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The effect of different platinum concentrations as nucleation agent in the BaO/SrO/ZnO/SiO2 glass system

Vladislavova, Liliya, Kracker, Michael, Zscheckel, Tilman, Thieme, Christian, Rüssel, Christian
Journal of materials science 2018 v.53 no.16 pp. 11204-11215
X-ray diffraction, crystallization, differential scanning calorimetry, energy-dispersive X-ray analysis, glass, glass transition temperature, heat treatment, microstructure, platinum, scanning electron microscopy, thermal expansion
The recently reported solid solution of Ba₁₋ₓSr ₓ Zn₂Si₂O₇ has a similar structure to the high-temperature phase of BaZn₂Si₂O₇ and possesses a coefficient of thermal expansion close to zero or even negative. Without nucleating agents, glasses in this system show solely surface crystallization. In order to stimulate volume crystallization, different quantities of platinum were added to the glass. The characteristic temperatures of the glasses were obtained by differential scanning calorimetry. In order to achieve volume crystallization, a two-step thermal treatment (nucleation and crystal growth) above the glass transition temperature was carried out. The phase identification was performed by X-ray diffraction, and the microstructure was studied by scanning electron microscopy including energy-dispersive X-ray spectroscopy and electron backscatter diffraction.