FORMATION OF ZRO2 FILMS BY LOW-PRESSURE CVD USING ZTI-O2 SYSTEM AND EVALUATION OF CORROSION RESISTANCES OF THE FILMS

In order to obtain high corrosion-resistant oxide films, ZrO2 films were formed on Pt substrates by low pressure CVD technique using zirconium-tetra-isopropoxide (ZTI; Zr(O-i-C3H7)4) and oxygen at temperatures between 523 K and 773 K. The changes in the growth rate, structure and corrosion resistance of the films were investigated as a function of deposition temperature. The growth rate increased with increasing deposition temperature. The films deposited below 523 K were amorphous and those deposited above 573 K had monoclinic crystalline structures. The corrosion resistance of the crystalline films in 12.0 kmol.m-3 HCl and 10.0 kmol.m-3 NaOH solutions were much higher than those of amorphous films. The corrosion resistance of both the amorphous and crystalline films increased with increasing deposition temperature. The crystalline films showed no sign of dissolution in a 10.0 kmol.m-3 NaOH solution.