STUDY ON ANODIC OXIDE FILMS IN Nb-Ta ALLOYS BY IN SITU OPTOELECTROCEMICAL MEASUREMENTS

摘要

It is well known that thin films of niobium and tantalum pentoxides and its mixed oxides, (Nb,Ta)_(2)O_(5), can be grown anodically on the surface of these metals and alloys, by placing samples in an electrochemical cell containing on aqueous solution and two or three electrodes under a suitable anodic voltage. These films exhibit varies colors depending on the thickness. Several techniques have been used to characterize the properties of the films. In this work, we present the results of a simplified experimental apparatus to follow by in situ optoelectrochemical measurements the potential versus time versus reflectance while the oxide films are growing by galvanostatic anodizing. The results are used to determine the refraction index and thickness of the films. The values are in agreement to theoretical and experimental results published elsewhere.