Amorphous Carbon Coatings for Locally Adjusted Tribological Properties in Sheet Bulk Metal Forming


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In sheet bulk metal forming, locally adapted friction properties of the contact tool/workpiece are an appropriate means for the targeted enhancement of the material flow, enabling an improved form filling and lowered forming forces. However, the implementation of desirable friction conditions is not trivial. And further, friction is inseparably linked to wear and damage of the contacting surfaces. This calls for a methodological approach in order to consider tribology as a whole already in the early phases of process layout, so that tribological measures which allow fulfilling the requirements concerning local friction and wear properties of the tool surfaces, can already be selected during the conceptual design of the forming tools. Thin tribological coatings are an effective way of improving the friction and wear properties of functional surfaces. Metal-modified amorphous carbon coatings, which are still rather new to the field of metal forming, allow tackling friction and wear simultaneously. Unlike many other types of amorphous carbon, they have the mechanical toughness to be used in sheet bulk metal forming, and at the same time their friction properties can be varied over wide ranges by proper choice of the deposition parameters. Based on concrete research results, the mechanical, structural and special tribological properties of tungsten-modified hydrogenated amorphous carbon coatings (a-C:H:W) are presented and discussed against the background of the tribological requirements of a typical sheet bulk metal forming process.



Key Engineering Materials (Volumes 504-506)

Edited by:

M. Merklein and H. Hagenah




H. Hetzner et al., "Amorphous Carbon Coatings for Locally Adjusted Tribological Properties in Sheet Bulk Metal Forming", Key Engineering Materials, Vols. 504-506, pp. 969-974, 2012

Online since:

February 2012




[1] H. Hetzner, J. Koch, S. Tremmel, S. Wartzack, M. Merklein, Improved Sheet Bulk Metal Forming Processes by Local Adjustment of Tribological Properties, J. Manuf. Sci. Eng. 133 (2011), No. 6, doi: 10. 1115/1. 4005313.


[2] E. Doege, B. -A. Behrens, Handbuch Umformtechnik, Springer, Berlin, (2007).

[3] Association of German Engineers, VDI guideline 2840, Carbon films, VDI, Düsseldorf, (2005).

[4] J. Fontaine, C. Donnet, A. Erdemir, Fundamentals of the Tribology of DLC Coatings, in: C. Donnet, A. Erdemir (Eds. ), Tribology of Diamond-Like Carbon Films, Springer, New York, 2008, pp.139-154.


[5] B. Schultrich, V. Weihnacht, Tribologisches Verhalten von harten und superharten Kohlenstoffschichten, Vakuum in Forschung und Praxis 20 (2008) No. 1, 12-17.


[6] J. C. Sánchez-López, A. Fernández, Doping and alloying effects on DLC coatings, in: C. Donnet, A. Erdemir (Eds. ), Tribology of Diamond-Like Carbon Films, Springer, New York, 2008, pp.311-338.


[7] A. Brückner, T. Stucky, V. Weihnacht, Potential von ta-C-Schichten für die Trockenumformung, Proc. EFDS-Workshop Kohlenstoffschichten, Dortmund, (2008).

[8] R. Westergard, F. Svahn, U. Wiklund, Novel load-carrying layers to support low-friction PVD coatings, Surf. Coat. Technol. 176 (2003) 14-22.


[9] M. Weber, K. Bewilogua, H. Thomsen, R. Wittorf, Influence of different interlayers and bias voltage on the properties of a-C: H and a-C: H: Me coatings prepared by reactive d. c. magnetron sputtering, Surf. Coat. Technol. 201 (2006) 1576-1582.


[10] M. Weber, K. Bewilogua, H. Thomsen, R. Wittorf, Carbon based multilayer systems for highly loaded forming tools, Vakuum in Forschung und Praxis 18 (2006) 17-23.

[11] S. Hessel, DLC-Hartstoffbeschichtungen für Komponenten in der Automobilindustrie und im Maschinenbau. Proc. VDMA Praxistag Intelligenter Produzieren, Frankfurt am Main, (2008).

[12] H. Hetzner, J. Schaufler, G. Pejić, S. Tremmel, K. Durst, S. Wartzack, Investigation on the tribological-mechanical behaviour of amorphous carbon coatings by load-scanning tests. Materialwiss. Werkst. (2012), accepted for publication.


[13] S. Hogmark, S. Jacobson, O. Wanstrand, A new universal test for tribological evaluation, Proc. 21st IRG-OECD Meeting, Amsterdam, (1999).

[14] C. Strondl, N.M. Carvalho, J. Th.M. De Hosson, T.G. Krug, Influence of energetic ion bombardment on W-C: H coatings deposited with W and WC targets, Surf. Coat. Technol. 200 (2005) 1142-1146.


[15] Q. Yang, L.R. Zhao, Dry sliding wear of magnetron sputtered TiN/CrN superlattice coatings, Surf. Coat. Technol. 173 (2003) 58-66.


[16] G. Dumitru, V. Romano, H.P. Weber, S. Pimenov, T. Kononenko, J. Hermann, S. Bruneau, Y. Gerbig, M. Shupegin, Laser Treatment of Tribological DLC Films, Diam. Relat. Mater. 12 (2003) 1034-1040.