Effect epitaxial

Epitaxial effects are not limited to single-crystalline substrates. The possibility for substrate-induced epitaxial development in the difficult case of ZnSe (cf. conventional electrodeposition) has been established also by using strongly textured, albeit polycrystalline, zinc blende (111) CdSe electrolytic films to sustain monolithic growth of ZnSe in typical acidic selenite baths [16]. Investigation of the structural relations in this all-electrodeposited ZnSe/CdSe bilayer revealed that more than 30-fold intensification of the (111) ZnSe XRD orientation can be obtained on the textured (111) CdSe films, compared to polycrystalline metal substrates (Fig. 4.2). The inherent problems of deposition from the Se(IV) bath, i.e., formation of... 

Strictly speaking, it is difficult to conclude which model is most reasonable. However, summing up the results obtained by the surface analyses, it is sure at least that bismuth molybdates are concentrated on the surface of the catalyst particle. Our investigations for Mo-Bi-Co2+-Fe3+-0 also support the conclusion mentioned above, and the core-shell structure proposed by Wolfs et al. may be essentially reasonable. However, since small amounts of divalent and trivalent metal cations are observed in the surface layers, the shell structure may be incompletely constructed. The epitaxial effect has been assumed on the condensation of bismuth molybdates on the divalent and trivalent metal molybdates on the basis of the fact that the y-phase of bismuth molybdate is mainly formed on NiMo04 but the a-phase is predominant on other divalent and trivalent metal molybdates (46). The... 

A solid phase extended upon another solid support may not possess its normal lattice structure due to epitaxial effects it may be more stable as a sheet of leptons, as a patchwork of small two-dimensional platelets, or as disseminated, isolated leptons. 

Anomalous structures (e.g. bcc gold, fee lithium) have sometimes been found these seem to occur most frequently with metals of low sublimation enthalpy, and less often with palladium and platinum. Their formation may be linked to an epitaxial effect of the support on which they are formed and grow. Clearly developed crystal planes were only shown by particles larger than about 2 nm ° Mdssbauer spectroscopy showed a platinum particle with 309 atoms to have the normal fee structure,but palladium-platinum particles suffered electron-beam-induced change from fee to cph. ... 

Particle size, shape and relative areas of different crystal planes can be determined by the way in which metal precursor reacts with the support surface and by epitaxial effects of the support on the metal particle during reduction. 

The epitaxial effect of the KBr surfaces on the nucleation of the y-form crystallites in poly(vinylidene flnoiide) was observed. The acceleration mechanism for y-form crystallization is unknown.It is known that the crystal lattice matching should induce the epitaxial growth of the y-form crystallites on the surfaces of KBr particles. The y-form crystals grow on KBr surfaces with the edge-on lamellar structure, because the lattice of... 

Third, and finally, it has been established that the lanthanide magnetism is in general remarkably robust, and in particular is insensitive to the interfaces, even in crystals only a few atomic layers thick. A reservation of critical importance in this regard is the central role of the state of strain in the description of the magnetic behavior. Specifically it has been established for Dy that epitaxial strains 2% are sufficient to double the Curie temperature or completely suppress the ferromagnetic phase. The twin assets of robustness and strain sensitivity make these materials at one time both ideal systems with which to explore epitaxial effects, and attractive models with which new states of magnetic order may be designed and synthesized. 

An epitaxial effect based on similar lattice parameters (McMillan 1979) presented a theoretical explanation for the favorable nucleating action of metals. Furthermore, mechanical strain was present at the substrate-glass interface, producing a high interfacial energy, as the coefficients of thermal expansion of the metal and the new nucleus were substantially different. As a result, catalyzation of nucleation could also be expected. 

In particular, epitaxial effects can appear at the interfaces. Figure 4.9 shows an HDPE/rubber blend with oriented lamellae perpendicular to the boundaries of the rubber particles. However, such an arrangement of oriented lamellae also appears under shear forces (such as in an extruder). 

A discussion is presented of problems associated with the corrosion of nonmetallic materials and of aspects of solid-state reactions related to corrosion processes. The effects of the various characteristics of surfaces and of attacking agents are considered, and the kinetics and some possible mechanisms of solid-state reactions are briefly reviewed. The effects of transition states, through their influence on reactivity, and of extreme environmental stresses are noted, as are epitaxial effects and effects produced by adsorbed gases. Emphasis is placed on the need for further research on problems of the corrosion of such materials as glasses, ceramics, plastics, and natural and synthetic stones, as well as on the need for interdisciplinary cooperation to help combat these problems. 

In connection with epitaxial effects attention should be drawn to the comparatively new field of biocrystallography. This field is of special importance in regard to the many cases of corrosion caused by attacks by different species of plants and microbes. It is very often overlooked that the first steps in damage to buildings and archaeological objects depend on such pro-... 

Obviously, the epitaxial effect of the neat PBT crystallites contributes to the perfection of the PBT crystallites arising from the copolymer, as concluded from... 

Polymer crystallization behavior near an inorganic surface has been the focus of extensive study. In most cases the inorganic surface is shown to produce a nucleating or epitaxial effect,which often stabilizes the bulk crystal phase or, in some cases, promotes growth of a different crystal phase. The polymer mechanical and thermal properties can be enhanced through this mechanism, where the surface-nucleated crystalline phase has better mechanical and thermal characteristics than the bulk crystal phases. Fillers with large surface area maximize these filler-induced enhancements of the material properties a dramatic manifestation of such a response is found in nylon-6/montmorillonite... 

---