Two Phase Monazite/Xenotime 30LaPO4–70YPO4 Coating of Ceramic Fiber Tows
Equiaxed yttrium–lanthanum phosphate nanoparticles (Y0.7,La0.3)PO4·0.7H2O were made and used to continuously coat Nextel™ 720 fiber tows. The particles were precipitated from a mixture of yttrium and lanthanum citrate chelate and phosphoric acid (H3PO4), and characterized with differential thermal analysis and thermogravimetric analysis, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The coated fibers were heat treated at 1000°–1300°C for 1, 10, and 100 h. Coating grain growth kinetics and coated fiber strengths were determined and compared with equiaxed La-monazite coatings. The relationships between coating porosity, coating hermeticity, and coated fiber strength are discussed.
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Document Type: Research Article
Affiliations: 1: UES Inc., Dayton, Ohio 45432 2: Air Force Research Laboratory, Materials and Manufacturing Directorate (AFRL/MLLN), Wright-Patterson Air Force Base, Ohio 45433
Publication date: January 1, 2008