STRUCTURE OF COMMENSURATE AND INCOMMENSURATE ORDERED PHASES IN THE SYSTEM ZRTIO4-ZR5TI7O24

被引:75
作者
CHRISTOFFERSEN, R
DAVIES, PK
机构
[1] Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
关键词
D O I
10.1111/j.1151-2916.1992.tb07843.x
中图分类号
TQ174 [陶瓷工业]; TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
The low-temperature, Zr-Ti-ordered, form of zirconium titanate has been investigated using high-resolution transmission electron microscopy in order to characterize the incommensurate structure of phases with compositions Zr-TiO4 to near Zr5Ti7O24. Electron diffraction reveals that compositions with Zr:Ti between 5:7 and 1:1 have incommensurate superstructures, and phases close to 1:1 are commensurate with an a-axis repeat 2x that of the disordered structure. High-resolution images show that the alpha-doubling in ZrTiO4 corresponds to a new structure, one that consists of two Zr-rich, distorted octahedral layers alternated with two Zr-rich octahedral layers. The incommensurate compositions are composed of blocks of the 1:1 structure intercalated with blocks of the commensurate 5:7 structure, the latter having a tripled a-repeat and a ZTTZTT sequence of cation layers. The intercalation can be described as an "interface-modulated" structure resulting from the quasi-periodic insertion of (100) faults with displacement vector R = -1/3 a(ord) in the ordered 5:7 phase. Although their spacing is variable, the faults are uniformly distributed in such a way as to produce incommensurate satellite reflections. The findings regarding the structure of ordered compositions in the ZrTiO4-Zr5Ti7O24 system provide an improved framework for understanding the effects of ordering on the properties of zirconium titanate dielectric ceramics.
引用
收藏
页码:563 / 569
页数:7
相关论文
共 21 条
[1]  
AMELINCKX S, 1979, MODULATED STRUCTURES, P102
[2]   POWDER NEUTRON-DIFFRACTION STUDY OF ZRTIO4, ZR5TI7O24, AND FENB2O6 [J].
BORDET, P ;
MCHALE, A ;
SANTORO, A ;
ROTH, RS .
JOURNAL OF SOLID STATE CHEMISTRY, 1986, 64 (01) :30-46
[3]   QUANTITATIVE-ANALYSIS OF THIN SPECIMENS [J].
CLIFF, G ;
LORIMER, GW .
JOURNAL OF MICROSCOPY-OXFORD, 1975, 103 (MAR) :203-207
[4]  
COWLEY JM, 1979, MODULATED STRUCTURES, P3
[5]  
COWLEY JM, 1984, DIFFRACTION PHYSICS, P384
[6]   DEFECT INTERGROWTHS IN BARIUM POLYTITANATES .2. BATI5O11 [J].
DAVIES, PK ;
ROTH, RS .
JOURNAL OF SOLID STATE CHEMISTRY, 1987, 71 (02) :503-512
[7]   DEFECT INTERGROWTHS IN BARIUM POLYTITANATES .1. BA2TI9O20 [J].
DAVIES, PK ;
ROTH, RS .
JOURNAL OF SOLID STATE CHEMISTRY, 1987, 71 (02) :490-502
[8]  
FRANZEN HF, 1986, PHYSICAL CHEM INORGA, P116
[10]   ORDERING IN COMPOUNDS OF A(B'0.33TA0.67)O3TYPE [J].
GALASSO, F ;
PYLE, J .
INORGANIC CHEMISTRY, 1963, 2 (03) :482-&