Pub Date : 2022-12-28DOI: 10.1080/21870764.2022.2159952
Jiabao Liu, Zhaofeng Chen, Lixia Yang, P. Chai, Qiang Wan
ABSTRACT Infrared temperature measurement is widely used in the MOCVD process, and improving the surface infrared emissivity of the graphite base is beneficial to improve the temperature measurement accuracy. In this study, SiC coatings were prepared by CVD on graphite substrate using different process parameters including CVD temperature, total pressure, H2/MTS ratio. The infrared emissivity of SiC coatings with different microstructures was investigated. All SiC coatings obtained were β-SiC. The infrared emissivities of the three samples with different surface morphologies are 0.93, 0.95 and 0.97, respectively. As the surface roughness increases, the reflection and scattering of thermally radiated electromagnetic waves increases, resulting in higher infrared emissivity. The loose structure of the grain surface makes the surface electromagnetic wave and light wave resonant coupling, thus increasing the infrared emissivity.
{"title":"The effect of SiC coatings microstructure on their infrared emissivity","authors":"Jiabao Liu, Zhaofeng Chen, Lixia Yang, P. Chai, Qiang Wan","doi":"10.1080/21870764.2022.2159952","DOIUrl":"https://doi.org/10.1080/21870764.2022.2159952","url":null,"abstract":"ABSTRACT Infrared temperature measurement is widely used in the MOCVD process, and improving the surface infrared emissivity of the graphite base is beneficial to improve the temperature measurement accuracy. In this study, SiC coatings were prepared by CVD on graphite substrate using different process parameters including CVD temperature, total pressure, H2/MTS ratio. The infrared emissivity of SiC coatings with different microstructures was investigated. All SiC coatings obtained were β-SiC. The infrared emissivities of the three samples with different surface morphologies are 0.93, 0.95 and 0.97, respectively. As the surface roughness increases, the reflection and scattering of thermally radiated electromagnetic waves increases, resulting in higher infrared emissivity. The loose structure of the grain surface makes the surface electromagnetic wave and light wave resonant coupling, thus increasing the infrared emissivity.","PeriodicalId":15130,"journal":{"name":"Journal of Asian Ceramic Societies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42643161","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}
Pub Date : 2022-12-13DOI: 10.1080/21870764.2022.2151102
S. Kim, Chang-Hyeon Jo, Min-Sung Bae, M. Ichimura, J. Koh
ABSTRACT Owing to its wide bandgap (3.4 eV) and high electron mobility, GaN has attracted significant attention for applications in solar cells, power transistors, and high-electron-mobility transistors. Crystallized GaN thin film can be hardly prepared in thin film form by employing physical vapor deposition processes, such as reactive RF sputtering and pulsed laser deposition, because a high driving energy is required to deposit a thin film due to its high binding energy. Herein, GaN thin films were prepared by CO2 laser-assisted RF sputtering at a relatively low temperature of 200°C. The CO2 laser with a 10,600 nm wavelength shows excellent conversion efficiency from optical energy to thermal energy. At the optimized laser energy density of 0.98 W/mm2, GaN thin film can have a (0002) orientation with a bandgap energy of 3.26 eV. The crystalline, surface morphological, and optical properties of the fabricated GaN thin films were evaluated using X-ray diffraction, FE-SEM, X-ray photoelectron (XPS), and photoluminescence (PL) spectroscopy, and UV-vis spectrometry. The energy bandgap of the fabricated GaN thin film was measured using the Tauc plot and confirmed via PL. The film composition thus obtained was analyzed using XPS.
{"title":"Low temperature processed CO2 laser-assisted RF-sputtered GaN thin film for wide bandgap semiconductors","authors":"S. Kim, Chang-Hyeon Jo, Min-Sung Bae, M. Ichimura, J. Koh","doi":"10.1080/21870764.2022.2151102","DOIUrl":"https://doi.org/10.1080/21870764.2022.2151102","url":null,"abstract":"ABSTRACT Owing to its wide bandgap (3.4 eV) and high electron mobility, GaN has attracted significant attention for applications in solar cells, power transistors, and high-electron-mobility transistors. Crystallized GaN thin film can be hardly prepared in thin film form by employing physical vapor deposition processes, such as reactive RF sputtering and pulsed laser deposition, because a high driving energy is required to deposit a thin film due to its high binding energy. Herein, GaN thin films were prepared by CO2 laser-assisted RF sputtering at a relatively low temperature of 200°C. The CO2 laser with a 10,600 nm wavelength shows excellent conversion efficiency from optical energy to thermal energy. At the optimized laser energy density of 0.98 W/mm2, GaN thin film can have a (0002) orientation with a bandgap energy of 3.26 eV. The crystalline, surface morphological, and optical properties of the fabricated GaN thin films were evaluated using X-ray diffraction, FE-SEM, X-ray photoelectron (XPS), and photoluminescence (PL) spectroscopy, and UV-vis spectrometry. The energy bandgap of the fabricated GaN thin film was measured using the Tauc plot and confirmed via PL. The film composition thus obtained was analyzed using XPS.","PeriodicalId":15130,"journal":{"name":"Journal of Asian Ceramic Societies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44878832","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}
Pub Date : 2022-12-08DOI: 10.1080/21870764.2022.2155341
L. Wen, J. Nie, Haoran Dong, Maoqi Ju, Y. Liang, M. Cai
ABSTRACT The demand for Al2O3-SiC-C castables (ASCs) with excellent strength and thermal shock resistance has expanded considerably. Here, the effects of Fe-Si3N4 on the thermal shock resistance and physical properties of ASCs were studied. The addition of Fe-Si3N4 to ASCs lead to the formation of SiC whiskers, enhancing the cold modulus of rupture and the cold crushing strength of the castables. The formed SiC can fill the pores left by the oxidation of carbon after heating at 1450°C for 3 h, thereby improving the bulk density of the castables. Additionally, the residual strength ratio of the castables after three thermal shock cycles was improved and this was attributed to the generation of microcracks due to the release of N2 and the generation of the whiskers. The optimal Fe-Si3N4 content was 4 wt%. Therefore, the results of this study revealed that the thermal shock resistance and physical properties of ASCs were enhanced by the addition of Fe-Si3N4.
{"title":"Enhancing the thermal shock resistance of Al2O3-SiC-C castables via the generation of in-situ SiC whiskers","authors":"L. Wen, J. Nie, Haoran Dong, Maoqi Ju, Y. Liang, M. Cai","doi":"10.1080/21870764.2022.2155341","DOIUrl":"https://doi.org/10.1080/21870764.2022.2155341","url":null,"abstract":"ABSTRACT The demand for Al2O3-SiC-C castables (ASCs) with excellent strength and thermal shock resistance has expanded considerably. Here, the effects of Fe-Si3N4 on the thermal shock resistance and physical properties of ASCs were studied. The addition of Fe-Si3N4 to ASCs lead to the formation of SiC whiskers, enhancing the cold modulus of rupture and the cold crushing strength of the castables. The formed SiC can fill the pores left by the oxidation of carbon after heating at 1450°C for 3 h, thereby improving the bulk density of the castables. Additionally, the residual strength ratio of the castables after three thermal shock cycles was improved and this was attributed to the generation of microcracks due to the release of N2 and the generation of the whiskers. The optimal Fe-Si3N4 content was 4 wt%. Therefore, the results of this study revealed that the thermal shock resistance and physical properties of ASCs were enhanced by the addition of Fe-Si3N4.","PeriodicalId":15130,"journal":{"name":"Journal of Asian Ceramic Societies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46042289","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}
ABSTRACT In this paper, we proposed a technique, ultrafast laser machining–picosecond laser welding, to fabricate an embedded thin film by placing a coating material (ZnO powders) between the interface of two glass substrates. We researched the thickness (embedding depth of ZnO powders) and the formation mechanism of the embedded thin film and the zinc content and distribution. Under our experimental conditions, an embedded thin film of 600 μm thickness was formed. At a distance of 340 μm within the embedded thin film, the zinc content peaked at 400 cps. Finally, we fabricate an embedded thin film with the bonding strength of 12.22 MPa. This technique breaks through the bottlenecks of thin films fabricated by conventional lasers, such as long duration, low precision and serious chemical pollution, which has great significance for achieving high-end manufacturing of thin-film devices.
{"title":"Embedded thin film fabrication via glass welding by an ultrafast laser","authors":"Hua Tan, Weijian Yang, Qi Huang, Jiahui Pan, Chao Li, Xiaoquan Fu","doi":"10.1080/21870764.2022.2148383","DOIUrl":"https://doi.org/10.1080/21870764.2022.2148383","url":null,"abstract":"ABSTRACT In this paper, we proposed a technique, ultrafast laser machining–picosecond laser welding, to fabricate an embedded thin film by placing a coating material (ZnO powders) between the interface of two glass substrates. We researched the thickness (embedding depth of ZnO powders) and the formation mechanism of the embedded thin film and the zinc content and distribution. Under our experimental conditions, an embedded thin film of 600 μm thickness was formed. At a distance of 340 μm within the embedded thin film, the zinc content peaked at 400 cps. Finally, we fabricate an embedded thin film with the bonding strength of 12.22 MPa. This technique breaks through the bottlenecks of thin films fabricated by conventional lasers, such as long duration, low precision and serious chemical pollution, which has great significance for achieving high-end manufacturing of thin-film devices.","PeriodicalId":15130,"journal":{"name":"Journal of Asian Ceramic Societies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43910189","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}
Pub Date : 2022-11-21DOI: 10.1080/21870764.2022.2148386
M. Amano, H. Shibata, K. Hashimoto
ABSTRACT We successfully prepared Hydroxyapatite/Zinc oxide (HAp/ZnO) composite particles with hexagonal plate-like shapes. The surface of the ZnO particles was treated with (3-aminopropyl)triethoxysilane (APTES) as a scaffold for the crystallization of HAp from the precursor solution. From the results of XRD measurements and SEM images of composite particles, formation of HAp on the ZnO particles was revealed. In addition, diffraction peaks associated with the (0 0 2) and (0 0 4) planes of HAp were clearly observed. They also revealed that the HAp/ZnO composite particles had a c-face orientation. Furthermore, element mapping analysis by EPMA showed that the elemental distributions of Ca, P and Zn of the composites were almost coincident. These results suggested that the formation of HAp occurred on the ZnO particles. In contrast, the ZnO particles without APTES treatment readily dissolved in the precursor solution and the diffused Zn2+ ions reacted with PO4 3- ions and Ca2+ ions to form CaZn2(PO4)2. APTES treatment of the ZnO surfaces appeared to prevent the dissolution of ZnO in the solution and induce the adsorption of anions such as phosphate on ZnO.
{"title":"Crystal growth of HAp on plate-like ZnO particles using APTES as surface treatment agents","authors":"M. Amano, H. Shibata, K. Hashimoto","doi":"10.1080/21870764.2022.2148386","DOIUrl":"https://doi.org/10.1080/21870764.2022.2148386","url":null,"abstract":"ABSTRACT We successfully prepared Hydroxyapatite/Zinc oxide (HAp/ZnO) composite particles with hexagonal plate-like shapes. The surface of the ZnO particles was treated with (3-aminopropyl)triethoxysilane (APTES) as a scaffold for the crystallization of HAp from the precursor solution. From the results of XRD measurements and SEM images of composite particles, formation of HAp on the ZnO particles was revealed. In addition, diffraction peaks associated with the (0 0 2) and (0 0 4) planes of HAp were clearly observed. They also revealed that the HAp/ZnO composite particles had a c-face orientation. Furthermore, element mapping analysis by EPMA showed that the elemental distributions of Ca, P and Zn of the composites were almost coincident. These results suggested that the formation of HAp occurred on the ZnO particles. In contrast, the ZnO particles without APTES treatment readily dissolved in the precursor solution and the diffused Zn2+ ions reacted with PO4 3- ions and Ca2+ ions to form CaZn2(PO4)2. APTES treatment of the ZnO surfaces appeared to prevent the dissolution of ZnO in the solution and induce the adsorption of anions such as phosphate on ZnO.","PeriodicalId":15130,"journal":{"name":"Journal of Asian Ceramic Societies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45243461","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}
Pub Date : 2022-11-11DOI: 10.1080/21870764.2022.2142368
Hang Zhao, Chang Gao, Cheng Guo, Bin Xu, Xiao-yu Wu, Jianguo Lei
ABSTRACT In this study, a (Ti + graphite)-Ni composite powder serving as a coating material was deposited on H13 steel to fabricate an in-situ TiC-reinforced Ni-based composite coating by a new type of ESD process, which was named ultrasonic-assisted electrospark powder deposition (UEPD). The composite coating has an average thickness of approximately 45.5 μm and metallurgically bonds with the substrate. The ultrasonic vibration exerted on the UEPD electrode can effectively improve the forming quality of the composite coating, which produces better compactness and thickness uniformity as well as few defects. The microstructure mainly consisted of submicron dendrites due to the rapid solidification of the molten pool. TiC particles as reinforcements were successfully synthesized in the coating via an in-situ reaction due to their low Gibbs free energy and high melting point. The formation of refined grains and in-situ reinforcements prompts the average hardness of the coating to reach 1400.5 HV0.05, which is approximately 2.5 times that of the substrate. The tribological properties of the composite coating are greatly improved in comparison with those of the substrate. The wear rate and friction coefficient of the composite coating decrease by two orders of magnitude and 46.2%, respectively.
{"title":"In-situ TiC-reinforced Ni-based composite coatings fabricated by ultrasonic-assisted electrospark powder deposition","authors":"Hang Zhao, Chang Gao, Cheng Guo, Bin Xu, Xiao-yu Wu, Jianguo Lei","doi":"10.1080/21870764.2022.2142368","DOIUrl":"https://doi.org/10.1080/21870764.2022.2142368","url":null,"abstract":"ABSTRACT In this study, a (Ti + graphite)-Ni composite powder serving as a coating material was deposited on H13 steel to fabricate an in-situ TiC-reinforced Ni-based composite coating by a new type of ESD process, which was named ultrasonic-assisted electrospark powder deposition (UEPD). The composite coating has an average thickness of approximately 45.5 μm and metallurgically bonds with the substrate. The ultrasonic vibration exerted on the UEPD electrode can effectively improve the forming quality of the composite coating, which produces better compactness and thickness uniformity as well as few defects. The microstructure mainly consisted of submicron dendrites due to the rapid solidification of the molten pool. TiC particles as reinforcements were successfully synthesized in the coating via an in-situ reaction due to their low Gibbs free energy and high melting point. The formation of refined grains and in-situ reinforcements prompts the average hardness of the coating to reach 1400.5 HV0.05, which is approximately 2.5 times that of the substrate. The tribological properties of the composite coating are greatly improved in comparison with those of the substrate. The wear rate and friction coefficient of the composite coating decrease by two orders of magnitude and 46.2%, respectively.","PeriodicalId":15130,"journal":{"name":"Journal of Asian Ceramic Societies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42308569","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}
Pub Date : 2022-11-02DOI: 10.1080/21870764.2022.2140497
N. Yamaguchi, J. Dąbek, T. Brylewski, Yen-Ling Kuo, M. Nanko
ABSTRACT A titanium aluminum carbide, Ti2AlC, which is classified among MAX phase ceramics, was studied as a potential candidate for various mechanical components used in high-temperature applications. The impact of its chemical composition on its high-temperature oxidation process was determined. Ti2AlC powders with various Al contents and with or without Nb addition were synthesized via a conventional reaction technique followed by 16 h of annealing in vacuum at 1300°C. The synthesized Ti2AlC powders were consolidated by means of 15 min of pulsed electric current sintering at a die temperature of 1300°C in vacuum under a uniaxial pressure of 30 MPa. In the presence of an aluminum reservoir in the form of TiAl3, Ti2AlC has excellent resistance against high-temperature oxidation. The promising results concerning the addition of Nb to TiAl provided the rationale for a similar modification of Ti2AlC. The results of oxidation tests on Nb-doped Ti2AlC likewise showed excellent oxidation resistance. Alloying with Nb can improve the oxidation resistance of Ti2AlC with low Al content, allowing the formation of a protective Al2O3 scale and inhibiting the growth of TiO2.
{"title":"Influences of Al concentration and Nb addition on oxidation behavior of Ti2AlC ceramics at high temperatures","authors":"N. Yamaguchi, J. Dąbek, T. Brylewski, Yen-Ling Kuo, M. Nanko","doi":"10.1080/21870764.2022.2140497","DOIUrl":"https://doi.org/10.1080/21870764.2022.2140497","url":null,"abstract":"ABSTRACT A titanium aluminum carbide, Ti2AlC, which is classified among MAX phase ceramics, was studied as a potential candidate for various mechanical components used in high-temperature applications. The impact of its chemical composition on its high-temperature oxidation process was determined. Ti2AlC powders with various Al contents and with or without Nb addition were synthesized via a conventional reaction technique followed by 16 h of annealing in vacuum at 1300°C. The synthesized Ti2AlC powders were consolidated by means of 15 min of pulsed electric current sintering at a die temperature of 1300°C in vacuum under a uniaxial pressure of 30 MPa. In the presence of an aluminum reservoir in the form of TiAl3, Ti2AlC has excellent resistance against high-temperature oxidation. The promising results concerning the addition of Nb to TiAl provided the rationale for a similar modification of Ti2AlC. The results of oxidation tests on Nb-doped Ti2AlC likewise showed excellent oxidation resistance. Alloying with Nb can improve the oxidation resistance of Ti2AlC with low Al content, allowing the formation of a protective Al2O3 scale and inhibiting the growth of TiO2.","PeriodicalId":15130,"journal":{"name":"Journal of Asian Ceramic Societies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48022948","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}
Pub Date : 2022-10-20DOI: 10.1080/21870764.2022.2136261
Se Woong Lee, Yurian Kim, Hyung Tay Rho, Sang‐il Kim
ABSTRACT Calcium phosphate ceramics have been studied as promising materials for biomaterial applications owing to their excellent biocompatibility and osteoconductivity. Herein, we investigated the influence of different mass ratios of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) in a calcium phosphate mixture (CPM) on the microhardness and microstructural properties of a series of xHA-(100-x)β-TCP (x = 0, 30, 50, 70, 90, and 100) mixture samples. The chemical compositions and structural properties of the CPM samples were characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The porosity of the HA/β-TCP composites decreased with increasing β-TCP content and reached a minimum porosity when the mass ratio of HA/β-TCP is 70/30, and then increased with increasing β-TCP content again. The surface microhardness of the CPM composites was measured and found to be inversely proportional to their porosities. Therefore, the CPM of HA/β-TCP with a mass ratio of 70/30 exhibited a maximum surface microhardness of 86.02 MPa.
{"title":"Microhardness and microstructural properties of a mixture of hydroxyapatite and β-tricalcium phosphate","authors":"Se Woong Lee, Yurian Kim, Hyung Tay Rho, Sang‐il Kim","doi":"10.1080/21870764.2022.2136261","DOIUrl":"https://doi.org/10.1080/21870764.2022.2136261","url":null,"abstract":"ABSTRACT Calcium phosphate ceramics have been studied as promising materials for biomaterial applications owing to their excellent biocompatibility and osteoconductivity. Herein, we investigated the influence of different mass ratios of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) in a calcium phosphate mixture (CPM) on the microhardness and microstructural properties of a series of xHA-(100-x)β-TCP (x = 0, 30, 50, 70, 90, and 100) mixture samples. The chemical compositions and structural properties of the CPM samples were characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The porosity of the HA/β-TCP composites decreased with increasing β-TCP content and reached a minimum porosity when the mass ratio of HA/β-TCP is 70/30, and then increased with increasing β-TCP content again. The surface microhardness of the CPM composites was measured and found to be inversely proportional to their porosities. Therefore, the CPM of HA/β-TCP with a mass ratio of 70/30 exhibited a maximum surface microhardness of 86.02 MPa.","PeriodicalId":15130,"journal":{"name":"Journal of Asian Ceramic Societies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45463445","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}
Pub Date : 2022-10-02DOI: 10.1080/21870764.2022.2127505
P. Boonsong, A. Watcharapasorn
ABSTRACT Dysprosium barium copper oxide – bismuth sodium titanate ((1-x)DyBCO−xBNT) ceramics, where x = 0−0.07 mole fraction, were successfully prepared by a solid-state reaction and sintering method. The DyBa2Cu3O7-δ and (Bi0.5Na0.5)TiO3 powders were separately synthesized by calcining their stoichiometric mixtures at 900°C for 4 h and 800°C for 2 h, respectively. The (1-x)DyBCO−xBNT powders were compacted into pellets and sintered at 930°C for 2 h under normal air atmosphere. Phase identification and morphology of all samples were determined using X-ray diffractometer (XRD). The quantitative phase analysis was analyzed by fitting the XRD pattern using the GSAS-II program. Scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) was used to study microstructure and chemical composition. In all cases, the result of XRD shows that the DyBa2Cu3O7–δ (Dy-123) was identified as the main crystalline phases, due to the good agreement between the observed and calculated patterns after Rietveld refinement. All BNT-doped DyBCO ceramics showed slightly higher density values than the undoped sample, suggesting that BNT helped improve the densification process. The sign of the Seebeck coefficient ( ) was positive for all samples at all measured temperatures, confirming a p-type conduction mechanism. Low BNT doping improved the overall thermoelectric properties of DyBCO ceramics by affecting electrical conductivity ( ), Seebeck coefficient ( ), and thermal conductivity ( ). The dimensionless figure of merit ( ) of all samples increased with increasing temperature. The highest value of 5.67 × 10−2 was observed for the 0.97DyBCO−0.03BNT sample at 863 K.
{"title":"High-temperature thermoelectric properties of (1-x)DyBCO − xBNT ceramics","authors":"P. Boonsong, A. Watcharapasorn","doi":"10.1080/21870764.2022.2127505","DOIUrl":"https://doi.org/10.1080/21870764.2022.2127505","url":null,"abstract":"ABSTRACT Dysprosium barium copper oxide – bismuth sodium titanate ((1-x)DyBCO−xBNT) ceramics, where x = 0−0.07 mole fraction, were successfully prepared by a solid-state reaction and sintering method. The DyBa2Cu3O7-δ and (Bi0.5Na0.5)TiO3 powders were separately synthesized by calcining their stoichiometric mixtures at 900°C for 4 h and 800°C for 2 h, respectively. The (1-x)DyBCO−xBNT powders were compacted into pellets and sintered at 930°C for 2 h under normal air atmosphere. Phase identification and morphology of all samples were determined using X-ray diffractometer (XRD). The quantitative phase analysis was analyzed by fitting the XRD pattern using the GSAS-II program. Scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) was used to study microstructure and chemical composition. In all cases, the result of XRD shows that the DyBa2Cu3O7–δ (Dy-123) was identified as the main crystalline phases, due to the good agreement between the observed and calculated patterns after Rietveld refinement. All BNT-doped DyBCO ceramics showed slightly higher density values than the undoped sample, suggesting that BNT helped improve the densification process. The sign of the Seebeck coefficient ( ) was positive for all samples at all measured temperatures, confirming a p-type conduction mechanism. Low BNT doping improved the overall thermoelectric properties of DyBCO ceramics by affecting electrical conductivity ( ), Seebeck coefficient ( ), and thermal conductivity ( ). The dimensionless figure of merit ( ) of all samples increased with increasing temperature. The highest value of 5.67 × 10−2 was observed for the 0.97DyBCO−0.03BNT sample at 863 K.","PeriodicalId":15130,"journal":{"name":"Journal of Asian Ceramic Societies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44280302","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}
Pub Date : 2022-10-02DOI: 10.1080/21870764.2022.2133378
Hong Wei, Li Wen-jie, Weng Xiao-wei, Zhang Yi-qin, Liu Xiao-Hui, Xu Wen-Chao, Tian Hao, Wang Ming
ABSTRACT This paper sketched the basic principles of ceramic materials radioactivity measurement and mathematical calculation formula of testing time. When the sample measurement conditions and the way of data analysis are constant, using sodium iodide gamma spectrometer for getting the radioactive spectra data of 5 groups of samples. In condition of the background count time tb or sample measurement time ts increasing gradually, study the radioactivity specific activity measurement error range of all samples. It is derived when the background count rate of nb and sample counting rate ns is constant, the measurement error ν2 and the sum of reciprocal of the background count time tb and reciprocal of the sample measuring time ts for approximately linear positive correlation. The measurement error of 226Ra, 232Th, 40K radioactive specific activity of different ceramic samples presents the corresponding fluctuations as their initial energy spectrum count rate differences. This study for coordination of the contradiction between ceramic materials radioactive measurement time and the uncertainty has certainly theoretical and practical value.
{"title":"Study on the correlation between radioactive counting time and measurement uncertainty of ceramic materials","authors":"Hong Wei, Li Wen-jie, Weng Xiao-wei, Zhang Yi-qin, Liu Xiao-Hui, Xu Wen-Chao, Tian Hao, Wang Ming","doi":"10.1080/21870764.2022.2133378","DOIUrl":"https://doi.org/10.1080/21870764.2022.2133378","url":null,"abstract":"ABSTRACT This paper sketched the basic principles of ceramic materials radioactivity measurement and mathematical calculation formula of testing time. When the sample measurement conditions and the way of data analysis are constant, using sodium iodide gamma spectrometer for getting the radioactive spectra data of 5 groups of samples. In condition of the background count time tb or sample measurement time ts increasing gradually, study the radioactivity specific activity measurement error range of all samples. It is derived when the background count rate of nb and sample counting rate ns is constant, the measurement error ν2 and the sum of reciprocal of the background count time tb and reciprocal of the sample measuring time ts for approximately linear positive correlation. The measurement error of 226Ra, 232Th, 40K radioactive specific activity of different ceramic samples presents the corresponding fluctuations as their initial energy spectrum count rate differences. This study for coordination of the contradiction between ceramic materials radioactive measurement time and the uncertainty has certainly theoretical and practical value.","PeriodicalId":15130,"journal":{"name":"Journal of Asian Ceramic Societies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43488774","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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