Optical Absorption in the Visible Range of Cu0.8−xZn0.2Pdx Alloys with 0 ≦ x ≦ 0.2 at Room Temperature1)

The optical absorptivity A of Cu0.8−xZn0.2Pdx alloys (0 ± x ± 0.2) was measured as a function of the wavelength between 250 nm < λ < 800 nm at room temperature in a vacuum system with < 10−6 Torr. A has a peak (or shoulder) close to 380 nm for x = 0.1. The alloy with x = 0.2 has a minimum at this wavelength. It is proposed that palladium impurities are responsible for virtual energy states which lead to an increase in A below 300 nm and above 500 nm. Additionally palladium in higher concentrations absorbs part of the extra electrons of zinc in the copper‐zinc matrix. This leads to the minimum of A in the alloy with 20 at% palladium.