RESUMEN
TCP-TiO2 ceramic biocomposites with various alpha-to-beta TCP ratios can be prepared by quenching the alpha phase. The presence of dopants (Ca, P, or Na) leads to the precipitation of secondary phases, which decreases the densification of titania. In the system TCP-TiO2, there is a eutectic with a composition of 63 wt% TCP-37 wt% TiO2 at a temperature of 1380 degrees C.
Asunto(s)
Materiales Biocompatibles/química , Fosfatos de Calcio/química , Cerámica/química , Titanio/química , Fenómenos Químicos , Química Física , Temperatura , TermodinámicaRESUMEN
The understanding of the microstructure of cement remains incomplete. Especially, the progressive setting of the material is still unclear. Micropore size distribution (microstructure) has been investigated by both standard proton nuclear magnetic relaxation (1H-NMR) and field-cycling relaxation in C3S hydrated paste. The non-exponential decay was interpreted as a distribution of discrete relaxation rates. The attribution of T1 is supported by both a spectral and a dispersion curve analyses. These experiments allow us to follow the structuration of the material during setting.
Asunto(s)
Compuestos de Calcio , Materiales de Construcción/análisis , Espectroscopía de Resonancia Magnética/métodos , Silicatos , Porosidad , AguaRESUMEN
We present a time evolution of 1H spin-lattice relaxation rates in the laboratory (1/T(1)) and in the rotating frame (1/T(1rho)) of a synthetic cement paste. The typical results found for both rates allows us to follow the main hydration stages of the cement paste and the refinement of its microporosity. In particular the texturation of the porosity and the structuration of the surface of the material is evidenced.