Electrochemical Evaluation of Protective Coatings with Ti Additions on Mild Steel Substrate with Potential Application for PEM Fuel Cells

• Published in: Materials Vol. 15; no. 15; p. 5364
• Main Authors: Avram, Diana N., Davidescu, Corneliu M., Dan, Mircea L., Mirza-Rosca, Julia C., Hulka, Iosif, Pascu, Alexandru, Stanciu, Elena M.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 04.08.2022; MDPI
• Subjects: Alloys; Calomel electrode; Coating effects; Corrosion; Corrosion resistance; Electrochemical analysis; Electrochemical impedance spectroscopy; Electrode polarization; Electrodes; Electrolytes; Electrolytic cells; Emissions; Energy; Engines; Environmental impact; Finite element method; Fluorides; Fuel cells; Gases; Laser beam cladding; laser cladding; Lasers; Low carbon steels; Manufacturing; Molybdenum; Open circuit voltage; Optical microscopy; Particle size; PEMFC; Permeability; Plates; Protective coatings; Proton exchange membrane fuel cells; Raw materials; Room temperature; Scanning electron microscopy; Spectrum analysis; Substrates; Sulfuric acid; Ti addition; Titanium; United States > US; Germany
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15155364

In this work, the corrosion behavior of NiCr(Ti) protective coatings deposited on mild steel substrates through laser cladding technology is studied as an alternative new material for metallic bipolar plates used in PEMFC applications. For electrochemical testing, a solution consisting of 0.5 M H2SO4 + 2 ppm F− at room temperature is used as an electrolyte. The fluoride ions are added to simulate the conditions in the PEM fuel cell due to degradation of the proton exchange membrane and fluoride release. A saturated calomel electrode (SCE) is used as a reference electrode and a platinum mesh as the counter electrode. Scanning electron microscopy (SEM) and optical microscopy (OM) are used for studying the morphology of the protective coatings and the effect of Ti addition. The electrochemical evaluation consisted of measuring the open circuit potential (OCP), followed by electrochemical impedance spectroscopy measurements (EIS) and potentiodynamic polarization. It is found that the coatings with 5% Ti, 7% Ti and 10% Ti addition comply with the conditions of the US DOE regarding corrosion performance to be used as materials for the manufacture of the bipolar plates.