Diamond-like carbon

Dome coated with DLC for optical and tribological purposes.
A ta-C thin film on silicon (15 mm diameter) exhibiting regions of 40 nm and 80 nm thickness.
A Co-alloy valve part from a producing oil well (30 mm diameter), coated on the right side with ta-C, in order to test for added resistance to chemical and abrasive degradation in the working environment.

Diamond-like carbon (DLC) is a class of amorphous carbon material that displays some of the typical properties of diamond. DLC is usually applied as coatings to other materials that could benefit from such properties.[1]

DLC exists in seven different forms.[2] All seven contain significant amounts of sp3 hybridized carbon atoms. The reason that there are different types is that even diamond can be found in two crystalline polytypes. The more common one uses a cubic lattice, while the less common one, lonsdaleite, has a hexagonal lattice. By mixing these polytypes at the nanoscale, DLC coatings can be made that at the same time are amorphous, flexible, and yet purely sp3 bonded "diamond". The hardest, strongest, and slickest is tetrahedral amorphous carbon (ta-C).[3] Ta-C can be considered to be the "pure" form of DLC, since it consists almost entirely of sp3 bonded carbon atoms. Fillers such as hydrogen, graphitic sp2 carbon, and metals are used in the other 6 forms to reduce production expenses or to impart other desirable properties.[4][5]

The various forms of DLC can be applied to almost any material that is compatible with a vacuum environment.

  1. ^ Robertson, J. (2002). "Diamond-like amorphous carbon". Materials Science and Engineering: R: Reports. 37 (4–6): 129–281. CiteSeerX 10.1.1.620.3187. doi:10.1016/S0927-796X(02)00005-0. S2CID 135487365.
  2. ^ "Name Index of Carbon Coatings". Archived from the original on January 20, 2007.
  3. ^ Lijie Tan, Hongwei Sheng, Hongbo Lou, Benyuan Cheng (February 6, 2020). "High-Pressure Tetrahedral Amorphous Carbon Synthesized by Compressing Glassy Carbon at Room Temperature". J. Phys. Chem. C. 124 (9): 5489–5494. doi:10.1021/acs.jpcc.0c00247. S2CID 214245976.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ Kržan, B.; et al. (2009). "Tribological behavior of tungsten-doped DLC coating under oil lubrication". Tribology International. 42 (2): 229–235. doi:10.1016/j.triboint.2008.06.011.
  5. ^ Evtukh, A.A.; et al. (2001). "Silicon doped diamond-like carbon films as a coating for improvement of electron field emission". IVMC 2001. Proceedings of the 14th International Vacuum Microelectronics Conference (Cat. No.01TH8586). p. 295. doi:10.1109/IVMC.2001.939770. ISBN 978-0-7803-7197-2. S2CID 135559981.