The cation doped polycrystalline compound La0.5Nd0.15Ca0.35MnO3 has been synthesized by a conventional solid state reaction method. The Rietveld analysis of the powder XRD of the composites reveals an orthorhombic structure with Pbnm space group symmetry. The cell parameters are a = 5.4505 ?, b = 5.4457 ? and c = 7.6876?. The AC magnetization studies show a semiconducting paramagnetic to metallic ferromagnetic transition at a temperature below the Curie temperature TC which is found to be 206.3K. It is also observed that metal to semiconductor transition temperature TMS is very close to TC. The sample also possesses high magnetoresistance, which is revealed in MR studies.
{"title":"Colossal magnetoresistance of Nd-doped LaCaMnO3 polycrystalline ceramics","authors":"Sam Rajan, K. V. A. Kumar, Jayakumari Isac","doi":"10.2298/PAC2101095R","DOIUrl":"https://doi.org/10.2298/PAC2101095R","url":null,"abstract":"The cation doped polycrystalline compound La0.5Nd0.15Ca0.35MnO3 has been synthesized by a conventional solid state reaction method. The Rietveld analysis of the powder XRD of the composites reveals an orthorhombic structure with Pbnm space group symmetry. The cell parameters are a = 5.4505 ?, b = 5.4457 ? and c = 7.6876?. The AC magnetization studies show a semiconducting paramagnetic to metallic ferromagnetic transition at a temperature below the Curie temperature TC which is found to be 206.3K. It is also observed that metal to semiconductor transition temperature TMS is very close to TC. The sample also possesses high magnetoresistance, which is revealed in MR studies.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68578691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Particulate Al2O3 matrix nanocomposites containing 1 vol.%Ni were prepared by the heterogeneous precipitation method and the addition of 5 vol.% ZrO2 (ANZ) or 1 vol.% Cr2O3 (ANC). The prepared samples were subjected to the low energy drop weight impact tests to compare the behaviour of the composites under low energy impact and to investigate the damage mechanisms. The pure Al2O3, Al2O3/Ni, Al2O3/ZrO2 and Al2O3/Cr2O3 compositions with the same additive ratios were also produced to make the comparison systematically. Also, the Vickers hardness measurements were carried out and a significant increase in hardness was attained for both ANZ and ANC composites. The average hardness value around 24.8?1.0GPa was measured for the ANZ and ANC composites which means ~15% improvement compared to the pure Al2O3. Between all the compositions, the maximum force (Fmax) value was obtained for the ANZ (for 12 J impact energy level Fmax = 26617N) according to the low energy drop weight impact test results. Tensile radial crack network formation, cone formation, fracture and crushing of the cone structure were observed as damage mechanisms for all compositions. The volume of conical frustum structure was evaluated for each composition and the effect of microstructure on possible ballistic performance was also discussed.
{"title":"Low velocity drop weight impact behaviour of Al2O3-Ni-ZrO2 and Al2O3-Ni-Cr2O3 ceramic composites","authors":"Yildiz Betül Kafkaslioğlu, Murat Buyuk, Y. Tür","doi":"10.2298/pac2102154k","DOIUrl":"https://doi.org/10.2298/pac2102154k","url":null,"abstract":"Particulate Al2O3 matrix nanocomposites containing 1 vol.%Ni were prepared by the heterogeneous precipitation method and the addition of 5 vol.% ZrO2 (ANZ) or 1 vol.% Cr2O3 (ANC). The prepared samples were subjected to the low energy drop weight impact tests to compare the behaviour of the composites under low energy impact and to investigate the damage mechanisms. The pure Al2O3, Al2O3/Ni, Al2O3/ZrO2 and Al2O3/Cr2O3 compositions with the same additive ratios were also produced to make the comparison systematically. Also, the Vickers hardness measurements were carried out and a significant increase in hardness was attained for both ANZ and ANC composites. The average hardness value around 24.8?1.0GPa was measured for the ANZ and ANC composites which means ~15% improvement compared to the pure Al2O3. Between all the compositions, the maximum force (Fmax) value was obtained for the ANZ (for 12 J impact energy level Fmax = 26617N) according to the low energy drop weight impact test results. Tensile radial crack network formation, cone formation, fracture and crushing of the cone structure were observed as damage mechanisms for all compositions. The volume of conical frustum structure was evaluated for each composition and the effect of microstructure on possible ballistic performance was also discussed.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68578869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shihao Wang, B. Fang, Shuai Zhang, Xiaolong Lu, Jianning Ding
Perovskite (1-x)Ba0.9Sr0.1TiO3-xBi(Mg1/2Ti1/2)O3 (BST-BiMT-x) ceramics were prepared by sintering the corresponding powders synthesized by combining of solid state reaction method with citrate sol-gel and selfcombustion techniques. Submicron grains morphology, high density and large resistivity were obtained in the BST-BiMT-x ceramics. In addition, the BST-BiMT-0.1 and BST-BiMT-0.075 ceramics exhibit ferroelectric hysteresis loops with slim shape which lead to enhanced energy-storage properties. The energy-storage density of these two ceramics increases almost linearly with increasing the applied electric filed. The energy-storage density and efficiency at 25 kV/cm of the BST-BiMT-0.1 and BST-BiMT-0.075 ceramics sintered at 1200?C are 141.2mJ/cm3 and 79.3%, and 158.1mJ/cm3 and 76.7%, respectively, surpassing many recently reported values for ferroelectric/antiferroelectric ceramics. The enhanced energy-storage density and efficiency under low electric field can be attributed to the slim polarization-electric field hysteresis loops, high density accompanied by submicron grains morphology and pure perovskite structure.
将固相反应法与柠檬酸溶胶-凝胶法及自燃法相结合合成的钙钛矿(1-x)Ba0.9Sr0.1TiO3-xBi(Mg1/2Ti1/2)O3 (bst - bmt -x)粉体进行烧结制备了钙钛矿(1-x)Ba0.9Sr0.1TiO3-xBi(Mg1/2Ti1/2)O3陶瓷。bst - bmt -x陶瓷具有亚微米晶粒形貌、高密度和大电阻率等特点。此外，BST-BiMT-0.1和BST-BiMT-0.075陶瓷具有细长形状的铁电磁滞回线，从而增强了储能性能。这两种陶瓷的储能密度几乎随外加电场的增加而线性增加。1200℃烧结BST-BiMT-0.1和BST-BiMT-0.075陶瓷在25 kV/cm下的储能密度和效率C分别为141.2mJ/cm3和79.3%，158.1mJ/cm3和76.7%，超过了许多最近报道的铁电/反铁电陶瓷的值。低电场条件下储能密度和效率的提高可归因于细极化电场滞回线、高密度伴随亚微米晶粒形貌和纯钙钛矿结构。
{"title":"Enhanced low electric-field energy-storage performance in Ba0.9Sr0.1TiO3-Bi(Mg1/2Ti1/2)O3 ceramics","authors":"Shihao Wang, B. Fang, Shuai Zhang, Xiaolong Lu, Jianning Ding","doi":"10.2298/pac2104410w","DOIUrl":"https://doi.org/10.2298/pac2104410w","url":null,"abstract":"Perovskite (1-x)Ba0.9Sr0.1TiO3-xBi(Mg1/2Ti1/2)O3 (BST-BiMT-x) ceramics were prepared by sintering the corresponding powders synthesized by combining of solid state reaction method with citrate sol-gel and selfcombustion techniques. Submicron grains morphology, high density and large resistivity were obtained in the BST-BiMT-x ceramics. In addition, the BST-BiMT-0.1 and BST-BiMT-0.075 ceramics exhibit ferroelectric hysteresis loops with slim shape which lead to enhanced energy-storage properties. The energy-storage density of these two ceramics increases almost linearly with increasing the applied electric filed. The energy-storage density and efficiency at 25 kV/cm of the BST-BiMT-0.1 and BST-BiMT-0.075 ceramics sintered at 1200?C are 141.2mJ/cm3 and 79.3%, and 158.1mJ/cm3 and 76.7%, respectively, surpassing many recently reported values for ferroelectric/antiferroelectric ceramics. The enhanced energy-storage density and efficiency under low electric field can be attributed to the slim polarization-electric field hysteresis loops, high density accompanied by submicron grains morphology and pure perovskite structure.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68579862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Si Yaochen, X. Miao, Hongxia Li, Sun Honggang, A. Guo, Du Yihao, Zhao Shixian, Shang Xinlian, Yongqiang Chen
In order to develop chrome-free refractory materials applicable in coal slurry gasification, SiC-CaAl12O19 (SiC-CA6) composite refractories were developed and prepared by using SiC aggregates and CA6 powders as main raw materials. The sintering behaviour of the composites was investigated. After firing at different temperatures under CO atmosphere, the effects of oxidation of SiC aggregates on the sintering behaviour and microstructures of SiC-CA6 composite refractorieswere investigated. SiC-CA6 composites could not be sintered when firing temperature was lower than 1500?C. SiC had a passive oxidation and the oxidation components were able to react with CA6 to form CaAl2Si2O8. The CaAl2Si2O8 melted into liquid when sintering temperature was in the range of 1500-1600?C, which promoted the sintering process of the SiC-CA6 composites. At temperatures above 1600 ?C, an active oxidation of SiC occurred. Simultaneously, SiC could also reacted with the SiO2(s,l) to form SiO, leading to the precipitation of Al2O3 and CaO in the liquid to generate plate-like CA6. Above this temperature, the sintering of the SiC-CA6 composite refractories was affected by the growth of CA6 and oxidation of SiC. This work demonstrates that the optimal sintering temperature for the SiC-CA6 composite refractories was 1600?C.
{"title":"Effects of oxidation of SiC aggregates on the sintering behaviour and microstructures of SiC-CaAl12O19 composite refractories","authors":"Si Yaochen, X. Miao, Hongxia Li, Sun Honggang, A. Guo, Du Yihao, Zhao Shixian, Shang Xinlian, Yongqiang Chen","doi":"10.2298/PAC2101011S","DOIUrl":"https://doi.org/10.2298/PAC2101011S","url":null,"abstract":"In order to develop chrome-free refractory materials applicable in coal slurry gasification, SiC-CaAl12O19 (SiC-CA6) composite refractories were developed and prepared by using SiC aggregates and CA6 powders as main raw materials. The sintering behaviour of the composites was investigated. After firing at different temperatures under CO atmosphere, the effects of oxidation of SiC aggregates on the sintering behaviour and microstructures of SiC-CA6 composite refractorieswere investigated. SiC-CA6 composites could not be sintered when firing temperature was lower than 1500?C. SiC had a passive oxidation and the oxidation components were able to react with CA6 to form CaAl2Si2O8. The CaAl2Si2O8 melted into liquid when sintering temperature was in the range of 1500-1600?C, which promoted the sintering process of the SiC-CA6 composites. At temperatures above 1600 ?C, an active oxidation of SiC occurred. Simultaneously, SiC could also reacted with the SiO2(s,l) to form SiO, leading to the precipitation of Al2O3 and CaO in the liquid to generate plate-like CA6. Above this temperature, the sintering of the SiC-CA6 composite refractories was affected by the growth of CA6 and oxidation of SiC. This work demonstrates that the optimal sintering temperature for the SiC-CA6 composite refractories was 1600?C.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"15 1","pages":"11-18"},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68578173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Souza, R. N. Duarte, M. Alves, J. Daguano, S. Dos, K. Strecker
Fatigue is one of the most important properties to be considered in ceramic dental implants due to cyclic mechanical stresses arising from the chewing process. In this work, the fatigue behaviour of hydrothermally degraded ZrO2-based ceramics stabilized with 3mol% Y2O3 (3Y-TZP) was studied in 4-point bending tests. Samples of 3Y-TZP were compacted (100MPa), sintered at 1475 ?C for 2 h, polished and hydrothermally degraded in an autoclave as described in the ISO-13356 standard. The samples were characterized by their relative density, crystalline phase composition, microstructure and surface roughness. The highly dense (>99.6%TD) sintered 3Y-TZP ceramics has only tetragonal t-ZrO2 phase, even after hydrothermal ageing. Furthermore, the ceramic materials presented a Vickers hardness of 12.7?0.2GPa, a fracture toughness of 7.1?0.3MPa?m1/2 and a 4-point bending strength of 940.1?67MPa. Based on the bending test results 5 different stress levels for the fatigue tests were selected and conducted by cyclic 4-point bending obtaining the S-N curve. Weibull statistics was used for the statistical analysis. The fatigue tests indicate that the limit of fatigue resistance of this 3Y-TZP ceramics is around 550MPa, i.e. higher than the limits established in the ISO-13356 standard for the use of Y-TZP ceramics for the manufacture of implants. The fatigue behaviour of the investigated 3Y-TZP ceramics was related to the toughening mechanisms acting in Y-TZP ceramics, such as transformation toughening related to t?m phase transformation and microcracking.
{"title":"Cyclic fatigue behaviour of hydrothermally aged 3Y-TZP ceramics in 4-point bending tests","authors":"R. Souza, R. N. Duarte, M. Alves, J. Daguano, S. Dos, K. Strecker","doi":"10.2298/pac2102184s","DOIUrl":"https://doi.org/10.2298/pac2102184s","url":null,"abstract":"Fatigue is one of the most important properties to be considered in ceramic dental implants due to cyclic mechanical stresses arising from the chewing process. In this work, the fatigue behaviour of hydrothermally degraded ZrO2-based ceramics stabilized with 3mol% Y2O3 (3Y-TZP) was studied in 4-point bending tests. Samples of 3Y-TZP were compacted (100MPa), sintered at 1475 ?C for 2 h, polished and hydrothermally degraded in an autoclave as described in the ISO-13356 standard. The samples were characterized by their relative density, crystalline phase composition, microstructure and surface roughness. The highly dense (>99.6%TD) sintered 3Y-TZP ceramics has only tetragonal t-ZrO2 phase, even after hydrothermal ageing. Furthermore, the ceramic materials presented a Vickers hardness of 12.7?0.2GPa, a fracture toughness of 7.1?0.3MPa?m1/2 and a 4-point bending strength of 940.1?67MPa. Based on the bending test results 5 different stress levels for the fatigue tests were selected and conducted by cyclic 4-point bending obtaining the S-N curve. Weibull statistics was used for the statistical analysis. The fatigue tests indicate that the limit of fatigue resistance of this 3Y-TZP ceramics is around 550MPa, i.e. higher than the limits established in the ISO-13356 standard for the use of Y-TZP ceramics for the manufacture of implants. The fatigue behaviour of the investigated 3Y-TZP ceramics was related to the toughening mechanisms acting in Y-TZP ceramics, such as transformation toughening related to t?m phase transformation and microcracking.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68578477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dani Syarif Gustaman, Djoko Prajitno Hadi, A. Kurniawan, Muhamad Febrian Basit, R. Lesmana
HAp and Zr-doped HAp nanoparticles were synthesized from bovine bone and local zircon material by using the hydrothermal method. XRD analysis showed that the HAp and Zr-doped HAp nanoparticles had hexagonal structure with a crystallite size of 20-36 nm and the lattice constants a = 9.8-9.9? and c = 6.5-6.8 ?. XRD data also showed that up to 20 at.% of Zr can be accommodated in HAp crystal structure. The lattice constant and cell volume decreased with increasing Zr concentration. FTIR data confirmed that the majority of functional groups that exist on the surface of the HAp and Zr-doped HAp nanoparticles were the hydroxyl and phosphate groups. Suspensions with the HAp and Zr-doped HAp nanoparticles prepared using citric acid as dispersant were stable with zeta potential between ?31 and ?35mV at pH = 7. Reactive oxygen species are generated on the produced HAp and Zr-doped Hap nanoparticles and confirm their potential for application in photodynamic therapy.
{"title":"Hydrothermally synthesis and characterization of HAp and Zr-doped HAp nanoparticles from bovine bone and zircon for photodynamic therapy","authors":"Dani Syarif Gustaman, Djoko Prajitno Hadi, A. Kurniawan, Muhamad Febrian Basit, R. Lesmana","doi":"10.2298/pac2102146s","DOIUrl":"https://doi.org/10.2298/pac2102146s","url":null,"abstract":"HAp and Zr-doped HAp nanoparticles were synthesized from bovine bone and local zircon material by using the hydrothermal method. XRD analysis showed that the HAp and Zr-doped HAp nanoparticles had hexagonal structure with a crystallite size of 20-36 nm and the lattice constants a = 9.8-9.9? and c = 6.5-6.8 ?. XRD data also showed that up to 20 at.% of Zr can be accommodated in HAp crystal structure. The lattice constant and cell volume decreased with increasing Zr concentration. FTIR data confirmed that the majority of functional groups that exist on the surface of the HAp and Zr-doped HAp nanoparticles were the hydroxyl and phosphate groups. Suspensions with the HAp and Zr-doped HAp nanoparticles prepared using citric acid as dispersant were stable with zeta potential between ?31 and ?35mV at pH = 7. Reactive oxygen species are generated on the produced HAp and Zr-doped Hap nanoparticles and confirm their potential for application in photodynamic therapy.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68578857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pure (CeO2) and Sm doped (Ce0.8Sm0.2O2-?) ceria were synthesized by the maltose and pectin-modified solgel process. The dense ceramic samples, with relative density of >96%TD, were prepared by sintering of the pressed pellets at 1300?C for 6 h. The structure and phase of Ce0.8Sm0.2O2-? samples were analysed by XRD method. Raman spectroscopy studies were carried out to study the Sm-doping effect. The microstructural images were recorded by FE-SEM. The electrical properties were measured by impedance spectroscopy. The association and the migration energies were calculated from the dielectric loss tangent. The Jonscher power law was applied to study the frequency variation of electrical conductivity. The electricmodulus studies confirm that the charge carriers follow the hopping mechanism.
{"title":"Transport properties of SM doped CeO2 ceramics","authors":"S. Ramesh","doi":"10.2298/pac2104366r","DOIUrl":"https://doi.org/10.2298/pac2104366r","url":null,"abstract":"Pure (CeO2) and Sm doped (Ce0.8Sm0.2O2-?) ceria were synthesized by the maltose and pectin-modified solgel process. The dense ceramic samples, with relative density of >96%TD, were prepared by sintering of the pressed pellets at 1300?C for 6 h. The structure and phase of Ce0.8Sm0.2O2-? samples were analysed by XRD method. Raman spectroscopy studies were carried out to study the Sm-doping effect. The microstructural images were recorded by FE-SEM. The electrical properties were measured by impedance spectroscopy. The association and the migration energies were calculated from the dielectric loss tangent. The Jonscher power law was applied to study the frequency variation of electrical conductivity. The electricmodulus studies confirm that the charge carriers follow the hopping mechanism.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68579725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yasmina Djoudi, F. Kahoul, L. Hamzioui, A. Guemache
Perovskite solid solution (1-x)Pb(Zr0.52Ti0.48)O3-xY(Ta1/2Sb1/2)O3 ceramics (abbreviated as PZT-YTS, where x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05) were synthesized by conventional solid state method. The phase structure, microstructure and corresponding electrical properties were studied. X-ray diffraction and Raman analyses show that tetragonal phase structure was obtained in all ceramics at room temperature. Scanning electron micrographs of the samples show uniform grain distribution and grain growth inhibition with the increase of doping content. The dielectric permittivity, dissipation factor, electromechanical coupling factor, Young modulus, mechanical quality factor, piezoelectric charge constant, actual density and piezoelectric voltage constant, for the ceramics with x = 0.04 were: ?r = 714.9, tan ? = 0.03345, KP = 0.635, Y = 10.528 ? 1010 N/m2, Qm = 622.254, d31 = 74.738 ? 10?12 C/N, ?a = 7.67 g/cm3 and g31 = 10.477 ? 10?3 m?V/N, respectively, which are optimal in comparison to other studied samples.
{"title":"Influence of YTS addition on structural and electrical properties of PZT-based ceramics","authors":"Yasmina Djoudi, F. Kahoul, L. Hamzioui, A. Guemache","doi":"10.2298/pac2103279d","DOIUrl":"https://doi.org/10.2298/pac2103279d","url":null,"abstract":"Perovskite solid solution (1-x)Pb(Zr0.52Ti0.48)O3-xY(Ta1/2Sb1/2)O3 ceramics (abbreviated as PZT-YTS, where x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05) were synthesized by conventional solid state method. The phase structure, microstructure and corresponding electrical properties were studied. X-ray diffraction and Raman analyses show that tetragonal phase structure was obtained in all ceramics at room temperature. Scanning electron micrographs of the samples show uniform grain distribution and grain growth inhibition with the increase of doping content. The dielectric permittivity, dissipation factor, electromechanical coupling factor, Young modulus, mechanical quality factor, piezoelectric charge constant, actual density and piezoelectric voltage constant, for the ceramics with x = 0.04 were: ?r = 714.9, tan ? = 0.03345, KP = 0.635, Y = 10.528 ? 1010 N/m2, Qm = 622.254, d31 = 74.738 ? 10?12 C/N, ?a = 7.67 g/cm3 and g31 = 10.477 ? 10?3 m?V/N, respectively, which are optimal in comparison to other studied samples.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68579736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Alwany, G. Youssef, M. Algradee, M. Abdel-Rahim, A. Abd-Elnaiem
Ge15Se75Zn10 thin films were deposited onto cleaned glass substrates by the vacuum thermal evaporation technique. The as-deposited and annealed thin films were characterized by scanning electron microscopy, X-ray diffraction and optical spectroscopy. The average particle sizes of the crystallized GeSe and ZnSe phases increase with increasing annealing temperature. Some optical parameters of the as-deposited and annealed Ge15Se75Zn10 thin films were studied using both transmittance T(?) and reflectance R(?) measurements. The analysis of T(?) and R(?) data revealed the existence of direct optical band gap (EG) and the corresponding values were calculated to be 2.913, 2.802 and 2.692 eV for the as-deposited and annealed thin films at 373 and 423 K, respectively. The dispersion of the refractive index is discussed in terms of the single oscillator Wemple-Didomenico (WD) model. The width of band tails of localized states (Ee), the single oscillator energy (E0), the dispersion energy (Ed), the high frequency dielectric constant (?L) and the steepness parameter (S) were estimated.
{"title":"Effect of annealing temperature on the structural and optical properties of Ge15Se75Zn10 thin films","authors":"A. Alwany, G. Youssef, M. Algradee, M. Abdel-Rahim, A. Abd-Elnaiem","doi":"10.2298/pac2104385a","DOIUrl":"https://doi.org/10.2298/pac2104385a","url":null,"abstract":"Ge15Se75Zn10 thin films were deposited onto cleaned glass substrates by the vacuum thermal evaporation technique. The as-deposited and annealed thin films were characterized by scanning electron microscopy, X-ray diffraction and optical spectroscopy. The average particle sizes of the crystallized GeSe and ZnSe phases increase with increasing annealing temperature. Some optical parameters of the as-deposited and annealed Ge15Se75Zn10 thin films were studied using both transmittance T(?) and reflectance R(?) measurements. The analysis of T(?) and R(?) data revealed the existence of direct optical band gap (EG) and the corresponding values were calculated to be 2.913, 2.802 and 2.692 eV for the as-deposited and annealed thin films at 373 and 423 K, respectively. The dispersion of the refractive index is discussed in terms of the single oscillator Wemple-Didomenico (WD) model. The width of band tails of localized states (Ee), the single oscillator energy (E0), the dispersion energy (Ed), the high frequency dielectric constant (?L) and the steepness parameter (S) were estimated.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68579781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nb5+-doped sodium bismuth titanate (NBT) ceramics ((Na0.5Bi0.5)1-x/2Ti1-xNbxO3 where x = 0, 0.005, 0.01 and 0.015) were obtained by microwave assisted solid state reaction route and microwave sintered at 1000 ?C. Microwave processing technique was chosen for the sintering as it is a powerfulmethod which enables sintering in a short time with fast heating rate avoiding grain growth. The influence of Nb5+-doping on microstructure and electrical properties of the NBT ceramics was studied. X-ray diffraction analyses revealed that solubility limit of niobium in NBT lattice is up to 1mol%, as with further increase in niobium concentration pyrochlore appeared. Microstructure of all the ceramics was investigated by field emission scanning electron microscopy and it was observed that the average grain size decreased with doping. Temperature dependent dielectric study was carried out for all the ceramics at different frequency. All ceramics show diffusive dielectric behaviour around Tm and introduction of Nb even increases compositional fluctuation compared to the parent NBT. Nb-doping shifts the Tm toward lower temperature. Leakage current study showed that for whole range of electric field ohmic type conduction mechanism is dominant for all the ceramics. Room temperature polarization-electric field (P-E) hysteresis loop confirms the ferroelectric behaviour of all the ceramics.
{"title":"Microstructure and electrical properties of microwave sintered Nb-doped NBT ceramics","authors":"R. Sahu, Pawan Kumar","doi":"10.2298/pac2104395s","DOIUrl":"https://doi.org/10.2298/pac2104395s","url":null,"abstract":"Nb5+-doped sodium bismuth titanate (NBT) ceramics ((Na0.5Bi0.5)1-x/2Ti1-xNbxO3 where x = 0, 0.005, 0.01 and 0.015) were obtained by microwave assisted solid state reaction route and microwave sintered at 1000 ?C. Microwave processing technique was chosen for the sintering as it is a powerfulmethod which enables sintering in a short time with fast heating rate avoiding grain growth. The influence of Nb5+-doping on microstructure and electrical properties of the NBT ceramics was studied. X-ray diffraction analyses revealed that solubility limit of niobium in NBT lattice is up to 1mol%, as with further increase in niobium concentration pyrochlore appeared. Microstructure of all the ceramics was investigated by field emission scanning electron microscopy and it was observed that the average grain size decreased with doping. Temperature dependent dielectric study was carried out for all the ceramics at different frequency. All ceramics show diffusive dielectric behaviour around Tm and introduction of Nb even increases compositional fluctuation compared to the parent NBT. Nb-doping shifts the Tm toward lower temperature. Leakage current study showed that for whole range of electric field ohmic type conduction mechanism is dominant for all the ceramics. Room temperature polarization-electric field (P-E) hysteresis loop confirms the ferroelectric behaviour of all the ceramics.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68579830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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