Convection–diffusion derived gradient films on porous substrates and their microstructural characteristics

By virtue of the convection–diffusion effect of solution in porous solid media, an alumina substratesupported electrolyte film (YSZ) with gradient microstructure has been successfully fabricated for the first time and structurally characterized by SEM and XRD– ADA (angular dispersion analysis). This novel fabrication technique is simple, controllable, economical and potentially applicable to fabricating electrodesupported gradient electrolyte films for SOFCs. The so-prepared YSZ-film/substrate structures are featured with a dense YSZ film of ~10 lm, a uniform filling layer of ~50 lm just beneath the interface and a successive diffuse layer stretching as deep as ~250 lm within the porous substrate matrix.