–37 . Monolithic Si 3 N 4 , which contained 2.68 wt.% SiO 2 but no carbon coating showed a rapid degradation in strength > 800°C.…”

Section: Si3n4–sic Micro–nanocomposites Prepared From Carbon‐coated Silicon Nitridementioning

confidence: 99%

“…The HT-bending strength was also improved by the carbon coating method. [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] Monolithic Si 3 N 4 , which contained 2.68 wt.% SiO 2 but no carbon coating showed a rapid degradation in strength > 800 • C. Strength of nanocomposites prepared from the same Si 3 N 4 coated with 0.29 wt.% C gradually decreased up to 1200 • C. These improvements were considered to be due to SiC particles dispersed at Si 3 N 4 -Si 3 N 4 interfaces acting to prevent Si 3 N 4 grain boundary sliding at elevated temperatures.…”

Section: Si N 4 -Sic Micro-nanocomposites Prepared From Carbon-coated...mentioning

confidence: 99%

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Silicon nitride–silicon carbide micro/nanocomposites: A review

Hampshire

Kennedy

2021

Int J Applied Ceramic Tech

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This paper reviews investigations of silicon nitride–silicon carbide micro–nanocomposites from the original work of Niihara, who proposed the concept of structural ceramic nanocomposites, to more recent work on strength and creep resistance of these unique materials. Various different raw materials are described that lead to the formation of nanosized SiC within the Si3N4 grains (intragranular) and at grain boundaries (intergranular). The latter exert a pinning effect on the amorphous grain boundary phases in the silicon nitride and also act as nucleation sites for β‐Si3N4, which limits grain growth during sintering. This finer microstructure results in strengths higher than for the monolithic silicon nitride. Intragranular SiC particles enhance strength and fracture toughness as a result of residual compressive thermal stresses within the nanocomposites. High temperature strength and creep resistance are also much higher than for monolithic silicon nitride and a few investigations of these topics are briefly reviewed and the proposed mechanisms are described. Within the context of other studies cited, work on Si3N4–SiC micro–nanocomposites by the current authors describes an aqueous processing route for better dispersion of commercial powders prior to sintering.

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Nanosized Si<sub>3</sub>N<sub>4</sub>/SiC-Powders by Polysilazane/Polycarbosilane-Pyrolsysis

Cited by 4 publications

References 0 publications

Spectroscopic Investigation of the Synthesis of Thin Silicon Nitride Films on Silicon Single-Crystal Wafers via Ammonia-Assisted Pyrolysis of Organosilicon Polymers

Spectroscopic Investigation of the Synthesis of Thin Silicon Nitride Films on Silicon Single-Crystal Wafers via Ammonia-Assisted Pyrolysis of Organosilicon Polymers

Structural development and properties of SiC-Si3N4 nano/microcomposites

Silicon nitride–silicon carbide micro/nanocomposites: A review

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