Hydroxide precursors to perovskite oxides of the formula, LnMO 3 (Ln = La, Pr, Nd; M = Al, Mn, Fe) and LaMO 3 (M = Co and Ni) were synthesized by electrogeneration of base by cathodic reduction of the appropriate mixed-metal nitrate solution. The precursors were heat treated at different temperatures to obtain the perovskite oxides. The bath composition for various systems was optimized to get a single-phase oxide product. This method can be adapted as a simple route to the synthesis of perovskite oxide coatings on conducting substrates.

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Calcite CaCO 3 has been electrocrystallized on stainless steel substrates by the galvanostatic cathodic reduction of aqueous calcium bicarbonate solutions. The deposition is controlled by pH changes occurring close to the cathode due to electrogeneration of base. The deposit morphology varies from facetted rhombs observed at low (1±20 mA cm À2) current densities to corner-rounded particles observed at high (40 mA cm À2) current densities.

While cathodic deposits of BaCO 3 obtained from a dilute barium bicarbonate bath are unoriented, those obtained from EDTA-stabilized baths have a (200) orientation with respect to the substrate; thick coatings obtained at longer deposition times have a stronger orientation compared to thin coatings. The orienting influence is shown to be due to the combined effect of EDTA and the use of electrochemistry.