Electrochemical properties and dissolution of UPd3 in nitric acid solutions

Resumo

Electrochemical properties of the intermetallic compound UPd₃ in 0.5–8 M HNO₃ solutions were studied by linear voltammetry. In 0.5–2 M HNO₃ solutions, the UPd₃ surface is in the passive state. At HNO₃ concentrations exceeding 4 M, the alloy passivation was not observed. The previously unknown electrochemical characteristics of UPd₃ in nitric acid solutions were obtained using the Tafel equation. The values of Е(i = 0) and v_corr increased from 39 mV and 38 μg cm^–2 h^–1 in 0.5 M HNO₃ to 821 mV and 11 mg cm^–2 h^–1 in 8 M HNO₃, respectively. Dissolution experiments have shown that UPd₃ can dissolve in HNO₃ solutions of concentration exceeding 4 M at room temperature. In 8 M HNO₃, the dissolution rate can reach 17 mg cm^–2 h^–1 at 25°С, with the dissolution being virtually equimolar and accelerating with time.