Transient and Steady States of Gd 2 Zr 2 O 7 and 2 ZrO 2 ∙ Y 2 O 3 ( Ss ) Interactions with Calcium Magnesium Aluminium Silicates

Reactions between calcium magnesium aluminium silicates (CMAS) and Gd2Zr2O7 or 2ZrO2∙Y2O3 (ss) are investigated within a temperature range of 1200–1300 °C and for durations of 1 h–100 h. The evolution of CMAS penetration depth in Gd2Zr2O7 and 2ZrO2∙Y2O3 (ss) pellets varies considerably depending on the interaction time. A quantitative analysis of the nature and composition of phases observed in stationary conditions (powder/ powder interaction) is performed by SEM-FEG coupled with WDS analyses using micro-agglomerated nanoparticles of Gd2Zr2O7 and 2ZrO2∙Y2O3. Faster kinetics of the gadolinium-based system are illustrated through an analysis of the morphology of the reaction area and of the resulting CMAS tightness of reaction products. The compositions and quantities of reaction products observed at equilibrium are very similar for the two systems, but transient states are significantly different.