TY - JOUR
T1 - Phase composition and tribomechanical properties of Ti-B-C nanocomposite coatings prepared by magnetron sputtering
AU - Sánchez-López, J. C.
AU - Abad, M. D.
AU - Justo, A.
AU - Gago, R.
AU - Endrino, J. L.
AU - García-Luis, A.
AU - Brizuela, M.
PY - 2012/9/19
Y1 - 2012/9/19
N2 - Protective nanocomposite coatings based on hard ceramic phases (TiC, TiB 2) combined with amorphous carbon (a-C) are of interest because of their adequate balance between mechanical and tribological performances. In this work, TiBC nanocomposite coatings were prepared by co-sputtering of graphite and TiB 2 targets. Varying the discharge power ratio applied to the graphite and TiB 2 targets from 0 to 2, the a-C content in the coatings could be tuned from 0 to 60%, as observed by means of Raman and x-ray photoelectron spectroscopy (XPS). The microstructural characterization demonstrated a progressive decrease in crystallinity from an initial nanocrystalline (nc) TiB 2-like structure to a distorted TiB xC y ternary compound with increasing C concentration. X-ray absorption near-edge structure measurements on the B K-edge helped to determine a hexagonal arrangement around the B atoms in the ternary TiB xC y phase. A fitting analysis of the C 1s XPS peak allowed us to evaluate the relative amount of a-C and TiB xC y components. A drastic change in hardness (from 52 to 13GPa) and friction coefficient values (from 0.8 to 0.2) is noticed when moving from nc-TiB 2 to TiBC/a-C nanocomposites. The fraction of a-C necessary to decrease the friction below 0.2 was found to be 45%. Raman observation of the wear tracks determined the presence of disordered sp 2-bonded carbon phase associated with the diminution of the friction level.
AB - Protective nanocomposite coatings based on hard ceramic phases (TiC, TiB 2) combined with amorphous carbon (a-C) are of interest because of their adequate balance between mechanical and tribological performances. In this work, TiBC nanocomposite coatings were prepared by co-sputtering of graphite and TiB 2 targets. Varying the discharge power ratio applied to the graphite and TiB 2 targets from 0 to 2, the a-C content in the coatings could be tuned from 0 to 60%, as observed by means of Raman and x-ray photoelectron spectroscopy (XPS). The microstructural characterization demonstrated a progressive decrease in crystallinity from an initial nanocrystalline (nc) TiB 2-like structure to a distorted TiB xC y ternary compound with increasing C concentration. X-ray absorption near-edge structure measurements on the B K-edge helped to determine a hexagonal arrangement around the B atoms in the ternary TiB xC y phase. A fitting analysis of the C 1s XPS peak allowed us to evaluate the relative amount of a-C and TiB xC y components. A drastic change in hardness (from 52 to 13GPa) and friction coefficient values (from 0.8 to 0.2) is noticed when moving from nc-TiB 2 to TiBC/a-C nanocomposites. The fraction of a-C necessary to decrease the friction below 0.2 was found to be 45%. Raman observation of the wear tracks determined the presence of disordered sp 2-bonded carbon phase associated with the diminution of the friction level.
UR - http://www.scopus.com/inward/record.url?scp=84865959265&partnerID=8YFLogxK
U2 - 10.1088/0022-3727/45/37/375401
DO - 10.1088/0022-3727/45/37/375401
M3 - Article
AN - SCOPUS:84865959265
SN - 0022-3727
VL - 45
JO - Journal of Physics D: Applied Physics
JF - Journal of Physics D: Applied Physics
IS - 37
M1 - 375401
ER -