Tkadletz M.,Materials Center Leoben Forschung |
Mitterer C.,University of Leoben |
Sartory B.,Materials Center Leoben Forschung |
Letofsky-Papst I.,University of Graz |
And 2 more authors.
Surface and Coatings Technology | Year: 2014
Hard coatings deposited by cathodic arc evaporation are often characterized by droplets, deteriorating their surface roughness and oxidation resistance. Within this work, the response of these droplets to tribological loading and their contribution to the tribological system was investigated. Ball-on-disk tests against Al2O3 counterparts were done on TiAlTaN coated cemented carbide disks at room temperature and 700°C. Surfaces as well as cross-sections through the wear tracks were investigated by scanning and transmission electron microscopy. While droplets were found to contribute to coating degradation by providing nucleation sites for shear cracks and by the release of abrasive fragments into the sliding contact, oxidation at elevated temperature leads to a more efficient embedding into the surrounding coating matrix. This suggests an oxidation induced self-healing process, contributing to the enhanced wear resistance of TiAlN-based hard coatings at elevated temperatures. © 2014 Elsevier B.V. Source
Wustefeld C.,TU Bergakademie Freiberg |
Rafaja D.,TU Bergakademie Freiberg |
Klemm V.,TU Bergakademie Freiberg |
Michotte C.,CERATIZIT Luxembourg S.ar.l. |
Kathrein M.,CERATIZIT Austria GmbH
Surface and Coatings Technology | Year: 2010
The effect of aluminium contents and bias voltage on the microstructure of cathodic arc evaporated Ti1-xAlxN coatings was investigated with the aid of X-ray diffraction experiments and transmission electron microscopy. The coatings were deposited from mixed Ti-Al targets with different Ti:Al ratios (60:40, 50:50, 40:60 and 33:67) at bias voltages ranging between -20V and -120V. The microstructure of the coatings was described in terms of the phase composition, crystallite size and residual stress and related to the indentation hardness. The microstructure features were found to be related to the uniformity of the local distribution of Ti and Al in (Ti,Al)N, which was controlled, for a certain overall chemical composition of the coatings, by the bias voltage. The consequences of large local fluctuations of the Ti and Al concentrations in Ti1-xAlxN that occurred at higher bias voltages were the phase segregation, which was indicated through the formation of the fcc-(Ti,Al)N/fcc-AlN nanocomposites and the increase of the compressive residual stress in the face-centred cubic (Ti,Al)N. Concurrently, the increasing bias voltage contributed significantly to the reduction of the crystallite size. Higher residual stress and smaller crystallite size increased the hardness of the coatings. The overall chemical composition of the coatings influenced mainly their phase composition. The high concentration of Al in (Ti,Al)N led to the formation of wurtzitic AlN in the coatings. © 2010 Elsevier B.V. Source
Riedl A.,Materials Center Leoben Forschung |
Schalk N.,Materials Center Leoben Forschung |
Czettl C.,Materials Center Leoben Forschung |
Czettl C.,CERATIZIT Austria GmbH |
And 2 more authors.
Wear | Year: 2012
The tribological behaviour of post-treated CVD α- and κ-Al 2O 3 hard coatings is investigated in this study between room temperature and 900°C. Friction and wear are correlated to the different coating surface topographies in the as-deposited state and generated by metal-blasting with AlSi granulate or polishing. As a result of its higher surface roughness, the quantity of AlSi transfer material is considerably higher for α- compared to κ-Al 2O 3. The coefficient of friction is comparable for both Al 2O 3 modifications and for all testing temperatures. Increased wear is observed for metal-blasted surfaces, especially for α-Al 2O 3 at high temperatures, which can be attributed to generation of abrasive wear debris by oxidation of the transfer material. Polishing reduces wear due to a decrease in surface roughness. © 2012 Elsevier B.V. Source
CERATIZIT Austria GmbH | Date: 2011-07-19
A rotary cutting tool has a main body with one or more segments exchangeably fastened to its circumference or internally thereof. The main body and the segment have fitting elements with mutually contacting faces. The exchangeable fastening is effected by a clamping piece, which is dovetailed on two sides and is additionally configured with a taper that wedges in the axial direction. The first dovetail-shaped part of the clamping piece engages in a corresponding recess of the main body and the second dovetail-shaped part of the clamping piece engages in a corresponding recess of the segment.
CERATIZIT Austria GmbH | Date: 2014-02-18
A milling tool has a tool shank and a cutting head fastened to the forward end of the tool shank by way of a clamping connection. The clamping connection has a protrusion with clamping faces, and a recess with centering faces that interact with the clamping faces. Each of the centering faces has a first region where the centering faces are spaced from a longitudinal axis of the tool shank by a first distance and a second region at a smaller distance. The first region merges into the second region. The clamping faces of the protrusion are introducible into the recess between the first regions of the centering faces and are movable, by rotation of the cutting head about the longitudinal axis, into a clamping position in which the clamping faces interact in a force-fit with the second regions of the centering faces.