Sol-gel synthesis and characteristics of the rare earth phosphate glasses

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1993

OSTI ID:7017705

Guo, Y

Rare earth (RE) phosphate glasses are potentially important for many applications because of their high thermal stability, chemical durability and high concentration of optical activity ions. For example, they have the potential of being used as laser glasses, composite matrices, and ceramic coatings. Conventional melt and vapor deposition (VD) methods are not applicable to the RE phosphate systems due to their high melt temperature. The synthesis of RE phosphate glasses was accomplished for the first time in this study using the sol-gel technique. This method involves the use of organic solvent as a reaction medium at room temperature and applying ultrasonic vibration during conversion of the sol to the gel, followed by drying at room temperature to obtain glassy RE phosphates. The properties and the structural characteristics of the synthesized RE phosphate glasses were compared with those of crystalline RE phosphates as references. Results of SEM, XRD and thermal analysis show that the synthesized RE phosphate products (LaPO[sub 4], NdPO[sub 4] and EuPO[sub 4]) always crystallizes. The fluorescence of NdPO[sub 4] glass, which makes it into a potential candidate material for very small lasers, has been identified. The refractive index of these glasses is high, about 1.65. The preparation of RE phosphate coatings on alumina and graphite is described. In addition to glasses, RE phosphate gels have also been characterized and their electrokinetic potentials measured. Over certain range of synthetic conditions, the gels can be stable for periods of at least 3 years.

• Research Organization: Catholic Univ. of America, Washington, DC (United States)
• OSTI ID: 7017705
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation & Manufacture
360606 -- Other Materials-- Physical Properties-- (1992-)
GLASS
OPTICAL PROPERTIES
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SOL-GEL PROCESS
STRUCTURAL CHEMICAL ANALYSIS