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Dry rotary blanking of aluminum |
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Interlayer for cemented carbide coatings |
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Drawing dies |
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Diamond coated axial seal rings |
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Diamond electrodes |
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Name Index of Carbon Coatings |
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Information Platform for Carbon Films |
Hotfilament CVD processes for large-area diamond deposition; the coating of axial seal rings.
Micro abrasive pencils with compeDIA® coating as the grinding coating, tip diameter 50 µm, ground groove in silicon.
CVD coating plant CVDiamond XXL developed at the Fraunhofer IST for large-area deposition of diamond coatings; maximum coating area 50 cm x 100 cm.
The manufacture and utilization of polycrystalline CVD diamond coatings with their extreme property combinations is one focus of work here at our institute. This has lead to worldwide recognition particularly in the area of hotfilament-activated diamond deposition (HFCVD), which makes possible the development of fully automatic and highly productive diamond coating on areas up to half a square meter.
The enormous performance potential of polycrystalline diamond coatings can be utilized for the most varied range of products by modifying coating properties (e.g. defined roughness, electrical conductivity), by scaling of the hotfilament-CVD process, as well as through the further development of HFCVD plant technology. Applications include tools, components, electrochemistry and micro-technology.
Diamond has an unsurpassed combination of important technologically important material properties: the highest hardness, wear and corrosion resistance, maximum thermal conductivity and good temperature stability, excellent anti-friction properties, and the largest electrochemical overvoltage for the electrolysis of water. These and other properties make CVD diamond coatings the ideal material for a wide range of uses, for example cutting and forming tools, axial seal rings and other components with a high tribological load.
In its electrically conducting form, boron doped CVD diamond is used as a material for electrodes e.g. for wastewater purification, water treatment and for electrochemical synthesis. Production and marketing of these novel and innovative electrode materials takes place through CONDIAS GmbH, a business founded by the Fraunhofer IST.
Some properties of CVD diamond:
| Hardness | approx. 100 GPa |
| E-modulus | approx. 1080 GPa |
| Density | 3,52 g/cm³ |
| Thermal stability |
in the presence of oxygen up to 600 °C in the absence of oxygen up to 1200 °C |
| Thermal conductivity |
up to 2000 W/(mK) (at 20 °C) |
| Thermal expansion |
0,8 x 10-6 K-1 (at 20 °C) |
| Specific resistance |
Doped: 10-5 ... 10 Wm Undoped: 107 ... 1011 Wm |
| Breakdown field strength |
2,5 MV/cm |
| Dielectrical constant |
5,7 |
| Transparency | IR, visible and near UV |
Diamond technology means more for us than just the manufacture of diamond coatings. It also includes an objective matching of the diamond-substrate material bonding with the technical and economic needs of the application under consideration. To work out tailor-made solutions we offer our customers a complete system consisting of: substrate selection, substrate pretreatment, coating and process optimization, analysis and testing technology, process monitoring and control plus plant and production technology.
Dr. Lothar Schäfer
Phone: +49 (0)5 31 / 21 55 - 520
Fraunhofer-Gesellschaft