SiC‐Whisker‐Reinforced Cellular SiO₂ Composites

Abstract

Fabrication of lightweight, cellular ceramic composites by foaming sol-gels is presented. Foams of ZO-vol%-Sic-whisker-reinforced Si02 can be tailored with relative densities as low as lo%, with either open or closed cell structures. In addition to reducing drying shrinkage and thus gel cracking, whisker reinforcement significantly increases the strength of the composite foams relative to pure silica foams. [

Preparation of Fibrous, Porous Hydroxyapatite Ceramics from Hydroxyapatite Whiskers

“…5 Porous HAp ceramics with improved strength may be fabricated using HAp fibers or whiskers. Fibrous, porous materials are known to exhibit improved strength due to interlocking of the fibers, 6 crack deflection, 7 and/or pull-out. 7 Moreover, the HAp fibrous skeleton may be an appropriate reinforcement for HAp/polymer biodegradable bone substitutes.…”

“…Fibrous, porous materials are known to exhibit improved strength due to interlocking of the fibers, 6 crack deflection, 7 and/or pull-out. 7 Moreover, the HAp fibrous skeleton may be an appropriate reinforcement for HAp/polymer biodegradable bone substitutes. 8 There are a few reports concerning fabrication of fibrous, porous calcium phosphate ceramics.…”

Processing Routes to Macroporous Ceramics: A Review

“…68 Figure 4 shows that the strut flaws reduce the compressive strength of replica-derived porous ceramics to levels usually lower than the strength theoretically predicted for open cell structures. 76 Many attempts have been made to avoid this shortcoming by, for instance, improving the wetting of the suspension on the sponge with the help of additives, 21,25 performing a second impregnation step to fill the cracks in the ceramic struts, [17][18][19]22 and introducing fibers 77,28 or reactive compounds 25 to enhance the material's Impregnation with preceramic polymers SiOC-C composites 63 Liquid precipitation of precursors Macroporous zeolites, 64 Calcium phosphate-based composites integrity. In contrast to ceramic suspension-derived reticulated structures, cellular materials obtained from preceramic polymers have crack-free struts due most likely to the improved wetting on the sponge and the partial melting of the cross-linked polymer during pyrolysis.…”

Tailoring Porosity and Pore Characteristics in Oxide Ceramic Foams through Controlled Processing

“…The sintered composite foams had three times higher flexural strength as compared to the unreinforced foams for the same total porosity. 59 A unique process based on sol-gel processing that results in porosity in the range of 94-99% and yet has closed cells has been reported. Grader et al 60 utilized crystals of aluminum chloride isopropyl ether complex AlCl 3 (Pr i 2 O) as the precursor to produce the alumina foams.…”