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

Abstract

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.

Mixed Electrical Conduction of Calcium Aluminates Synthesized by Polymeric Precursors

“…37 The final solution was stirred at 70 to 85 ºC for 2 h until formation of a solid polymer resin or viscous clear gel. This gel was subjected to thermal treatment in an oxidizing atmosphere at 400 ºC for 3 hours with a heating rate of 0.5 ºC/min for total removal of water and organic materials 2,13,37 , resulting in solid black mass. After grinding and sieving, the heat treatment was carried out for calcination at temperature of 1350 ºC for 2 hours in the precursor powder.…”

“…11,12 C12A7 has attracted attention in material science due to its unique structure and related properties. 13 Mayenite has recently achieved the status of an advanced material of unusual potential for technological applications. 14 Mayenite is formed by sub-nanometer-sized cages, which promote a three-dimensional cubic lattice phase 12 and have been found to have a body-centered cubic structure with an I-43d space group with the cell parameter 11.99 Å.…”

“…5 Actually, among these, the polymeric precursor technique is known to be simple, cost-effective, and versatile. 2,13 The synthesis of polymeric precursors comprises mixing metals with citric acid cations, after which ethylene glycol is added and the solution is concentrated by heating under stirring. 2,5,13 The eutectic point composition can promote self-modified celite and mayenite biphasic composition (SMCM) with a variable range of phase proportions.…”

“…One of these biphasic products was obtained, and a detailed experimental synthesis based on the polymer precursor method was reported elsewhere. 2,13 According to the phase diagram, 32 during the sintering stage at 1350 ºC, the eutectic point composition produces two coexisting and reproducible phases (celite and mayenite).…”