Production of Ni₆₅Cr₁₅P₁₆B₄ metallic glass-coated bipolar plate for fuel cell by high velocity oxy-fuel (HVOF) spray coating method

In this study, the newly designed bipolar plate for proton exchange membrane fuel cells (PEMFC) was produced by spray-coating the Ni ₆₅Cr₁₅P₁₆B₄ metallic glassy alloy on Al plate. The Ni₆₅Cr₁₅P₁₆B₄ metallic glass was adopted as a coating material because of its excellent corrosion resistance and the high velocity oxy-fuel (HVOF) spray coating was used for the metallic glass deposition on the Al plates having a bipolar plate flow field. The corrosion resistance of the Ni₆₅Cr₁₅P ₁₆B₄ glassy alloy film produced by the HVOF spray-coating was studied under simulated PEMFC environments. As a result, the Ni ₆₅Cr₁₅P₁₆B₄ glassy alloy film showed lower corrosion current density than the high-corrosion-resistant stainless steel SUS316L. Then, the electricity generation tests with the single cell having the Ni₆₅Cr₁₅P₁₆B₄ glassy alloy-coated bipolar plates produced in this study were conducted. As a result, the single cell with the metallic glass-coated bipolar plates showed very high I-V performance as well as the cell with the carbon bipolar plates. The long time durability tests for 24 h were also conducted at the constant current density of 200mA·cm^-2. As a result, the single cell with the glass-coated bipolar plates showed no voltage drop during the test. So, it was found in this study that the Ni₆₅Cr₁₅P₁₆B ₄ glassy alloy-coated bipolar plate produced by the HVOF spray-coating have a potential for practical use for the fuel cells.