2018 Fiscal Year Final Research Report
Creation of radio wave absorbers and refractory materials for melting rare-earth containing steel by using lanthanum sulfides
| Project/Area Number |
16H04542
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Metal making/Resorce production engineering
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| Research Institution | Muroran Institute of Technology |
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Principal Investigator |
Hirai Shinji 室蘭工業大学, 大学院工学研究科, 教授 (10208796)
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| Co-Investigator(Kenkyū-buntansha) |
中村 英次 室蘭工業大学, 工学研究科, 特任教授 (60525517)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | 軽希土類三二硫化物 / 雰囲気パルスCVI / CS2ガス硫化 / 誘電正接 / 整合吸収型電波吸収体 / 誘電体型電波吸収体 / 反射係数 / 透過係数 |
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| Outline of Final Research Achievements |
We aimed to introduce oxygen while heating the γ-Ce2S3 powder to the phase transformation temperature, or lower, by using a pulse CVI apparatus to generate β single phase or β, γ mixed phase. The S11 of the resins in which theγ-Ce2S3 of starting material or high oxygenγ-Ce2S3 and a β, γ-Ce2S3 were dispersed were nearly at the practical level, reaching -20 dB and -35 dB, respectively, in the high-frequency range of 11 GHz to 15 GHz. The absorption properties of S21 were not seen. Next, the resins in which β-La2S3 powder synthesized by CS2 gas sulfurization of La2O3 was dispersed were prepared, and the radio wave absorption properties were examined. The oxygen content in the β-La2S3 powder decreased as the sulfurization temperature increased. Although the reflection properties of S11 exceeded -20 dB, oxygen dependency was not confirmed.
It has become clear that, in order to use cerium sulfide as a refractory material, sufficient oxidation suppression of Ce2S3 is important.
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| Free Research Field |
金属・資源生産工学
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| Academic Significance and Societal Importance of the Research Achievements |
大量に余るCeやLaを用い、ニッチな用途としてCe2S3やLa2S3の電波吸収特性を有した顔料、希土類含有鋼溶解用耐火物を提案しようとするものであり、社会的意義は十分ある。
一方、学術的な意義は、誘電性電波吸収体は、分子の分極反応に起因する誘電正接が大きい材料ほど誘電損失も大きくなり、吸収率も大きくなるため、筆者らが見出してきた巨大誘電率と大きな誘電正接を有したβ-La2S3あるいはβ-Ce2S3をそのまま電波吸収体に応用できたことである。β,γ-Ce2S3のS11は－35 dBとなり、β-La2S3粉末でも－20 dBとなり実用化レベルの電波吸収特性が得られた。
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