Mechnich, Peter (2019) Slurry-based Protective Coatings for Oxide/Oxide Composites. 13th International Pacific Rim Conference on Advanced Ceramic & Glass Technoloy (PacRim-13), 27.-31. Okt. 2019, Ginowan, Japan.
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Abstract
Ceramic matrix composites based on oxide fibers and porous oxide matrices are attractive materials for various applications in harsh environments. State-of-the art all-oxide CMC are based on alumina or mullite fibers and porous matrices. A key issue is the relative low mechanical stability of the porous oxide matrices, therefore CMC surfaces are prone to selective erosion in high-velocity gas stream. Moreover, thermo-chemical degradation of the constituents SiO2 and Al2O3 is associated with hydroxylation in hot H2O-rich atmospheres and subsequent volatilization of Si- or Al-hydroxide species. Degradation of CMC can effectively be reduced by protective coatings. Beyond classical coating techniques such as thermal spraying, a simple process based on deposition of slurry based coatings and subsequent consolidation by sintering is attractive for cost-efficient fabrication of CMC components. A serious drawback, however, is the low thermal stability of state-of-the art oxide fibers which requires short-term sintering of slurry-based coatings at temperatures not exceeding about 1300°C. This can be achieved by means of transient phases which bond particles and substrate at moderate temperatures. Since transient phases are reactive constituents, no residual non-crystalline phases affecting thermal stability are present after processing. Due to the rigid CMC substrates sintering of coatings is constrained, therefore excess volume shrinkage during processing must be avoided. As a consequence, slurry based coatings for all-oxide CMC exhibit generally a relative high porosity. Examples presented include slurry based coatings consisting of Al2O3, SiO2, Y2O3, and ZrO2.
Item URL in elib: | https://elib.dlr.de/130305/ | ||||||
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Document Type: | Conference or Workshop Item (Speech) | ||||||
Title: | Slurry-based Protective Coatings for Oxide/Oxide Composites | ||||||
Authors: |
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Date: | October 2019 | ||||||
Refereed publication: | No | ||||||
Open Access: | No | ||||||
Gold Open Access: | No | ||||||
In SCOPUS: | No | ||||||
In ISI Web of Science: | No | ||||||
Status: | Published | ||||||
Keywords: | CMC, Coating | ||||||
Event Title: | 13th International Pacific Rim Conference on Advanced Ceramic & Glass Technoloy (PacRim-13) | ||||||
Event Location: | Ginowan, Japan | ||||||
Event Type: | international Conference | ||||||
Event Dates: | 27.-31. Okt. 2019 | ||||||
Organizer: | The Japanese Ceramic Society | ||||||
HGF - Research field: | Aeronautics, Space and Transport | ||||||
HGF - Program: | Aeronautics | ||||||
HGF - Program Themes: | propulsion systems | ||||||
DLR - Research area: | Aeronautics | ||||||
DLR - Program: | L ER - Engine Research | ||||||
DLR - Research theme (Project): | L - Combustion Chamber Technologies (old) | ||||||
Location: | Köln-Porz | ||||||
Institutes and Institutions: | Institute of Materials Research > Structural and Functional ceramics | ||||||
Deposited By: | Mechnich, Dr.rer.nat. Peter | ||||||
Deposited On: | 21 Nov 2019 09:02 | ||||||
Last Modified: | 21 Nov 2019 09:02 |
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