GALVANOSTATIC ELECTRODEPOSITION AND MICROSTRUCTURE OF COPPER(I) OXIDEFILM

Polycrystalline copper (I) oxide films were deposited on stainless ste el substrate by galvanostatic electrodeposition method and were charac terized by Xray diffraction and scanning electron microscopy. The effe ct of bath temperature, bath pH and current density on the compositon, grain size, surface texture and surface morphology of the electrodepo sited films were investigated. The films deposited at low bath pH (les s than or equal to 7) consisted of copper (I) oxide and metallic coppe r; while the films deposited at bath pH between 8 and 12 and bath temp erature of 60 degrees C were pure copper (I) oxide. The preferred orie ntation of the copper (I) oxide films depended on the relative growth rate of (111) and (200) faces and could be controlled by adjusting the bath pH and/or the cathodic current density. (100)-oriented copper (1 ) oxide films could be deposited at pH=9 and current densities in the range of 0.25-1 mA/cm(2) while (111)-oriented films could be prepared at pH=12 or at pH=9 using the current densities between 1.5-2.5 mA/cm( 2). Computer simulated crystallite shapes showed that the crystal shap e changed from octahedral for (100)-oriented film to trucated pyramids and cubs for (111)-oriented film. And they were approved by scanning electron microscopy.