Growth Mechanism of 123 Columnar Crystal in Superconducting YBCO Oxide
Growth Mechanism of 123 Columnar Crystal in Superconducting YBCO Oxide
复制标题
超导YBCO氧化物中123柱状晶的生长机理
DOI：
10.2320/jinstmet1952.58.12_1444
复制
发表时间：
1994
影响因子：
--
通讯作者：
K. Ōgi
中科院分区：
文献类型：
--
作者：
N. Mori;K. Ōgi
The growth mechanism of 123 crystals is investigated to explain how the 123（YBa2Cu307＿κ）columnar crys− tal grows with a facet interface from liquid十211（Y2BaCuO5）through a peritectic reaction with solute diffusion in liquid． The following relation is conducted between 123 growth rate（R）and undercooling（∠」乃。＝π一コ》，π：in− terface temperature，乃：peritectic temperature）by the analysis of kinetics for 123 crystal growth， which occurs by sequential three primitive processes：（1）growth of the 123 phase，（2）melting of the 211 phase，（3）diffusion of solute in liquid． 1〜＝（Cα／η）・｛（M乙・∠1η》〇十∠Cκ）／（27》／窺L123十α・η）／甥乙211）｝2， where Cσis a constant，ηis the viscosity， ル琵＝1／甥L123−1／勉L2ユユ，〃za23 and〃zム21ユare the gradients of liquidus of 123 and 211，∠Cκis the change in equilibri− um solute concentration caused by surface energy of 211 particles at the 123 freezing front，αis a constant． This relation agrees well with the experimental results． The following approximate relation is also obtained between the maximum radius（7）of 211 particles which melts in the diffusion layer and the distance（灘）from the 123 freezing front． transition