Electrodeposition of iridium-ruthenium alloys from chloride melts: the structure of the deposits

The structure and composition of deposited Ir-Ru alloys is studied as a function of the electrolysis conditions. It is found that the maximum temperature at which continuous layers of Ir-Ru deposits can be obtained increases relative to pure components. The continuous layers form as solid solutions throughout the entire range of compositions (from 0 to 100% of either component), An anomalous predominant deposition of the more negative component (ruthenium) into the alloy is discovered. Several types of the alloy structure are found: columnar, spherulitic, layered, and spiral. Conditions leading to the deposition of layered structures are analyzed.