Electrophoretic deposition of La2Zr2O7 coating in non-aqueous media on Cf/SiC substrate

Pyrochlore-type lanthanum zirconate (La2Zr2O7) coatings were deposited via electrophoretic deposition (EPD) on Cf/SiC substrates prepared by polymer infiltration and pyrolysis. The alcohol and iodine system is an effective solvent-dispersant system for EPD of the La2Zr2O7 particles. The suspension characteristics were investigated in terms of particle size, electrical conductivity, and iodine content. The EPD conditions leading to uniform La2Zr2O7 coatings were applied featuring a current density of 1 mA/cm2, a deposition time of 3 to 6 min, and an electrodes' space of 2 cm. After sintering at 1300 °C for 5 h, coatings become compacted with the thickness of about 30 μm. Sinterability was evaluated by microstructure and the microstructure evolution during sintering was evaluated. The C/SiC samples protected by La2Zr2O7 coatings showed excellent corrosion resistance during the testing period at 1200 °C in water vapor for 30 min.