| AVS 64th International Symposium & Exhibition | |
| Thin Films Division | Thursday Sessions |
| Session TF-ThP |
| Session: | Thin Films Poster Session |
| Presenter: | Yuri Chipatecua, CINVESTAV-Unidad Queretaro, Mexico |
| Authors: | Y. Chipatecua, CINVESTAV-Unidad Queretaro, Mexico O. Tengstrand, Linköping University, Sweden J.J. Olaya-Florez, Universidad Nacional de Colombia G. Greczynski, Linköping University, Sweden I. Petrov, University of Illinois at Urbana-Champaign J.E. Greene, University of Illinois at Urbana-Champaign A. Herrera-Gomez, CINVESTAV-Unidad Queretaro, Mexico |
| Correspondent: | Click to Email |
Transition metal nitrides (TMN) are valuable coatings because they provide desirable properties of practical use. Their physical and chemical properties are also interesting from the fundamental perspective . Through the combination of sputtering power modes (HIPIMS and DCMS), it is possible to control, at least partially, harmful structures such as porosity, defects among grains, vacancies and dislocations.
We employed a hybrid high-power pulsed and dc magnetron co-sputtering with synchronized substrate bias to grow TMN films. Ti and Al were deposited in DCMS and Ta in HIPIMS mode. The bias was applied in synchronous with the Ta-ion portion of each HIPIMS pulse to minimize Ar+ bombardment. TiN coatings were deposited in the modes of direct current (TiN_DC) and direct current pulsed (TiN_P) with a constant substrate bias. TiTaN, TiTaAlN, TiN_DC and TiN_P coatings were grown onto stainless steel AISI 304 with thickness ~ 300 nm. Corrosion studies were carried out in a NaCl solution at room temperature by electrochemical impedance spectroscopy and potentiodynamic polarization. By Tafel extrapolarization from the potentiodynamic curves, corrosion current density values (Icorr) were three orders of magnitude lower than substrate AISI 304. While TiN (DC and P) coatings showed degradation or products of corrosion accumulation, TiTaN and TiTaAlN coatings proved to be efficient as corrosion protection barrier. Their integrity was not affected (there was no evidence of microcracks, delamination or failure). This is probably associated to a more intense ion bombardment due to higher applied potential in the range of 4 to 6 kW. These coatings showed lower oxygen content than TiN_DC and TiN_P. The chemical composition of all coatings was evaluated by XPS sputter resulting in Ti0.82Ta0.35N and Ti0.30Ta0.12Al0.78N, respectively, both with a small amount of oxygen contamination (4%). In the case of titanium nitride, the composition was Ti1.09N O0.53 for DC mode and TiN O0.24 for DC pulsed mode. The background associated to the Ti 2p spectra show an interesting behavior with composition. In this paper we will also discuss the relationship between corrosion and sputtering power mode.