Single flux method

Borides have been prepared as single crystals by making use of gas-phase, liquid-phase and flux methods, depending on the thermal stability of the boride and on the required size and perfection of the single crystals. 

Table 1. Growth Cond[tions of Some Boride Single Crystals Obtained by the Flux Method... 

This method emplosrs a molten flux which dissolves the material and re-deposits it upon a seleeted substrate. That is, the molten flux acts as a transport medium. The temperature of the flux can be varied to suit the material and to promote high solubility of the solute material in the molten solvent. One example is YIG", yttrium iron garnet, i.e.- Y3FesOi2 -This material is used in the Electronics Industry as single crystals for microwave generating devices. It can be grown via the molten flux method. 

Single crystals of WC were grown by two methods the flux method and the floating zone method. In the flux method, a mixture of 14 mol%WC and... 

Most of the single crystals used for physical investigations have been grown by the flux method (Xu et al., 1994 Canfield and Fisher, 2001). Single crystals with... 

An attractive method to produce single crystals (in the dimension range from pm to several nun) is the high-temperature solution (flux) method, becanse of its simphcity and the low temperature required. The elements are dissolved in the solvent metal (often Al) and subseqnently the solntion is slowly cooled to room temperature. A prerequisite is, of course, that the solubility of the used solvent in the desired boride is insignificant. The solubility of Al in most boron-rich binary borides has been found to be extremely small. Crystals prepared in this manner are suitable for measurement of physical properties, for instance, microhardness, electrical resistivity, and so on. 

The flux method is a well-known method used for single crystal growth. It has not been applied to the synthesis of fine powders because usually high temperature heating is necessary to obtain molten salts. However, the modified flux method has been reported for the preparation of fine panicles of Ce,. Pr Oj solid solutions.In the preparation of the powders by the flux method, molten salts of alkali metal hydroxides, nitrates, and chlorides are used as solvents. The use of molten salts. 

A detailed investigation about the growth of cobalt ferrite single crystals through a borax flux method and its characterization was reported by Wang and Ren [40]. 

The classical calibration of NAA methods involves comparison of sample activities with those of co-irradiated standards of the same element. Especially at multi-element analysis, the need for a large number of standards has limited the sample throughput capacity. To circumvent this, alternative calibration techniques have been elaborated. The single comparator method makes multi-element determinations possible, by use of a single element standard (neutron flux monitor). The mass of the analyte is calculated by use of an experimentally determined element-specific factor (k-value), valid for the analytical equipment in question (Girardi et al., 1965 Linekin, 1973 Simonits et al., 1975). Later, a more generalized standardization method, based on accurately determined constants for the active compound nuclei (ko-factors), and applicable to various analytical equipments, has been proposed (Moens et al., 1984 De Code et al., 1987). 

Single crystals of the T1 (1223) phase of the Tl-Sr-Ca-Cu-0 system are prepared by a conventional flux method. An example of the starting composition is... 

Figure 6-15. Ce02 single crystals grown by the flux method. (Reproduced with permission from ref. 111. Copyright 1967 Elsevier LTD.)...

The Y concentration in the BaO-CuO liquid is very low. Therefore, the self-flux method, which is commonly used to obtain single crystals in incongruent melting systems, might not be helpM in production of large crystals. 

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