Arsenic Adsorption on Copper–Palladium Alloy Films

The adsorption of arsine by copper–palladium alloys was studied using a high-throughput composition spread alloy film (CSAF) sample library. A CuxPd1–x CSAF coupon that spanned the complete alloy composition space (x = 0–1) was prepared by an evaporative deposition technique. The coupon was exposed to AsH3 in a N2 background at 288 °C in a small flow reactor. Arsenic uptake was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy (SEM-EDX), and micro X-ray diffraction (μ-XRD). Pd- and Cu-rich alloy compositions exhibited large surface concentrations of As after exposure to AsH3. In the Cu-rich alloy, composition and structure measurements suggest the formation of a Cu3As phase. Arsenic uptake at Pd-rich alloy compositions is consistent with Pd2As or Pd8As3 phases; structural results suggest Pd2As with a hexagonal structure. In contrast, over a wide range of intermediate compositions (xCu ≈ 0.20–0.75), little As uptake was observed. These results contribute to a basis for rat...