EXAMINATION OF THE MIXED-ALKALI EFFECT IN (LI,NA) DISILICATE GLASSES BY NUCLEAR-MAGNETIC-RESONANCE AND CONDUCTIVITY MEASUREMENTS

被引:40
作者
ALI, F
CHADWICK, AV
GREAVES, GN
JERMY, MC
NGAI, KL
SMITH, ME
机构
[1] UNIV KENT,PHYS LAB,CANTERBURY CT2 7NR,KENT,ENGLAND
[2] UNIV KENT,CHEM LAB,CANTERBURY CT2 7NH,KENT,ENGLAND
[3] DARESBURY LAB,DRAL,WARRINGTON WA4 4AD,CHESHIRE,ENGLAND
[4] USN,RES LAB,WASHINGTON,DC 20375
关键词
GLASSES; SI-29 NUCLEAR MAGNETIC RESONANCE; NA-23 NUCLEAR MAGNETIC RESONANCE; LI-7 NUCLEAR MAGNETIC RESONANCE; ELECTRICAL CONDUCTIVITY; MAGIC-ANGLE SPINNING; ALKALI DISILICATES; MIXED-ALKALI EFFECT;
D O I
10.1016/0926-2040(95)00033-M
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Results from Si-29, Na-23 and Li-7 magic-angle spinning nuclear magnetic resonance (NMR) spectroscopy, Li-7 NMR relaxation and electrical conductivity in a series of [Li-(1-x). Na-x]O-2 . 2SiO(2) (disilicate) glasses are used to investigate the mixed-alkali effect. From the Si-29 NMR spectra there is relatively little change of the network with alkali composition. Na-23 and Li-7 NMR linewidths and shifts change continuously as a function of composition, indicating that the alkali ions are intimately and uniformly mixed rather than separated into lithium and sodium-rich domains. The activation energy from electrical conductivity shows a distinct maximum at the central composition (x = 0.5), whereas the local activation energy for lithium motion determined from NMR shows only a smaller but monotonic increase as the lithium-content decreases.
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页码:133 / 143
页数:11
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