Monazite Coatings on Fibers: II, Coating without Strength Degradation

Autor: L. M. Douglas, Pavel Mogilevsky, Emmanuel E. Boakye, Randall S. Hay
Rok vydání: 2001
Předmět:
Zdroj: Journal of the American Ceramic Society. 84:2793-2801
ISSN: 1551-2916
0002-7820
DOI: 10.1111/j.1151-2916.2001.tb01096.x
Popis: Washed and unwashed rhabdophane (LaPO4·xH2O) sols were used to apply monazite coatings to 3M Nextel 720 and 610 fibers. This precursor was designed to minimize stress corrosion from gaseous decomposition products at high temperature. The coatings were heat-treated in-line at 900°–1300°C, in air, using a continuous vertical coater with immiscible liquid displacement. Coatings were characterized by optical microscopy, scanning electron microscopy, and transmission electron microscopy. The sol was characterized with light-scattering and zeta-potential measurements. Precursor phase evolution was studied with differential thermal analysis/thermogravimetric analysis and X-ray diffractometry. The washed sol had a higher pH and lower weight loss than the unwashed sol. The as-coated fibers were tensile tested, along with coated fibers heat-treated in air at 1200°C for 100 h. The precursor was slightly phosphate-rich, and this excess phosphate reacted with alumina in the fiber to occasionally make very small (
Databáze: OpenAIRE