R. Yimnirun - Academia.edu (original) (raw)
Papers by R. Yimnirun
Materials Science and Engineering: B, 2006
A perovskite phase of lead magnesium niobate, Pb(Mg 1/3 Nb 2/3 )O 3 or PMN, powders has been synt... more A perovskite phase of lead magnesium niobate, Pb(Mg 1/3 Nb 2/3 )O 3 or PMN, powders has been synthesized by a rapid vibro-milling technique. Both columbite MgNb 2 O 6 and corundum Mg 4 Nb 2 O 9 have been employed as magnesium niobate precursors, with the formation of the PMN phase investigated as a function of calcination conditions by thermal gravimetric and differential thermal analysis (TG-DTA) and X-ray diffraction (XRD). The particle size distribution of the calcined powders was determined by laser diffraction technique. Morphology, crystal structure and phase composition have been determined via a combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) techniques. The magnesium niobate precursor and calcination condition have been found to have a pronounced effect on the phase and morphology evolution of the calcined PMN powders. It is seen that optimisation of calcination conditions can lead to a single-phase PMN in both methods. However, the formation temperature and dwell time for single-phase PMN powders were lower for the synthetic method employing a columbite MgNb 2 O 6 precursor.
Materials Letters, 2006
A perovskite-like phase of lead titanate, PbTiO 3 , nanopowder was synthesized by a solid-state r... more A perovskite-like phase of lead titanate, PbTiO 3 , nanopowder was synthesized by a solid-state reaction via a rapid vibro-milling technique. The effect of milling time on the phase formation and particle size of PbTiO 3 powder was investigated. Powder samples were characterized using TG-DTA, XRD, SEM and laser diffraction techniques. It was found that an average particle size of 17 nm was achieved at 25 h of vibro-milling after which a higher degree of particle agglomeration was observed on continuation of milling to 35 h. In addition, by employing an appropriate choice of the milling time, a narrow particle size distribution curve was also observed.
Journal of Electroceramics, 2008
... A. Ngamjarurojana (*) .O. Khamman .S. Ananta .R. Yimnirun Department of Physics, Faculty of S... more ... A. Ngamjarurojana (*) .O. Khamman .S. Ananta .R. Yimnirun Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50200 ... most compositions the perovskite phase is formed in a sudden nature, which is significantly different from previous research [16] in ...
Journal of Alloys and Compounds, 2009
Journal of Alloys and Compounds, 2009
Dense perovskite ferroelectric PbTiO 3 (or PT) ceramics reinforced with SiC nanofibers have been ... more Dense perovskite ferroelectric PbTiO 3 (or PT) ceramics reinforced with SiC nanofibers have been successfully fabricated by a simple solid-state mixed oxide and conventional sintering method. Phase formation, densification, microstructure and dielectric properties of the composites were investigated as a function of SiC content. Addition of SiC nanofibers to a PT matrix did not result in unexpected reaction phase. Microstructural observations revealed that some SiC nanofibers were heterogeneously dispersed in PT matrix and at the matrix boundaries. The grain size was decreased significantly with addition of SiC nanofiber. Though the densification and mechanical strength were improved, the dielectric properties of PT/SiC composites were degraded dramatically.
Inorganic Chemistry Communications, 2004
Cubic fluoroperovskite KMnF3 nanostructures including acicular nanocrystals and ultrafine nanopar... more Cubic fluoroperovskite KMnF3 nanostructures including acicular nanocrystals and ultrafine nanoparticles were solvothermally synthesized.
Ceramics International, 2009
ABSTRACT
Applied Physics A, 2006
Lead titanate ceramics have been prepared by two different processing methods: conventional (or s... more Lead titanate ceramics have been prepared by two different processing methods: conventional (or single-stage) and two-stage sintering. Effects of designed sintering conditions on phase formation, densification, microstructure and dielectric properties of the ceramics were characterized via X-ray diffraction, Archimedes density measurement, scanning electron microscopy and dielectric measurement, respectively. The potentiality of a two-stage sintering technique as a simple ceramic fabrication method to obtain highly dense and pure lead titanate ceramics was demonstrated. It has been found that, under suitable two-stage sintering conditions, dense perovskite lead titanate ceramics can be successfully achieved with better dielectric properties than those of ceramics from a single-stage sintering technique. PACS 77.22.-d; 77.84.-s; 77.84.Dy
Advances in Materials Science and Engineering, 2013
ABSTRACT Lead-free specimens of [ 1 β π§ { ( B i 1 β π₯ L a π₯ ) 0 . 5 ( N a 1 β π¦ L i π¦ ) 0 . 5 T i... more ABSTRACT Lead-free specimens of [ 1 β π§ { ( B i 1 β π₯ L a π₯ ) 0 . 5 ( N a 1 β π¦ L i π¦ ) 0 . 5 T i O 3 } - π§ BaTiO3] (BLNLT-BT, where π₯ = 0 . 0 4 , π¦ = 0 . 0 2 5 , and π§ = 0 , 0.02, 0.04, and 0.06) ceramic system were synthesized by a semiwet technique. In the present study, we have investigated the effect of Ba on the structure, morphology, and dielectric, ferroelectric, and piezoelectric properties of BLNLT system. The XRD patterns of all the specimens showed rhombohedral structure at room temperature. Field emission scanning electron microscopy images (FE-SEM) showed grain growth inhibition with Ba content in BLNLT system. The temperature dependence of dielectric constant revealed that the temperature of maximum dielectric constant β π π β and depolarization temperature β π π β decreased for the sample π§ = 0 . 0 6 and showed high value of dielectric constant with low dielectric loss. These samples exhibited nonlinear behaviour of hysteresis loop. The values of dielectric constant ( π π ), dissipation factor (tan Ξ΄), piezo charge coefficient ( π 3 3 ), remnant polarization ( π π ), and coercive field ( πΈ π ) for the composition π§ = 0 . 0 6 were 1495, 0.06, 20 pC/N, 5 ΞΌC/cm2, and 10.5 kV/cm, respectively.
Current Applied Physics, 2009
Lead indium niobate, Pb(In 1/2 Nb 1/2 )O 3 or (PIN), is an interesting ferroelectric material, be... more Lead indium niobate, Pb(In 1/2 Nb 1/2 )O 3 or (PIN), is an interesting ferroelectric material, because it can be changed from a disordered state to ordered state by long-time thermal annealing. However, the temperature related to the maximum dielectric constant (T max ) of PIN in relaxor phase is low (at 1 kHz, T max = 66Β°C). In this study, to increasing T max of PIN, lead titanate, PbTiO 3 (PT) was thus added to PIN with compositions (1 Γ x)PIN-xPT (for x = 0.1-0.5). The influence of stress on the dielectric properties of (1 Γ x)PIN-xPT ceramics was then investigated. The dielectric properties were measured under various uniaxial compressive stress up to 400 MPa. The results showed that the superimposed compression load reduced the dielectric constant in 0.9PIN-0.1PT. For the other compositions, the dielectric constants first increased with the compressive stress, and then decreased when the stress was further increased up to 400 MPa. The dielectric loss tangent of all composition was found to decrease with increasing compressive stress.
Materials Science and Engineering: B, 2006
A perovskite phase of lead magnesium niobate, Pb(Mg 1/3 Nb 2/3 )O 3 or PMN, powders has been synt... more A perovskite phase of lead magnesium niobate, Pb(Mg 1/3 Nb 2/3 )O 3 or PMN, powders has been synthesized by a rapid vibro-milling technique. Both columbite MgNb 2 O 6 and corundum Mg 4 Nb 2 O 9 have been employed as magnesium niobate precursors, with the formation of the PMN phase investigated as a function of calcination conditions by thermal gravimetric and differential thermal analysis (TG-DTA) and X-ray diffraction (XRD). The particle size distribution of the calcined powders was determined by laser diffraction technique. Morphology, crystal structure and phase composition have been determined via a combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) techniques. The magnesium niobate precursor and calcination condition have been found to have a pronounced effect on the phase and morphology evolution of the calcined PMN powders. It is seen that optimisation of calcination conditions can lead to a single-phase PMN in both methods. However, the formation temperature and dwell time for single-phase PMN powders were lower for the synthetic method employing a columbite MgNb 2 O 6 precursor.
Materials Letters, 2006
A perovskite-like phase of lead titanate, PbTiO 3 , nanopowder was synthesized by a solid-state r... more A perovskite-like phase of lead titanate, PbTiO 3 , nanopowder was synthesized by a solid-state reaction via a rapid vibro-milling technique. The effect of milling time on the phase formation and particle size of PbTiO 3 powder was investigated. Powder samples were characterized using TG-DTA, XRD, SEM and laser diffraction techniques. It was found that an average particle size of 17 nm was achieved at 25 h of vibro-milling after which a higher degree of particle agglomeration was observed on continuation of milling to 35 h. In addition, by employing an appropriate choice of the milling time, a narrow particle size distribution curve was also observed.
Journal of Electroceramics, 2008
... A. Ngamjarurojana (*) .O. Khamman .S. Ananta .R. Yimnirun Department of Physics, Faculty of S... more ... A. Ngamjarurojana (*) .O. Khamman .S. Ananta .R. Yimnirun Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50200 ... most compositions the perovskite phase is formed in a sudden nature, which is significantly different from previous research [16] in ...
Journal of Alloys and Compounds, 2009
Journal of Alloys and Compounds, 2009
Dense perovskite ferroelectric PbTiO 3 (or PT) ceramics reinforced with SiC nanofibers have been ... more Dense perovskite ferroelectric PbTiO 3 (or PT) ceramics reinforced with SiC nanofibers have been successfully fabricated by a simple solid-state mixed oxide and conventional sintering method. Phase formation, densification, microstructure and dielectric properties of the composites were investigated as a function of SiC content. Addition of SiC nanofibers to a PT matrix did not result in unexpected reaction phase. Microstructural observations revealed that some SiC nanofibers were heterogeneously dispersed in PT matrix and at the matrix boundaries. The grain size was decreased significantly with addition of SiC nanofiber. Though the densification and mechanical strength were improved, the dielectric properties of PT/SiC composites were degraded dramatically.
Inorganic Chemistry Communications, 2004
Cubic fluoroperovskite KMnF3 nanostructures including acicular nanocrystals and ultrafine nanopar... more Cubic fluoroperovskite KMnF3 nanostructures including acicular nanocrystals and ultrafine nanoparticles were solvothermally synthesized.
Ceramics International, 2009
ABSTRACT
Applied Physics A, 2006
Lead titanate ceramics have been prepared by two different processing methods: conventional (or s... more Lead titanate ceramics have been prepared by two different processing methods: conventional (or single-stage) and two-stage sintering. Effects of designed sintering conditions on phase formation, densification, microstructure and dielectric properties of the ceramics were characterized via X-ray diffraction, Archimedes density measurement, scanning electron microscopy and dielectric measurement, respectively. The potentiality of a two-stage sintering technique as a simple ceramic fabrication method to obtain highly dense and pure lead titanate ceramics was demonstrated. It has been found that, under suitable two-stage sintering conditions, dense perovskite lead titanate ceramics can be successfully achieved with better dielectric properties than those of ceramics from a single-stage sintering technique. PACS 77.22.-d; 77.84.-s; 77.84.Dy
Advances in Materials Science and Engineering, 2013
ABSTRACT Lead-free specimens of [ 1 β π§ { ( B i 1 β π₯ L a π₯ ) 0 . 5 ( N a 1 β π¦ L i π¦ ) 0 . 5 T i... more ABSTRACT Lead-free specimens of [ 1 β π§ { ( B i 1 β π₯ L a π₯ ) 0 . 5 ( N a 1 β π¦ L i π¦ ) 0 . 5 T i O 3 } - π§ BaTiO3] (BLNLT-BT, where π₯ = 0 . 0 4 , π¦ = 0 . 0 2 5 , and π§ = 0 , 0.02, 0.04, and 0.06) ceramic system were synthesized by a semiwet technique. In the present study, we have investigated the effect of Ba on the structure, morphology, and dielectric, ferroelectric, and piezoelectric properties of BLNLT system. The XRD patterns of all the specimens showed rhombohedral structure at room temperature. Field emission scanning electron microscopy images (FE-SEM) showed grain growth inhibition with Ba content in BLNLT system. The temperature dependence of dielectric constant revealed that the temperature of maximum dielectric constant β π π β and depolarization temperature β π π β decreased for the sample π§ = 0 . 0 6 and showed high value of dielectric constant with low dielectric loss. These samples exhibited nonlinear behaviour of hysteresis loop. The values of dielectric constant ( π π ), dissipation factor (tan Ξ΄), piezo charge coefficient ( π 3 3 ), remnant polarization ( π π ), and coercive field ( πΈ π ) for the composition π§ = 0 . 0 6 were 1495, 0.06, 20 pC/N, 5 ΞΌC/cm2, and 10.5 kV/cm, respectively.
Current Applied Physics, 2009
Lead indium niobate, Pb(In 1/2 Nb 1/2 )O 3 or (PIN), is an interesting ferroelectric material, be... more Lead indium niobate, Pb(In 1/2 Nb 1/2 )O 3 or (PIN), is an interesting ferroelectric material, because it can be changed from a disordered state to ordered state by long-time thermal annealing. However, the temperature related to the maximum dielectric constant (T max ) of PIN in relaxor phase is low (at 1 kHz, T max = 66Β°C). In this study, to increasing T max of PIN, lead titanate, PbTiO 3 (PT) was thus added to PIN with compositions (1 Γ x)PIN-xPT (for x = 0.1-0.5). The influence of stress on the dielectric properties of (1 Γ x)PIN-xPT ceramics was then investigated. The dielectric properties were measured under various uniaxial compressive stress up to 400 MPa. The results showed that the superimposed compression load reduced the dielectric constant in 0.9PIN-0.1PT. For the other compositions, the dielectric constants first increased with the compressive stress, and then decreased when the stress was further increased up to 400 MPa. The dielectric loss tangent of all composition was found to decrease with increasing compressive stress.