Short-Term Strong Cathodic Polarization of Ni/YSZ and Pt/YSZ
| Autor: | Torben Jacobsen, Vignesh Balasubramanian, Karin Vels Hansen, Kosova Kreka |
|---|---|
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Hansen, K V, Kreka, K, Balasubramanian, V & Jacobsen, T 2021, ' Short-term strong cathodic polarization of Ni/YSZ and Pt/YSZ ', Journal of the Electrochemical Society, vol. 168, no. 4, 044528 . https://doi.org/10.1149/1945-7111/abf87e |
| ISSN: | 1945-7111 0013-4651 |
| DOI: | 10.1149/1945-7111/abf87e |
| Popis: | The initial stages of YSZ reduction and formation of intermetallic phases at Ni∣YSZ interfaces on strongly cathodically polarized electrodes were studied by a number of potential sweep and impedance techniques. The measurements were carried out in the potential range −1.0 V to −3.0 V vs E°(O2) in H2/H2O at 650 and 750 °C. Below −1.7 V the cathodic current increases almost exponentially, mainly due to electronic conductivity in the YSZ. Reduction and oxidation peaks develop below and above −1.9 V, respectively. The peaks reveal a simultaneous reduction of YSZ at the Ni∣YSZ interface and reoxidation of a Ni-Zr phase. Charges calculated from the reoxidation peaks indicate a thickness of 200 nm for the layer formed by conditioning the electrode for 300 s at −2.6 V vs E°(O2). Impedance measurements show a suppressed arc decreasing with increasing polarization. Below −2.3 V vs E°(O2) a capacitive high frequency arc segment and an inductive low frequency loop develop. Both are ascribed to electronic conductivity. SEM/EDS microscopy on cross sections of samples cooled with and without polarization showed the formation of uniform and homogeneous intermetallic reaction layers which after reoxidation resulted in a two-phased nanostructures. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|