The degradation of thermal barrier coatings by molten deposits: introducing the concept of basicity
| Autor: | John Nicholls, N. L. Ndamka, R. G. Wellman |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Materials science
Turbine blade chemistry.chemical_element 02 engineering and technology 01 natural sciences law.invention Thermal barrier coating law 0103 physical sciences Materials Chemistry Porosity Chemical composition 010302 applied physics Magnesium Mechanical Engineering Metallurgy Metals and Alloys 021001 nanoscience & nanotechnology Condensed Matter Physics Microstructure chemistry Mechanics of Materials Ceramics and Composites Degradation (geology) 0210 nano-technology Volcanic ash |
| Zdroj: | Materials at High Temperatures. 33:44-50 |
| ISSN: | 1878-6413 0960-3409 |
| Popis: | Airborne particles such as dust, sand and volcanic ash, otherwise termed ‘CMAS’ (Calcia Magnesia Alumina-Silicate) are ingested into the engine where at the elevated temperatures this deposit can melt and induce degradation of the thermal barrier coating (TBC). The columnar, high porosity microstructure of electron beam physical vapour deposited (EB-PVD) TBCs, typically found on HP turbine blades, makes them particularly susceptible to CMAS molten deposit attack. This paper investigates the effect of modifying the chemical composition of molten CMAS deposits and, therefore, the degradation mechanisms of EB-PVD TBCs. This paper identifies a parameter termed ‘Basicity Index’, which modifies the severity and damage caused by these molten deposits to TBCs. It is believed that with the higher temperatures likely to result in next generation aero-engines and with sand chemistry varying around the world, basicity driven TBC degradation will become more prevalent. |
| Databáze: | OpenAIRE |
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