A Study of the Crystallization of ZrO
ZrO{sub 2}-SiO{sub 2} sol-gel powders were produced using tetraethoxysilane (TEOS) and zirconium propoxide. After gellation, the ZrO{sub 2} crystallization process was investigated using X-ray diffraction (XRD), thermal analysis (DTA/TGA), and scanning electron microscopy (SEM). Fresh gels were amorphous. Thermal treatments were carried out from 100 to 1400 C for a total annealing time of 182 h. Tetragonal zirconia, (Z(t)) was the first phase to crystallize, between 300 and 500 C. Crystallization temperature was lower for zirconia-rich compositions, increasing as silica content was raised. DTA analysis showed that Z(t) crystallization occurred in two stages. Complete tetragonal-monoclinic zirconia transformation occurred near 1000 C, and was clearly observed only in ZrO{sub 2}-rich compositions (>80%). Silica remains amorphous until 1200 C, when ZrSiO{sub 4} formation took place. A metastable sol-gel phase diagram was proposed to show the crystallization process between 100 and 1400 C.
- Research Organization:
- Facultad de Ciencias Quimicas, Division de Estudios Superiores, Universidad Autonoma de Nuevo Leon, Monterrey, Nuevo Leon (MX); Departamento de Quimica, Universidad Autonoma Metropolitana-Iztapalapa, Mexico, DF (MX); CINVESTAV-IPN-Unidad Merida, Merida, Yucatan (MX)
- Sponsoring Organization:
- CONACYT (Consejo Nacional de Ciencia y Tecnologia) (US)
- OSTI ID:
- 784452
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 158; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMORPHOUS STATE
ANNEALING
CHEMICAL PREPARATION
CRYSTALLIZATION
DIFFERENTIAL THERMAL ANALYSIS
EXPERIMENTAL DATA
GELS
MONOCLINIC LATTICES
PHASE DIAGRAMS
SCANNING ELECTRON MICROSCOPY
SILICA
SOLS
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
TETRAGONAL LATTICES
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
X-RAY DIFFRACTION
ZIRCONIUM OXIDES