Anodic Oxide Films on Niobium and Tantalum in Different Aqueous Electrolytes and Their Impedance Characteristics |
| N. Vermaa, K.C. Singh a, B. Marí b, M. Mollar b and J. Jindal a
aDepartment of Chemistry, Maharshi Dayanand University, Rohtak 124001, Haryana, India bInstitut de Disseny per la Fabricació Automatitzada, Departament de Física Aplicada, Universitat Politècnica de València, Camí de Vera s/n, 46022 València, Spain |
| Received: November 22, 2014; Revised version: January 12, 2016; In final form: January 20, 2016 |
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| The anodic oxide films were prepared on the niobium and tantalum in aqueous electrolyte mixtures containing 1 M CH3COOH + 1 M H3PO4 or 1 M CH3COOH + 1 vol.% HF or 1 M CH3COOH + 1 M H3PO4 + 1 vol.% HF at 30 V for 30 min. The barrier films were obtained on both niobium and tantalum surfaces in all electrolyte mixtures except niobium oxide film formed in 1 M CH3COOH + 1 vol.% HF which is porous in nature. The anodic oxide films were characterized by FESEM. Also, electrochemical impedance spectroscopy at open-circuit potential on Nb and Ta was applied and obtained data were analyzed by fitting with four different equivalent circuits. |
DOI: 10.12693/APhysPolA.129.297 PACS numbers: 68.37.Hk, 68.55.J-, 68.60.Bs |