A novel method of electrochemical synthesis of yttrium aluminum garnet (YAG) thin - film coating on IN617 has been successfully developed in the mixture of Y(NO3)(3) and Al(NO3)(3) aqueous solution. The coating films were further annealed and characterized by thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The coating film was composed of hydrated Y(OH)(3) and Al(OH)(3), the physically adsorbed water evaporated between 25 and 103 degrees C, dehydrated into Y(OH)(3) and Al(OH)(3) between 103 and 400 degrees C, condensed into YOOH and AlOOH between 400 and 890 degrees C, and finally transformed into single - phase YAG (Y3Al5O12) between 890 and 1000 degrees C. The YAG coating film with a thickness about 2 mu m revealed the uniform and adherent interface on the substrate. (c) 2006 The Electrochemical Society.