固溶体晶体中溶质的分布规律——Ⅱ.溴化铊在逐区溶化法生长 KRS-5晶体中的分布

Distribution of Solute in Solid Solution Crystals——Ⅱ.Distribution of TlBr in KRS-5 Crystal Grown by Zone Melting

本文研究逐区熔化法生长固熔体晶体 KRS-5时生长条件对晶体中次要成分 T1Br 分布的影响。实验结果表明:熔区长度 l 影响晶体中 T1Br 的有效分凝系数 K_6;晶体的生长速度范围内,T1Br 的原始浓度 C_o=0.420mol 的情况下,K_6=K_o′+0.0015L;熔区移动速度对 T1Br 分布的影响类似于正常凝固法:K_6=K_o′+0.008v;在 T1Br 原始浓度不变的情况下(C_o=0.420m0l),正常凝固生长和区熔法生长的平衡分凝系数K_6′相同。

In order to investigate the distribution of minor components insolid solution crystal grown by zone melting growth,the distribution of TlBrin KRS-5 crystals grown by this method has been studied.The results of mea-surement for a group of KRS-5 crystal samples grown with the same soluteconcentration and different molten zone lengths at the same travel rate showthat there exists a linear relationship between the effective segregation co-efficiert K_o of TlBr and the molten zone length l,i.e.K_o=K＇_o+0.0015l,where K_o＇is the equilibrium segregation coefficient.As the second term inthe right side of the expression is so small that it can be neglected.Hencethe distribution of TIBr in KRS-5 crystals depends mainly on its equilibriumsegregation coefficient K_o＇.The measurement results of another group of KRS-5 crystal samples grown with the same solute concentration and moltenlength at different zone travel rates indicate that the effect of zone travelrate v on the effective segregation coefficient K_o is similar to that in thecase of normal freezing growth,and it can be expressed as K_o=K＇+0.008v.It is also shown by experiment that in the growth of KRS-5 crystal with thesame solute concentration,the values of TlBr equilibrium segregation coeffi-cient for both the normal freeing growth and the zone melting growth arethe same