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Environmental barrier coatings having a ysz top coat
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Lee, Kang N. |
| Copyright Year | 2002 |
| Description | Environmental barrier coatings (EBCs) with a Si bond coat, a yttria-stabilized zirconia (YSZ) top coat, and various intermediate coats were investigated. EBCs were processed by atmospheric pressure plasma spraying. The EBC durability was determined by thermal cycling tests in water vapor at 1300 C and 1400 C, and in air at 1400 C and 1500 C. EBCs with a mullite (3Al2O3 (dot) 2SiO2) + BSAS (1 - xBaO (dot) xSrO (dot) Al2O3 (dot) 2SiO2) intermediate coat were more durable than EBCs with a mullite intermediate coat, while EBCs with a mullite/BSAS duplex intermediate coat resulted in inferior durability. The improvement with a mullite + BSAS intermediate coat was attributed to enhanced compliance of the intermediate coat due to the addition of a low modulus BSAS second phase. Mullite + BSAS/YSZ and BSAS/YSZ interfaces produced a low melting (less than 1400 C) reaction product, which is expected to degrade the EBC performance by increasing the thermal conductivity. EBCs with a mullite + BSAS / graded mullite + YSZ intermediate coat showed the best durability among the EBCs investigated in this study. This improvement was attributed to diffused CTE (Coefficient of Thermal Expansion) mismatch stress and improved chemical stability due to the compositionally graded mullite+YSZ layer. |
| File Size | 6749554 |
| Page Count | 7 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20020078319 |
| Archival Resource Key | ark:/13960/t4wh7hw52 |
| Language | English |
| Publisher Date | 2002-01-01 |
| Access Restriction | Open |
| Subject Keyword | Nonmetallic Materials Mullites Barium Compounds Aluminum Compounds Thermal Cycling Tests Durability Melting Points Silicon Compounds Thermal Control Coatings Strontium Compounds Yttria-stabilized Zirconia Thermal Conductivity Plasma Spraying Protective Coatings Ntrs Nasa Technical Reports ServerĀ (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |