Comparison of the corrosion of Cu50Pd50 and Cu50Pd44M6 (M = Y, Mg, or Al) hydrogen separation membrane alloys in simulated syngas containing H2S

• The corrosion resistance of CuPdY, CuPdMg, and CuPdAl was compared to CuPd binary alloy.
• The alloys were exposed to simulated syngas containing varying amounts of H2S.
• The corrosion scale was characterized using gravimetric data, XRD, and SEM/EDS.
• The Y alloy displayed severe degradation.
• The Al alloy showed the best corrosion resistance, and the Mg alloy was slightly worse.

The resistance to sulfidation was examined by exposing coupons including a Cu–Pd binary alloy and three ternary alloys with 6 at% Y, Mg, or Al to simulated syngas containing varying amounts of H2S. The mass change of the samples was determined and the exposed surfaces were characterized by SEM/EDS and XRD. The best corrosion resistance of the ternary alloys was observed in the Cu50Pd44Al6 alloy. A slight decrease was observed when Mg was added, but both the Al and Mg alloys were roughly on par with the binary composition. The Y addition resulted in a degradation in the corrosion resistance by forming extensive internal Y2O3 and Cu1−xYxS and external Pd4−xCuxS and Pd 13Cu3S7.