The color efficiency of ceramic glaze blue pigments obtained by the Pechini method was presented in this work. The fired pigments
and enameled samples were characterized by thermogravimetry (TG) and differential thermal analysis (DTA), XRD, UV-VIS-NIR
spectroscopy and CIE-L*a*b* color-measurements. The pigments obtained by the Pechini method present a better solubility in
the molten glazes than the pigments obtained by the mechanical mixture of the precursor oxides.
The synthesis and the characterization of Al2O3-based nanocrystalline inorganic pigments are reported. The pigments were synthesized by the polymeric precursor (Pechini
method) using Cr2O3 as chromophore. XRD results only evidenced the corundum phase. The average particle size was about 34 nm. The samples were
also characterized by differential scanning calorimetry (DSC) and thermogravimetry (TG), and CIE-L*a*b* calorimetry. The pigments
obtained in this work presented different colors, ranging from green to rose.
Sr(Ti,Nd)O3 was synthesized in order to evaluate the influence of the amount of neodymium on the thermal and structural properties of
SrTiO3. The synthesis was carried out using the polymeric precursor method. A small mass gain was observed for the SrTiO3 and SrTi0.98Nd0.02O3 samples accompanied by an exothermic peak in the DTA curves. Other steps at higher temperatures are assigned to the combustion
of the organic material and carbonate. Elimination of defects by previous calcination of the precursors is responsible by
the short and long range ordering of the perovskite. Cubic phase was obtained for undoped and doped SrTiO3.
The use of clays for ceramic filter processing may reduce its cost, leading to different applications, as water treatment.
In this work, a low cost tile clay mixed with kaolin, for use in ceramic filters, were evaluated. Mineralogical and thermal
changes occurring during sintering were characterized by differential thermal analysis, thermogravimetry, thermomechanical
analysis and X-ray diffraction. An increase in the initial melting temperature of samples due to kaolin addition was observed.
Mullite formation in kaolin was observed by DTA and in other samples by XRD. TMA analysis permitted the observation of pre-sintering
step, around 850C. This step is difficult to observe in other types of analysis.
The pigments used in ceramic applications are of nature predominantly inorganic and they should be thermally stable, insoluble
in glazing, resistant to the chemical and physical agents' attacks. This work aimed at the synthesis by the polymeric precursor
method of ZrO2-based inorganic pigments, doped with Fe, Ni, Co, Cr and Cu cations. The fired pigments were characterized by thermogravimetry
(TG), differential thermal analysis (DTA) and X-ray diffraction (XRD). Among the metals used to zirconium-doping, the best
result was achieved with the cations Cu, which presented the monophase pigment, even as 20 mol% of dopant. Up to the temperature
of 1000C the pigments presented a good thermal stability.
materials are used as sensors, catalysts and in electro–optical devices.
This work aims to synthesize and characterize the SnO2/Sb2O3-based
inorganic pigments, obtained by the polymeric precursor method, also known
as Pechini method (based on the metallic citrate polymerization by means of
ethylene glycol). The precursors were characterized by thermogravimetry (TG)
and differential thermal analysis (DTA). After characterization, the precursors
were heat-treated at different temperatures and characterized by X-ray diffraction.
According to the TG/DTA curves basically two-step mass loss process was observed:
the first one is related to the dehydration of the system; and the second
one is representative to the combustion of the organic matter. Increase of
the heat treatment temperature from 500 to 600C and 700C resulted
higher crystallinity of the formed product.
The present work investigates
the influence of milling and calcination atmosphere on the thermal decomposition
of SrTiO3 powder precursors. Both pure and neodymium-modified SrTiO3 samples
were studied. Milling did not significantly influence numerical mass loss
value, but reduced the number of decomposition steps, modifying the profiles
of the TG and DTA curves. On the other hand, milling increases the amount
of energy liberated by the system upon combustion of organic matter. It was
also observed that the milling process, associated to the calcination in an
oxygen atmosphere, considerably decreases the amount of organic matter and
increases the final mass loss temperature.
CaSnO3 was synthesized by the polymeric precursor
method, using different precursor salts as (CH3COO)2CaH2O,
CaCl22H2O and CaCO3,
leading to different results. Powder precursor was characterized using thermal
analysis. Depending on the precursor different thermal behaviors were obtained.
Results also indicate the formation of carbonates, confirmed by IR spectra.
After calcination and characterization by XRD, the formation of perovskite
as single phase was only identified when calcium acetate was used as precursor.
For other precursors, tin oxide was observed as secondary phase.