Annealing texture

Placencia D, Wang WN, Shallcross RC, Nebesny KW, Brumbach M, Armstrong NR (2009) Organic photovoltaic cells based on solvent-annealed, textured titanyl phthalocyanine/Ceo heterojunctions. Adv Fund Mater 19 1913... 

The important process variables that affect the annealing texture are grain boundary mobility and major deformation texture (or degree of cold work), preferred orientation of nuclei of the recrystallized grains, composition, initial grain size, and annealing temperature and time. 

The development of a sharp COE texture in the finished strip requires complex control of numerous variables. The conventional commercial process (18) involves hot-rolling a cast ingot at ca 1370°C to a thickness of about 2 mm, annealing at 800—1000°C, and then cold-rolling to a final thickness of 0.27—0.35 mm in two steps of 70 and 50%, respectively, with a recrystallization (800—1000°C) aimeal in between. The cold-roUed strip is decarburized (800°C) to ca 0.003% C in mixtures of wet results in a primary recrystallized stmcture containing grains of the COE... 

The present review shows how the microhardness technique can be used to elucidate the dependence of a variety of local deformational processes upon polymer texture and morphology. Microhardness is a rather elusive quantity, that is really a combination of other mechanical properties. It is most suitably defined in terms of the pyramid indentation test. Hardness is primarily taken as a measure of the irreversible deformation mechanisms which characterize a polymeric material, though it also involves elastic and time dependent effects which depend on microstructural details. In isotropic lamellar polymers a hardness depression from ideal values, due to the finite crystal thickness, occurs. The interlamellar non-crystalline layer introduces an additional weak component which contributes further to a lowering of the hardness value. Annealing effects and chemical etching are shown to produce, on the contrary, a significant hardening of the material. The prevalent mechanisms for plastic deformation are proposed. Anisotropy behaviour for several oriented materials is critically discussed. 

Preliminary room temperature x-ray data of 0.65 Me4C00-PECH indicates that the sample presents a highly ordered smectic mesophase which was not yet completely assigned. The textures seen by polarized optical microscopy are also typical of smectic phases. Due to the very high molecular weights involved, textures specific to mesophase in thermodynamic equilibrium could not be developed within a reasonable amount of time by annealing. 

The electrodeposited precursor films, annealed in air at 870 °C in the presence of a TBSBCCO pellet, produce a biaxial textured Tl-1223 phase, as confirmed by an XRD pole-figure measurement. The omega and phi scans indicate full-width at half-maximum (FWHM) values of only 0.92° and 0.6°, respectively, which indicates a very high-quality film. The superconductive transition temperature of the Tl-1223 film, determined resistively, was about 110 K. Figure 7.11... 

The dry nematic solution exhibits a smooth texture after being annealed, with a field of disclinations at any glass-solution interface. A nematic phase produced by cooling the isotropic phase will exhibit a complex, mottled texture that slowly anneals to the smooth texture. The ratio Rvv(q)/ Hv(q) (for e = 20 deg.) for either morphology indicates appreciable orientational averaging of the orientation fluctuation. Photon correlation scattering on the... 

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