Electrophoretic Deposition Mechanism of YSZ/n-Propanol Suspension

Abstract

The technological feasibility of utilizing electrophoretic deposition ͑EPD͒ has been studied. The EPD mechanism of 8 mol % yttria-stabilized zirconia ͑8YSZ͒ powder as the electrolyte material of solid oxide fuel cells ͑SOFCs͒ in n-propanol has been investigated from the viewpoint of dc and ac electrochemical experiments under applied constant voltages. A fine particle suspension can be prepared by ultrasonic vibration and is stable, and the dispersed particle becomes charged. The charged particle acts by migration of the electric charge when a dc potential is applied. The charge-transfer quantity from a particle to the deposition layer is constant with the applied EPD. The initial deposit layer, which has a high resistance, is immediately formed. This formation is accompanied by a decreasing potential gradient in the EPD bath, therefore, the deposition rate decreased. However, the bulk EPD bath characteristic itself does not change with the applied EPD. The amount of the deposit and velocity of the particles have a mutual relation and the EPD model is considered. The present investigation's objective is the technological feasibility of applying the EPD technique.In recent years, new technology to create additive properties by systematic arrangement of size-controlled fine particles in two or three dimensions has attracted great attention as a coating technology in the field of ceramic processing. 1-3 The wet-process fabrication is especially attractive because of its low cost and mass productivity. To advance the ceramic powder assembling technology, it is required to significantly improve the control of the interaction between powder-powder, powder-solution, and powder-substrate of the current technology. As for the systematic arrangement of particles on a substrate, controlling the interaction of the particleparticle and/or particle-substrate in the colloidal solution based on the simultaneous colloidal processing and added electrical field, magnetic field, gravitation field, and so on from outside has become interesting.The electrophoretic deposition ͑EPD͒ process is one of such ceramic powder assembling technologies. The EPD process is a coating technique using a simultaneous colloidal process and electrochemical driving force. 4 This process is very simple; the dispersed and charged particles in a solvent migrate to an electrode substrate under some potential gradient with a dc power source. The EPD technique has some advantages compared with the other fabrication techniques especially for decreasing the fabrication costs and structural flexibility of the substrates. 5 Therefore, the EPD technique has been gaining increasing interest as a ceramic processing technique for a variety of technical applications, e.g., electrodes, solid oxide fuel cells ͑SOFCs͒, fiberreinforced and graded ceramic composites, nanostructured materials and coatings for electronic, biomedical, optical, catalytic, and electrochemical applications. 1 For instance, experimental results using the EPD technique with several kinds of zeolit...

Preparation of Thin and Dense Lanthanum Cobaltite Coating on Porous Tubular Alumina Supports by Electrophoretic Deposition

“…1 The EPD technique has been investigated for the fabrication of thin electrolyte materials such as yttria-stabilized zirconia YSZ, scandia-stabilized zirconia ScSZ, gadolinium-doped ceria CGO and so on, on porous cathodes or anodes such as lanthanum manganate, NiO-ScSZ and NiO-YSZ, for the SOFCs. [4][5][6][7][8][9] Based on these reports, the feasibility of the EPD technique has been confirmed.…”

Fabrication of gadolinium biphthalocyanine nano/microwires by electrophoretic deposition

“…2d). The mechanism on change of stacking pattern is not very clear at this moment, but it is probably related to the deposition rate, which decreases with the deposition going on [39].…”

Methods for functionalization of microsized polystyrene beads with titania nanoparticles for cathodic electrophoretic deposition

“…In our interpretation, this is due to the different surface charge obtained in the two TiO 2 suspensions. The charge of the particles in isopropanol is attributed to a small amount of H 2 O included in commercially available organic solvents [28]: H + and OH − ions are generated by electrolytic dissociation; the generated H + ions adsorb on the amphoteric hydroxyl groups at the surface of the TiO 2 particles and are responsible for the positive surface charge of TiO 2 (like other ceramic particles like ZrO 2 ) in organic solvents. However, the charge of the particles in the alkaline solution is negative, since the amphoteric hydroxyl groups get deprotonated above the isoelectric point of TiO 2 .…”