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Co-doped alumina powders were synthesized by means of the polymeric precursor method to obtain ceramic pigments. The effect of different contents of Co2+ on phase transition to -Al2O3 and appearing of CoAl2O4 spinel were studied by means of X-ray diffraction. A partial phase diagram of the system CoAl2O3 was proposed from these data by means of determination of the percentages of these phases according to the calcining temperature. Critical particle size to phase transition was determined ...
Titanium citrate and lead and titanium citrate were prepared by polymeric precursor method in aqueous solution. This citrate was analyzed by 1H, 13C NMR and gHMBC–NMR (Hetero-nuclear multiple-bond correlation) to investigate the formation of the citrate complexs and influence of the Pb2+ ion in this complex. These complexs were characterized by interaction between Ti4+ ion and citric acid carboxyls. Quantum mechanic simulations in level ab initio were used to study the electronic structure a...
A produção de cerâmica vermelha é uma atividade industrial que provoca um intenso impacto ambiental. Os principais efeitos deletérios decorrentes desta atividade são a desertificação de florestas e serrados, devido ao uso irracional da lenha, a degradação do solo, devido a extração da argila e ainda a utilização de grandes áreas para deposição das peças rejeitadas. Estes problemas podem ser minimizados, indiretamente, reduzindo-se o desperdício por meio da análise racional mineralógica. Esta...
CaIn2O4 (CIO) nanocrystals (NCs) were prepared by ultrasonic spray pyrolysis at 1223 K without the use of surfactants to investigate the influences of the nanostructure on the photoluminescence and photo-catalytic properties of this white-light emitter. The optical properties were analyzed by ultraviolet evisible (UVevis) absorption spectroscopy, which indicated a band gap energy of 3.83 eV, and photo-luminescence (PL) measurements at room temperature that showed a broad and intense emission ...
The TiO2/In2 O3 thin films were prepared by the spin coating method, varying their number of layers (4, 8 and 16 layers). The Method of polymerization of complex (CPM) was used to synthesize the precursor resins in order to produce thin films. The TiO2/In2 O3 films were heat–treated at 300°C, 500°C and 700°C and characterized by X–ray diffraction, scanning electron microscopy (FEG–SEM), atomic force microscopy (AFM), UV–vis spectrophotometer and photoluminescence (PL). It was found that the b...