Evaluation of ceramic coatings on silicon carbide

Federer, J.I.; Roode, Mark van; Price, Jeffrey R.

doi:10.1016/0257-8972(89)90042-x

Cited by 10 publications

(6 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Refractory oxides are promising candidates for use as a coating material due to their excellent environmental stability. [1][2][3] It has been shown that chemicallyvapor-deposited (CVD) mullite coatings (a few micrometers thick) improve the resistance of silicon-based ceramics to corrosive or oxidative attack by molten salt 4 and water vapor. 5 For example, no evidence of mullite volatility was observed after 500 h of oxidation in a static high-pressure air environment containing 15% water vapor at 1200°C.…”

Section: Introductionmentioning

confidence: 99%

Effects of Thin Mullite Coating on the Environmental Stability of Sintered Si₃N₄

Tsarenko

Lee

2004

Journal of the American Ceramic Society

View full text Add to dashboard Cite

We investigated the effects of a chemically‐vapor‐deposited mullite coating (∼100 nm) on the oxidation resistance of sintered Si3N4 in air and steam environments. The coating was sacrificially incorporated into the thermally grown oxide (TGO) on Si3N4 during isothermal oxidation in air at 1400°C, leading to significantly reduced TGO growth as well as markedly improved TGO morphology. This improvement can be attributed to the refractory and viscous nature of the SiO2‐Al2O3 system, compared with SiO2, when under the influence of alkali and/or alkaline‐earth fluxing elements. However, the mullite coating had little effect on the stability of the ceramic in the steam environment at 1200°C, due likely to high activity of SiO2 in mullite.

show abstract

Section: Introductionmentioning

confidence: 99%

Effects of Thin Mullite Coating on the Environmental Stability of Sintered Si₃N₄

Tsarenko

Lee

2004

Journal of the American Ceramic Society

View full text Add to dashboard Cite

show abstract

“…This is almost always the case when the operating conditions involve thermal cycling. Mullite adheres very well to SiC and has a similar thermal expansion coefficient, [5,7] but the Si contained in it can lead to similar problems to those experienced by the SiO 2 scale. A solution that combines the advantages of mullite and alumina is offered by graded coatings, either multi-layered [7] or exhibiting functional grading, that is, composite materials with composition changing in steps or in a smooth manner between that of an inner layer of mullite in contact with the SiC substrate and an outer layer of alumina.…”

Section: Introductionmentioning

confidence: 99%

Co-deposition of Silica, Alumina, and Aluminosilicates from Mixtures of CH3SiCl3, AlCl3, CO2, and H2. Thermodynamic Analysis and Experimental Kinetics Investigation

Nitodas

Sotirchos

1999

Chem. Vap. Deposition

View full text Add to dashboard Cite

The co-deposition of silica, alumina, and aluminosilicates from mixtures of methyltrichlorosilane, aluminum trichloride, carbon dioxide, and hydrogen was investigated in this study. In order to elucidate some aspects of the co-deposition process, the deposition of pure silica and pure alumina from mixtures of methyltrichlorosilane and aluminum trichloride, respectively, with CO 2 and H 2 was also investigated. Kinetic data were obtained by carrying out CVD experiments on SiC substrates in a hot-wall reactor of tubular geometry, which permitted continuous monitoring of the deposition rate through the use of a microbalance. Reaction rate data are presented for temperatures between 1073 and 1373 K (800±1100 C) at 13.3 kPa (100 torr) pressure for various feed compositions and various positions along the axis of the deposition reactor. Thermodynamic equilibrium computations were performed on the Al/Si/Cl/C/O/H, Al/Cl/C/O/H, and Si/Cl/C/O/H systems at the conditions used in the deposition experiments. The experimental observations are discussed in the context of the results of the equilibrium analysis and of past studies. Among the most interesting findings of this study is that the presence of AlCl 3 has a catalytic effect on the incorporation of silica in the deposit, leading to co-deposition rates that are a factor of 2±3 higher than the deposition rates that are obtained when only one of the two chlorides (CH 3 SiCl 3 or AlCl 3 ) is present in the feed.

show abstract

“…Mullite adheres very well to SiC and has a similar thermal expansion coefficient (5.05 10 ±6 /C), [5,10] but the Si contained in it may lead to similar problems to those experienced with the SiO 2 scale. A solution that combines the advantages of mullite and alumina is offered by graded coatings, either multilayered [11] or exhibiting compositional grading, that is, composite materials where the composition changes, either in steps or in a smooth manner, between that of an inner layer of mullite in contact with the SiC substrate and an outer layer of alumina. This compositional grading leads to the bridging of the thermal expansion coefficient over the thickness of the material, and in this way the local thermal stressesÐdeveloped at the coating/substrate interface during thermal cyclingÐare reduced, and excessive damage to the coating is avoided.…”

Section: Introductionmentioning

confidence: 99%

Deposition of Compositionally Graded Mullite/Alumina Coatings from Mixtures of SiCl₄, AlCl₃, CO₂ and H₂

Nitodas

Sotirchos

2003

Chemical Vapor Deposition

View full text Add to dashboard Cite

Using CVD, compositionally graded coatings of mullite (3 Al 2 O 3´2 SiO 2 ) and alumina (Al 2 O 3 ) were deposited on Si-coated substrates from mixtures of silicon tetrachloride, aluminum trichloride, carbon dioxide, and hydrogen. The coatings were compositionally graded, with the Al/Si ratio increasing towards the outer layer of the coatings. The preparation of the coatings was carried out in a vertical, hot-wall CVD reactor. The results of previous experimental studies on the deposition of aluminosilicate species have been used to identify operating conditions where deposition of coatings with alumina content equal to, or greater than, that corresponding to stoichiometric mullite was possible. The scheme for the preparation of the graded mullite/alumina coatings was based on utilizing the positive effect of decreasing the residence time of the reactive mixture in the reactor, and of increasing the Al/Si ratio in the feed on the incorporation of Al 2 O 3 in the deposit.

show abstract

Evaluation of ceramic coatings on silicon carbide

Cited by 10 publications

References 5 publications

Effects of Thin Mullite Coating on the Environmental Stability of Sintered Si₃N₄

Effects of Thin Mullite Coating on the Environmental Stability of Sintered Si₃N₄

Co-deposition of Silica, Alumina, and Aluminosilicates from Mixtures of CH3SiCl3, AlCl3, CO2, and H2. Thermodynamic Analysis and Experimental Kinetics Investigation

Deposition of Compositionally Graded Mullite/Alumina Coatings from Mixtures of SiCl₄, AlCl₃, CO₂ and H₂

Contact Info

Product

Resources

About

Evaluation of ceramic coatings on silicon carbide

Cited by 10 publications

References 5 publications

Effects of Thin Mullite Coating on the Environmental Stability of Sintered Si3N4

Effects of Thin Mullite Coating on the Environmental Stability of Sintered Si3N4

Co-deposition of Silica, Alumina, and Aluminosilicates from Mixtures of CH3SiCl3, AlCl3, CO2, and H2. Thermodynamic Analysis and Experimental Kinetics Investigation

Deposition of Compositionally Graded Mullite/Alumina Coatings from Mixtures of SiCl4, AlCl3, CO2 and H2

Contact Info

Product

Resources

About

Effects of Thin Mullite Coating on the Environmental Stability of Sintered Si₃N₄

Effects of Thin Mullite Coating on the Environmental Stability of Sintered Si₃N₄

Deposition of Compositionally Graded Mullite/Alumina Coatings from Mixtures of SiCl₄, AlCl₃, CO₂ and H₂