| dc.description.abstract | In the present study, perovskite-type NiTiO3 ceramic pigments were
prepared by the polymeric precursor method, originally proposed by Pechini.
The transluscent and viscous polymeric resin was characterized by
thermogravimetric analysis. The product of the resin s pyrolysis, also known as
"puff", was desagglomerated and calcined at different temperatures, under room
atmosphere. The evolution of the crystalline phase with increasing heat
treatment temperature was studied by X-ray diffraction (XRD). A comparative
study of the characteristics of the ceramic pigments, which resulted from the
calcination of the attrition-milled "puff", was made. The calcined powders
presented high specific superficial area values, as determined by the BET
method. The pigment colors were measured by the CIE - L*a*b* colorimetric
system. It was observed, through the colorimetrics coordinates, that the
pigments are yellow. The morphology of the prepared NiTiO3 powders was
studied by scanning electron microscopy. A mean particle diameter of
approximately 30nm was estimated through transmission electron microscopy
(TEM) measurements. The isoelectric point of the particles dispersed in ethanol
was determined. Afterwards, the attrition-milled, nanometric, single-phase
pigments, calcined at 600ºC for 2 hours, were coated with an amorphous SiO2
layer. The encapsulation was done by a sol-gel process. Moreover, the
encapsulation was confirmed through TEM characterization, X-ray dispersive
energy analysis and a shift on the position of the isoelectric point of the
dispersed particles | |
