About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
|
Symposium
|
High Temperature Oxidation of Metals and Ceramics
|
Presentation Title |
High-temperature High-velocity Water Vapor Exposures of Ytterbium-silicate Dual-phase Mixture Compositions |
Author(s) |
Eric Stone, Elizabeth Opila |
On-Site Speaker (Planned) |
Eric Stone |
Abstract Scope |
Projecting environmental barrier coating (EBC) lifetimes for hot-section turbine engine SiC-based ceramic matrix composite components under realistic service conditions is needed. Toward this end, the effect of controlled amounts of second-phase ytterbium monosilicate (YbMS) on SiO2-depletion of ytterbium disilicate (YbDS) EBC candidate materials was investigated. Dual-phase mixtures of 10/20/30 vol% YbMS/balance YbDS were fabricated by spark-plasma-sintering. High-temperature (T=1200, 1300, and 1400 °C) high-velocity (50-150 m/s) water vapor exposures were conducted at a total pressure of 1 atmosphere. YbDS reacted with high-velocity steam forming a porous YbMS reaction product layer that increased in thickness with exposure time and temperature. Average SiO2-depletion depths of 1200 °C exposed samples were similar for all phase mixtures. Otherwise, average SiO2-depletion reaction depth decreased as YbMS second-phase content was increased. The temperature dependence of parabolic rate constants calculated from 10 and 30 vol% YbMS reaction depth trends are presented and discussed. |