High-velocity suspension flame spraying (HVSFS) is a promising technology to manufacture yttria stabilized zirconia (YSZ) as solid electrolyte for solid oxide fuel cells (SOFC). In this paper isothermal ageing and thermal cycling have been carried out in order to evaluate their microstructural and mechanical stability. X-ray diffraction (XRD), scanning electron microscopy (SEM) and focused ion beam (FIB) techniques have used to analyze the microstructure of YSZ electrolyte before and after ageing at high temperature. Elastic modulus has been monitored by nanoindentation, while scratch tests have been performed in order to estimate the influence of ageing on the interface electrolyte/anode adhesion.