Boehlerit GmbH and Co. KG

Kapfenberg, Austria

Boehlerit GmbH and Co. KG

Kapfenberg, Austria
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Endler I.,Fraunhofer Institute for Ceramic Technologies and Systems | Hohn M.,Fraunhofer Institute for Ceramic Technologies and Systems | Herrmann M.,Fraunhofer Institute for Ceramic Technologies and Systems | Holzschuh H.,SuCoTec AG | And 5 more authors.
Surface and Coatings Technology | Year: 2010

Ti1-xAlxN is a well established material for cutting tool applications exhibiting a high hardness and an excellent oxidation resistance. A main route for increasing the performance of Ti1-xAlxN is the incorporation of further elements. Therefore the main objective of this work is to improve the properties and wear resistance of aluminum-rich CVD-TiAlN coatings by incorporating carbon. A new Low Pressure CVD process was employed for the deposition of a very aluminum-rich TiAlCN layers. The process works with a gas mixture of TiCl4, AlCl3, NH3, H2, N2, Ar and ethylene as carbon source. In this work microstructure, composition, properties and cutting performance of CVD-TiAlCN coatings were investigated.Hard aluminum-rich TiAlCN coatings were obtained at 800°C and 850°C consisting of a composite of fcc-Ti1-xAlxN and minor phases of TiN, h-AlN and amorphous carbon. WDX analysis indicates only a low carbon content <2at.%. Lattice constant calculations suggest that carbon atoms should not be incorporated in the Ti1-xAlxN lattice. From TEM analysis and Raman spectroscopy it is evident that carbon is mainly located at the grain boundaries as a-C phase. Therefore these fcc-Ti1-xAlxN(C) coatings with low carbon content are rather a composite of fcc-Ti1-xAlxN and an amorphous carbon phase (a-C). At 900°C the metastable fcc-Ti1-xAlxN nearly disappears and co-deposition of TiN and h-AlN occurs. The layers deposited at 800°C and 850°C possess a high hardness around 3000 HV and compressive stress. CVD-TiAlCN coatings prepared at 850°C shows also an amazing thermal stability under high vacuum conditions up to 1200°C. Aluminum-rich composites fcc-Ti1-xAlxN/a-C with x>0.8 exhibit a superior cutting performance in different milling tests. © 2010 Elsevier B.V.


Garcia J.,Helmholtz Center Berlin | Pitonak R.,Boehlerit GmbH and Co. KG | Weissenbacher R.,Boehlerit GmbH and Co. KG | Kopf A.,Boehlerit GmbH and Co. KG | And 6 more authors.
Advanced Engineering Materials | Year: 2010

Multilayer CVD coatings for high speed cutting applications were designed to achieve high wear and heat resistance during machining of steel alloys. In this work the microstructure and cutting performance of these novel multilayer CVD coatings are investigated and compared with standard CVD multilayer coatings. 3D-FIB tomography is used to characterize the microstructure of the layers, especially the transition between the Ti(C,N) and the Al 2O3 layer. The 3D reconstruction of the surface of the Ti(C,N) layer shows the formation of protruded Ti(C,N) grains with a very particular architecture, which penetrate into the Al2O3 top-layer, providing a mechanical anchoring between both layers. Cemented carbides coated with the novel CVD multilayer present reduced crater and flank wear as well as improved adherence between the Al2O3 top-layer and the Ti(C,N) layer leading to a dramatic improvement of cutting performance. The microstructure and cutting performance of multilayer CVD coatings with a novel transition between the Ti(C,N) and the Al 2O3 layer are investigated. 3D-FIB tomography shows the formation of protruded Ti(C,N) grains with a particular architecture, which penetrate into the Al2O3 top-layer, providing a mechanical anchoring between both layers. Cutting tools coated with the novel CVD multilayer show dramatic improvement of cutting performance, due to reduced crater and flank wear and improved adherence between the Ti(C,N) and the Al 2O3 top-layer. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Haubner R.,Vienna University of Technology | Lessiak M.,Vienna University of Technology | Lessiak M.,Boehlerit GmbH and Co. KG | Pitonak R.,Boehlerit GmbH and Co. KG | And 2 more authors.
International Journal of Refractory Metals and Hard Materials | Year: 2016

The investigation of hard materials started already in the 1930s by depositing TiC, although it took until the 1950s that coatings were deposited on steel substrates and further 20years till the first commercial TiC coatings on hardmetal tools were available. The development of coatings was deemed necessary because conventional hardmetal tools were no longer cost-effective for its use in the new generation of metal working machines. However it was not until the introduction of TiN and Ti(CN) that the machines could be used to their full capability. Further progress for hard coatings was the development of CVD processes for industrial deposition of other compounds like Al2O3, ZrN, Zr(C,N), Ti-Zr-C, TiB2, various TaxCy- and CrxCy-layers. Parallel to CVD the development of PVD coatings started in the 1980s. The next step was to control the microstructure of the hard coatings. The crystal size could be varied by changing the deposition temperature and adding impurities. Medium temperature (MT) and Plasma CVD processes were developed. For improving cutting tool performances various coatings were combined to multilayers like TiN/MT-TiCN/Al2O3/TiN. The newest investigations are interested in nano-structured coatings mixing two phases within one layer. (Al,Ti)N-coatings with high Al-content show great potential and are one example developed during the last years. © 2016 Elsevier Ltd.


Kopf A.,Boehlerit GmbH and Co KG | Keckes J.,University of Leoben | Todt J.,University of Leoben | Pitonak R.,Boehlerit GmbH and Co KG | Weissenbacher R.,Boehlerit GmbH and Co KG
International Journal of Refractory Metals and Hard Materials | Year: 2016

Since the technical means for the preparation and examination of nanostructured materials have been provided, a new generation of wear resistant coatings with grain sizes and structural effects in the nano-scale has emerged. In this contribution the authors will present a short summit of the state of the art in the field of nanostructured coatings and will then emphasise on the most recent developments in preparing CVD AlTiN. © 2016.


Bartosik M.,University of Leoben | Pitonak R.,Boehlerit GmbH and Co. KG | Keckes J.,University of Leoben
Advanced Engineering Materials | Year: 2011

High temperature X-ray diffraction (XRD) is used to characterize residual stress depth-profiles and volume-averaged residual stresses in blasted 9 μm thick TiN coatings on WC/Co substrates in the temperature range of 25-1100 °C using a dedicated high temperature attachment from Anton Paar GmbH. Room temperature measurements reveal that the blasting process changes the almost constant tensile residual stress of 560 MPa across the coating to compressive stress which decreases exponentially within the coating surface region of 1-3 μm. The magnitude of the compressive stresses is dependent on the particle pressure used during the blasting process. Heating up results in rapid compressive stress relaxation already at relatively low temperatures and is accompanied by relaxation of stresses of II and III order. During cooling down from 1100 °C, tensile residual stresses are formed. After reaching the original stress value of about 560 MPa, the tensile stresses do not increase upon cooling anymore but are relaxed by cracks. The analysis of diffraction peaks shows that blasting results in anisotropic nano-structural changes in the coating surface. In summary, the approach documents that HT-XRD can provide important insights into the high temperature behavior of engineering components. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Lessiak M.,Vienna University of Technology | Haubner R.,Vienna University of Technology | Pitonak R.,Boehlerit GmbH and Co. KG | Kopf A.,Boehlerit GmbH and Co. KG | Weissenbacher R.,Boehlerit GmbH and Co. KG
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2015

Research on high-performance CVD coatings follows the target to increased hardness and oxidation resistance. Such coatings and coating systems are required for machining tools to optimize the manufacturing parameters for new materials and new processes. The use of chromium-containing coatings is requested because of its feature to increase the corrosion resistance. The production of various chromium-containing coatings is already shown by PVD, but for industrial scale CVD processes there are problems with the chromium precursors. Especially the chromium chlorides have a low vapour pressure and therefore high temperatures are needed for evaporation. To overcome the disadvantages of CrCl3 the relatively good evaporation of halide complexes was reported, showing potential for new CVD processes. Numerous metal compounds form gaseous complexes with Aluminium chloride but also Cr. Based on this characteristic the transport reaction of CrCl2/Al2Cl6 as chromium tetrachloraluminate is investigated. The focus of this work lies in the preparation of the chromium precursors as well as in the optimization of the transport reaction which required various changes in the conventional experimental CVD-setup. To measure the amount of transported chromium the gas phase was condensed and their Cr-content was analyzed. For the CVD deposition of Cr containing coatings, this precursor gas flow can be used directly. Further the interaction between aluminum chloride and the chromium precursor, different process parameters, as well as existing difficulties regarding the transport reaction are discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Garcia J.,Helmholtz Center Berlin | Pitonak R.,Boehlerit GmbH and Co KG
International Journal of Refractory Metals and Hard Materials | Year: 2013

In this work the influence of the cemented carbide outer-surface modification on the wear performance of coated cutting tool inserts was investigated. Cemented carbides were sintered in de-nitriding and nitriding conditions to produce functionally graded outer-surface layers with tailored properties. The graded substrates were coated by chemical vapor deposition. The functionally graded substrate/coating systems were designed for interrupted and finishing turning conditions. Nitrided cemented carbides showed increased wear performance compared to standard grades. The cubic carbide enriched outer-surface behaves as a wear resistance layer. Best cutting results in longitudinal turning were obtained for the combination of nitrided substrate and a CVD multilayer made of TiN-HT-Ti(C,N)-κ-Al2O 3-TiN. In operations dominated by interrupted cutting conditions with high loads/impacts coated cemented carbides with WC-Co graded outer-surfaces presented superior wear properties mainly due to stable cutting tip performance. © 2011 Elsevier Ltd.


Pasquazzi A.,Boehlerit GmbH and Co KG | Schubert W.-D.,Vienna University of Technology | Weissenbacher R.,Boehlerit GmbH and Co KG
Materials Science Forum | Year: 2015

The formation of a surface layer of cobalt on cemented carbides which occurs on cooling during sintering is an often observed phenomenon which has been discussed in the recent literature. The presented work shows different factors which influence the formation of the layer and proposes factor-related mechanisms. For this purpose cemented carbide samples with different compositions, WC grain sizes and carbon contents were produced and studied. The results reveal that besides the cooling conditions also the variations in composition and microstructure of the material play an essential role for the formation of a surface layer. © (2015) Trans Tech Publications, Switzerland.


Garcia J.,Helmholtz Center Berlin | Pitonak R.,Boehlerit GmbH and Co KG | Agudo L.,Ruhr University Bochum | Kostka A.,Max Planck Institute Für Eisenforschung
Materials Letters | Year: 2012

Titanium carbonitride coating layers with star-shaped crystallite morphology were produced by chemical vapor deposition. Crystallites presenting a pentagonal symmetry nucleate at 880 °C and grow perpendicular to the surface by controlling the heating rate of the deposition process. Detailed transmission electron microscopy analyses of star-shaped crystallites along the [110] zone axis showed that each crystallite consists of five tetrahedra separated by (111) twins. A small-angle boundary consisting of edge dislocations forms as a result of elastic stress relaxation in the crystallites. The coatings presented a preferential texture in the direction (110) and an overall composition of Ti(C 0.15 N 0.85). © 2011 Elsevier B.V. All rights reserved.


Garcia J.,Helmholtz Center Berlin | Pitonak R.,Boehlerit GmbH and Co. KG | Weissenbacher R.,Boehlerit GmbH and Co. KG | Kopf A.,Boehlerit GmbH and Co. KG
Surface and Coatings Technology | Year: 2010

Wear resistant Ti(C,N) coatings were produced by changing the heating rate during the chemical vapor deposition process (CVD). The modification of the CVD process led to the formation of Ti(C,N) coatings with a particulate grain architecture consisting of two different crystallites (star-shaped and lenticular-like morphologies) co-existing in the coating layer. The microstructure formation of the Ti(C,N) layer was investigated by interrupting the CVD process at different temperatures. Depending on the deposition temperature, rounded, star-shaped and/or lenticular-like crystallites formed. The overall C/N ratio of the Ti(C,N) layer was 0.16/0.84, as determined by x-ray diffraction. TEM/EELS investigations of Ti(C,N) crystallites revealed an inhomogeneous distribution of carbon and nitrogen in the grains. Cutting tests showed outstanding wear resistance of the Ti(C,N) layers produced by the modified CVD process. © 2010 Elsevier B.V.

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