Wüest M. 51 Wykes M. 82 Yamaguchi M. 17 Ybarra G. 129 Yubero F ...

JUNE 26 MONDAY AFTERNOON
ETCHC-MoA-OR.10 MODIFICATIONS OF TRIBOLOGICAL BEHAVIOUR OF
STAINLESS STEELS BY DUPLEX TREATMENTS. R. J. Rodriguez, J.A. Garcia, R.
martinez, G. G. Fuentes. AIN. Centro de Ingeniería Avanzada de Superficies. 31191 Cordovilla,
Pamplona, Spain
Ordinary PVD coatings exhibites adequate properties from the point of view of hardness, friction or
wear coefficient to provide a solution good enough for many of the problems. However, they are 2 –
5 μm thick, a limit that can not be surpassed due to internal stresses that lead to crack formation and
delamination. In addition, soft substrates like stainless steels are not adequate to be coated by a hard
material (hardness beyond 15 GPa), because the plastic flow of the substrate induces the fracture of
the hard coating even at medium contact pressures.
DUPLEX treatments (ion nitriding + PVD coatings) have been proposed as a solution for the
treatment of metal alloys like, stainless steels, titanium alloys or, even, aluminium alloys, as well as
tool steels. Most of PVD industrial systems could be adapted to provide an ion nitriding treatment
prior to the PVD deposition process. Both treatments can be applied in the same chamber, without
breaking the high vacuum conditions to prevent contamination.
This papers reports the results obtained on on AISI 304 and 316 stainless steels by a DUPLEX
treatments: Ion nitriding + PVD coating. An adapted arc-evaporation PVD coater has been employed
to produce nitrided layers of 10 – 20 μm with different process parameters, by employing an original
nitriding process based on the AEGD configuration. The same equipment has been used to
subsequently deposit the PVD coatings.
GD-OES analysis and FE-SEM inspection have allowed to characterise the main features of
DUPLEX treatments in comparison with ordinary coatings. Changes in roughness, micro-hardness,
adhesion, friction and wear coeficcients have been measured. As an overall conclusion, both
DUPLEX treatments have shown improved properties and better behaviour.
KEYWORDS PVD, nitriding, duplex treatment, tribology.
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