Containerless solidification of undercooled SrO–Al₂O₃ binary melts

Abstract

The solidification of the SrO-Al2O3 binary system was investigated under containerless conditions using an aerodynamic levitation furnace. Glass formation was observed in compositions with 35-45 mol% SrO and 55-75 mol% SrO. Cooling curves were obtained at a constant cooling rate in the range of 1-1000 °C s(-1). The crystallization temperature was apparently independent of the cooling rate and far below the melting point when the sample was fully crystallized, whereas it decreased when the sample was partially crystallized. The difference between the crystallization temperature and the melting point under containerless conditions is considered a good measure of the glass-forming ability when there is not much difference in the critical cooling rates between the melt compositions. Furthermore, the homogeneous nucleation theory suggests that the apparent time-independent crystallization temperature is attributed to the high glass-forming ability of the SrO-Al2O3 binary system. The results suggest that the experimentally obtained continuous cooling transformation diagrams under containerless conditions provide new insights regarding solidification from an undercooled melt.

Mixed alkaline‐earth effects on several mechanical and thermophysical properties of aluminate glasses and melts

“…Second, all the yAl 2 O 3 •xSrO• (100‐ y ‐ x ) CaO glasses can be easily prepared utilizing the laser‐heated aerodynamic levitation furnace (ALF) built at Wuhan University of Technology. For the glass‐forming regions through the similar equipment in the Al 2 O 3 ‐SrO and Al 2 O 3 ‐CaO systems, see the recent report . Therefore, a series of aluminate glasses with the compositions (mol%): 58Al 2 O 3 •xSrO• (42‐ x ) CaO ( x = 0, 10.5, 21, 31.5, 42 molar percent), were prepared by melting a batch of Al 2 O 3 , CaO and SrO powder with the purity of 99.99%.…”

Understanding the structure, thermal, and optical properties in Al2O3‐incorporated La2O3‐TiO2‐Nb2O5 glasses

“…However, TiO 2 ‐based glasses without any conventional network‐former can only be prepared by containerless processing due to their poor glass‐forming abilities 6−8 . To date, TiO 2 ‐based, Nb 2 O 5 ‐based, 9−11 Al 2 O 3 ‐based, 12−14 and Ga 2 O 3 ‐based 15−17 glasses have been vitrified by containerless processing technique. Arai et al 18 synthesized a La 4 Ti 9 O 24 glass, which exhibited a high refractive index of 2.231 at 1313 nm.…”

Effect of rare‐earth ion size on elasticity and crack initiation in rare‐earth aluminate glasses

“…Al 2 O 3 ‐based glasses are generally difficult to fabricate in bulk because of their low glass‐forming ability. A levitation technique that promotes deeper undercooling and avoids crystallization of the melt allows the production of bulk glasses with a small size, for example, A O–Al 2 O 3 ( A = alkaline‐earth elements), Al 2 O 3 –SiO 2 , R 2 O 3 –Al 2 O 3 ( R = are earth elements), and Ta 2 O 5 –Al 2 O 3 . It has already been reported that Al 2 O 3 –SiO 2 and Ta 2 O 5 –Al 2 O 3 glasses have fascinating mechanical properties.…”

“…(R = are earth elements), and Ta 2 O 5 -Al 2 O 3 . 11,22,[24][25][26] It has already been reported that Al 2 O 3 -SiO 2 and Ta 2 O 5 -Al 2 O 3 glasses have fascinating mechanical properties. In this paper, we report the elastic properties and crack initiation in a variety of rare-earth aluminate glasses.…”