The use of suspensions as an intermediate step in the processing of the ZrO2-MgO mixture arises as an alternative to obtain homogeneity on the final product. A relationship between the stability control of this suspensions and the achievement of homogeneity on the product may be established. The behavior of oxide mixture suspensions depends on the physical-chemical characteristic and of the relative content of each component. In this work the behavior of each component of the ZrO2-MgO mixture was studied, either in aqueous or ethylic suspension, and also the behavior of the mixture. Zirconium oxide in ethylic suspension shows a highly negative potential; Magnesium oxide, on the other hand, shows a positive potential. The explanation was found after Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy measurements, revealing a reaction between the solvent and surface of the oxides. A new mechanism for the desagglomeration effect of the ZrO2 ethylic suspensions, as a function of the highly electrostatic potential of the suspension is proposed. The study of suspensions of a mixture of both oxides for 3 wt% of MgO (~ 8.6 mol%) content shows that the final paH as well as the zeta potential are determined by the surface characteristics of the latter, even being the minor component in the mixture.
Ceramic suspensions; zirconia; magnesia; surfaces; DRIFT
