This thesis covers the synthesis and the characterization of sodium lanthanide oxide
phosphates, rare earth added strontium pyrophosphates and the Rietveld structural
analysis of rare earth orthoborates. Solid state and microwave-assisted synthesis
method was employed for the synthesis of desired materials. The formation of the
produced phases was confirmed by X-ray Diffraction (XRD), Infrared FT-IR,
Raman, Scanning Electron Microscopy (SEM) methods. By using Rietveld
Refinement method, structural analysis of rare earth orthoborates were done and
three dimensional crystal structures were found.
In the first part of the thesis, some new sodium lanthanide oxide phosphates were
synthesized by solid state reaction method from Ln2O3 (where Ln= La, Nd, Sm, Gd,
Dy, Ho, Er, Yb), Na2CO3, NH4H2PO4 at 1100 oC. Na2LaOPO4, Na2NdOPO4, and
Na2SmOPO4 produced with the space group is Pmm2. With the help of the same
procedure new orthorhombic Na2DyOPO4, Na2HoOPO4, Na2ErOPO4, and
Na2YbOPO4 were synthesized for the first time in the literature at 1100 oC with the
same space group Pmm2.
v
In the second part of the thesis, Sr2P2O7 - ZrP2O7 solid solution was obtained by the
solid state reaction and they were characterized for the first time in literature and
subjected to thermoluminescence measurements showing Sr2P2O7 has glow curve
around 100 oC. Then CuO and some rare earth oxides (Y2O3, La2O3, CeO2, Pr6O11,
Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, Lu2O3)
0.5-15% (by weight) were added to pure Sr2P2O7. After structural determinations by
XRD, thermoluminescence studies showed two glow peaks of Pr, Ho, and Nd along
with Cu-added samples, one of them is always at around 90 oC and the other TLthermoluminescence-
peak around 180, 275, and 285 oC, respectively. This study
showed that rare earth added Sr2P2O7 materials can be promising material for
dosimetric applications.
In the third part of this work, time saving microwave-assisted synthesis method was
applied to produce pure LnBO3 (Ln=La, Nd, Dy, Ho) by using urea and sucrose as a
microwave active organic additive. For LaBO3 and NdBO3, space group found as
Pnma and for DyBO3 and HoBO3 powders crystallized in hexagonal unit cell with
P-6c2 space group. All microwave-assisted products have particle sizes lower than 1 micrometer.
In the final part of this study, pure LnBO3 (Ln=Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er,
Tm, Yb, Lu) powder samples were produced by using solid state reactions of Ln2O3
and H3BO3 (ratio=1:2) heated at 900 oC for 10 hours and 1000 oC for 5 hours. The
crystallographic studies conducted with rietveld structural refinement and unit cell
parameters, background functions, profile parameters, zero shift, atomic positions,
and unisotropic thermal parameters were refined. LaBO3 and NdBO3 were solved
based on Pnma orthorhombic structure while the crystal structure of YBO3, DyBO3
and HoBO3 were monoclinic C2/c. SmBO3 showed triclinic P-1 structure.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/2/12611091/index.pdf |
| Date | 01 October 2010 |
| Creators | Seyyidoglu, Semih |
| Contributors | Yilmaz, Aysen |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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