Investigação experimental das transições de fase do aluminato de cálcio e suas características óticas e estruturais

Abstract

The acquisition of ceramics from polymeric precursors has been the subject of numerous studies due to lower cost energy, particle morphology and properties compared to conventional processing. The calcium aluminates (CAs) are employed for different applications as cements, Biomaterials and components for high temperature fuel cells, which present various properties such as optical, electrical, thermal and mechanical properties. In addition to good performance in corrosive environments and are also bioactive and biocompatible since they offer a lower toxicity to man and the environment. The aim of this study was to investigate and improve the study of powder synthesis of nanoparticles C3A. Thus, we investigated the influence of temperature in the range of 700-1300°C at a concentration of 70% calcium and 30% aluminum with the obtaining of ceramic powders in addition, another objective was to develop samples in tablet form from the ceramic powder. To perform the synthesis was by the method of chemical precursors of polymeric precursors were used as the nitrates of aluminum and calcium, further, we used ethylene glycol and citric acid in the proportions ordinarily employed technique to form the polymeric resin. The same was subjected to pre-calcination was soon desaglomerada for the starting powder and this powder was calcined at different temperatures. With this method the polymeric precursor particles become more homogeneous thereby, the synthesis of CAs can be obtained at lower temperatures, resulting monophasic powders of high purity. We carried out a study of the evolution of the crystalline phases by X-ray diffraction (XRD) and allowed identification of single phase powder predominantly Furthermore, studies on the vibrational modes of nuclear localization of the crystalline phases by micro-Raman spectroscopy and IR. Chemical analysis was performed by means of X-ray spectroscopy (EDX) and a study of the morphology of the C3A, the measurements of the crystallite size and particle size, as well as images of scanning electron microscopy and transmission. Studies on optical properties C3A by UV-visible spectroscopy and thermal properties with the thermal thermogravimetric analysis, differential thermal analysis and dilatometry to verify thermal expansion. From the characterizations carried out it may be concluded that the results presented relate to the literature, since the methodology of the polymeric precursor is presented efficiently to synthesize the C3A phase pure.