Electrochemical deposition of hydroxyapatite and its biomedical applications

Electrochemical deposition has been widely used for the preparation of thin films (TFs) and coatings [1]. It has been developed as an effective method of metal coating for the processing of electronic components, but electrochemical deposition of ceramic coatings onto metals has also been carried out for various applications, including the improvement of corrosion resistance of the metal or the creation of a more refractory surface for a high-temperature service. Although electrochemical deposition can be performed by cathodic or anodic methods, anodic deposition has limited utility in terms of the materials that can be deposited by this method and the types of substrates that can be used for deposition. Cathodic deposition, however, has important advantages for industrial applications. Two processes are commonly used to prepare ceramic coatings by cathodic electrochemical deposition: the electrophoretic process using suspensions of ceramic particles and the electrolytic process using solutions of metal salts, as shown in Figure 2.1 [2]. The electrophoretic deposition (EPD) process is often used for thick ceramic films, whereas the electrolytic deposition (ELD) process is often used for the formation of nanostructured thin ceramic films.