Fiber monazite

Davis, J.B., et al., Influence of interfacial roughness on fiber sliding in oxide composites with La-monazite interphases, J. Am. Ceram. Soc., 86(2) 305-316 (2003). 

FIGURE 25.1 Technical application 1. Monazite on alumina fibers as a barrier layer in a ceramic-matrix composite. 

R., Shao, H., Hornis, H.G., and Hunt, A.T. (1998) Combustion chemical vapor deposition (CCVD) of LaP04 monazite and beta-alumina on alumina fibers for ceramic matrix composites, Mater. Sci. Eng. A, 244, 91. Copyright 1998, with permission from Elsevier. 

Goettler, R.W., and S. Sambasivan. 1996. Slurry and solution derived monazite fiber coatings for sol-gel oxide matrix CFCC. Presented at the American Ceramic Society 98th Annual Meeting and Exposition (paper no.B-185-96 replacement), April 14-17, 1996, Indianapolis, Indiana. 

FIGURE 2. a) Schematic showing toughening through crack deflection at the fibei/matrix interface, b) SEM micrograph of fracture surface ofNextel 610/monazite/alumina composite tested at 1200°C showing fiber pullout and c) fracture surface ofNextel 610/alumina composite tested under the same conditions. Absence of crack deflection mechanism led to brittle failure in c). 

FIGURE 7. SEM micrograph showing Nextel 610/monazite/alumina fracture surface. Monazite coatings can be seen on the pulled-out fibers and in the fibertroughs. 

Monazites and xenotimes are two classes of weak oxide coatings that satisfy the criteria for crack deflection for the currently available fibers [84, 85]. Of these, monazite (LaP04) has been the most widely studied. 

The production of composites containing higher volume fractions of monazite-coated fibers has been somewhat limited and a summary of the relevant work is listed in Table 3. These composites were subjected to mechanical testing, either tensile or flexural, to evaluate the effectiveness of the coatings. 

Monazite coatings were also evaluated in Nextel 312 and 610/aluminosilicate matrix composites [102]. In this case, the monazite coating was deposited using an aqueous slurry (for 312 fabric) or solution (for 610 fabric). Composites containing either fiber type displayed... 

At the current time, liquid precursor (solution/sol/slurry) coating techniques have been the most successful for the deposition of oxides, such as monazite (LaP04) and porous oxides (carbon-oxide mixtures) onto oxide fiber tows [178, 179, 191, 192]. Atypical fiber coater is shown in Figure 10a [193]. In the coating process, a lighter, immiscible liquid is floated on the surface of the coating precursor. The immiscible liquid is used to remove excess sol from the coated tow and it allows for the coating of individual filaments with... 

K. K. Chawla, H. Liu, J. Janczak-Rusch, and S. Sambasivan, Microstmcture and properties of monazite (LaP04) coated saphikon fiber/alumina matrix composites, J. Eur. Ceram. Soc., 20 551—559 (2000). 

D.-H. Kuo, W. M. Kriven, and T. J. Mackin, Control of Interfacial Properties through Fiber Coatings Monazite Coatings in Oxide-Oxide Composites, J. Am. Ceram. Soc., 80 [12] 2987-2996 (1997). 

K. A. Keller, T. Mah, E. E. Boakye, T. A. Parthasarathy, and P. Mogilevsky. Evaluation of Dense Monazite Fiber-Coatings in Oxide-Oxide Minicomposites. Presented at the 27th Annual Cocoa Beach Conference Exposition on Advanced Ceramics Composites. Cocoa Beach, FL, January 29, 2003, 2003. 

T. A. Parthasarathy, E. Boakye, K. A. Keller, and R. S. Hay, Evaluation of Porous Zirconia Silica and Monazite Coatings using Nextel 720 Fiber Reinforced Blackglas Minicomposites, /. Am. Ceram. Soc., 84 [7] 1526-1532(2001). 

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