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.com
Volume 5, Issue 5
Res. Rev. J Mat. Sci. 2017
ISSN: 2321-6212
Advanced Materials 2017
September 07-08, 2017
September 07-08, 2017 | Edinburgh, Scotland
Advanced materials & Processing
11
th
International Conference on
Luminescence of morphologically-controlled calcium silicon nitride particles through combined techniques of
ultrasonic spray pyrolysis and carbothermal reduction/nitridation
S. Ono
1
, H. Kuwahara
2
, H. Kuroe
2
and
K. Itatani
1
1
Department of Materials and Life Sciences, Sophia University, Japan
2
Department of Engineering and Applied Sciences, Sophia University, Japan
T
he morphologically-controlled preparations of Eu
2+
-doped calcium silicon nitride (Ca
2-x
EuxSi
5
N
8
: x = 0.05) particles, i.e., the
spherical and columnar particles, were conducted by combined techniques of ultrasonic spray pyrolysis and carbothermal
reduction/ nitridation. Relating to the ultrasonic spray pyrolysis, the precursor oxides for Ca
2-x
EuxSi
5
N
8
particles were prepared by
this technique at 600ºC in air, using Ca(NO
3
)
2
/Eu(NO
3
)
3
solution (total concentration: 2.86 × 10
-2
mol·dm
-3
) with suspended Si
3
N
4
particles. The spray-pyrolyzed powder was further mixed with carbon, and carbothermally reduced in N
2
atmosphere. The spherical
and columnar Ca
1.95
Eu
0.05
Si
5
N
8
particles could be prepared by controlling the heating rate and temperature for carbothermal reduction/
nitridation. The spherical Ca
1.95
Eu
0.05
Si
5
N
8
particles could be obtained when the spray-pyrolyzed powder (or precursor oxides) was
heated to 1000ºC at the rate of 30ºC•min
-1
and then to 1400ºC for 2 h at the rate of 10ºC•min
-1
. On the other hand, the columnar
Ca
1.95
Eu
0.05
Si
5
N
8
particles could be obtained when the spray-pyrolyzed powder was heated to 1100ºC at the rate of 30ºC•min
-1
and then
to 1500ºC for 2 h at the rate of 10ºC•min
-1
. The morphological control was conducted by the kinds of liquid phases formed during
the heating process. The morphological control of Ca
1.95
Eu
0.05
Si
5
N
8
particles could be achieved by the nitridation of spherical and
columnar particles formed at 1000ºC or 1100ºC. The emission peaks of spherical and columnar Ca
1.95
Eu
0.05
Si
5
N
8
particles appeared
at 622 nm and 618 nm, respectively, under the excitation at 375 nm. Overall, the spherical and columnar Ca
1.95
Eu
0.05
Si
5
N
8
particles
could be formed by controlling the heating rate and temperatures for the carbothermal reduction/nitridation of spray pyrolyzed oxide
powders. The spherical and columnar particles emitted the lights with the peak wavelength at 622 and 618 nm under excitation at
375 nm.
Biography
Satoshi Ono is a student of Sophia graduate school. His research interest is preparation and characterization of Si
3
N
4
-containing nitride ceramics.
satoshi0517@eagle.sophia.ac.jpS. Ono et al., Res. Rev. J Mat. Sci. 2017, 5:5
DOI: 10.4172/2321-6212-C1-006
Figure1
:
Morphological changes
of particles with temperature