Jose R. Jurado

Chemical Synthesis and Sintering Behaviour of Ca3Al206 Obtained by Polymeric Precursor Method

Tricalcium aluminate (C3A) are used for different applications such as thermal insulation, cement, refractory concrete as binders or binders. The aim of this work is to study the synthesis and sintering behaviour of C3A samples. The chemical synthesis was performed by means of polymeric precursor method from metalic nitrates dissolved in ethylene glycol and citric acid forming a polymeric resin. The evolution of the crystalline phases was accomplished by X ray Diffraction (XRD). Thermogravimetric (TG), Differential Thermal Analysis (DTG) and Thermal Expansion were performed in order to verify the thermal properties of the material. From the characterizations carried out it may be concluded that the synthesis of polymeric precursors via allowed obtaining pure phase of C3A at 1000°C low temperatures. The temperature of 1350°C it possible to obtain materials having grain morphology with uniform size and densely packed.

Electrochemical Impedance Spectroscopy: Evaluation of Drug Delivery System of Alpha-Tricalcium Phosphate Cement

Tricalcium phosphate cement (α-TCP) can be used in various fields of health, including as drug delivery systems. The application of a biomaterial based on α-TCP could enable both the constant drug delivery as support and shape damaged muscleskeletics tissues until which can be regenerated by the organism itself, replacing the biomaterial, while maintaining stable levels of the drug in the organism. The aim of this study was to evaluate the release of gentamicin sulfate using the technique of electrochemical impedance spectroscopy in drug delivery systems of α-TCP. The results obtained in vitro study validated the proposed methodology for assessment of controlled drug delivery systems on the basis of α-TCP.

Study of the Evolution of Phase Calcium Aluminate through the Method for Polymeric Precursors C12A7

The synthesis of ceramic materials from polymeric precursors has been the subject of numerous studies due to lower energy cost compared to conventional processing. The study aims to research and develop synthesis of calcium aluminate powders via the polymeric precursor method, in order to obtain the pure phase of hepta-aluminate dodecálcio (C12A7) with mayenita mineral name, since it has applications like: special cements and components for high temperature fuel cells. A study of the evolution of crystalline phases by X-ray diffraction was performed, the vibrational modes of atomic location in crystalline phases were studied by micro-Raman spectroscopy was also performed and images from scanning electron microscopy. From the characterizations carried out on the material can be seen that the sintering temperature of 1200°C was obtained pure phase, so the choice of synthesis shown to be effective due to the complexity of obtaining this phase pure.

Microstructure and Thermal Conductivity of Porous Al2O3-ZrO2 Ceramics

The improvement on the development of porous ceramic materials has leaded to new technologies in thermal insulation, for example, composite materials for better performance of pressure vessels in rocket engines. Within this context, the present work aims to evaluate the ability of a refractory ceramic base alumina/zirconia through the processes of co-precipitation and replica method in an organic fiber template. The green body was burnt-out and sintered at 1200-1600°C to obtain the continuous porous ceramic fibers. In the FEG-SEM analysis, an interconnected porous structure with small grains was observed. The crystalline phases were determined by X-ray diffraction and compared to micro-Raman results regarding the crystalline structure confirms that there present in the material zirconia is composed of more than one phase. Porosity was calculated through a mercury porosimeter as 77.9%, and the Laser Flash method gave a thermal conductivity value of 1.61 K W.m−1.K−1 for the Al2O3-ZrO2 fibers.