TY - JOUR A1 - Aristia, Gabriela A1 - Bäßler, Ralph A1 - Nofz, Marianne A1 - Sojref, Regine A1 - Kohl, Anka T1 - Short-term exposure tests of ɣ-Al2O3 Sol-gel coating on X20Cr13 in artificial geothermal waters with different pH JF - Geothermics N2 - The suitability of an Al2O3 coating for corrosion protection on X20Cr13 was evaluated in various artificial geothermal brines, focusing on the influence of different pH (4, 6 and 8) and their chemical compositions on the coating properties. All experiments were performed in the laboratory using autoclaves at 150 ◦C and 1 MPa in deaerated condition for 1 and 7 days. Results showed that the pH of geothermal waters is the most detrimental factor in the transformation of ɣ-Al2O3 and its protective abilities. Delaminations were found in the Coating exposed to geothermal brines with pH 4. FTIR spectra indicated a transformation of ɣ-Al2O3 to boehmite AlOOH after exposure to pH 4 and 6, and bayerite Al(OH)3 was formed after exposure to pH 8. Different Crystal structures of the hydrated Al2O3 also contribute to the stability of the coatings, observed by the SEM- EDX of the surface and cross-section of coatings. This study indicated that ɣ-Al2O3 sol-gel coating presents a promising aspect of corrosion protection in geothermal environment with a neutral pH. KW - Al2O3 KW - Corrosion KW - Coating KW - Martensitic steel PY - 2021 DO - https://doi.org/10.1016/j.geothermics.2021.102193 SN - 0375-6505 VL - 96 SP - 102193 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-52931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Nofz, Marianne T1 - High temperature coatings (Book review) T2 - Materials and Corrosion N2 - All in all, practicing professionals as well as researchers can read this book with pleasure and great benefit. It presents a comprehensive collection of data and practical examples manifested in about 100 graphs, 80 schemes of processes and devices, a manifold of images showing the microstructure of alloys or details of components and several phase diagrams. Tables containing data on commercially available coatings, alloys, compositions of corrosive salts, function of constituents of coatings add further important pieces of information. Thus, this book is a valuable source of information for anyone engaged in work with or research on high temperature coatings. KW - Coating KW - High temperature PY - 2018 DO - https://doi.org/10.1002/maco.201870104 SN - 0947-5117 VL - 69 IS - 10 SP - 1490 EP - 1490 PB - Wiley‐VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-46749 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 JF - Journal of sol gel science and technology 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 DO - 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 - 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 JF - Interceram 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 -