|
4840 |
|
Thursday, May 12, 2016, Yellow River Hall 10:00 AM Power Generation II |
|
Effect of neodymia, samaria and yttria co-doping on the phase stability, thermal conductivity and long-term performance of the zirconia-based thermal barrier coatings |
|
Ivan Mazilin* / Technological Systems for Protective Coatings, Ltd., Russian Federation Nikolay Zaitsev / TSPC Ltd., Russia Lev Baldaev/ TSPC Ltd., Russia Eugeny Marchukov/ A.M. Lyulka Development Design Bureau, Russia Dmitri Drobot/ Lomonosov Moscow University of Fine Chemical Technology, Russia |
|
As a part of a new thermal barrier coating (TBC) material development projects some co-doped compositions were proved to be very promising. Usually in the co-doped compositions the primary component is yttria and the secondary is rare-earth oxide, both components are stabilizers for zirconia. These compositions were shown to be effective in decreasing thermal conductivity, but phase stability and fracture toughness can be optimized further by changing the type and amount of the stabilizing components. In this work we are to report the results of our development in the field of powder synthesis and coating production with neodymia, samaria and yttria co-doped zirconia compositions. The present paper focuses on the comparison of thermal conductivity, phase stability and up to 500 hours isothermal heating test performance of the co-doped coatings with state-of-the-art YSZ ones. According to the LFA data, thermal conductivity of all as-sprayed coatings was shown to be similar and very low, but after annealing there is at least 15% decreasing for co-doped composition compared to YSZ. XRD data shows trace amounts of m-ZrO2 in as-sprayed coatings, but after annealing and during long-term heating test all tested coatings are having t-ZrO2 structure. Using different bondcoats and ceramic interlayers under co-doped ceramic layer we were able to extend the TBC isothermal heating life up to 500 hours. |