TY - JOUR A1 - Krüger, Jörg A1 - Meja, P. A1 - Autric, M. A1 - Kautek, Wolfgang T1 - Femtosecond pulse laser ablation of anodic oxide coatings on aluminium alloys with on-line acoustic observation JF - Applied surface science N2 - The 125-fs laser ablation behaviour (800 nm) of aluminium and anodic oxide coatings on an AlMgSi1 alloy was investigated. The multi-pulse ablation threshold of aluminium at 1.2 J cm-2 was less than that of the oxides of 2–3 J cm-2. Aluminium exhibited a single pulse modification (melting) threshold of 0.3 J cm-2. These values derived from an evaluation of the crater geometry coincided with on-line acoustic measurements. The detected microphone voltage amplitude increased linearly with the laser fluence. The morphology of the ablation craters on aluminium indicated melt formation and displacement of a homogeneous melt phase due to the recoil action of the expanding metal vapour. The laser-processed ceramic oxide phases, on the other hand, showed a spongy resolidified melt layer, which denotes a collocated in-depth formation both of a melt and a gas phase. These phenomena are discussed in terms of the relative dominance of penetration depth of laser light and heat affected zones in the investigated materials with strongly varying optical and thermodynamical properties. KW - Laser ablation KW - Acoustic measurement KW - Microphone KW - Aluminium KW - Aluminium oxide PY - 2002 SN - 0169-4332 SN - 1873-5584 VL - 186 IS - 1-4 SP - 374 EP - 380 PB - North-Holland CY - Amsterdam AN - OPUS4-6324 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 - Wäsche, Rolf A1 - Brandt, Guido A1 - Ehrke, Roman A1 - Nolze, Gert A1 - Schmid, Thomas A1 - Sasaki, S. A1 - Woydt, Mathias T1 - Wear behaviour of alpha-alumina in hot steam at high contact pressure JF - Wear N2 - The work examines the wear behaviour of α-aluminium oxide by combining thermodynamic modelling with advanced wear testing as well as analytical methods to get a better understanding of this structural ceramic material wear behavior and its possible use in high temperature steam environment. KW - Aluminium oxide KW - Temperature KW - Hot steam KW - Diaspore KW - Ceramic KW - Wear PY - 2018 DO - https://doi.org/10.1016/j.wear.2018.02.012 SN - 0043-1648 SN - 1873-2577 VL - 404-405 SP - 22 EP - 30 PB - Elsevier B.V. AN - OPUS4-44449 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -