Evaluation of corrosion behavior of an amorphous Ni₆₀Nb₄₀–alloy with its crystalline form in stimulated PEMFC conditions

Abstract

Ni₆₀Nb₄₀ amorphous ribbon was prepared by melt spinning method and its corrosion property compared with its crystalline counter part i.e., Ni₆₀Nb₄₀ crystalline plate were prepared by copper mold suction casting technique. The amorphicity of these alloys were characterized by XRD technique. The corrosion properties of these alloys were also tested by electrochemical potentiodynamic polarization technique as well as chemical immersion test in 1 M H₂SO₄ (80 °C) with air and H₂ bubbling to simulate cathodic and anodic conditions of Polymer Exchange Membrane Fuel Cell (PEMFC), respectively. The corrosion resistance property of amorphous alloy was found to be more than one order higher than that of its counterpart. The stability and occurrence of pitting during corrosion were monitored by cyclic polarization technique. The changes in surface morphologies of alloys before and after corrosion were characterized by EPMA. The change in cationic concentrations and passive layer thickness on the surfaces during corrosion were measured by using XPS technique.

Graphical Abstract

Potentiodynamic polarization curves of amorphous and crystalline Ni₆₀−Nb₄₀ − alloys recorded in 1M H₂SO₄ + 2ppm F^- in air bubbled conditions.

Keywords:

• Ni60Nb40 amorphous and crystalline alloy
• corrosion
• potentiodynamic polarization
• passive layer
• PEFMC conditions

Additional information

Funding

Dr. A. Daniel ArulRaj acknowledges support from the Science and Engineering Research Board (SERB)-National Post-Doctoral Fellowship (N-PDF) Program, New Delhi, India under Grant Number PDF/2016/001209.