Corrosion Behavior of Ni-P/Cu Catalyst in Optimization of Electroplating Process Inside the NaBH4 Seawater Fuel Cell

Lamellar structure Ni-P catalysts were prepared on copper by the electrochemical deposition method for the hydrolysis of NaBH4 solution. Voltage, time and temperature are key variables in the electroplating process, affecting the corrosion performance of the catalyst. The results show that as the deposition voltage (4–7 V) increases, the corrosion resistance of Ni-P at first is enhanced and then decreases, peaking at 5 V due to a more complete structure. Electroplating time and temperature affect the deposition of the nickel-phosphorus catalyst and then the corrosion resistance of the catalyst. Prolonged time and elevated temperature cause holes and cracks, degrading corrosion resistance. Therefore, a mild electroplating environment is preferred. The optimal electroplating temperature and time are 30 °C and 3 min, respectively. The polarization curve test shows that the Ni-P catalyst is greatly influenced by seawater temperature and chloride ion concentration in the actual service process, that the chloride ion is the dominant factor, and that the corrosion rate increases exponentially. Moreover, Ni-P/Cu catalysts mainly undergo localized corrosion and dissolution. Combined with Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS) analyses, the corrosion mechanism in seawater was systematically discussed.