Fig xA The photograph and optical transmittance
Analysis of the kinetic dependences (Fig. 5 and Fig. 6) of the crystalline phase composition on the crystallization time for the sample Al5(NO3)3(OH)12·3Y(OH)2(OOCCH3) prepared according to the scheme (III) shows that in this case formation of the yttrium aluminum garnet phase is more complete and faster as compared with the sample (I); this phase becomes obviously predominant. The kinetic parameters of the crystallization reactions for the amorphous phase of Al5(NO3)3(OH)12·3Y(OH)2(OOCCH3) (III) are shown in Table 5. As it lgk974 can be seen from Fig. 5, YAG fraction approaches ~100% with an increase in the synthesis temperature and time of the isothermal soaking. At 850 °C, as in the sample (I), YAG is formed directly from the amorphous phase A→YAG, but in competitive exclusion case the reaction A→YAH and “long” chains of reactions A→YAM→YAH→YAG are involved. As distinct from sample (I), at 900 °C the “long” synchronized chain of reactions A→YAM→YAH→YAG makes a substantial contribution to the formation of the garnet, alongside with the reaction A→YAG.