TY - JOUR A1 - Nofz, Marianne A1 - Dörfel, Ilona A1 - Sojref, Regine T1 - Microstructure of sol-gel derived corundum containing coatings N2 - Up to ~ 3 µm thick alumina coatings on corundum ceramic, soda–lime–silica glass and Inconel718™ were produced from mixtures of boehmite sols and corundum suspensions. Transmission electron micrographs in combination with electron diffraction and energy dispersive X-ray spectroscopy served to identify crystallographic phases and to characterize the microstructure of the coatings. Using corundum ceramic as substrate the initially deposited boehmite transforms via transition aluminas to corundum while heating to 1200 °C. In the cases of glass and Inconel718™ thermal treatments up to 520 °C and 1100 °C, respectively, cause diffusion of ions from the substrates into the coatings. Thus additional oxide phases were formed. All coatings are free of cracks or delaminations and do not show any directed crystal growth. KW - Aluminium oxide KW - Coatings KW - Ceramics KW - Transmission electron microscopy KW - TEM KW - Sol-gel KW - Corundum KW - Alumina PY - 2007 SN - 0040-6090 VL - 515 IS - 18 SP - 7145 EP - 7154 PB - Elsevier CY - Amsterdam AN - OPUS4-15016 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nofz, Marianne A1 - Sojref, Regine A1 - Dreßler, Martin A1 - Hünert, Daniela A1 - Dörfel, Ilona A1 - Saliwan Neumann, Romeo T1 - Sol-gel alumina coatings for high-temperature corrosion protection of Ni-base alloy SC16 in water vapour containing atmosphere N2 - Alumosols in combination with well dispersed corundum were successfully used to form up to 2.5 ìm thick coatings on the Ni-base alloy SC16. These coatings withstood heat treatments at 700 °C in a water vapour containing atmosphere. The heat treatment caused formation of delta-alumina in the coating and diffusion of chromium and titanium into the coating. KW - Alumina KW - Coating KW - Sol-gel KW - Corrosion KW - Protection PY - 2009 SN - 0020-5214 VL - 58 IS - 4 SP - 192 EP - 195 PB - DVS-Verl. CY - Düsseldorf AN - OPUS4-19726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Feigl, Michael A1 - Nofz, Marianne A1 - Sojref, Regine A1 - Kohl, Anka T1 - Improved wetting of bare and pre-coated steels by aqueous alumina sols for optimum coating success N2 - Alumina coatings are a promising candidate for the protection of metals prone to high temperature corrosion. If applied via sol–gel process, especially by using so called aqueous modified Yoldas-sols, the deposition is hardened by differences in surface free energy of substrate and sol. In this paper the apparent surface properties of samples to be coated and sols were examined by contact angle measurements, IR-spectroscopy and tensiometry. The results imply, after consideration of possible uncertainties, the use of surface tension reducing 2-butanol already present during hydrolysis of the sols to obtain an easy and successful coating process. KW - Sol-gel KW - Wetting KW - Coating KW - IR-spectroscopy PY - 2010 U6 - https://doi.org/10.1007/s10971-010-2232-7 SN - 0928-0707 SN - 1573-4846 VL - 55 IS - 2 SP - 191 EP - 198 PB - Kluwer Academic Publ. CY - Dordrecht AN - OPUS4-22602 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -