TY - JOUR
T1 - Thermal characteristics and crystallization behavior of zinc borosilicate glasses containing Nb2O5
AU - Monteiro, Regina C. C.
AU - Lopes, Andreia A. S.
AU - Lima, Maria M. R. A.
AU - Veiga, João P. B.
N1 - This work was supported by Project M-ERA.NET/0010/2012 and by FEDER funds through the COMPETE 2020 Program and National Funds through FCT - Portuguese Foundation for Science and Technology under the project number POCI-01-0145-FEDER-007688 , Reference UID/CTM/50025. Authors thank N. Fernandes for help with the preparation of glass samples.
PY - 2018/7/1
Y1 - 2018/7/1
N2 - Glasses based on the molar composition 60ZnO·(40-x)B2O3·xSiO2, x = 10 or 20, with small additions of Nb2O5 (2.5, 5, 7.5 and 10 mol%), were prepared by melt-quenching. Increasing the Nb2O5 content decreased the glass transition and softening temperatures. Thermal stability increased with Nb2O5 addition and it was higher for glasses based on the composition having the highest SiO2 content. The thermal expansion coefficient tended to increase with the Nb2O5 amount. Zinc borate and zinc niobate were identified in glasses containing Nb2O5 ≤ 5 mol%, however in glasses based on the highest SiO2 composition, an additional crystalline phase, willemite, was detected. At the highest Nb2O5 additions, willemite formation was suppressed and zinc niobate plus zinc borate were detected. The non-isothermal crystallization kinetics was investigated, and the effect of Nb2O5 addition and of the base glass composition on the crystallization activation energy and crystallization mechanism was discussed.
AB - Glasses based on the molar composition 60ZnO·(40-x)B2O3·xSiO2, x = 10 or 20, with small additions of Nb2O5 (2.5, 5, 7.5 and 10 mol%), were prepared by melt-quenching. Increasing the Nb2O5 content decreased the glass transition and softening temperatures. Thermal stability increased with Nb2O5 addition and it was higher for glasses based on the composition having the highest SiO2 content. The thermal expansion coefficient tended to increase with the Nb2O5 amount. Zinc borate and zinc niobate were identified in glasses containing Nb2O5 ≤ 5 mol%, however in glasses based on the highest SiO2 composition, an additional crystalline phase, willemite, was detected. At the highest Nb2O5 additions, willemite formation was suppressed and zinc niobate plus zinc borate were detected. The non-isothermal crystallization kinetics was investigated, and the effect of Nb2O5 addition and of the base glass composition on the crystallization activation energy and crystallization mechanism was discussed.
KW - Glass crystallization
KW - Niobium doped oxide glasses
KW - Thermal properties
KW - Zinc borosilicate glasses
UR - http://www.scopus.com/inward/record.url?scp=85053359147&partnerID=8YFLogxK
U2 - 10.1016/j.jnoncrysol.2018.03.054
DO - 10.1016/j.jnoncrysol.2018.03.054
M3 - Article
AN - SCOPUS:85053359147
SN - 0022-3093
VL - 491
SP - 124
EP - 132
JO - Journal of Non-Crystalline Solids
JF - Journal of Non-Crystalline Solids
ER -