High temperature infiltration behavior of three volcanic ashes of YSZ APS-deposited thermal barrier coatings

Conference Dates

June 24-29, 2018


Thermal Barrier Coatings (TBC) have enabled the increase of the operational temperature of aero engines. Raise in the turbine inlet temperatures (TIT) poses a threat to phase stability and safety for the state of the art material 7-8 wt% yttria stabilized zirconia (7YSZ). In addition to the inherent physicochemical restrictions of this material at high temperatures, the interaction of 7YSZ with siliceous airborne particles at temperatures above 1200 °C has been a major concern since the last decades. Sediments of Calcium-Magnesium-Aluminum-Silicates (CMAS) have been found in failed engines and have been correlated to the failure mechanisms of high temperature components. In 2010 the eruption of the Eyjafjallajökull volcano in Iceland heavily disrupted air traffic in Europe. This volcanic event lead to regulations regarding volcanic ash (VA) concentrations in the atmosphere at which aircrafts are allowed to safely fly. Also, it brought to sight the risks associated to VA in the safety of aircrafts with routes close to active volcanos. Nevertheless, reports of the assessment of the high temperature risk using real volcanic ashes is still limited in comparison to analyses carried out with CMAS. Additionally, most reported studies have been focused on the study of electron beam physical vapor deposition (EB-PVD) rather than atmospheric plasma spray (APS) produced TBCs. This contribution addresses the study of the infiltration mechanisms of VA from three sources: Colima and Popocatepetl Mexican volcanoes as well as Eyjafjallajökull Icelandic volcano.

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