Diphase composites

In the above example PZT is connected to itself in one direction while the polymer phase is interconnected in all three dimensions (1-3 connectivity). Other types of connectivities in ceramic-polymer diphasic composites (such as 2-3 or 3-3 composites) can be visualied, as in Fig. 6.57. In a 2-3 connected diphasic composite, we can, in principle, exploit two different properties of the ceramic in two different directions, or the same property in an additive manner. 3-3 composites have been made by the so-called replamine lost-wax technique. A natural template for 3-3 connectivities is... 

Figure 10.8 Schematic diagram representing a diphase composite with piezomagnetic phase as matrix and piezoeiectric phase dispersed with 0-3 connectivity. The figure shouid be considered as a schematic to...

The ways of connectivity of the separate ceramic and polymer phases of composite were arranged by Newnham et al. [15]. In accordance with their idea, each phase in a composite may be self-connected in zero, one, two, or three dimensions. In the case of diphasic composites, there are 10 connectivities, designated as (MX l-O. 2-0, 3-Ot l-L 2-1, 3-1, 2-2, 3-2, and 3-3 (The 10 different connectivities are illustrated after Newnham [15,16] in Figure 1 using a cube as the basic building block). In general, for n phases the number of connectivity patterns is (n -f 3)t/3ln . 

A sum property is one where the composite coefficient depends on the corresponding coefficients of the individual phases. For example, the permittivity of a two-phase (or diphasic) composite is given by... 

Fig. 6. Connectivity patterns for a diphasic soHd showing zero-, one-, two-, or three-dimensional connectivity of each phase to itself. In the 3—1 composite, for instance, the shaded phase is three-dimension ally connected. Arrows are used to indicate the connected directions.

Table 7.2 Compositions of the Acetonitrile/[C4C Im][PF ]/Water Diphasic Liquid Systems Shown in Figure 7.5...

Figure 6.57 Ten connectivity patterns for a diphasic solid. Each phase has zero-, one-, two-, or three-dimensional connectivity to itself. In the 3-1 composite, for example, the shaded phase is three-dimensionally connected and the unshaded phase is one-dimensionally connected. Arrows are used to indicate the connected directions. Two views of the 3-3 and 3-2 patterns are given because the two interpenetrating networks are difficult to visualize on paper. The views are related by 90° counterclockwise rotation about Z. (After Newnham Cross, 1981.)...

Figure 4.27. Changes in the Si spectra of A. monophasic, and B. diphasic gels of mullite composition on heating. Note the predominantly aluminosilicate resonance (— 85 ppm) in the monophasic gel at lower temperatures, compared with the predominantly siliceous resonance (— 108 ppm) in the diphasic gel. From Jaymes et al. (1996), by permission of copyright owner.

Figure 4.29. Effect of grinding on the Si spectra of the alumina-silica system. A. Mixture of gibbsite, Al(OH)3 and silica gel, and B. Diphasic gel of mullite composition. Note in both systems the evidence of Si-O-Al bond formation (peak at about — 84 ppm). Adapted from Temuujin et al.

Duxin N ef a/1997 Nanosized Fe-Cu-B alloys and composites synthesized in diphasic systems J. Phys. Chem. B 101 8907... 

The YbCo.gj carbide reported by Haschke and Eick (1970a) was not verified to exist in the ytterbium-carbon system by other workers. Its crystal structure was not determined by these authors. In contrast, the two forms of the YCq.s+z compound, the face-centered cubic Fe4N-type form and the rhombohedral CdCl-type form, have been well determined. Their lattice parameters are in good agreement with the systematic variation between those of the other heavy lanthanide hypocarbides, although the composition range for this diphase mixture was not determined. The only information about this material was provided by Spedding et al. (1958). They reported that a carbon-rich YbsC compound exists. 

Table 2.3 List of some non-setting non-allogenic pastes with indication of producer, product name, composition and form (pre-mixed or to be mixed). Denominations HA = Hydroxyapatite / -TCP = / -Tricalcium phosphate BCP = diphasic calcium phosphate (composite between HA and /3-TCP) CMC = carboxymethylcellulose H PMC hydroxypropylmethylcellulose... 

Duxin, N., Brun, N., BonviUe, R, CoUiex, C., Pileni, M.P. Nanosized Fe-Cu-B alloys and composites synthesized in diphasic systems. 1. Phys. Chem. B 101, 8907-8913 (1997)... 

Komarneni S., Roy R. MulUte derived from diphasic nanocomposite gels. In Ceramic Transactions MuUite and MulUte Matrix Composites, Vol. 6S, Davies R.F., Pask J.A., eds. Ohio American Ceramic Society, 1990... 

Thus, a wide range of surface chemistries are possible. These classes of reactions are not limited to catalyst formation, however they also represent potential routes for composite (diphasic) structures, optical and electronic materials, and sensors. This is obviously a promising area for future research. Additional information concerning these types of reactions is found in refs. [113-120]. 

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