Application aspects of joint anaphoresis/substrate anodization in production of biocompatible ceramic coatings

Abstract

Electrophoretic deposition (EPD) can occur as a cataphoretic deposition - the coating is deposited on the cathode, and anaphoretic deposition - the coating is deposited on the anode. The primary purpose of EPD is to obtain compact and uniform organic/inorganic coatings of the desired thickness and adhesion on metal surfaces by applying an electric field to the particles of coating precursor. EPD basic principles for coatings deposition concerning fundamental explanations and considerations of practical parameters of the process are presented. Cataphoretic deposition has become popular because it can apply organic coatings to complex structures that are otherwise very difficult to coat. These coatings were found to improve the characteristics of the substrate, such as biocompatibility, appearance and the resistance to the corrosion processes. The key EPD parameters are composition, pH value and viscosity of deposition medium, as well as zeta potential of the particles, electric field strength, etc. A special survey is given to the process of anaphoretic deposition, which is relatively new, and its advantages over cataphoretic deposition are discussed. Through the process of joint anaphoresis/substrate anodization process, the surface of the substrate is simultaneously anodized and modified by incorporation of the foreign particles into the anodic layer. Resulting coatings of mixed composition of better adhesion and corrosion resistance with respect to cataphoretically-deposited coatings are obtained.