MECHANISM OF THE FORMATION AND DISCHARGE OF ELECTROCHEMICALLY ACTIVE SPECIES DURING THE ELECTROCHEMICAL SYNTHESIS OF TITANIUM DIBORIDE IN ACHLORIDE-FLUORIDE MELT

The mechanism governing the formation and discharge of electrochemical ly active species during the electroreduction of titanium and boron an d during the electrochemical synthesis of titanium diboride in chlorid e and chloride-fluoride melts is studied using linear and cyclic volta mmetry and potentiostatic electrolysis. Titanium trichloride and potas sium (sodium) fluoborate are used as the titanium rind boron sources. The electrochemical reduction of the titanium and boron ions is preced ed by the reaction in which electrochemically active chloride-fluoride complexes of titanium and boron are formed. The synthesis of titanium diboride is preceded by the formation of heteronuclear complexes of t he type [B2TiFxCl12-x](3-). At high potential variation rates, the lim iting role is played by the formation of joint titanium and boron comp lexes. With the fluoride ions in excess, the principal form, in which heteronuclear titanium and boron complexes exist, is [B2TiF12](3-). Du ring the electroreduction of an electrochemically active species, the charge transfer stage occurs reversibly, with a single stage involving transfer of nine electrons.