Induced crystallization of amorphous silicon oxide

Németh-Sallay, M.; Barna, Á.; Lörinczy, A.; Szép, I.C.

doi:10.1002/pssa.2210430249

Cited by 4 publications

(2 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By contrast, the oxidation of the elemental Si particles began at ≈750 °C in air by the formation of an amorphous and dense SiO 2 scale. [55][56][57][58][59][60][61] The passive oxidation of elemental Si is limited by the inward diffusion of oxygen through the forming SiO 2 scale, exhibiting a parabolic rate at constant temperatures, which increases linearly with a rising temperature. [55] This explains the rapid mass gain of 25 wt% detected up to 1415 °C and the final yield of ≈128 wt% after further annealing at 1415 °C for 5 h in air, corresponding to a conversion of 25 mol% of Si to SiO 2 .…”

Section: Pyrolysis Behavior Of the Yb(2:1) Composite Powdermentioning

confidence: 99%

“…Nevertheless, the oxidation of the Si particles was accompanied by a molar volume expansion by a factor of 2.2, which can partially compensate the shrinkage of the silazane up to 900 °C reducing the porosity. [55][56][57][58][59][60][61] Despite the formation of ytterbium silicate and secondary phases above 1000 °C, no apparent change in the porosity content was measured up to 1100 °C, which remained constant at ≈33 vol%. In this regard, the formation of β-Yb 2 Si 2 O 7 (6.15 g cm −3 ) [67] and I2/a-Yb 2 SiO 5 (7.28 g cm −3 ) [31] phases from Yb 2 O 3 (9.17 g cm −3 ) [31] and SiO 2 (α-cristobalite, 2.33 g cm −3 ) [68] should lead to a volume shrinkage of up to 11.5%, by considering the total volume of Yb 2 O 3 and α-cristobalite before and after the stoichiometric conversion in ytterbium mono-or disilicate.…”

Section: Composition and Microstructure Of The Yb(2:1) Monolithsmentioning

confidence: 99%

See 1 more Smart Citation

In Situ Generated Yb₂Si₂O₇ Environmental Barrier Coatings for Protection of Ceramic Components in the Next Generation of Gas Turbines

Leite

Degenhardt²,

Krenkel

et al. 2022

Adv Materials Inter

View full text Add to dashboard Cite

CO 2 emissions should be cut in half by 2050 compared to 2009 in order to limit the increase in the world average temperature to 2 °C. Despite the advances in renewable energy alternatives, their supply strongly depends on favorable weather conditions and their efficient storage is still difficult. Thus, the key factor for the transition towards a more sustainable future relies on decarbonizing power generation. Alone the substitution of heavy fossil fuels by natural gas can decrease the related emissions in ≈50%. [1][2][3][4] Nevertheless, a developing interest has been shown for carbon-free sources as ammonia and liquid hydrogen, which are potential fuel alternatives to produce energy with a cleaner emission profile. [5] Besides the compactness and low maintenance costs, gas turbines can operate with versatile fuel sources, which make them a natural choice for the efficient production of energy. For this reason, they have found increasing service in the past 40 years in the power industry both among utilities and industrial plants as well as for aviation. [6] In combined cycle operation and with inlet temperatures exceeding 1400 °C, efficiencies as high as 63% can be achieved. [2] Therefore, different strategies are adopted to protect the currently used Nibased superalloys such as the deposition of yttria-stabilized-zirconia thermal barrier coatings (TBC) and intensive film cooling. This standard is, however, not realistic when considering service for considerable amount of times (t > 10 000 h), since the rapid creep of the TBC at above 900 °C, associated with the great mismatch between its coefficient of thermal expansion (CTE) with the alloy, increase the risk of spallation and limit the use of metal-based components in turbine engines. [7][8][9][10] Especially envisioning the use of carbon-free fuel sources in future gas turbines like hydrogen or ammonia, water vapor is one of the main products of combustion, which intensifies the degradation of these alloys. [5,[11][12][13] Hence, advances towards reduced greenhouse gas emissions and more efficient gas turbines require their substitution by more robust materials resistant to oxidation and corrosion, which can endure service at higher temperatures.Due to their reduced density, lower CTE (3-5.5 × 10 −6 K −1 ), high temperature creep resistance and melting points, nonoxide silicon based ceramics as Si 3 N 4 , SiC, and SiC/SiC composites stand out for application in combustion environments. [14][15][16][17][18][19][20][21] In face of an accelerating climate change, the reduction and substitution of fossil fuels is crucial to decarbonize energy production. Gas turbines can operate with versatile fuel sources like natural gas and future fuels such as hydrogen and ammonia. Furthermore, thermal efficiencies above 60% can be achieved using non-oxide silicon-based ceramic components. However, water vapor is one of the main combustion products leading to rapid corrosion because of volatilization of the protective SiO 2 layer at 1200 °C. An in situ generated Yb 2 Si 2 ...

show abstract

Section: Pyrolysis Behavior Of the Yb(2:1) Composite Powdermentioning

confidence: 99%

Section: Composition and Microstructure Of The Yb(2:1) Monolithsmentioning

confidence: 99%

In Situ Generated Yb₂Si₂O₇ Environmental Barrier Coatings for Protection of Ceramic Components in the Next Generation of Gas Turbines

Leite

Degenhardt²,

Krenkel

et al. 2022

Adv Materials Inter

View full text Add to dashboard Cite

show abstract

Crystalline anodic silicon dioxide on silicon

Konova

Michailov

1978

Phys. Stat. Sol. (a)

View full text Add to dashboard Cite

Multi‐layer oxide film grows in anodic oxidation of silicon p‐type in 0.1 N water diluted hydrofluoric acid. The inner layer of the oxide film on the silicon monocrystal substrate is of α‐quartz, while the outer layer of the oxide film to the electrolyte interface is amorphous. By electron diffraction in transmission a orientation, [00.1], of α‐quartz layer on the silicon [111] surface is identified. It is supposed that such structure of the oxide film is a result of existing high electric fields on the silicon anode surface in suitable electrolyte and that strong nonequilibrium condition of oxidation are possible.

show abstract

Room temperature transformations induced in SiO2 layers by chemical compounds: I

et al. 1978

View full text Add to dashboard Cite

Induced crystallization of amorphous silicon oxide

Cited by 4 publications

References 2 publications

In Situ Generated Yb₂Si₂O₇ Environmental Barrier Coatings for Protection of Ceramic Components in the Next Generation of Gas Turbines

In Situ Generated Yb₂Si₂O₇ Environmental Barrier Coatings for Protection of Ceramic Components in the Next Generation of Gas Turbines

Crystalline anodic silicon dioxide on silicon

Room temperature transformations induced in SiO2 layers by chemical compounds: I

Contact Info

Product

Resources

About

Induced crystallization of amorphous silicon oxide

Cited by 4 publications

References 2 publications

In Situ Generated Yb2Si2O7 Environmental Barrier Coatings for Protection of Ceramic Components in the Next Generation of Gas Turbines

In Situ Generated Yb2Si2O7 Environmental Barrier Coatings for Protection of Ceramic Components in the Next Generation of Gas Turbines

Crystalline anodic silicon dioxide on silicon

Room temperature transformations induced in SiO2 layers by chemical compounds: I

Contact Info

Product

Resources

About

In Situ Generated Yb₂Si₂O₇ Environmental Barrier Coatings for Protection of Ceramic Components in the Next Generation of Gas Turbines

In Situ Generated Yb₂Si₂O₇ Environmental Barrier Coatings for Protection of Ceramic Components in the Next Generation of Gas Turbines