Abstract
During the quenching of a melt with the composition 2SrO·TiO2·2.75SiO2, cubic SrTiO3- and tetragonal Sr2TiSi2O8-crystals are formed at the surface. Subsequent crystal growth leads to dendritic fresnoite structures which become increasingly finer until the mechanism changes to viscous fingering during further cooling. In the final stages of this initial growth step, the crystal orientations of these dendrites systematically change. Due to a complete absence of bulk nucleation in this system, crystal growth is resumed upon reheating to 970°C and fractal growth with the c-axis tilted by about 45° from the main growth direction is observed. The results are interpreted to confirm the link between viscous fingering and dendritic growth in the case of a true crystallization process.
Highlights
During the quenching of a melt with the composition 2SrO?TiO2?2.75SiO2, cubic SrTiO3- and tetragonal Sr2TiSi2O8-crystals are formed at the surface
While a model of reoccurring oriented nucleation of STS was formulated in Ref. 22, where some K2O and B2O3 was added to the composition, this model was questioned in Ref. 5 where it was noted that the crystal growth morphology in Ref. 22 may rather imply dendritic growth
While it must be noted that these simulations concern the interaction of two liquids, crystal growth morphologies indicating tip splitting and possibly viscous fingering have been observed in glass ceramics[25,26]
Summary
During the quenching of a melt with the composition 2SrO?TiO2?2.75SiO2, cubic SrTiO3- and tetragonal Sr2TiSi2O8-crystals are formed at the surface. The additional SiO2 in the glass melt is added to allow comparability to the surface crystallization experiments of barium titanium silicate (BTS1) and STS5 and experiments concerning the electrochemically induced nucleation of fresnoite in glasses[15,16,17,18,19]. Multiple growth mechanisms of one phase have been observed within one glass-ceramic sample, e.g. the dendritic and polygon growth of YAG localized to a stria of slightly different chemical composition[27]. Please note that these mechanisms each lead to single crystalline areas of a certain morphology which is in contrast to agglomerations of single crystals such as spherulites[28] which are not being discussed here
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
