Synthesis of 3 Mol% Yttria Stabilized Zirconia (3YSZ) and Study on Corrosion Behavior of CMAS on Sintered 3YSZ Pellets

Abstract

The present work describes the corrosion behavior of CMAS (CaO-MgO-Al2O3-SiO2 phase) on the Yttria-Stabilized Zirconia (YSZ) used for thermal barrier coating. CMAS deposited on YSZ pellets and at high temperature it forms glassy phases and wets the surface of YSZ pellets and gets infiltrated into the surface. CMAS reacted with YSZ and form several compounds showing degradation of YSZ material meanwhile yttria get dissolve in the CMAS solution and induced tetragonal to the monoclinic transformation which is associated with the vol. expansion and hence causes cracks formation. Our objective is to synthesize Yttria-Stabilized Zirconia(YSZ) by using 3mol%Y2O3 by chemical precipitation method, preparation of CMAS solution and study the corrosion and degradation behavior of YSZ pellets on which CMAS was deposited. In the first part of work stabilization of tetragonal zirconia phase at different sintering temperatures were studied and it revealed that totally tetragonal phase was retained up to 1300°C. So we used 1300°C sintered pellets for our experimental work because it contains a high amount of tetragonal phase as well as and it has desired amount of porosity essential to lower the thermal conductivity of coating material. In the result section, XRD of CMAS deposited YSZ pellets and the FE-SEM of reaction interface between YSZ and CMAS region were studied and it shows the degradation of YSZ material in the presence of CMAS.