abstract
A mechanical sealing tribosystem based on multilayer microcrystalline/nanocrystalline diamond (MCD/NCD) coatings is proposed. The tribological behaviour was investigated in ring-on-ring self-mated planar contact configuration. Tests were carried out under biodiesel lubrication and pressurized water (2 bar) sealing conditions. A 3D optical confocal profilometer was used to obtain for the first time the wear coefficients of seal rings, revealing a value of k=6.3 x 10(-10) mm(3)/N.m for biodiesel lubrication that is two orders of magnitude lower than for reciprocating sliding ball-on-flat experiments. The advantage of the multilayer strategy was demonstrated in the sealing of pressurized water, where full sealing conditions were achieved within the P x V range of 0.75-5.5 MPa ms(-1). For these coatings, full delamination is prevented due to structural discontinuity at the MCD/NCD interfaces whereas for a MCD monolayer coating, premature failure takes place and sealing is not reached. (C) 2017 Elsevier B.V. All rights reserved.
keywords
DRY LINE CONTACT; NANOCRYSTALLINE DIAMOND; TRIBOLOGICAL BEHAVIOR; FACE MATERIALS; THIN-FILMS; PERFORMANCE; COATINGS; GROWTH; CARBON; TOOLS
subject category
Engineering; Materials Science
authors
Shabani, M; Carrapichano, JM; Oliveira, FJ; Silva, RF
our authors
Filipe José Alves de Oliveira
Principal Researcher
Mehdi Shabani
Post-Doc Fellowship
Rui Ramos Ferreira e Silva
Associate Professoracknowledgements
This work was developed within the scope of project POCI-01-0247-FEDER-006318 co-financed by FEDER through the POCI program and project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UlD/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement.