Recently, we have reported on low friction CrN/TiN coatings deposited using a hybrid sputtering technique. These multilayers exhibit friction coefficients μ below 0.1 when tested in atmosphere with a relative humidity ≈25, but μ ranges between 0.6-0.8 upon decreasing the humidity below 5%. Here we use first principle calculations to study O and H adatom energetics on TiN and CrN (001) surfaces. The diffusional barrier of H on TiN(001) is about half of the value on CrN(001) surface, while both elements are stronger bonded on CrN. Based on these results we propose a mechanism for a water-based self-assembled nanobearing.
@article{arxiv.1202.3234,
title = {First principles study of water-based self-assembled nanobearing effect in CrN/TiN multilayer coatings},
author = {David Holec and Jörg Paulitsch and Paul H. Mayrhofer},
journal= {arXiv preprint arXiv:1202.3234},
year = {2012}
}