{"title":"Novel Functional Oxide Materials","authors":"Yuichi Shimakawa","doi":"10.2497/jjspm.23-00020","DOIUrl":"https://doi.org/10.2497/jjspm.23-00020","url":null,"abstract":"","PeriodicalId":35600,"journal":{"name":"Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69151016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Sakka, Shotaro Musha, Kouji Morita, A. Kasahara, M. Tosa, Tohru S. SUZUKI
{"title":"Ti2AlN配向体の摩耗特性","authors":"Y. Sakka, Shotaro Musha, Kouji Morita, A. Kasahara, M. Tosa, Tohru S. SUZUKI","doi":"10.2497/jjspm.22-00059","DOIUrl":"https://doi.org/10.2497/jjspm.22-00059","url":null,"abstract":"","PeriodicalId":35600,"journal":{"name":"Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69150610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"メカノケミカル反応によるCsSnBr3前駆体合成と前駆体から製造した溶融凝固体の電気伝導度","authors":"Kiyoshi Kobayashi, Shogo Miyoshi, Tohru S. Suzuki","doi":"10.2497/jjspm.23-00022","DOIUrl":"https://doi.org/10.2497/jjspm.23-00022","url":null,"abstract":"","PeriodicalId":35600,"journal":{"name":"Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69151044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Kondoh, Eri Ichikawa, Ammarueda Issariyapat, J. Umeda
{"title":"Mechanical Functionalization of Additively Manufactured Titanium with Light Elements","authors":"K. Kondoh, Eri Ichikawa, Ammarueda Issariyapat, J. Umeda","doi":"10.2497/jjspm.23-00031","DOIUrl":"https://doi.org/10.2497/jjspm.23-00031","url":null,"abstract":"","PeriodicalId":35600,"journal":{"name":"Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy","volume":"82 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69151066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we report on our group’s efforts to improve the coercivity of Sm2Fe17N3 powder, especially on reducing the particle size to submicron scale, smoothing the particle surface, and suppression of the formation of coarse particles by developing a new reduction-diffusion process. During the course of a series of these works, it was revealed that the washing step, which is performed to remove excess Ca, supplied hydrogen into the Sm2Fe17N3 crystal structure, and induced unfavorable elongation of the crystal structure along the c-axis. To avoid this problem, the powders were subjected to dehydrogenation treatment, demonstrating reasonably high coercivity values that we expect from the known relationship between particle size and coercivity. It was also found that the conventional dissolution and the removal of impurities by acetic acid were roughening the particle surfaces. Thus, development of an alternative process to acetic acid cleaning prevented the surface roughening and showed the further improvement of the coercivity. Finally, the development of a new uniform reduction-diffusion reaction using a rotary furnace brought about a breakthrough for further improvement of coercivity by suppressing the formation of coarse particles. As a result, we succeeded in synthesizing Sm2Fe17N3 anisotropic powder with an ultra-high coercivity (i.e. the current world record) of 31.7 kOe, and also showed that the powder can maintain a coercivity higher than 10 kOe at 200°C.
{"title":"Synthesis of High Coercivity Sm<sub>2</sub>Fe<sub>17</sub>N<sub>3</sub> Powder","authors":"Shusuke OKADA, Kenta TAKAGI, Ryuji HASHIMOTO","doi":"10.2497/jjspm.23-00029","DOIUrl":"https://doi.org/10.2497/jjspm.23-00029","url":null,"abstract":"In this paper, we report on our group’s efforts to improve the coercivity of Sm2Fe17N3 powder, especially on reducing the particle size to submicron scale, smoothing the particle surface, and suppression of the formation of coarse particles by developing a new reduction-diffusion process. During the course of a series of these works, it was revealed that the washing step, which is performed to remove excess Ca, supplied hydrogen into the Sm2Fe17N3 crystal structure, and induced unfavorable elongation of the crystal structure along the c-axis. To avoid this problem, the powders were subjected to dehydrogenation treatment, demonstrating reasonably high coercivity values that we expect from the known relationship between particle size and coercivity. It was also found that the conventional dissolution and the removal of impurities by acetic acid were roughening the particle surfaces. Thus, development of an alternative process to acetic acid cleaning prevented the surface roughening and showed the further improvement of the coercivity. Finally, the development of a new uniform reduction-diffusion reaction using a rotary furnace brought about a breakthrough for further improvement of coercivity by suppressing the formation of coarse particles. As a result, we succeeded in synthesizing Sm2Fe17N3 anisotropic powder with an ultra-high coercivity (i.e. the current world record) of 31.7 kOe, and also showed that the powder can maintain a coercivity higher than 10 kOe at 200°C.","PeriodicalId":35600,"journal":{"name":"Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134887728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We produced silicon-containing CrFeCoNi high-entropy alloy (HEA) deposits using the low-pressure plasma spraying method and assessed their structural and characteristic properties. The alloy deposits, once manufactured, underwent a heat treatment process, during which we closely examined the formation of precipitates. These HEAs were fabricated on substrates, regardless of whether they were subjected to water-cooling or not. In the case of both deposits acquired with and without water-cooling of the substrates, diffraction peaks corresponding to the face-centered cubic (FCC) phase were clearly observed when subjected to high temperature heat treatment at 1273 K. Additionally, we identified the presence of silicon-containing compounds on the deposits. As the heat-treatment temperatures increased, we observed the coarsening of the precipitates. Notably, within the crystal granules of the water-cooled as-sprayed deposits, nanoscale precipitates were generated. Among all the samples, deposits heat-treated at 973 K exhibited the highest precipitate area fraction and hardness. This suggests a correlation between the heat treatment temperature and the resulting properties of the HEA deposits, with 973 K being the point at which the highest precipitate area fraction and hardness were achieved.
{"title":"Effect of Heat Treatment on Microstructure of Silicon-containing CrFeCoNi High Entropy Alloys Produced by Low-Pressure Plasma Spraying","authors":"Yasuhiro HOSHIYAMA, Kanta BESSHO, Tomoki MARUOKA","doi":"10.2497/jjspm.23-00040","DOIUrl":"https://doi.org/10.2497/jjspm.23-00040","url":null,"abstract":"We produced silicon-containing CrFeCoNi high-entropy alloy (HEA) deposits using the low-pressure plasma spraying method and assessed their structural and characteristic properties. The alloy deposits, once manufactured, underwent a heat treatment process, during which we closely examined the formation of precipitates. These HEAs were fabricated on substrates, regardless of whether they were subjected to water-cooling or not. In the case of both deposits acquired with and without water-cooling of the substrates, diffraction peaks corresponding to the face-centered cubic (FCC) phase were clearly observed when subjected to high temperature heat treatment at 1273 K. Additionally, we identified the presence of silicon-containing compounds on the deposits. As the heat-treatment temperatures increased, we observed the coarsening of the precipitates. Notably, within the crystal granules of the water-cooled as-sprayed deposits, nanoscale precipitates were generated. Among all the samples, deposits heat-treated at 973 K exhibited the highest precipitate area fraction and hardness. This suggests a correlation between the heat treatment temperature and the resulting properties of the HEA deposits, with 973 K being the point at which the highest precipitate area fraction and hardness were achieved.","PeriodicalId":35600,"journal":{"name":"Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135668084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effect of Al addition in ZnO varistors revealed to be the suppression of grain growth, not the lowering of the electric resistance of ZnO. This Al effect can explain the change in the E-J characteristics by the following three points. (i) The grain boundary becomes thinner and the proportion of boundary layers with a thickness of 10 nm or less increases, which enlarges the effective cross-sectional area of the tunnel current generation. (ii) The delay in densification during the sintering makes it easier for pores to remain at the grain boundary, which increases discontinuities of boundary layers between ZnO grains and increases leakage current, resulting in reduced non-ohmic properties in the low current range. (iii) Abnormal grain growth of ZnO is suppressed and the particle size becomes more uniform, which improves non-ohmic characteristics. This paper proposes a new barrier model for the conduction mechanism of ZnO varistors, based on the tunneling effect and taking into account the influences caused by microstructural inhomogeneities specific to polycrystalline ceramics, such as discontinuities in grain boundary layers and variations in ZnO grain size.
{"title":"ZnOバリスタにおけるAl添加効果の解明と伝導機構モデルの構築","authors":"Hideyuki OKINAKA, Wataru SAKAMOTO","doi":"10.2497/jjspm.23-00045","DOIUrl":"https://doi.org/10.2497/jjspm.23-00045","url":null,"abstract":"The effect of Al addition in ZnO varistors revealed to be the suppression of grain growth, not the lowering of the electric resistance of ZnO. This Al effect can explain the change in the E-J characteristics by the following three points. (i) The grain boundary becomes thinner and the proportion of boundary layers with a thickness of 10 nm or less increases, which enlarges the effective cross-sectional area of the tunnel current generation. (ii) The delay in densification during the sintering makes it easier for pores to remain at the grain boundary, which increases discontinuities of boundary layers between ZnO grains and increases leakage current, resulting in reduced non-ohmic properties in the low current range. (iii) Abnormal grain growth of ZnO is suppressed and the particle size becomes more uniform, which improves non-ohmic characteristics. This paper proposes a new barrier model for the conduction mechanism of ZnO varistors, based on the tunneling effect and taking into account the influences caused by microstructural inhomogeneities specific to polycrystalline ceramics, such as discontinuities in grain boundary layers and variations in ZnO grain size.","PeriodicalId":35600,"journal":{"name":"Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136207679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development of Fundamental Technologies on Computational Granular Dynamics towards Construction of a Digital Twin for Powder Compaction Process","authors":"M. Sakai","doi":"10.2497/jjspm.69.490","DOIUrl":"https://doi.org/10.2497/jjspm.69.490","url":null,"abstract":"","PeriodicalId":35600,"journal":{"name":"Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43195761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Ohno, Takahiro Maruyama, Taiki Miura, S. Hirai, Hisao Suzuki, T. Matsuda
{"title":"Preparation of Barium Titanate Nanocoated Silica Nanoparticles by Chemical Solution Deposition","authors":"T. Ohno, Takahiro Maruyama, Taiki Miura, S. Hirai, Hisao Suzuki, T. Matsuda","doi":"10.2497/jjspm.69.503","DOIUrl":"https://doi.org/10.2497/jjspm.69.503","url":null,"abstract":"","PeriodicalId":35600,"journal":{"name":"Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43561010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hisao Suzuki, T. Kawaguchi, N. Sakamoto, N. Wakiya, T. Arai, S. Hirai, T. Ohno
{"title":"Preparation and Phase Transition Temperature Control of VO2 Nano-particles by Micro-emulsion Method from Molecular-designed Precursors","authors":"Hisao Suzuki, T. Kawaguchi, N. Sakamoto, N. Wakiya, T. Arai, S. Hirai, T. Ohno","doi":"10.2497/jjspm.69.496","DOIUrl":"https://doi.org/10.2497/jjspm.69.496","url":null,"abstract":"","PeriodicalId":35600,"journal":{"name":"Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44301068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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