TY - JOUR A1 - Nofz, Marianne A1 - Dörfel, Ilona A1 - Sojref, Regine T1 - Microstructure of sol-gel derived corundum containing coatings JF - Thin solid films 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 - Dreßler, Martin A1 - Nofz, Marianne A1 - Saliwan Neumann, Romeo A1 - Dörfel, Ilona A1 - Griepentrog, Michael T1 - Sol-gel derived alumina layers on nickel-base superalloy Inconel-718 (IN-718) JF - Thin solid films N2 - Modified Yoldas sols can be used to prepare crack-free well adherent layers on different substrate materials such as soda–lime glass, corundum and metal (IN-718). These layers having thicknesses of 0.6 µm are strain tolerant and withstand thermal cycling between 810 °C and room temperature. Introducing alpha-Al2O3 filler particles into modified Yoldas sols allows the preparation of thicker layers of 1.6 µm, which as well can be thermally cycled without noticeable delaminations. Chemical bonding seems to be the predominant layer bonding mechanism. KW - Sol-gel KW - Alumosol KW - Filler particles KW - Inconel-718 KW - Scanning electron microscopy PY - 2008 DO - https://doi.org/10.1016/j.tsf.2008.08.124 SN - 0040-6090 VL - 517 IS - 2 SP - 786 EP - 792 PB - Elsevier CY - Amsterdam AN - OPUS4-18263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -