Theses supervised by Prof. Dr. Ayşe Morkan
16 theses · Bolu Abant İzzet Baysal University
Çeşitli borfosfat ve vanadat malzemelerin sentezi ve karakterizasyonu
In this thesis, two different synthesis methods namely, Solid State and Solution Combustion Synthesis Methods were used. First part of this study covers the synthesis of rare earth borophosphate compounds, LnB(PO4)2 (Ln= Nd, Ce, Pr, Sm, Eu, Yb, Tb, Ho, Tm, Lu) prepared by solid state method. The characterization studies were carried out by XRD, FT-IR, TG/DTA, SEM and EDX techniques. Monazite (Ln= Nd, Ce, Pr, Sm, Eu) and xenotime (Ln=Yb, Tb, Ho, Tm, Lu) type borophophates were successfully synthesized. From these compounds, YbB(PO4)2, HoB(PO4)2 and LuB(PO4)2 were indexed in tetragonal crystal system, space group: I41/amd. Their refined unit cell parameters were calculated as a=6.820(3) c=5.975(2), V=277.945 (YbB(PO4)2), a=6.891(5) c=6.031(7), V=286.46 (HoB(PO4)2) and a= 6.798(9) c= 5.962(6) V= 275.62 (LuB(PO4)2). The characteristic bands of PO4 and BO4 units of the obtained materials were examined with FT-IR. In the second part of this work, the fabrication of pyrovanadates (M2V2O7, M= Cu, Ni, Co, Zn, Mn) and orthovanadates (M3V2O8, M= Cu, Ni, Co, Zn, Mn, Mg) was studied by solution combustion synthesis method. Characterization studies showed that the orthorhombic α-Cu2V2O7, monoclinic β-Cu2V2O7, α-Zn2V2O7 and β-Mn2V2O7 as single phase whereas Co2V2O7 and Ni2V2O7 pyrovanadates were produced as multiphase products. For the orthovanadate compounds, Ni3V2O8 and Co3V2O8 in orthorhombic structures were found as a single phase while in the synthesis process of M3V2O8 containing Mg, Cu and Zn metals, the products were determined as mixture with pyrovanadates, M2V2O7 (M=Mg, Cu, Zn). During the synthesis process of Mn3V2O8 compound, α and β Mn2V2O7 were obtained.
The influence of synthesis conditions on the crystal structure of some nanosized zinc orthoborate materials
In this present study, nanosized zinc orthoborate materials were successfully synthesized using various fuels (urea, glycine, tartaric acid, HMTA, citric acid, and β-Alanine) with starting materials, zinc (II) nitrate hexahydrate and boric acid by Solution Combustion Synthesis (SCS) method. The products were characterized using X-Ray Diffraction (XRD), Infrared spectroscopy (FTIR) and UV-VIS spectroscopy. The effects of different fuels and temperatures (400-900oC) on the structural properties of synthesized products were analyzed using XRD technique. Examining XRD data, the alpha-Zn3B2O6 as triclinic was detected at 600oC for all fuels except glycine fuel. The transformation of alpha phase to beta-Zn3B2O6 as monoclinic was observed at 700oC and higher temperatures. The particle size of the synthesized alpha and beta form of zinc orthoborates were found in nano scale through the calculation of XRD data by Debye-Scherrer's equation. Due to these calculations, the crystallite sizes of the alpha zinc orthoborates were found in the range of 14-24 nm whereas beta zinc orthoborates between 22-31 nm. Analyzing the FTIR data, the bending of BO3 vibration at 695-720 cm-1, symmetric stretching BO3 vibrations at 1010-1065 cm-1 and asymmetric stretching BO3 vibrations at 1220-1245 cm-1 were detected as the characteristic bands of zinc orthoborates. Optical properties of the products were investigated by diffuse reflectance spectroscopy, DRS measurements. The absorbance and reflectance spectra were assigned between 200-900 nm. At 600oC and 700oC the spectra of all synthesized products with different fuels are observed in blue shift in order of citric acid, HMTA, urea, tartaric acid, glycine and beta-alanine. KEYWORDS: Solution Combustion Synthesis (SCS), zinc orthoborate, nanosized, XRD, FTIR.
The impact of thermal processing on the fabrication of some nanosized metal borates and hydrotalcite materials
This work investigated the impact of thermal processing on the fabrication of some nanosized metal borates and layered double hydroxides (LDHs). Metal borates and hydrotalcite materials were prepared via solution combustion synthesis (SCS), and sol-gel method, respectively. X-ray diffraction and FTIR spectroscopy were conducted for structural analysis, while UV-Vis, FESEM, and EDX provided insights into optical properties, morphology, and elemental composition of the synthesized materials. In the first part of this study, The XRD analysis revealed that rare earth-doped magnesium pyroborates, Mg2B2O5: RE3+ (RE: Ce3+, Eu3+, Tb3+) crystallized in monoclinic phases at 800°C, transitioning to triclinic phases at higher temperatures. Tartaric acid was identified as the most effective fuel and the optical band gap energy found to be between 3.20-5.70 eV. The FESEM-EDX studies confirming the presence of all elements in irregular granular morphology. In the second part, nanosized beta-Li4B2O5 was successfully synthesized for the first time using SCS with tartaric acid and glycine fuel, achieving high crystallinity rhombus-like morphology at 640°C and decomposing into Li3BO3 and Li6B4O9 at higher temperatures. The optical band gap calculated to be varied from 3.00-3.05 eV. Additionally, the lithium magnesium borate was also prepared for the first instances with tartaric acid fuel at 400°C. In the last part, nanosized double-metal substituted, Mg3-x-yZnxMy (M: Cu and Mn)/Al1 LDHs were fabricated in plate-like morphology through low-temperature processing. EDX analysis confirmed the presence of all elements, while DRS analysis revealed that MgZnMn/Al LDHs had smaller optical band gaps (2.24-2.51 eV) than MgZnCu/Al LDHs (2.98–3.02 eV).
Impact of temperature and lanthanide ion doping on the fabrication of nano sized zinc borate materials
In this present study, nanosized zinc orthoborate materials were successfully synthesized using various rare earth elements (Dy3+, Eu3+, Sm3+ and Tb3+) with starting materials, zinc (II) nitrate hexahydrate, boric acid and glycine fuel via Solution Combustion Synthesis (SCS) method. The doped zinc orthoborates were synthesized in different lanthanide ion concentrations (0.005, 0.01, 0.02, 0.25 mol) and the products obtained were analyzed using XRD method for the determination of the structural properties. FTIR analysis was performed for the band variation studies. Aditionally, the optical properties were examined by UV-VIS spectroscopy.The effect of different lantanide elements and temperatures (400-900oC) on the structural properties of synthesized zinc orthoborates were studied using XRD characterization. The alpha-zinc orthoborates was obtained at the lower themperature (400-500oC) while the beta form formed at higher temperature (≥700oC) in the formed of triclinic and monoclinic crystal structure, respectively. Analyzing the FTIR data, the bending of BO3 vibrations at 695-720 cm-1, symmetric stretching BO3 vibrations at 1010-1065 cm-1 and asymmetric stretching BO3 vibrations at 1220-1245 cm-1 were determined as the characteristic bands of zinc orthoborates.Optical properties of the products were examined by UV-VIS spectroscopy. The absorbance and reflectance spectra were identified between 200-900 nm. According to the UV-VIS spectra, the bands were detected in the ultraviolet region in the range of 200-400 nm. The optical band gap energies were determined by using UV-VIS absorbance values by taking the intercept of the curve in the x-axis of Tauc plot. It can be seen that the band gap energies found were between 5,14 and 5,40. These values vary depending on the concentration of the lanthanide ion and temperature
Fabrication of nano-crystalline undoped and some lanthanide ions (Eu³⁺ and Sm³⁺) doped calcium pyroborate ceramic powders.
In this study, nano-crystalline undoped and some lanthanide ion (Eu⁺ and Sm³⁺) doped calcium pyroborate ceramic powders production were successfully synthesized by solution combustion synthesis (SCS) method using calcium nitrate, boric acid, rare earth metals, and several fuels (urea, tartaric acid, glycine, citric acid and HMTA) as starting materials. Different concentrations of rare earth metals were applied such as Eu³⁺ (0.005, 0.01, 0.02, 0.05) and Sm³⁺(0.005, 0.01, 0.015). The characterization processes of products were analyzed using X-Ray Diffraction (XRD) and Infrared spectroscopy (FTIR). The impact of several fuel resources and annealing temperatures (400-900 °C) on the structural features of the synthesized products was examined by the XRD technique. Based on the XRD data, it was found that the single-phase alpha forms of undoped and lanthanide ion doped calcium pyroborates were fabricated at 900 °C with monoclinic crystal structure. Examining the FT-IR spectra, the bond variation of calcium pyroborates were observed at >1000 cm−1 assigned to the B–O stretching modes of the triangular [BO₃]3− . It was also determined that the bands betweeen 600 to 820 cm−1 originated from the bending vibrational motions of B-O bond of BO₃ groups.
Study of synthesis and optical properties of transition metal substituted LDH nanoparticles
Mg3-x-yM×M'y/Al1 is the general formula of double metal-substituted magnesium aluminum layered double hydroxides. In this study, Mg-Al LDH, where magnesium is substituted by two different metal cations, M (Zn) and M' (Ni or Co), in the brucite-like layers of the LDH. MgZnNiAl LDH and MgZnCoAl LDH were successfully synthesized through the sol-gel method under optimized conditions. The corresponding LDH materials were prepared with different stoichiometry by varying the molar ratios of Mg:Ni and Mg:Co whereas zinc and aluminum concentrations were kept constant. The as-prepared LDH materials were thoroughly investigated by a range of analytical techniques such as FT-IR spectroscopy, X-ray diffraction and also ultraviolet-visible spectroscopy, which provided a wide understanding of the compositional and structural characteristics of the Mg-Al LDH. The obtained data of UV-Vis spectroscopy and XRD were utilized to calculate lattice parameters (a and c), crystallite sizes (D), microstrain (ε), positions and displacements of atoms (u), volume of the unit cell (v), band gap, and dielectric constant. XRD data revealed similar patterns for the MgZnNiAl LDH and MgZnCoAl LDH, suggesting that they have common structural backbone, moreover, MgZnNiAl LDH samples showed a higher crystallinity. FT-IR spectra showed the distinct bands corresponding to the vibrational modes of the hydroxyl groups (OH-) and nitrate (NO3-) groups within LDH structure. Moreover, it was found that varying concentrations of metal cations significantly affected the composition, structure, optical properties and functional characteristics of LDH materials.
Synthesis and characterization of some nanosized orthoborates and bimetallic metal oxides
In the first part of this thesis, the synthesis and structural characterization of magnesium orthoborate (Mg₃B₂O₆) with the kotoite crystal structure were investigated. Initially, the effects of various starting materials and different boron source ratios on the formation of a pure kotoite phase were examined. To obtain products with high phase purity and desirable structural properties, optimal synthesis parameters were systematically determined. Subsequently, doping with selected rare earth elements (RE³⁺) was carried out to evaluate the effects of dopant type and concentration on the physicochemical properties of the synthesized orthoborate materials. The influence of dopant type and concentration was analyzed by assessing changes in crystallite size, surface area, and density, providing insights into the structure–property relationships of doped magnesium orthoborates at the nanoscale. In the second part of the thesis, spinel-type mixed metal oxide nanoparticles with the general formula MMn₂O₄ (where M = Mg, Co, Ni) were synthesized using the solution combustion method. Tartaric acid, glycine, and urea were utilized as fuels to investigate the role of fuel type in governing the structural and chemical characteristics of the resulting spinel phases. The synthesized materials were characterized using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). In addition, thermal treatments at various calcination temperatures were applied to assess their influence on crystallinity, phase development, and structural stability. Overall, this work provides a comprehensive understanding of how compositional and processing parameters affect the synthesis, phase formation, and structural properties of borate-based and spinel-type oxide nanomaterials, with potential implications for advanced functional material design.
Synthesis and characterization of kotoite-type nickel borate nanoparticles
In this study, the synthesis and characterization of nickel borate (Ni₃(BO₃)₂) nanoparticles were investigated. The materials were prepared using two different organic fuels, tartaric acid and hexamethylenetetramine (HMTA) via the solution combustion synthesis (SCS) method. Nickel nitrate and boric acid were used as the precursor materials, and the reaction conditions were carefully optimized based on stoichiometric calculations. The resulting products were calcined at 400°C and 900°C and thoroughly characterized. X-ray diffraction (XRD) analyses confirmed the successful formation of Ni₃(BO₃)₂ nanoparticles with both fuel types. Fourier-transform infrared (FTIR) spectroscopy revealed the characteristic vibration bands of the BO₃ units. The results demonstrated that both the choice of fuel and the calcination temperature play a significant role in determining the crystalline structure and thermal stability of the products. Nickel borates synthesized with tartaric acid exhibited greater structural stability at higher temperatures, whereas HMTA-derived (hexamethylenetetramine) samples showed more efficient performance at lower temperatures. These findings provide valuable insights for the effective optimization of nickel borate nanoparticles in industrial applications and serve as a useful reference for future research in this area.
Synthesis, structural characterization and optical properties of magnesium pyroborate nanoparticles
In this study, Pure Mg2B2O5 were successfully synthesized using different kinds of organic fuels (carbohydrazide, citric acid, glycine, HMDA, HMTA, tartaric acid and urea) via Solution Combustion Synthesis (SCS) method. The structural and optical properties of as-prepared products were comparatively characterized by Infrared spectroscopy (FTIR), X-Ray Powder Diffraction (XRD), Ultra Violet- Visible spectroscopy (UV-VIS) techniques. During the process of preparation, Mg(NO3)2.6H2O, 5wt% excess H3BO3, and fuel were used as the starting materials. The effects of fuels and temperature on the structural properties of the products were examined by XRD studies. It is shown that at low temperatures between 400 and 800°C, Mg2B2O5 was resulted in monoclinic phase except for carbohydrazide fuel. At 900°C, the transformation of monoclinic phase of Mg2B2O5 into triclinic phase was obtained. Most accurately, the single phase triclinic was acquired for all fuels at 1000°C. In the analysis of infrared spectra, the bands around 680 cm-1 and 720 cm-1 represent to the B-O-B bending and the bands assigned at 1175 cm-1, 1290 cm-1 and 1490 cm-1 belong to stretching vibrations of trigonal BO3 confirmed the formation of magnesium pyroborate. The effects of fuels and heating temperatures on optical properties of Mg2B2O5 were further examined using Ultra Violet- Visible spectroscopy (UV-VIS). It was found that the optical band gap energy of the products decreases as the temperature increases. The calculated optical band gap energy was attained at range of 4.66-4.91 eV for different fuels. The lowest band gap of Mg2B2O5 was detected for citric acid fuel whereas highest value was found for urea fuel.
Synthesis and characterization of some garnet materials using sol-gel processing
In the first part of this study, Ho3Al5O12 garnets were synthesized as undoped and doped with Eu3+, Mn3+, Fe3+ and Cr3+ metal ions in different molar concentrations of 0.10, 0.25, 0.50, 0.75, 1.00 by sol-gel technique. In the second part, the synthesis of undoped and doped with Eu3+ ion Dy3Al5O12 and Tb3Al5O12 garnets was succesfully done through sol-gel process using with 1,2 ethanediol as complexing agent. The two different heat conditions as 800˚C and 1000˚C were applied to the obtained gels for all products. In spite of heating at 800°C was not suitable temperature for the products, the reactions are monitored by sampling after 800˚C. However, all of these products showed that a single phase which has been occured at 1000˚C. The FTIR analysis indicated that the organic residues have flown after 10 hours and the typical vibrational bands of M-O bonds have been seen under 1000cm-1 for all products. The XRD patterns showed similar hkl values belong to the typical cubic garnet structures and the doping of the metal ions did not cause any change in the crystal structure of the monophasic host garnet materials. The products were found thermodynamically stable upon 900oC by analyzing TG/DTA curves. The SEM studies showed that the lanthanide aluminum garnets were in the same plate-like shape, independently the nature of the lanthanides or doping agents of Eu3+, Cr3+, Mn3+, Fe3+. The presence of dopants was confirmed by EDX anaylsis. The optical properties of all products were determined by UV-vis/DRS technique.
Synthesis, structural characterization and optical properties of Dy, Ho and Er doped magnesium pyroborate nanoparticles
In this study, Dy3+, Ho3+, Er3+ doped magnesium pyroborates were synthesized with various concentrations at different temperatures by solution combustion synthesis method. The final products were well characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet Visible Spectroscopy (UV-VIS). In the first part of this work, 0.005, 0.010, 0.020, 0.050 mole amount of RE (Dy3+, Ho3+, Er3+) metal ion doped Mg2B2O5 were synthesized using five different fuels; glycine, tartaric acid, citric acid, urea and hexamethylenetetramine (HMTA) with magnesium nitrate (Mg(NO3)2.6H2O) and boric acid (H3BO3) sources via solution combustion technique. The synthesized materials were furtherly subjected to the heating processes at 400oC with 10 min. in which the combustion reaction was completed and followed at 700oC with 2h, 800oC with 1h and 900oC with 1h. to remove organic residues and to obtain pure, crystalline RE doped Mg2B2O5 nanoparticles. In the FTIR study, the strong vibrational bands assigned at 1450-1550 cm-1 and 600-750 cm-1 indicated the characteristic vibrations of Mg2B2O5. Additionally, the crystallite size of the products were calculated using Debye Scherrer equation and founed between 10-19 nm which proved the products were nanoparticles. In the UV-VIS analysis, the effect of temperature and the doping concentration of Dy3+, Ho3+, Er3+ ion on the optical properties of the products was examined due to the changed in wavelengths as red shift and/or blue shift.
Synthesis, structural characterization and optical properties of Ce, Eu and Tb doped strontium pyroborate nanoparticles
In this study, undoped and Ce, Eu and Tb doped Strontium Pyroborate nanoparticles were successfully synthesized by using Solution Combustion Synthesis (SCS), as well as the structural and optical properties of as-prepared products were comparatively characterized by Infrared spectroscopy (FTIR), X-Ray Powder Diffraction (XRD), Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-VIS). During the preparation process, Sr(NO3)2, H3BO3, glycine, Tb(NO3)3.5H2O, Eu(NO3)3.5H2O, and Ce(NO3)3.6H2O were used as the starting materials. The effect of temperature and dopant ion on the crystal structure of the products were examined. It was found that undoped and lanthanide element doped Sr2B2O5 nanopowders obtained at 900°C were crystallized in monoclinic structure by examining XRD patterns. The formation of Sr2B2O5 was also confirmed with FT-IR spectroscopy by analyzing the vibrational modes belong to boron-oxygen bonds that occurred between 625 cm-1 to 1450 cm-1. Through UV-visible diffuse reflectance spectroscopic studies, the absorbance and reflectance spectra of the products were only observed in the ultraviolet region depending upon the host material, Sr2B2O5. It was also detected that the optical band gap energies of the pyroborates synthesized were decreasing as the temperature increasing.
Katkısız ve katkılı magnezyum oksit nanoparçacıkların sentezi ve karakterizasyonu
In this study, undoped and rare earth, RE, metal ion (RE:Pr+3, Ho+3, Tb+3) doped magnesium oxide nanoparticles were synthesized by solution combustion synthesis method. The products obtained were well characterized by X-ray Diffraction (XRD), Infrared Spectroscopy (IR), Scanning Electron Microscopy (SEM), EDX (Energy Dispersive X-ray Analysis) techniques. In the first part of this work, undoped magnesium oxide (MgO) was prepared using magnesium nitrate (Mg(NO₃)₂.6H₂O) as an oxidizer and various fuels; tartaric acid, urea, citric acid, 1,6-Diaminohexane, hexamethylenetetramine, β-Alanine, glycine and carbohydrazide as reducers through the solution combustion method. It was found that tartaric acid, urea, citric acid, 1,6-diaminohexane, hexamethylenetetramine fuels were suitable while β-alanine, glycine and carbohydrazide fuels were not suitable in the synthesis of MgO nanoparticles because of causing very low amount of yield of the products. Hence the appropriate fuels were selected for the further processes in the synthesis of nano sized magnesium oxides. In the second part of this thesis, 0.005, 0.01, 0.03 moles of RE metal ion (Pr+3, Ho+3, Tb+3) doped MgO were synthesized using five different fuels; tartaric acid, hexamethylenetetramine, 1,6-Diaminohexane, citric acid, urea. In order to get rid of the organic compounds and to obtain a more crystalline material, the prepared products by combustion process at 400°C for 10 min. were heated at 400°C, 500°C respectively for one hour. Then, characterization was performed with IR, XRD, SEM, EDX for each concentration and temperature. Continuation of this work, the effect of temperature, fuel, type of RE metal, concentration of RE metal on the properties of synthesized magnesium oxides such as crystallinity, crystallite size, purity and morphology were investigated.
Çeşitli anorganik fosfatların, boratların ve borfosfatların sentezi ve yapısal karakterizasyonu
This thesis covers the preparation and characterization of some novel compounds namely magnesium transition metal borates, lithium lanthanide oxyphosphates, lithium sodium lanthanide oxyphosphates, rare earth oxyapatites and lanthanide borate phosphates. Solid state method was employed for the synthesis of the desired materials. The characterization of the products was investigated by X-ray Powder Diffraction (XRPD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis-Differential Thermal Analysis (TG/DTA) methods.In the first part of this thesis, MgNi2(BO3)2, MgCo2(BO3)2, Mg2Ni(BO3)2 and Mg2Co(BO3)2 compounds were prepared through the following solid state reactions at 900oC for 48h.2M(NO3)2 6.H2O(s)+ MgO(s)+2H3BO3(s)? MgM2(BO3)2(s) + 4NO2(g)+15H2O(g)+ O2(g)(M: Ni, Co)M(NO3)2.6H2O(s)+2MgO(s)+2H3BO3(s)? Mg2M(BO3)2(s)+2NO2(g)+9H2O(g)+1/2 O2(g)(M: Ni, Co)It was found that all these compounds crystallized in the orthorhombic system and isostructural with the kotoite type of compounds, M3(BO3)2 (M: Mg, Ni, Co). It was also detected that these compounds were thermodynamically stable with 20-1000oC using thermal analysis technique.In the second part, the synthesis of new oxyphosphates of the type Li2LnOPO4 (Ln: Nd, Gd, Dy), which were not reported before have been done through the following solid state reactions at 1000oC.Ln2O3(s) + 2Li2CO3(s) + 2(NH4)2HPO4(s) ? 2Li2LnOPO4(s) +4NH3(g) +2CO2(g) +3H2O(g)Examination of the X-ray powder diffraction data and Infrared spectra of the products showed the existence of Li2NdOPO4, Li2GdOPO4, Li2DyOPO4 compounds which have an orthorhombic crystal structures with the refined unit cell parameters of a=14.865(1), b=10.734(2), c=13.231(1); a=14.686(3), b=10.634(5) c=13.047(9); a=14.554(1), b=10.589(8), c= 12.926(2) Å, respectively.In the third part of this study, LiNaNdOPO4, LiNaGdOPO4, LiNaDyOPO4, have also been prepared and indexed in orthorhombic system with the refined unit cell parameters a=14.903(8), b=10.861(3), c=13.247(1); a =14.745(0), b=10.651(6), c=13.096(8); a= 14.622(2), b=10.581(0), c= 13.018(2) Å, respectively. The thermal analysis (TG/DTA) of the compounds, Li2LnOPO4 and LiNaLnOPO4 (Ln: Nd, Gd, Dy) showed that all these compounds were stable up to1100oC.In the fourth part of this study were investigated using different rare earths to obtain Ca8Ln2(PO4)6O2 (Ln: Nd, Gd, Dy) the solid state reactions of Ln2O3 with CaHPO4 and CaCO3 (ratio:1:6:2) at different temperatures.In the last part, the attempt to prepare rare earth borate phosphates, Ln2O3, (Ln:Nd, Gd, Dy) B2O3 and (NH4)2HPO4 were done through the solid state reactions of 2Ln2O3 + B2O3+ 2(NH4)2HPO4 ? 2Ln2(BO3)(PO4) + 4NH3 + 3H2O
Yeni karma-metal-ortoboratlarin sentezi ve karakterizasyonu
In this study, magnesium orthoborate and novel-mixed-metal orthoborates were synthesized by high temperature solid state reaction method and the characterization of products were examined by powder X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Thermogravimetric/Differential Thermal Analysis (TG/DTA) methods.In the first part of this study, magnesium orthoborate, Mg3(BO3)2, was synthesized using different magnesium sources, MgO, MgCO3, MgSO4, by conventional ceramic method. It was found that the magnesium orthoborate with the highest purity was prepared from the MgSO4.In the second part of this study, different amounts of manganese (II) ion were doped to magnesium, cobalt and nickel orthoborate to obtain novel-mixed-metalorthoborate compounds, at the formula M3-xMnx(BO3)2 (M = Mg, Co, Ni; 0 ? x ? 0.10).All these compounds obtained were indexed in the orthorhombic crystal system and their unit cell parameters refined by Jana2006 are given as follows;For magnesium manganese orthoborates, Mg3-xMnx(BO3)2 ( 0 ? x ? 0.10),Mg2.99Mn0.01(BO3)2: a= 5.406(3), b= 8.430(4), c= 4.508(4),Mg2.95Mn0.05(BO3)2: a= 5.410(4), b= 8.436(2), c= 4.507(8),Mg2.90Mn0.1(BO3)2: a= 5.144(4), b= 8.444(3), c= 4.512(0) Å;For cobalt manganese orthoborates, Co3-xMnx(BO3)2 ( 0 ? x ? 0.10),Co2.99Mn0.01(BO3)2: a= 5.469(7), b= 8.451(2), c= 4.533(5),Co2.95Mn0.05(BO3)2: a= 5.469(9), b= 8.452(8), c= 4.533(8),Co2.90Mn0.1(BO3)2: a= 4.483(4), b= 8.476(4), c= 4.538(4) Å;For nickel manganese orthoborates, Ni3-xMnx(BO3)2 ( 0 ? x ? 0.10),Ni2.99Mn0.01(BO3)2: a = 5.397(4), b= 8.301(8), c= 4.458(9),Ni2.95Mn0.05(BO3)2: a= 5.403(6), b= 8.311(6), c= 4.463(3),Ni2.50Mn0.50(BO3)2: a= 5.405(8),b= 8.313(3), c= 4.465(2) Å.It was determined that all these compounds were found isostructural with kotoite type of borates, M3(BO3)2 (M= Mg, Ni, Co).The IR study showed that these borates have the BO3 units in planar triangles. Besides, SEM images showed that these compounds were homogeneus. It was also detected that these orthoborates prepared were thermodynamically stable in the temperature range of 20-1200 oC by TG/DTA method.Anahtar Kelimeler: Karma Metal Ortoborat, Kotoit, Boratlara Mn(II) katkılanması, XRD, FTIR, TG/DTA, SEM.
10gdc, 10gdc/ceo2, 10gdc/y2o3 ve 10gdc/yb2o3 kompozitlerinin sentezi ve karakterizasyonu
In this study, 10 mol % gadolinium doped ceria was taken as a basic compound and new compositions with additional amounts of CeO2, Y2O3 and Yb2O3 in various ratios were prepared using sol-gel combustion synthesis technique. For comparison, all compounds were also synthesized by solid state reaction method. The annealing conditions (temperature and heating time) were identical for both synthesis routes. For the characterization of synthesized products, infrared (IR) spectroscopy, X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM) were used. It was demonstrated that single-phase compounds synthesized by sol-gel combustion technique were obtained independent on the amount of CeO2, Y2O3 and Yb2O3 while in the case of solid-state reaction synthesis route the mixture of oxides was obtained. IR results showed that the final products of the sol-gel combustion technique after heating at 800 oC have identical bands compared to each other and rare earth oxides. XRD results showed that the sol-gel combustion products were single phase compounds with no additional phase; however, the solid state products have additional diffraction lines belonging to Gd2O3, Y2O3 and Yb2O3. SEM results showed that the morphology of particles does not depend on the nature and amount of addition of rare-earth oxide. EDX results were in a good agreement with nominal compositions of elements.