Multicomponent ceramics

Fig. 10. Exploded view of a monolithic multicomponent ceramic substrate. Layers (a) signal distribution (b) resistor (c) capacitor (d) circuit protection ...

The reaction between two (or more) types of solid is finquently practiced to produce multicomponent ceramic powders. Several examples include... 

The sol-gel process was first focused on silica glasses and then on multicomponent ceramics. The aim was to... 

In addition, aUcynyl groups not only inhibit thermally inducted depolymerization, they can also be functionalized by, for example, hydroboration, hydro-silylation, or by attaching transition metal complex fragments. Accordingly, nnits provide an access to multicomponent ceramics. For example, Corriu et al. reported that [SiR2C=C-C=C] are precursors with interpenetrating networks to... 

Sintering with a liquid phase. Solid stale sintering is characteristic particularly for modern technical ceramics most theoretical studies are based on results from sintering pure oxides. Traditional multicomponent ceramics, however, contain liquid phase at sintering temperatures the main problem is then the distribution of the melt in a porous system. 

Alkoxide groups can also bridge two different metal atoms, leading to the formation of heteroalkoxides, which are often used a precursors for the sol-gel synthesis of multicomponent ceramics [15], Condensation can even go one step further, leading to p,-oxo bridges via ether elimination. 

Strongly complexing P-diketones are currently employed to stabilize highly reactive metal alkoxides, such as W(OEt)6 [25]. Aluminum sec-butoxide, modified by ethylacetoacetate (etac), appears to be quite attractive as a precursor for the sol-gel synthesis of multicomponent ceramics, such as cordierite. Al(OsBu)2(etac) is more soluble and less reactive than the corresponding alkoxide [26]. 

Since complicated multicomponent ceramic materials with precise levels of doping are required for some of the new materials that show promise in solid oxide fuel cells, we aim to use the relatively low-cost, simple steric entrapment method to synthesize several solid oxide fuel cell materials, and evaluate some of their characteristics. We have selected lanthanum gallates doped with strontium and magnesium, samarium doped ceria and a promising non-stoichoimetric composition composed of strontium iron and cobalt. 

Padmini, P., Kutty, T.R.N. Wet chemical syntheses of ultrafine multicomponent ceramic powders through gel to crystallite conversion. J. Mater. Chem. 4, 1875-1881 (1994)... 

Based on equivalent circuit models of the cell component resistances [66], maximum ceU performance of SC-SOFCs with coplanar electrodes is predicted for very small electrode widths (6-10 pm) and gap sizes (2-12 pm). Performance comparisons of macro-, miUi-, and microcells [71] revealed a 10 times higher power density for the micro SC-SOFC which had smaller inter-electrode gaps and electrode widths. As closely spaced small-scale electrodes lower the ohmic resistance and the inter-digitated electrode pattern maximizes the electrode surface area, miniaturization of SC-SOFCs with coplanar, interdigitated electrodes is expected to yield suitable cell performance for small- and microscale power applications. The fabrication of microcells (Figure 2.3) presents many challenges and requires the manufacturing of coplanar microscale electrode patterns from multicomponent ceramic materials. 

Mah et al. (14) provides an overview of several double alkoxides for the preparation of multicomponent ceramics. 

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