SVIBOR - Papers quoted in CC - project code: 2-15-023
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Papers quoted in Current Contents on project 2-15-023
Quoted papers: 4
Other papers: 29
Total: 33
Title: The Influence of Dopants on Nucleation and Growth of
High-Quartz Solid Solution in Lithium-Aluminosilicate Glass
- Authors:
- Tkalčec, Emilija (49605)
- Šenija, Davor (180533)
- Dondur, Vesna
- Petranović, Nada
Journal: J. Am. Ceram. Soc.,
Number: 7
ISSN: 0002-7820
Volume: 75
Year: 1992
Pages: from 1958 to 1963
Number of references: 15
Language: engleski
Summary: The kinetic parameters of nucleation and crystal growth of
high-quartz solid solution in multicomponent lithium aluminosilicate
glasses doped with various transition-metal ions were studied by
non-isothermal DTA. The crystallization of glasses nucleated at different
temperatures was carried out,and plots of the DTA peak versus the
nucleation temperatures were used to determine the maximum nucleation rate
temperature. Peak temperature data of nucleated samples at varying heating
rates(5-20K/min) were used to determine the activation energy for
crystallization via the JMA equation. The temperature of maximum nucleation
rate depends greatly on the doped transition-metal ions present.The
activation energy for crystallization obtained for undoped glass or glass
doped with Fe2O3 is of the same order as that already published,and the
Avrami exponent is consistent with predominantly three-dimensional crystal
growth.The much higher activation energy values for glasses doped with CoO
could be a consequence of two crystallization processes proceeding
simultaneously.
Keywords: glass, kinetics, nucleation, crystal growth, quartz.
Title: Determination of kinetic parameters for nucleation and
growth from DTA data."
- Authors:
- Bezjak, Aleksandar (3466)
- Tkalčec, Emilija (49605)
- Ivanković, Hrvoje (107251)
- Ereš, Milica
Journal: Thermichimica Acta
ISSN: 0040-6031
Volume: 221
Year: 1993
Pages: from 23 to 29
Number of references: 16
Language: engleski
Summary: A mathematical model has been derived for non-isothermal
kinetic analysis from overlapped exotherm and endotherm DTA effects
occuring due to simultaneous nucleation and growth processes. In the course
of the mathematical treatment the refinement of the initial values of the
kinetic parameters is performed. The procedure for the determination of
kinetic parameters from DTA has been demonstrated on a model system and on
a kinetic analysis of mullite formation from diphasic gel.
Title: Crystallization of High-Quartz Solid Solution in Gahnite
Glass-Ceramics
- Authors:
- Tkalčec, Emilija (49605)
- Ivanković, Hrvoje (107251)
- Gržeta, Biserka
Journal: J. Non-Cryst. Solids
ISSN: 0022-3093
Volume: 129
Year: 1991
Pages: from 174 to 182
Number of references: 13
Language: engleski
Summary: The crystallization of ZnO-(MgO)-Al2O3-B2O3-SiO2 glasses,
having molar ratio ZnO/Al2O3=1 and variable content of MgO, with TiO2 or
ZrO2 or both as nucleating agents, has been studied. Phase composition and
microstructure of the obtained glass-ceramics were examined by XRD,SEM, EDX
and TEM analyses. The maincrystalline phase obtained is gahnite, ZnAl2O4.
High-quartz solid solution,as an additional phase, crystallizes in glasses
containing ZrO2 or ZrO2+TiO2 as nucleating agents. When ZrO2 is present
alone,the unit cell parameter, a, of high quartz solid solution decreases
linearly with temperature. However,if TiO2 is added as another nucleating
agent, a non linear dependence of the parameter, a, on temperature occurs.
Inside the primary separated droplet-shaped phase, from which gahnite
precipitates,B2O3 is concentrated in the centre and extends radially to the
phase boundary,including a specific microstructure of gahnite.
Title: Monofazni mulitni gelovi s dodatkom kroma
- Authors:
- Nass, Rudiger
- Tkalčec, Emilija (49605)
- Ivanković, Hrvoje (107251)
Journal: J. Am. Ceram. Soc.,
ISSN: 0002-7820
Volume: 78
Year: 1995
Language: engleski
Summary: The influence of chromium on homogeneity of gels and on
mullite formation at 980oC was examined by DTA coupled with quadrupole mass
spectrometry (QMS), X-ray diffraction and SEM, EDX and TEM analyses.
Mullite precursors were prepared according to the method which provides
completely homogeneous gels in Al2O3-SiO2 system, with a constant molar
ratio of (Al+Cr)/Si=3/1 and various Al/Cr ratios. DTA and QMS analyses
revealed the same process of dehydration, combustion of organic, as well as
the decomposition of nitrates independently of chromium content. The
differences were observed in the crystallization path at 980oC. Under
nonisothermal conditions, two processes of mullite crystallization were
observed, which were apparent as an discontinuity of mullite a-axis vs.
temperature. Under isothermal conditions, gels segregation is suppressed;
therefore, only one crystallization process of mullite was observed.
Keywords: Chromium, sol-gel synthesis procedure, mullite, differential thermal analysis, isothermal and nonisothermal crystallization, quadrupole mass spectrometry, X-ray diffraction.
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