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.