Synthesis and phase stability of zirconia-lanthania-ytterbia-yttria nanoparticles; a promising advanced TBC material
A. Keyvani, N. Mostafavi, M. Bahamirian, Hossein Sina, Amin Rabiezadeh
Abstract
Advanced thermal barrier coatings (TBCs) developed by incorporating multicomponent rare earth oxide dopants into zirconia are promising alternative to replace yttria-stabilized zirconia (YSZ) thermal barrier coatings. In this study, a zirconia-based nanopowder coating doped by multiple rare earth oxides (YLaYbZr: 5.86 Mol.%Y2O3-1.99 Mol.%La2O3-1.98 Mol.%Yb2O3-ZrO2) was synthesized using co-precipitation technique which is advantageous in terms of simplicity and cost-effectiveness. The product was then characterized using X-ray diffraction (XRD) method and field emission scanning electron microscopy (FESEM). The stability of YLaYbZr compound was studied after a heat treating the product at 1300°C for 50 h. The results indicated that the initially obtained powder was a metastable tetragonal (t-prime) zirconia. Rietveld refinement of the XRD data from YLaYbZr powder after 50 h of heat treatment at 1300°C confirmed stabilization of zirconia in the t-prime phase with around 15 wt.% monoclinic impurity. Furthermore, FESEM results (before and after heat treatment) indicated orderly particles of uniform shape and size with a small tendency toward agglomeration.