Abstract

BARON, Yliana Shakira; RUIZ, Augusto  and  NAVAS, Gladys. Yttria-stabilized zirconia coating to improve the oxidation resistance at 600°C of 1.25Cr-0.5Mo wt% steel. Rev. Téc. Ing. Univ. Zulia [online]. 2007, vol.30, n.Especial, pp.252-260. ISSN 0254-0770.

A zirconia coating was applied to improve the oxidation resistance of 1.25Cr-0.5Mo wt% steels. An 8 wt% yttria-stabilized zirconia coating was deposited by sol-gel technique. One problem with this method is that the hydrolysis of the organometallic precursors is faster than condensation; and the formation of precipitates is favored. Ethyl acetate was used to slow the hydrolysis rate, in order to obtain a more continuous layer. The air oxidation behavior of the coating was studied at 600°C by the continuous measurement of the weight gain. The microstructural characterization was performed by scanning electron microscopy (SEM), and composition was determined by energy dispersive spectroscopy (EDS). The weight gain of the one-layer coated 1.25Cr-0.5Mo wt% was diminished in about 40% respect to uncoated samples, because the zirconia cations form pairs with the iron vacancies in the oxide. The formation of such pairs reduces cationic diffusion.

Keywords : Oxidation; sol-gel; partially stabilized zirconia.