Simulation of electrocodeposition

Electrocodeposition is the process of depositing a thin metallic layer onto a surface in which small particles of ceramics and organic materials are occluded during electroplating to produce a composite film. These composite coatings have been used for wear and abrasion resistant surfaces and high hardness.; The goal of this study was to provide a fundamental understanding of the physical mechanism of the particle incorporation process: to simulate a particle being incorporated into a growing metallic film. The shape evolution of the metal film around the particle was investigated to understand particle entrapment by the growing metal film. The metal surface can become irregular by the nonuniform surface current distribution. The numerical solution used the level set method to track the moving interface as it grew around the particle, and the governing equations were solved by a finite element method. This study showed a mechanism for void generation depending upon the current distributions induced by the presence of a non-conducting particle.; In order to simulate the morphological behavior of a metallic film, the current distribution along the metal surface was computed. For a primary current distribution (ohmic controlled electrodeposition), where only electric field effects are considered, the local current density distribution along the surface were affected by the presence of an insulating particle, and the influence was maximized when the particle contacted the electrode. The metallic film does not grow along the non-conducting particle surface. For a secondary current distribution (kinetically-controlled electrodeposition), the current density even at the contact point is a non-zero value. This produces a more uniformly deposited film compared to that for a primary current density distribution. As the exchange current density increases, the resistance increment decreases and converges to a fixed value of that for a primary current density distribution. However, as the value of the exchange current density becomes smaller, the kinetic effects of the electrode reaction become important. From simulation results, it was verified that the primary current density distribution is the limiting case for the secondary current density distribution with a high exchange current density. For a tertiary current distribution, where concentration gradients, kinetics and electric field effects are considered, one single polarization parameter was derived to include the effects of the exchange current density and the applied potential. (Abstract shortened by UMI.)...