TY - JOUR
T1 - Effect of ZnF2 addition on the crystallization behaviour of a zinc borosilicate glass
AU - Kullberg, A. T. G.
AU - Lopes, A. A. S.
AU - Monteiro, Regina C. C.
N1 - This work is funded by FEDER funds through the COMPETE 2020 Programme and National Funds through FCT - Portuguese Foundation for Science and Technology under the project UID/CTM/50025/2013, and by the project M-ERA.NET/0010/2012.
PY - 2017/7/15
Y1 - 2017/7/15
N2 - A series of zinc borosilicate glasses with a molar composition (65-x) ZnO-x ZnF2-15B(2)O(3)-20SiO(2), where x ranged from 0 to 5 mol%, were prepared by a melt quenching technique. The effect of zinc fluoride (ZnF2) substitution for ZnO on the structural, thermal and crystallization features of the glasses was investigated. Structural information via vibration modes was provided by FTIR analysis that revealed an increased band definition and intensity for the highest content of ZnF2. The incorporation of F- ions caused the Si-O-Si bond breakage and appearance of non-bridging oxygens in the network. DTA results indicated that ZnF2 addition decreased slightly the onset and peak crystallization temperatures, lowering the thermal stability of the glasses. XRD analysis of glasses heat-treated at 615 C revealed the formation of willemite (Zn2SiO4) crystals, which was enhanced in glasses containing the highest ZnF2 addition. Microstructural observations by SEM of heat-treated glasses confirmed that the amount and the mean size of willemite crystals precipitated within the glass matrix increased with the addition of ZnF2, which acted as a crystallization promoting agent.
AB - A series of zinc borosilicate glasses with a molar composition (65-x) ZnO-x ZnF2-15B(2)O(3)-20SiO(2), where x ranged from 0 to 5 mol%, were prepared by a melt quenching technique. The effect of zinc fluoride (ZnF2) substitution for ZnO on the structural, thermal and crystallization features of the glasses was investigated. Structural information via vibration modes was provided by FTIR analysis that revealed an increased band definition and intensity for the highest content of ZnF2. The incorporation of F- ions caused the Si-O-Si bond breakage and appearance of non-bridging oxygens in the network. DTA results indicated that ZnF2 addition decreased slightly the onset and peak crystallization temperatures, lowering the thermal stability of the glasses. XRD analysis of glasses heat-treated at 615 C revealed the formation of willemite (Zn2SiO4) crystals, which was enhanced in glasses containing the highest ZnF2 addition. Microstructural observations by SEM of heat-treated glasses confirmed that the amount and the mean size of willemite crystals precipitated within the glass matrix increased with the addition of ZnF2, which acted as a crystallization promoting agent.
KW - Borosilicate glasses
KW - Glass crystallization
KW - Willemite crystals
KW - Zinc fluoride
UR - http://www.scopus.com/inward/record.url?scp=85018371568&partnerID=8YFLogxK
U2 - 10.1016/j.jnoncrysol.2017.04.030
DO - 10.1016/j.jnoncrysol.2017.04.030
M3 - Article
AN - SCOPUS:85018371568
SN - 0022-3093
VL - 468
SP - 100
EP - 104
JO - Journal of Non-Crystalline Solids
JF - Journal of Non-Crystalline Solids
ER -