ИСТИНА

Electrodeposted palladium attracts a lot of interest due its unique catalytic and hydrogen-sorption properties. Previously it was demonstrated that electrodeposit properties can be substantionally altered via electrodeposition potential or introduction of different organic molecules into the electrodeposition solution [1,2]. It is often stated that due polycrystallinity and relatively high thickness such deposits properties are more or less independent of substrate narure and structure. However there is evidence that substrate nature can drastically affect, for example, hydrogen-sorption properties [3]. Mostly for electrocrystallization studies of precious metals Au or Pt foils or wires are used as substrates. They are used as reusable substrates after acid etching. It is possible that residual stress of such substrate affect electrodeposit properties. The purpose of this work was to develop laboratory protocol for nonreusable substrate preparation and to compare palladium electrodeposits on these 'stress-free' substrates with conventional ones. Nonreusable one-sided substrates was prepared by means of electrochemical deposition of successive layers of copper (copper sulfate acid electrolyte) and gold (cyanide electrolyte) on top of graphite disk with 0.5 cm2 surface area. All non-working surfaces were covered with non-conducting lacquer. As comparative substrates square-shaped gold foils with the same area was used. Palladizing of all electrodes was carried out in potentiostatic mode. The samples microstructure was investigated using scanning probe microscopy and X-Ray diffraction. With X-Ray diffraction data by means of Whole Powder Pattern Modelling approach it was determined that deposition potential can be correlated with dislocations densities and stacking faults concentration. It was supposed that substrate residual stress is responsible for residual stress generation in electrodeposit. [1] Yu.E. Roginskaya, E.N. Lubnin, T.Ya. Safonova, A.L. Chuvilin, E.D. Politova, G.A. Tsirlina, Russ. J. Electrochem 39, 283 (2003). [2] G.A. Tsirlina, O.A. Petrii, T.Ya. Safonova, I.M. Papisov, S.Yu. Vassiliev, A.E. Gabrielov, Electrochim. Acta 47, 3749 (2002). [3] Y. Pivak, R. Gremaud, K. Gross, M. Gonzales-Silveira, A. Walton, D. Book, H. Schreuders, B. Dam, R. Griessen, Scripta Mater. 60, 348 (2009)