In this work, X-ray techniques have been used to study coatings of zirconia and yttria doped zirconia. The experimental techniques used were laboratory-based X-ray diffraction (XRD) and synchrotron radiation based small-angle X-ray scattering techniques in both transmission mode; small-angle X-ray scattering (SAXS), and reflection mode; grazing-incidence small-angle x-ray scattering (GISAXS). By using XRD and (GI)SAXS measurements, information has been gained about the crystal structure of the coatings, and about the size- and surface structure of the scattering particles, respectively. Two types of in situ experiments were performed; in situ dipping-and-heating cycles, and in situ incremental heating. SAXS was used for the measurements on the former, whilst both SAXS and GISAXS was used for the latter. The coatings have been studied at various stages during calcination, and a novel methodology used for tracing the morphology quantitatively in systems subject to change, is presented here. This type of measurement and methodology is important, for example, in understanding mechanisms of corrosion and catalysis or ageing of materials. I found that the coatings transform from polymeric gels to particulate films featuring agglomeration and Ostwald ripening, as the sample is heated. The yttria concentration was found to influence the size- and the surface structure of the scattering particles; the more yttria, the smaller particles. When the samples were heated, I found that the particles within the coatings with higher yttria concentration gets a rougher surface structure at lower temperature than the particles in the lower yttria concentration coatings.
|Date of Award||25 Nov 2010|
|Supervisor||Rudolf Winter (Supervisor) & Xing Li (Supervisor)|
Nanostructure of dip-coated Yttria-doped Zirconia Sol-Gel coatings studied by grazing-incidence small-angle x-ray scattering
Hoydalsvik, K. (Author). 25 Nov 2010
Student thesis: Doctoral Thesis › Doctor of Philosophy