Boonchom, Banjong
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Boonchom, Banjong
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BOONCHOM, Banjong
Boonchom, B.
Boonchom, And Banjong
Boonchoma, Banjong
Boomchom, Banjong
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banjong.bo@kmitl.ac.th
35 results
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Item type:Publication, A rapid synthesis of cobalt cyclotetraphosphate Co2P 4O12 at low temperature(2013-05-01); The cobalt cyclotetraphosphate, Co<inf>2</inf>P<inf>4</inf>O<inf>12,</inf> was synthesized by evaporating a mixture of cobalt chloride hexahydrate, phosphoric acid and water at 70 °C, with further calcinations at 400 °C, 500 °C and 600 °C for 3 h. XRD results indicated that the Co <inf>2</inf>P<inf>4</inf>O<inf>12</inf> compounds obtained had only monoclinic phase with space group C<inf>2h</inf><sup>6</sup> (Z=4). From FT-IR spectra, vibrational modes corresponding to internal vibrations of the P <inf>4</inf>O<inf>12</inf><sup>4-</sup> anion were identified. The morphologies and crystallite sizes for the Co<inf>2</inf>P<inf>4</inf>O<inf>12</inf> obtained from SEM data and X-ray line broadening showed non-uniform particles and 37-68 nm, respectively. All characterization methods showed that the monoclinic phase of Co<inf>2</inf>P<inf>4</inf>O<inf>12</inf> could be synthesized at the low temperature of 400 °C with short time consumption. The temperature was about 400 °C lower than that used in the previous synthesis method with CoCl <inf>2</inf> as reactant, and resulted in a cost-, energy-, and time-saving method. © 2012 Elsevier Ltd and Techna Group S.r.l. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study on thermal transformation of CuHPO4.H2O obtained by acetone-mediated synthesis at ambient temperature(2012-11-01); Copper hydrogenphosphate monohydrate, Cu- HPO<inf>4</inf>.H<inf>2</inf>O, was synthesized for the first time through simple and rapid method using the mixing of copper carbonate and phosphoric acid in acetone medium at ambient temperature. The obtained CuHPO<inf>4</inf>.H<inf>2</inf>O decomposed in three stages via dehydration and deprotonated hydrogenphosphate reactions, revealed by TG/DTG and DSC techniques. The kinetic triplet parameters (E<inf>a</inf>, A, and n) and thermodynamic functions (δHz.ast;, δGz.ast;, and δS*) for the first two decomposed steps were calculated from DSC data. All the obtained functions indicate that the deprotonated HPO<inf>4</inf> <sup>2-</sup> reaction for the second step occurs at a higher energy pathway than the dehydration reaction for the first step. The calculated wavenumbers based on DSC peaks were comparable with FTIR results, which support the breaking bonds of OH (H<inf>2</inf>O) and P-OH (HPO<inf>4</inf> <sup>2-</sup>) according to decomposed mechanisms. All the calculated results are consistent and in good agreement with Cu- HPO<inf>4</inf>.H<inf>2</inf>O's thermal transformation mechanisms. © Akademiai Kiado, Budapest, Hungary 2012. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Phase transition behaviour and electrical properties of lead-free (K 0.5Na0.5)NbO3-LiNbO3-LiSbO 3 piezoelectric ceramics(2011-05-01); ; The ternary system of 0.945(K<inf>0.5</inf>Na<inf>0.5</inf>NbO <inf>3</inf>)-(0.055 - x)LiNbO<inf>3</inf>-xLiSbO<inf>3</inf> [0.945KNN-(0.055 - x)LN-xLS]; x = 0.0-0.055 lead-free piezoelectric ceramics was fabricated by the conventional mixed oxide method with normal sintering. The crystal structure was studied by means of X-ray diffraction (XRD). The results of XRD patterns show that complete solid solutions of the mixed phase between the orthorhombic and tetragonal perovskite phase were observed. The DSC and dielectric data show that the amount of LiSbO<inf>3</inf> in K<inf>0.5</inf>Na<inf>0.5</inf>NbO <inf>3</inf>-LiNbO<inf>3</inf> solid solution slightly decreases the paraelectric cubic-ferroelectric tetragonal phase transition (T<inf>C</inf>) to a low temperature. Furthermore, good dielectric and piezoelectric properties were observed at composition, x = 0.03. The polymorphic phase transition between the orthorhombic and tetragonal phases plays a very important role in enhancement of the piezoelectric properties of KNN-LN-LS ceramics. © 2010 Elsevier B.V. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A simple synthesis and characterization of binary Co0.5Fe 0.5(H2PO4)2·2H2O and its final decomposition product CoFeP4O12(2011-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A rapid synthesis of blue-pigment copper cyclotetraphosphate (cu2P4O12) ricelike grain nanoparticles at low temperature(2012-12-01); ; A blue-pigment copper cyclotetraphosphate Cu<inf>2</inf>P<inf>4</inf>O<inf>12</inf> was synthesized by a simple wet preparation method using copper oxide and phosphoric acid at 350 °C. The crystallite size obtained from X-ray line broadening is 53 ± 11 nm for the Cu<inf>2</inf>P<inf>4</inf>O<inf>12</inf>. The FTIR spectrum of Cu<inf>2</inf>P<inf>4</inf>O<inf>12</inf> is assigned a base on the P<inf>4</inf>O<inf>12</inf><sup>4-</sup> ion in the structure, which indicates the most striking feature of cyclotetraphospate. XRD and FTIR results of the synthesized CuCu<inf>2</inf>P<inf>4</inf>O<inf>12</inf> indicate the pure monoclinic phase with space group C<inf>2h</inf><sup>6</sup> (C2/c). SEM micrographs of the synthesized Cu<inf>2</inf>P<inf>4</inf>O<inf>12</inf> show rice-like grains, a porous structure and agglomerations, which are important for a specific application. The UV-Vis-NIR spectrum confirms the octahedral coordination of the Cu (II) ion and blue pigment. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Optical properties of Cu0.95Pt0.05Fe0.97Sn0.03O2 for p-type transparent conducting oxide materials(2013-08-30); ; ; The Cu<inf>0.95</inf>Pt<inf>0.05</inf>Fe<inf>0.97</inf>Sn<inf>0.03</inf>O<inf>2</inf> sample has been synthesized by a solid-state reaction to investigate optical properties of materials of transparent conducting oxide. Crystal structure was characterized by XRD. The Seebeck coefficient and electrical conductivity were measured in the high temperature (300 to 860 K), while the XPS and UV-VIS-NIR spectra were analyzed at room temperature. The XRD peaks confirm the samples forming the delafossite structure phase. The Seebeck coefficient reveals the samples displays the p-type conducting. The XPS spectra show the Sn2+ state stabling in this compound. The optical direct gap is 3.45 eV as a visible-transparent material. These results support that the Cu<inf>0.95</inf>Pt<inf>0.05</inf>Fe<inf>0.97</inf>Sn<inf>0.03</inf>O<inf>2</inf> oxide compounds, of which the Cu<sup>1+</sup> and Fe<sup>3+</sup> sites are substituted by the Pt<sup>1+</sup> and Sn<sup>2+</sup> ions respectively, are p-type transparent conducting oxide materials. © (2013) Trans Tech Publications, Switzerland. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Non-isothermal kinetics of the thermal decomposition of sodium oxalate Na2C2O4(2012-03-01); ; The thermal transformation of Na<inf>2</inf>C<inf>2</inf>O<inf>4</inf> was studied in N<inf>2</inf> atmosphere using thermo gravimetric (TG) analysis and differential thermal analysis (DTA). Na<inf>2</inf>C<inf>2</inf>O<inf>4</inf> and its decomposed product were characterized using a scanning electron microscope (SEM) and the X-ray diffraction technique (XRD). The non-isothermal kinetic of the decomposition was studied by the mean of Ozawa and Kissinger-Akahira-Sunose (KAS) methods. The activation energies (Eα) of Na<inf>2</inf>C<inf>2</inf>O<inf>4</inf> decomposition were found to be consistent. Decreasing Eα at increased decomposition temperature indicated the multi-step nature of the process. The possible conversion function estimated through the Liqing-Donghua method was 'cylindrical symmetry (R <inf>2</inf> or F<inf>1/2</inf>)' of the phase boundary mechanism. Thermodynamic functions (DH*, DG* and DS*), calculated by the Activated complex theory and kinetic parameters, indicated that the decomposition step is a high energy pathway and revealed a very hard mechanism. © Akadémiai Kiadó, Budapest, Hungary 2011. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Dehydration behavior of synthetic Al0.5Fe0.5PO 4·2.5H2O(2010-09-09); The dehydration behavior of the experimentally produced Al <inf>0.5</inf>Fe<inf>0.5</inf>PO<inf>4</inf>·2.5H<inf>2</inf>O solid solution is assessed from thermogravimetrical (TG, differential thermogravimetric, DTG, and differential thermal analysis, DTA) and differential scanning calorimetry (DSC) analyses. The dehydration proceeded through a well-defined step at low temperatures (< 300 °C), which corresponds to the loss of 2.5 water molecules. The fluctuating dependence of the activation energies on fraction mass loss (α) for the dehydration reaction of Al <inf>0.5</inf>Fe<inf>0.5</inf>PO<inf>4</inf>·2.5H<inf>2</inf>O calculated through isoconversional methods (Ozawa and the Kissinger-Akahira-Sunose) indicates the existence of a complex multistep mechanism. The Avrami exponent value of 1.11 is indicative of one-dimensional growth as a phase boundary mechanism. The thermodynamic functions (ΔH<sup>*</sup>, ΔG<sup>*</sup>, and ΔS<sup>*</sup>) of the dehydration reaction calculated from the DSC technique are discussed for the first time. © 2010 American Chemical Society. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of Pb(In1/2Nb1/2)O3 on the phase transitions, electrical, and thermal properties of a PbZrO3 ceramic(2011-10-01); ; ; The solid solution of a (1-x)PbZrO<inf>3</inf>-xPb(In<inf>1/2</inf>Nb <inf>1/2</inf>)O<inf>3</inf> (PZ-PIN) system, with x=0.00-0.50, was synthesized using the wolframite precursor method. The effects of the PIN content on the crystal structure, and the electrical and thermal properties of a PbZrO <inf>3</inf> ceramic were investigated using X-ray diffraction, dielectric spectroscopy, hysteresis measurement, and differential scanning calorimetry techniques. Furthermore, the morphology and grain size were determined using scanning electron microscopy. The results indicated that the pure perovskite phase was obtained for all compositions, and the solid solution, PZ-PIN, changed from orthorhombic to rhombohedral symmetry when the amount of PIN increased. A ferroelectric intermediate phase began to appear between the paraelectric and the antiferroelectric phases of pure PZ, with increasing PIN content. The temperature range width of the ferroelectric phase also increased continuously with increasing PIN. At room temperature, the polymorphic phase transition (PPT) was identified from the orthorhombic to the rhombohedral phase in (1-x)PZ-xPIN at the composition, x=0.40. The ceramics (x=0.40) with PPT close to room temperature exhibited excellent electrical properties (ε<inf>rmax</inf>= 33240 and P<inf>r</inf>=26.94 μC/cm<sup>2</sup>). © 2011 The American Ceramic Society. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The phase evolution with temperature in 0.94PbZrO3-0. 06Pb(Mg1/2W1/2)O3 antiferroelectric ceramic(2010-09-10); ;