Mojtaba Ahmadi - Department of Materials Engineering, University of Tabriz, Tabriz, P.O. Box: ۵۱۶۶۶۱۶۴۷۱, Iran
Hossein Aghajani - Department of Materials Engineering, University of Tabriz, Tabriz, P.O. Box: ۵۱۶۶۶۱۶۴۷۱, Iran

Yttria-stabilized zirconia (YSZ) is the most widely used material in thermal barrier coatings. The main difficulty in fabricating ceramic coatings on metal substrates using the electrophoretic deposition process (EPD) is problems caused by the volume shrinkage during the sintering of the green form ceramic coating. In this research, a combination of EPD and reaction bonding processes has been used for fabrication of an adherent and crack-free coating on Iron-Nickel superalloy. Aluminum particles were added to the suspension of YSZ in acetone. By using EPD of aluminum and YSZ particles, a uniform green coating formed on the substrate by applying voltage of 6 V during 3 min. After oxidation of aluminum at 660°C for 2 h and sintering at 1100°C for 2 h, an adherent and crack-free coating was obtained. Addition of aluminum to the green coating not only has reduced the sintering temperature of the YSZ coating about 200°C, but also has compensated the shrinkage of the coating by the volume expansion due to the oxidation of aluminum.

Aluminum, Yttria-stabilized Zirconia, Electrophoretic deposition, Reaction bonding, Coating