Temperature Dependence of the Kinetics of Electrochemical Vapor Deposition of CeO₂

Dense films of CeO₂ were deposited on dense Y₂O₃_-doped CeO₂ substrates by electrochemical vapor deposition (EVD) using CeCl₃ as the source of cerium over a range of temperatures between 1050 and 1200°C. A substrate of a variable thickness was used to determine rate constants for the substrate and the film. The kinetics of film deposition were analyzed by considering transport processes through both the substrate and the film. An analysis which takes into account spatially dependent transport processes is presented. The analysis reduces to the equivalent circuit approach provided transport properties are uniform in each region. Numerical calculations of the kinetics of film growth were conducted using conductivities that are dependent on the partial pressure of oxygen. A simple analysis based on the assumption of constant conductivities in a given region is satisfactory. The implication is that an average of transport properties is reflected in the measured rate constants. The temperature dependence of rate constants for the substrate and the film were determined as; K_s~ 0.1195 X exp [-35,030/T] and K_f ~ 0.7387 X exp [-41,030/T] m₂/s, respectively.