Hartstoffbeschichtete Körper aus Metall, Hartmetall, Cermet oder Keramik und Verfahren zur Herstellung derartiger Körper

The invention relates to articles consisting of metal, hard metal, cermet or ceramic and coated with a hard material, and to a method for producing such articles. The hard material layers according to the invention can be used, for example, as anti-wear layers for cutting tools, as protective layers for turbine blades or as diffusion barriers in microelectronics. The problem addressed by the invention is that of providing hard material layers which have a high level of hardness, oxidation resistance and excellent wear resistance. This problem includes providing a cost-effective method for producing such hard material layers. The problem is solved by articles consisting of metal, hard metal, cermet or ceramic and coated with hard material and by a method for producing such articles, which are coated with a single or multiple layer system using a thermal CVD method without plasma excitation, wherein the single or multiple layer system has at least one nanocomposite layer having a first, nanocrystalline phase consisting of cubic titanium oxycarbonitride and a second, amorphous phase consisting of silicon oxycarbonitride or silicon oxycarbide

Hartstoffbeschichtete Körper aus Metall, Hartmetall, Cermet oder Keramik sowie Verfahren zur Herstellung derartiger Körper

The invention relates to hard-material-coated bodies composed of metal, cemented hard material, cermet or ceramic, coated with a TiSiCN composite layer or with a multilayer layer system which contains at least one TiSiCN composite layer, where the TiSiCN composite layer is, according to the invention, a nanocomposite layer which has been produced by means of a thermal CVD process without additional plasma excitation and contains a nanocrystalline phase composed of TiCxN1-x having a crystallite size in the range from 5 nm to 150 nm and a second phase composed of amorphous SiCxNy. The layer according to the invention is characterized by a high hardness, a high oxidation and heat resistance and a high adhesive strength. To produce this TiSiCN nanocomposite layer, the invention comprises a process in which the layer is deposited from a gas mixture containing one or more titanium halides, one or more silicon-containing precursors, hydrogen and reactive compounds having carbon and nitrogen atoms and/or nitrogen compounds and/or hydrocarbons and/or inert noble gases by means of a thermal CVD process at temperatures in the range from 700 DEG C to 1100 DEG C and pressures in the range from 10 Pa to 101.3 kPa without additional plasma excitation, where the molar ratio of the titanium halides to the silicon-containing precursors is selected so that an atomic ratio of Si to Ti of greater than 1 is present in the gas mixture. The process of the invention also permits inexpensive production of such coatings under industrial conditions

TiSiCN nanocomposite hard coatings by CVD

TiN and TiCxNy are commercial CVD coatings widely used for cutting tool applications. A promising route for improving hardness and oxidation resistance is the addition of silicon [1]. Therefore investigations were performed using a thermal CVD process with a gas mixture containing TiCl4 and SiCl4. This work is focused to the investigation of structure, composition and properties of the TiSiCN coatings deposited on hardmetal inserts. The ratio of the silicon precursor to TiCl4 is varied. The structure was analyzed by SEM, TEM and XRD. A maximum hardness about 40 GPa was observed at a silicon content around 12 at.% . In this silicon concentration range a TiCxNy grain size below 20 nm was determined. The investigation of the oxidation behavior shows an increase of the oxidation resistance with the silicon content. [1] I. Endler, M. Höhn, J. Schmidt, S. Scholz, M. Herrmann, M. Knaut, Surface & Coatings Technology, 215 (2013), 133

Characterisation and wear behaviour of TiN- and TiC(x)N(1-x)-coated cermets

Handelsübliche Cermet-Schneidplatten (TCN 27 und TCN 54) wurden mit Titannitrid (TiN) und Titancarbonitrid (TiC(x)N(1-x) durch plasmaaktivierte CVD bei 500-700 Grad C beschichtet. Die Abscheidungstemperatur zeigte einen starken Einfluß auf auf die Härte, Adhäsionsfestigkeit, Verschleißfestigkeit, Biegebruchfestigkeit und die Schneidfestigkeit der Schichten. Die kritische Last bei der Ritzhärteprüfung erreichte bei den Proben mit Beschichtungstemperaturen > = 600 Grad C ähnliche Werte wie bei den mit der CVD beschichteten Hartmetallen. Der Festigkeitsabfall wird eher durch metallurgische Veränderungen im Innern des Substrates als durch die harte und spröde Schicht hervorgerufen. Mit Cermet-Schneidplatten, die bei Temperaturen zwischen 600 und 700 Grad C mit TiN und Ti(x)N(y) beschichtet worden waren, wurden Schneidtests an Stahl C60N und Grauguß GGL25 durchgeführt. Die PA-CVD-Beschichtung führte im allgemeinen zur Verbesserung des Schneidverhaltens. Sowohl beim Schneiden von Stahl als auch von Grauguß führte die höhere Substrattemperatur bei der Beschichtung der Cermets zu besseren Ergebnis bezüglich der Werkzeuglebensdauer. Auch zeigte die Schichtdicke einen deutlichen Einfluß auf die Lebensdauer. Jedoch hängt der Einfluß der Beschichtung auf die Betriebsdauer wesentlich von den Schneidbedingungen ab

CMOS kompatible, nanomodifizierte Multi-Elektroden-Arrays

The integration of carbon nanotubes (CNT) on a CMOS compatible multi-electrode-array (MEA) is presented. Within the project InMEAs, CNTs are deposited directly on a high-temperature-stable MEA platform. The Fraunhofer IMS has developed a 0.8 µm bulk-substrate CMOS-technology based on tungsten metallization, in this case the threshold voltage is shifted only slightly after a temperature step of 700 °C / 30 min. By using the mixed catalyst PtFe the Fraunhofer IKTS could reduce the process temperature for CNT deposition to 620 °C

Powder Diffraction Data of Aluminum-Rich FCC-Ti1−xAlxN Prepared by CVD

Fcc-Ti1−xAlxN-based coatings obtained by Physical Vapor Deposition (PVD) or Chemical Vapor Deposition (CVD) are widely used as wear-resistant coatings. However, there exists no JCPDF card of fcc-Ti1−xAlxN for the XRD analysis of such coatings based on experimental data. In this work, an aluminum-rich fcc-Ti1−xAlxN powder was prepared and, for the first time, a powder diffraction file of fcc-Ti1−xAlxN was determined experimentally. In the first step, a 10 µm thick Ti1−xAlxN coating was deposited on steel foil and on cemented carbide inserts by CVD. The steel foil was etched and flakes of a free-standing Ti1−xAlxN layer were obtained of which a part consisted of a pure fcc phase. A powder was produced using the major part of the flakes of the free-standing Ti1−xAlxN layer. Following the Ti1−xAlxN coating, a flake of the free-standing layer and the powder were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), selected area electron diffraction and high-resolution transmission electron microscopy (SAED–HRTEM), wavelength dispersive X-ray spectroscopy (WDS) and energy dispersive X-ray spectroscopy (EDS). The powder consisted of 88% fcc-Ti1−xAlxN. The stoichiometric coefficient of fcc-Ti1−xAlxN was measured on a flake containing only the fcc phase. A value of x = 0.87 was obtained. Based on the powder sample, the XRD data of the pure fcc-Ti1−xAlxN phase were measured and the lattice constant of the fcc-Ti1−xAlxN phase in the powder was determined to be a = 0.407168 nm. Finally, a complete dataset comprising relative XRD intensities and lattice parameters for an fcc-Ti0.13Al0.87N phase was provided

Gamma radiation effects in vertically aligned carbon nanotubes

This paper describes an experimental study of gamma radiation effects in low-density arrays of vertically aligned carbon nanotubes. These arrays are characterized by excellent anti-reflective and absorbing properties for wavelengths from UV to IR, which makes them an interesting option for stray light control in optical space applications. Gamma irradiation equivalent to an estimated surface lifetime exposition in geostationary orbit does not affect the reflectivity of the structures. First high-energy proton irradiation studies indicate that the reflectivity of the carbon nanotubes forests remains unchanged

Properties of retinal precursor cells grown on vertically aligned multiwalled carbon nanotubes generated for the modification of retinal implant-embedded microelectrode arrays

Background. To analyze the biocompatibility of vertically aligned multiwalled carbon nanotubes (MWCNT), used as nanomodification to optimize the properties of prostheses-embedded microelectrodes that induce electrical stimulation of surviving retinal cells. Methods. MWCNT were synthesized on silicon wafers. Their growth was achieved by iron particles (Fe) or mixtures of iron-platinum (Fe-Pt) and iron-titanium (Fe-Ti) acting as catalysts. Viability, growth, adhesion, and gene expression of L-929 and retinal precursor (R28) cells were analyzed after nondirect and direct contact. Results. Nondirect contact had almost no influence on cell growth, as measured in comparison to reference materials with defined levels of cytotoxicity. Both cell types exhibited good proliferation properties on each MWCNT-coated wafer. Viability ranged from 95.9 to 99.8%, in which better survival was observed for nonfunctionalized MWCNT generated with the Fe-Pt and Fe-Ti catalyst mixtures. R28 cells grown on the MWCNT-coated wafers showed a decreased gene expression associated with neural and glial properties. Expression of the cell cycle-related genes CCNC, MYC, and TP53 was slightly downregulated. Cultivation on plasma-treated MWCNT did not lead to additional changes. Conclusions. All tested MWCNT-covered slices showed good biocompatibility profiles, confirming that this nanotechnology is a promising tool to improve prostheses bearing electrodes which connect with retinal tissue