Cubic to monoclinic phase transformations in alumina

被引：89

作者：

Levin, I

Bendersky, LA

Brandon, DG

Ruhle, M

机构：

[1] NIST,DIV MET,GAITHERSBURG,MD 20899

[2] MAX PLANCK INST MET RES,INST WERKSTOFFWISSENSCH,D-70174 STUTTGART,GERMANY

来源：

ACTA MATERIALIA | 1997年 / 45卷 / 09期

关键词：

Number:; 040-55; 1; Acronym:; -; Sponsor:;

D O I：

10.1016/S1359-6454(97)00040-2

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Cubic to monoclinic phase transformations in alumina were studied by high-resolution electron microscopy of anodic films annealed at 1200 degrees C. In addition to the known monoclinic theta-Al2O3 structure a new metastable alumina polymorph was identified also with apparent monoclinic symmetry. This new phase appears to evolve from gamma-alumina by cation ordering. The stoichiometric structure of this polymorph is consistent with the C2/m space group and unit cell containing 40 ions (8Al(2)O(3)). Reasonably good fit between experimental and computer-simulated lattice images was obtained for the suggested structural model. The transformations of gamma-Al2O3 to both monoclinic alumina structures were assumed to be non-reconstructive and the possible transformation paths were analyzed in terms of symmetry group/subgroup relationships. (C) 1997 Acta Metallurgica Inc.

引用

页码：3659 / 3669

页数：11