The MAESTRO platform has for topics the study of severe accidents (nuclear core degradation) which are liable to occur in the Nuclear Power Plants. The test section fabrication includes researches concerning a protection liner of a tube against steam oxidation at high temperature. The several ways studied have concluded that a thin ceramic layer can delay the oxidation of structural materials. The SULZER METCO company, specialist of thermal spray development and application , took over the carrying out of the ceramics protections on different supports (rhenium and iridium). Zirconia and Hafnia ceramics have been used in this application. These coated samples have been tested at different temperatures and in steam atmosphere. The results obtained on the samples indicate a good behaviour of the Hafnia coating up to 3632°F (2000°C) and for the whole ceramics tested (zirconia and hafnia) a significant role of barrier against oxidation (gain of 4 to 11).