The crystallization of an aluminosilicate glass in the K2O-Al2O3-SiO2 system.
OBJECTIVE
The aims of the study were to explore the nucleation and crystallization kinetics of an aluminosilicate glass in K2O-Al2O3-SiO2 system and to characterize it.


OBJECTIVE
A starting glass composition of wt%; 64.2% SiO2, 16.1% Al2O3, 10.9% K2O, 4.3% Na2O, 1.7% CaO, 0.5% LiO and 0.4% TiO2 was heated in an electric furnace and later quenched to produce glasses. The glass powders were heat treated using differing heat treatment schedules and quenched. Dta, Xrd, Eds and Sem analyses were used to characterize and explore the crystallization kinetics of the glasses.


RESULTS
Phase separation of the glasses was identified and characterized in the glasses. Tetragonal leucite, cubic leucite and sanadine glass-ceramics were produced. Fine leucite crystals (1 microm2) were crystallized with minimal matrix microcracking.


CONCLUSIONS
Amorphous phase separation appeared to be an important precursor to nucleation and crystal growth in the alkali aluminosilicate glasses explored. It was possible to control the crystallization of tetragonal leucite and sanidine phases by selected heat treatment of glass powders and monoliths, resulting in the production of fine grained tetragonal leucite glass-ceramics.
Cattell
Michael J
MJ
Centre for Adult Oral Health, Bart's and the London, Queen Mary's School of Medicine and Dentistry, Turner Street, Whitechapel, London, E1 2AD, UK. m.cattell@qmul.ac.uk
Chadwick
Thomas C
TC
Knowles
Jonathan C
JC
Clarke
Richard L
RL
D000537:Aluminum Oxide / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D004055:Differential Thermal Analysis; D004577:Electron Probe Microanalysis; D005898:Glass / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D007700:Kinetics; D018020:Lithium Compounds / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry; D010316:Particle Size; D017680:Potassium Compounds / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D017670:Sodium Compounds / Q000737:chemistry; D014025:Titanium / Q000737:chemistry; D014961:X-Ray Diffraction
D000538:Aluminum Silicates; D017610:Calcium Compounds; D018020:Lithium Compounds; D010087:Oxides; D017680:Potassium Compounds; D017670:Sodium Compounds; C078519:leucite; C009495:titanium dioxide; C096707:sodium oxide; C068440:potassium oxide; D012822:Silicon Dioxide; C016538:lime; D014025:Titanium; D000537:Aluminum Oxide