Electrophoretic deposition (EPD) exploits the presence of an electrical charge on the surface of particles in suspension and the migration of the particles under the effect of an electric field enabling their consolidation into films onto any shaped substrate or forming bulk ceramic components. EPD has been known since the last century. Earlier applications have been in the shaping of ceramic articles and in coating technology. New areas of applications of EPD are related to the manipulation of nanomaterials and as such EPD has become an important tool in nanotechnology enabling the production of components of macroscopic shapes and dimensions from nanoscale particles, nanotubes or nanorods. In addition, EPD involves very short processing times; e.g. films and coatings can be made in minutes what adds to the attractiveness of the method for practical applications.
This special issue of Advances in Applied Ceramics includes nine invited papers which reflect the broad applicability and potential of EPD for shaping materials for a wide range of applications, such as structural components, ceramic membranes, ionic conductor layers, mesoporous structures and bioactive coatings.
All manuscripts in this special issue evidence the most important characteristic of EPD, which is its suitability for packaging in an effective manner many types of particulate solids (and molecules). The key challenge in EPD is the ability to prepare stable suspensions of the starting powders in suitable liquid media, where particles are the main charge carriers. In this context, the research articles in this special issue report the success of EPD in shaping many inorganic particles which are different in nature (e.g. SiC, YSZ, TiO2, Zeolite, Al2O3, Fe2O3) or in size (from micrometers to tens of nanometers). Moreover the co-deposition of organic and inorganic entities, e.g. TiO2 nanoparticles, bioactive glass and alginate, micelles (SiO2-CTAB), and the co-deposition of mixtures of nanoscale and microsized population of particles (SiC and Al2O3) were described.
While the regular substrates used in EPD are conductors and semiconductors, e.g. metals, graphite and Si wafers, research works presented in this special issue show also the coating of non-conventional substrates by EPD. For example, Uchikoshi et al.Citation1 proved the versatility of EPD demonstrating the deposition of Al2O3 and zeolite powders on sacrificial polymer layers of polypirrole, while Das and BasuCitation2 studied the deposition of YSZ on porous non-conductive susbtrates (NiO-YSZ composites).
Moreover results presented in the papers in this special issue also cover a range of coating thicknesses, from a monolayer of nanoparticles to bulk parts, proving the versatility of the method and evidencing that dimensions and shapes of the coatings and free standing parts directly depend on the size of the particles, the concentration of the suspensions and the geometry of the electrophoretic cells. In addition, the parameters governing the EPD process, namely electrokinetics and electric parameters, which control the kinetics of the deposition process, have been optimized for the different systems investigated. For example, Novak et al.Citation3 describe the optimization of parameters of a SiC suspension to obtain 4 cm thick and 60% dense deposits, Ata et al.Citation4 compare in terms of charge to mass ratio, the effectiveness of different dyes as dispersing agents in the deposition of MnO2, Castro et al.Citation5 prove the viability of displacing and depositing micelles by electrophoresis, Fleckenstein et al.Citation6 validate an automated robotic EPD set-up for the fabrication of multilayered tretragonal-cubic ZrO2, and Cordero-Arias et al.Citation7 investigate the co-deposition of ceramic particles (TiO2 and bioactive glass) and organic molecules (alginate) to form composite coatings for biomedical applications.
Moreover, new methods of characterization of electrophoretic films are presented, such as the measurement of fractional surface coverage, proposed by Krejci et al.,Citation8 and chronopotentiometric measurements to explain particle deposition at heterogeneously charged surfaces, proposed by Falk et al.Citation9 In addition, specific techniques have been described for the evaluation of the particular properties of the coatings or layers shaped by EPD, which includes the evaluation of bioactivity and corrosion protection properties of electrophoretic TiO2/Bioglass-alginate layers in the study of Cordero-Arias et al.,Citation7 the viability of EPD for fabrication of YSZ electrolytes for SOFC presented by Das and BasuCitation2 and the development of EPD for MnO2-based supercapacitors by Ata et al.Citation4
We hope that this collection of papers in Advances in Applied Ceramics will not only demonstrate the high versatility and usefulness of EPD in a variety of applications but will also increase the interest of readers in this deposition method prompting new research avenues and novel opportunities for its application in the general fields of ceramic materials and coating technology.
Guest editors
Aldo R. Boccaccini, University of Erlangen-Nuremberg, Germany
Begoña Ferrari, Instituto de Cerámica y Vidrio, Madrid, Spain
References
- Uchikoshi T., Kreethawate L., Matsunaga C., Larpkiattaworn S., Jiemsirilers S. and Besra L.: ‘Fabrication of ceramic membranes on porous ceramic supports by electrophoretic deposition’, Adv. Appl. Ceram., January2014, 113, (1), 3–7.
- Das D. and Basu R. N. : ‘Electrophoretically deposited thin film electrolyte for solid oxide fuel cell’, Adv. Appl. Ceram., 2014, 113, (1), 8–13.
- Novak S., Ivekovic A., and Hattori Y.: ‘Production of bulk SiC parts by electrophoretic deposition from concentrated aqueous suspension’, Adv. Appl. Ceram., 2014, 113, (1), 14–21.
- Ata M. S. , Zhu G.-Z., Botton G. A. and Zhitomirsky I.: ‘Electrophoretic deposition of manganese dioxide films using new dispersing agents’, Adv. Appl. Ceram., 2014, 113, (1), 22–27.
- Castro Y., Molero E., Parente P., Duran A., Sanchez-Herencia A. J. , and Ferrari B.: ‘Electric field driven assembly of hybrid micelles for shaping of porous silica films’, Adv. Appl. Ceram., 2014, 113, (1), 28–34.
- Fleckenstein C., Mochales C., Frank S., Kochbeck F., Zehbe R., Fleck C. and Mueller W.-D.: ‘Tetragonal and cubic zirconia multilayered ceramics: investigation of electrical parameters during automated EPD processing’, Adv. Appl. Ceram., 2014, 113, (1), 35–41.
- Cordero-Arias L., Cabanas-Polo S., Gilabert J., Goudouri O. M. , Sanchez E., Virtanen S., and Boccaccini A. R. : ‘Electrophoretic deposition of nanostructured TiO2/alginate and TiO2 2 bioactive glass/alginate composite coatings on stainless steel’, Adv. Appl. Ceram., 2014, 113, (1), 42–49.
- Krejci A. J. , Gebre T., Ruggiero C. A. , Mochena M. D. , and Dickerson J. H. : ‘Kinetics of monolayer and bilayer nanoparticle film formation during electrophoretic deposition’, Adv. Appl. Ceram., 2014, 113, (1), 50–54.
- Falk G., Nold A., and Wiegand B.: ‘Experimental and Numerical Analysis of Electrophoretic Deposition on Charge Selective Surfaces in External Electric Fields’, Adv. Appl. Ceram., 2014, 113, (1), 55–64.