Effect of LiF addition on sintering behavior and dielectric breakdown mechanism of MgO-based microwave dielectric ceramics
Glass-free MgO-based microwave dielectric ceramics (1-x) wt% (0.98 MgO-0.02 Al2O3)-x wt% LiF (x = 0.5, 1, 2, 3, 4) were synthesized where LiF and Al2O3 were utilized as sintering additive and reinforcement phase in MgO matrix respectively. It was found that ion substitution is apt to occur between L...
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| Format: | Article |
| Language: | English |
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Elsevier
2021-05-01
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| Series: | Journal of Materiomics |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S235284782030513X |
| _version_ | 1797706323018645504 |
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| author | Chi Zhang Ying Chen Xin Li Haishen Ren Genshui Wang Xianlin Dong |
| author_facet | Chi Zhang Ying Chen Xin Li Haishen Ren Genshui Wang Xianlin Dong |
| author_sort | Chi Zhang |
| collection | DOAJ |
| description | Glass-free MgO-based microwave dielectric ceramics (1-x) wt% (0.98 MgO-0.02 Al2O3)-x wt% LiF (x = 0.5, 1, 2, 3, 4) were synthesized where LiF and Al2O3 were utilized as sintering additive and reinforcement phase in MgO matrix respectively. It was found that ion substitution is apt to occur between LiF and MgO, leading to the formation of oxygen vacancies and MgF2. Nevertheless, different from ordinary liquid-phase sintering, morphologies of ceramics were distinctly altered with grains changing from polyhedron to sphere-like shape and densities underwent obvious decrease when excessive amount of LiF was introduced and we call it excessive liquid-phase sintering. Grain boundary weakening caused by this circumstance would exert an adverse effect on physical properties. Moreover, LiF addition dramatically reduced dielectric breakdown strength and altered the dielectric breakdown behavior of MgO-based ceramics, which is dominated by electrical breakdown mechanism. Combination of good properties were achieved in 1 wt% LiF modified MgO-based ceramics sintered at 950 °C which exhibited superior microwave properties (εr = 9.56, tanδ = 9.2 × 10−5, Qf = 124,600 GHz), high flexural strength (184.5 MPa), high thermal conductivity (21.3 W/(m⋅K)), high coefficient of thermal expansion (∼12 ppm/°C) and moderate electrical properties (Eb = 35.9 kV/mm, ρ = 4.9 × 1012 Ω cm). |
| first_indexed | 2024-03-12T05:49:32Z |
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| id | doaj.art-6565c90180f346969b9eaeaf8a8bb711 |
| institution | Directory Open Access Journal |
| issn | 2352-8478 |
| language | English |
| last_indexed | 2024-03-12T05:49:32Z |
| publishDate | 2021-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materiomics |
| spelling | doaj.art-6565c90180f346969b9eaeaf8a8bb7112023-09-03T05:14:57ZengElsevierJournal of Materiomics2352-84782021-05-0173478487Effect of LiF addition on sintering behavior and dielectric breakdown mechanism of MgO-based microwave dielectric ceramicsChi Zhang0Ying Chen1Xin Li2Haishen Ren3Genshui Wang4Xianlin Dong5Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 588 Heshuo Road, Jiading District, Shanghai, 201800, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 19 Yuquan Road, Shijinshan District, Beijing, 100049, ChinaKey Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 588 Heshuo Road, Jiading District, Shanghai, 201800, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 19 Yuquan Road, Shijinshan District, Beijing, 100049, China; Corresponding author. Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 588 Heshuo Road, Jiading District, Shanghai, 201800, China.Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 588 Heshuo Road, Jiading District, Shanghai, 201800, ChinaKey Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 588 Heshuo Road, Jiading District, Shanghai, 201800, ChinaKey Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 588 Heshuo Road, Jiading District, Shanghai, 201800, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 19 Yuquan Road, Shijinshan District, Beijing, 100049, China; State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 588 Heshuo Road, Jiading District, Shanghai, 201800, ChinaKey Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 588 Heshuo Road, Jiading District, Shanghai, 201800, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 19 Yuquan Road, Shijinshan District, Beijing, 100049, China; State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 588 Heshuo Road, Jiading District, Shanghai, 201800, China; Corresponding author. Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 19 Yuquan Road, Shijinshan District, Beijing, 100049, China.Glass-free MgO-based microwave dielectric ceramics (1-x) wt% (0.98 MgO-0.02 Al2O3)-x wt% LiF (x = 0.5, 1, 2, 3, 4) were synthesized where LiF and Al2O3 were utilized as sintering additive and reinforcement phase in MgO matrix respectively. It was found that ion substitution is apt to occur between LiF and MgO, leading to the formation of oxygen vacancies and MgF2. Nevertheless, different from ordinary liquid-phase sintering, morphologies of ceramics were distinctly altered with grains changing from polyhedron to sphere-like shape and densities underwent obvious decrease when excessive amount of LiF was introduced and we call it excessive liquid-phase sintering. Grain boundary weakening caused by this circumstance would exert an adverse effect on physical properties. Moreover, LiF addition dramatically reduced dielectric breakdown strength and altered the dielectric breakdown behavior of MgO-based ceramics, which is dominated by electrical breakdown mechanism. Combination of good properties were achieved in 1 wt% LiF modified MgO-based ceramics sintered at 950 °C which exhibited superior microwave properties (εr = 9.56, tanδ = 9.2 × 10−5, Qf = 124,600 GHz), high flexural strength (184.5 MPa), high thermal conductivity (21.3 W/(m⋅K)), high coefficient of thermal expansion (∼12 ppm/°C) and moderate electrical properties (Eb = 35.9 kV/mm, ρ = 4.9 × 1012 Ω cm).http://www.sciencedirect.com/science/article/pii/S235284782030513XDielectric breakdown mechanismMgO-Based ceramicsMicrowave substrateExcessive liquid-phase sintering |
| spellingShingle | Chi Zhang Ying Chen Xin Li Haishen Ren Genshui Wang Xianlin Dong Effect of LiF addition on sintering behavior and dielectric breakdown mechanism of MgO-based microwave dielectric ceramics Journal of Materiomics Dielectric breakdown mechanism MgO-Based ceramics Microwave substrate Excessive liquid-phase sintering |
| title | Effect of LiF addition on sintering behavior and dielectric breakdown mechanism of MgO-based microwave dielectric ceramics |
| title_full | Effect of LiF addition on sintering behavior and dielectric breakdown mechanism of MgO-based microwave dielectric ceramics |
| title_fullStr | Effect of LiF addition on sintering behavior and dielectric breakdown mechanism of MgO-based microwave dielectric ceramics |
| title_full_unstemmed | Effect of LiF addition on sintering behavior and dielectric breakdown mechanism of MgO-based microwave dielectric ceramics |
| title_short | Effect of LiF addition on sintering behavior and dielectric breakdown mechanism of MgO-based microwave dielectric ceramics |
| title_sort | effect of lif addition on sintering behavior and dielectric breakdown mechanism of mgo based microwave dielectric ceramics |
| topic | Dielectric breakdown mechanism MgO-Based ceramics Microwave substrate Excessive liquid-phase sintering |
| url | http://www.sciencedirect.com/science/article/pii/S235284782030513X |
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