Influence of oxide and alloy formation on the Electrochemistry of Ti deposition from the NaCl-KCl-NaF-K-2 TiF6 melt reduced by metallic Ti

The redox reactions in KCl-NaCl-NaF-K2TiF6 melts reduced by titanium metal have been studied by cyclic voltammetry and chronopotentiommetry. At platinum and nickel electrodes waves due to alloy formation were seen preceding the Ti(III) --> Ti metal deposition wave. The presence of oxide species could be detected as waves on voltammograms performed with platinum electrodes.

Deposits on nickel plates in general consisted of multiphase Ni-Ti layers. By varying the deposition potential outer layers with compositions ranging from pure titanium over NiTi to nickel-rich alloys such as Ni3Ti could be obtained. Pulse plating produced the best titanium coating. With constant potential electrolyses it was also possible to deposit titanium diboride coatings of high quality from the mixed chloride-fluoride melts. (C) 2004 The Electrochemical Society.