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Mixed modifier effect in lithium‐calcium borosilicate glasses
Author(s) -
Shih YuehTing,
Jean JauHo
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15059
Subject(s) - borosilicate glass , lithium borate , dielectric , boron , activation energy , analytical chemistry (journal) , materials science , lithium (medication) , mineralogy , glass transition , dielectric loss , indentation hardness , borate glass , electrical resistivity and conductivity , softening point , atmospheric temperature range , chemistry , composite material , thermodynamics , microstructure , medicine , polymer , optoelectronics , organic chemistry , chromatography , engineering , electrical engineering , endocrinology , physics
The mixed modifier effect ( MME ) in the lithium‐calcium borosilicate glasses, which have a composition of 0.4[(1− x )Li 2 O– x CaO ]–0.6[(1− y )B 2 O 3 – y SiO 2 ] with x in the range of 0~1 and y in the range of 0.33~0.83, is investigated. The MME manifests itself as a positive deviation from linearity in the activation energy of electrical conductivity (Ea σ ) and as a negative deviation from linearity in the fraction of four‐coordinated boron ( N 4 ), glass transition temperature ( T g ), dilatometric softening temperature ( T d ), Vickers microhardness (H v ), dielectric constant (ε), and dielectric loss (tanδ). Moreover, the deviation, which exhibits a maximum at [CaO]/([CaO]+[Li 2 O])=0.5, is enhanced with increasing [SiO 2 ]/[B 2 O 3 ] ratio in the glass network. The observed MME in T g , T d , and H v are attributed to the bond weakening in the network; however, the MME in ε, tanδ, and Ea σ are caused by the obstruction of modifier transport in the glass network.