Heat treatment colorants obtained

The color obtained is a function of both the composition and the particle size of the precipitated crystals. A redder color results from both increased selenium to sulfur ratio and from larger crystals, caused by a more severe heat treatment. Hence, it is possible to make, from the same glass, a series of color filter types, by controlled reheating. 

In the manufacture of orange to deep red cadmium sulfoselenides using the precipitation process, selenium is dissolved in the sodium sulfide solution in an amount consistent with the color required. Particularly brilliant hues are obtained, if the precipitated raw colorant undergoes brief heat treatment in molten salt at ca. 800°C whereby an optimum particle size of ca. 0.2 to 0.4 pm can be obtained. 

Transparent colored YAG ceramics doped with Ti and Zr ions as possible broad-band materials for tunable and ultra-short pulses lasers were obtained. The procedure of doped ceramics fabrication included chemical co-precipitation, precursors heat treatment, YAG powder grinding, high pressure colloidal slip-casting for nanopowders compaction and vacuum sintering of performs at 1730-1800 C. Absorption spectra of Zr ceramics samples are similar to the spectra of correspondingly doped YAG single crystals. Zr luminescence was observed for the first time. Possibility to obtain laser action is discussed. 

Odell et ah [424] studied the role of heat treatment, which is known to enhance mechanical properties, using PBZT (model) films. The extruded films have a rather poorly developed crystallinity. On heat treatment the films change color from light straw to blue. Dark field EM studies show that the increase in modulus with heat treatment is likely due to the increase in crystal size and perfection. Electron diffraction shows nearly perfect alignment along the fiber direction. However, the fibers exhibit only two dimensional order [421,424,492,493], even though higher modulus can be obtained than from PPTA [422]. 

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