Electrodeposition of actinides: Optimization of deposition parameters by chronoamperometric studies

To quantify alpha-emitting radionuclides by alpha spectrometry, it is necessary to prepare a thin and uniform alpha source on a suitable substrate. Electrodeposition is the most used electrochemical technique for this purpose. In order to better understand the electrochemical process carried out in the electrodeposition of actinides, in particular the selection of the current densities applied, a chronoamperometric study of the electrodeposition of actinides (Th, U, Pu, Am and Cm), in three different electrolytes (Na 2 SO 4 /H 2 SO 4 , NH 4 NO 3 , NaF) using stainless steel and platinum as cathode and anode, respectively, is presented. The corresponding polarization curves (potential vs. current density), characteristic for each electrolyte and actinide used, were constructed from the chronoamperometric data. The limiting diffusion current as well as the minimum current necessary for the electrodeposition process to take place were determined. To achieve a quantitative electrodeposition of actinides, a balance between OH − production and the thickness of the OH − layer formed near the cathode must be reached. These parameters are controlled by the electrolyte used and the current density applied to the electrochemical system. Actinides were electrodeposited mainly in the form of oxides, according to Raman spectroscopy results. • Chronoamperometry is a valuable tool for determining the best conditions for electrodeposition of actinides. • The polarization curves obtained from chronoamperometric tests allow the determination of the actinide deposition current. • Limiting current produces the maximum current density with the lowest energy consumption. • The limiting current achieved is independent of the electrolyte concentration. • The electrochemical deposition of actinides depends mainly on the electrolyte and not on the actinides.