ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The nucleation and crystallization kinetics of P2O5-B2O3-ZnO-BaO-Al2O3-TiO2 crystals inbulk glass in which this crystals were found to crystallize in the heating process of the glass, werestudied by non-isothermal measurements using differential thermal analysis (DTA). A nucleationrate-temperature was determined by plotting either the reciprocal of the temperature corresponding tothe crystallization peak maximum, 1/Tp, or the height of the crystallization peak, (*T)p, as a functionof nucleation temperature, Tn. The temperature where nucleation can occur for this glass ranges from700°C to 890°C and the temperature for maximum nucleation is 760±5°C. The correct activationenergy for crystallization, Ec, for this glass is the same for surface and/or bulk crystallization, and is533±15°CkJ/mol. The analysis of the crystallization data with the Kissinger equation and the Marottaequation yields the correct value for Ec only crystal growth occurs on a fixed number of nuclei. Thecrystallization process of a sample heat treated at the temperature of the maximum nucleation rate wasfitted to kinetic equations with an Avrami constant, n ≈2 and a dimensionality of crystal growth, m ≈2
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.569.153.pdf
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