In the present work, tribological performances of duplex coatings (Ti/TiN PVD and WC-Co HVOF) on Ti6Al4V substrates were investigated by analytical modelling and experimental assessment of mechanical/tribological properties. An analytical study of the contact stress distribution under a spherical indenter was performed, considering changes in stress distribution after adoption of the WC-Co intermediate coating as a load support layer. Experimental activities consisted of micro- and nanoindentation testing, HRC adhesion test and ball-on-disc sliding wear test (Alumina counterpart) under dry atmosphere. Morphology of the worn surface and layer failure mechanisms (i.e. wear mechanisms, coating surface and sub-surface delamination, crack propagation modes, role of interfaces) were then analysed by FlB-SEM techniques. Results showed that the use of a WC-Co interlayer with intermediate hardness and stiffness provides a more effective distribution of contact strain, with a significant increase of load carrying capacity and wear resistance of samples. A correlation between results of simulations, H/E and H(3)/E(2) ratios and wear resistance of coatings is finally proposed. (C) 2008 Elsevier B.V. All rights reserved.
Bemporad, E., Sebastiani, M., Staia, M.h., Cabrera, E.p. (2008). Tribological studies on PVD/HVOF duplex coatings on Ti6Al4V substrate. SURFACE & COATINGS TECHNOLOGY, 203(5-7), 566-571 [10.1016/j.surfcoat.2008.06.055].
Tribological studies on PVD/HVOF duplex coatings on Ti6Al4V substrate
BEMPORAD, Edoardo;SEBASTIANI, MARCO;
2008-01-01
Abstract
In the present work, tribological performances of duplex coatings (Ti/TiN PVD and WC-Co HVOF) on Ti6Al4V substrates were investigated by analytical modelling and experimental assessment of mechanical/tribological properties. An analytical study of the contact stress distribution under a spherical indenter was performed, considering changes in stress distribution after adoption of the WC-Co intermediate coating as a load support layer. Experimental activities consisted of micro- and nanoindentation testing, HRC adhesion test and ball-on-disc sliding wear test (Alumina counterpart) under dry atmosphere. Morphology of the worn surface and layer failure mechanisms (i.e. wear mechanisms, coating surface and sub-surface delamination, crack propagation modes, role of interfaces) were then analysed by FlB-SEM techniques. Results showed that the use of a WC-Co interlayer with intermediate hardness and stiffness provides a more effective distribution of contact strain, with a significant increase of load carrying capacity and wear resistance of samples. A correlation between results of simulations, H/E and H(3)/E(2) ratios and wear resistance of coatings is finally proposed. (C) 2008 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
