Electrically Polarized Hydroxyapatite: Influence of the Polarization Process on the Microstructure and Properties.
Langmuir
; 35(46): 14782-14790, 2019 11 19.
Article
em En
| MEDLINE
| ID: mdl-31647245
ABSTRACT
Semipermanently polarized hydroxyapatite, named SP/HAp(w), is obtained by applying a constant dc electric field of 1-10 kV/cm at 300-850 °C to the samples previously sintered in water vapor, while permanently polarized hydroxyapatite, PP/HAp(a), is produced by applying a dc electric field of 3 kV/cm at 1000 °C to the samples sintered in air. SP/HAp(w) has been used for biomedical applications, while PP/HAp(a) has been proved to be a valuable catalyst for N2 and CO2 fixation. In this work, structural differences between SP/HAp(w) and PP/HAp(a) have been ascertained using Raman microscopy, wide-angle X-ray diffraction, scanning electronic microscopy, high-resolution transmission electron microscopy, and grazing incidence X-ray diffraction. Results prove the existence of crystal distortion in the form of amorphous calcium phosphate and ß-tricalcium phosphate (ß-TCP) phases close to the surface because of the atmosphere used in the sintering process. The existence of an amorphous layer in the surface and the phase transition through ß-TCP of SP/HAp(w) are the structural factors responsible for the differences with respect to PP/HAp(a). Moreover, a superstructure has been identified in PP/HAp(a) samples, which could be another structural factor associated with enhanced conductivity, permanent polarization, and catalytic activity of this material.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Langmuir
Assunto da revista:
QUIMICA
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Espanha