III International Conference

PP-III-16THE TUNGSTEN TRIOXIDE LAYERS ON ALUMINIUM AND TITANIUMLukiyanchuk I.V., Rudnev V.S.Institute of Chemistry, Far Eastern Branch of RAS, Vladivostok, RussiaE-mail: lukiyanchuk@ich.dvo.ru, rudnevvs@ich.dvo.ruThe compositions of valve metal/oxide film, containing WO 3 , MoO 3 , Nb 2 O 5 , V 2 O 5 , are ofinterest of the catalysis. The data on the formation of surface structures with WO 3 onaluminium and titanium by plasma electrolytic oxidation technique (PEO – theelectrochemical oxidation by reactions caused by electric discharges) have been reported.The compositions metal/film have been formed in aqueous solutions containing tungstateisopoly and heteropolyoxoanions (IPAs and HPAs) .Aqueous solutions of K 8 [BW 11 O 39 H], Na 2 H[PW 12 O 40 ], H 4 [SiW 12 O 40 ],(NH 4 ) 10 [H 2 W 12 O 42 ] with concentration of W(VI) 0.1 mol·l -1 have been used, table 1. Oxidestructures have been formed during 10 min in solutions of room temperature.Table 1. The effect of nature of tungstate HPAs on the phase composition of PEO-layers,formed on aluminium and titanium in isopoly and heteropoly electrolytes.The electrolytecompositionpHThe phase compositionof PEO-layersOn AlOn TiK 8 [BW 11 O 39 H] 6.9 WO 3 WO 3Na 2 H[PW 12 O 40 ] 2.0 WO 2.9 (islets) WO 2.9 (islets)H 4 [SiW 12 O 40 ] + K 2 CO 3 5.7 H 0.23 WO 3 H 0.23 WO 3(NH 4 ) 10 [H 2 W 12 O 42 ] 6.5 WO 3 No dataBoth surface structures composition and morphology depend on the pH value (Fig. 1).When IPAs and HPAs are stable (pH