首页   按字顺浏览 期刊浏览 卷期浏览 Kinetics of Cation Redisribution in Ferrospinels
Kinetics of Cation Redisribution in Ferrospinels

 

作者: K. Sujata,   Thomas O. Mason,  

 

期刊: Journal of the American Ceramic Society  (WILEY Available online 1992)
卷期: Volume 75, issue 3  

页码: 557-562

 

ISSN:0002-7820

 

年代: 1992

 

DOI:10.1111/j.1151-2916.1992.tb07842.x

 

出版商: Blackwell Publishing Ltd

 

关键词: cation exchange;ferrites;spinels;mechanism;kinetics

 

数据来源: WILEY

 

摘要:

In situ electrical resistivity measurements were employed to follow the kinetics of cation redistribution in ferrospinels,xFe3O4–(1 –x)MeFe2O4(Me = Co, Mg, Mn, or Ni) orxFe3O4–FeMe2O4(Me = Al) withx≥ 0.2. Relaxation temperatures (at 20°C/min heating rate) were established and kinetic parameters—activation energies and time constants—were determined for each cation. These parameters were insensitive to grain size, cation ratio, and oxygen nonstoichiometry. The mechanism was shown to be a local “homogeneous” point defect reaction in contrast to the “heterogeneous” nucleation and growth mechanism reported to take place in ferrispinels lacking Fe2+. Electron hopping between Fe2+and Fe3+in ferrospinels apparently screens the excess ionic charge associated with the diffusing species and enables homogeneous point defect reactions with lower attendant activation en

 

点击下载:  PDF (703KB)



返 回