Effect of glass phase in coatings on the vacuum insulation performance of alumina ceramics

Yang Jie; He Jialong; Chen Xin; Liu Ping; Zhao Wei; Li Chen; Qin Zhen; Huang Gang; Xiang Jun; Li Tiantao; Li Jie; Dong Pan; Wang Tao

doi:10.11884/HPLPB202638.250395

Article Contents

Article Navigation > High Power Laser and Particle Beams > 2026 > Accepted Manuscript

Yang Jie, He Jialong, Chen Xin, et al. Effect of glass phase in coatings on the vacuum insulation performance of alumina ceramics[J]. High Power Laser and Particle Beams. doi: 10.11884/HPLPB202638.250395

Citation:

Yang Jie, He Jialong, Chen Xin, et al. Effect of glass phase in coatings on the vacuum insulation performance of alumina ceramics[J]. High Power Laser and Particle Beams. doi: 10.11884/HPLPB202638.250395

Citation:

PDF( 6087 KB)

Effect of glass phase in coatings on the vacuum insulation performance of alumina ceramics

doi: 10.11884/HPLPB202638.250395

Institute of Fluid Physics, CAEP, Mianyang 621900, China

Received Date: 2025-11-04
Accepted Date: 2026-01-09
Rev Recd Date: 2026-01-14

Available Online: 2026-01-29

Abstract

Abstract

Background
Alumina (Al₂O₃) ceramics are extensively employed as insulating components in vacuum electronic devices. However, under high voltage, charge accumulation on their surface can easily lead to surface flashover, which severely degrades the insulation performance of the device and affects its operation. Therefore, enhancing the vacuum surface insulation performance of Al₂O₃ ceramics holds significant academic value and practical implications. Surface coating represents a widely adopted strategy for enhancing the insulation performance of Al₂O₃ ceramics. Nevertheless, the specific influence of the glass phase within the coating on the insulating properties remains largely unexplored.
Purpose
The present work is dedicated to exploring how the glass phase in coatings affects the vacuum insulation performance of Al₂O₃ ceramics.
Methods
A Cr₂O₃-based coating was fabricated on the surface of Al₂O₃ ceramics, and the effects of the glass phase within the coating on phase structure, surface morphology, secondary electron emission coefficient (SEE), surface resistivity, and the vacuum insulation performance of the coated ceramics were systematically investigated.
Results
The results indicate that Al element from the substrate diffuses into the coating under high-temperature firing. The content of Cr₂O₃ phase in the coating exhibits a gradual decrease and eventually disappears with the rise of the glass phase content, causing it to fully react with the ceramic substrate to form Al_2-xCr_xO₃ (0＜x＜2)、Mg(Al_2-yCr_y)O₄ (0＜y＜2), along with small amounts of ZnAl₂O₄ and (Na,Ca)Al(Si,Al)₃O₈. The coating improves the surface grain homogeneity and the density of the ceramic surface, although variations in the glass phase content have a negligible effect on its microstructure. Additionally, the Cr₂O₃ coating reduces both the SEE coefficient and the surface resistivity of the Al₂O₃ ceramic. However, as the glass phase content in the coating increases, both the SEE coefficient and surface resistivity of the coated ceramics exhibit a gradual upward trend. The optimal insulation performance is achieved when the glass phase content reaches 20%. At this point, the vacuum surface hold-off strength attains 119.63 kV/cm.
Conclusions
Modulation of the glass phase content in the surface coating enables the tunability of the vacuum surface insulation performance of the Al₂O₃ ceramics, with the performance improvement stemming from the decreased SEE coefficient and the appropriate surface resistivity.
- glass phase,
- Cr₂O₃ coating,
- alumina,
- vacuum surface hold-off voltage performance

FullText(HTML)

References(22)

References

[1]	Zhang Guanjun, Sun Guangyu, Song Baipeng, et al. Global model for flashover phenomena in vacuum: a comprehensive perspective[J]. Journal of Applied Physics, 2025, 137: 100901. doi: 10.1063/5.0255764
[2]	Li Zhen, Liu Ji, Ohki Y, et al. Surface flashover in 50 years: theoretical models and competing mechanisms[J]. High Voltage, 2023, 8(5): 853-877. doi: 10.1049/hve2.12340
[3]	李逢, 王勐, 任靖, 等. 不同微槽结构绝缘子真空沿面闪络特性[J]. 强激光与粒子束, 2014, 26: 045049 doi: 10.3788/HPLPB20142604.45049 Li Feng, Wang Meng, Ren Jing, et al. Characteristics of grooved insulator flashover under pulsed voltage[J]. High Power Laser and Particle Beams, 2014, 26: 045049 doi: 10.3788/HPLPB20142604.45049
[4]	Zhang Tao, Du Jishi, Lei Yangjun, et al. Effect of pores on dielectric breakdown strength of alumina ceramics via surface and volume effects[J]. Journal of the European Ceramic Society, 2020, 40(8): 3019-3026. doi: 10.1016/j.jeurceramsoc.2020.03.024
[5]	Miller H C. Improving the voltage holdoff performance of alumina insulators in vacuum through quasimetallizing[J]. IEEE Transactions on Electrical Insulation, 1980, EI-15(5): 419-428.
[6]	朱明冬. Al₂O₃陶瓷表面离子注入与沉积及沿面闪络特性研究[D]. 哈尔滨: 哈尔滨工业大学, 2020: 53-77 Zhu Mingdong. Ion implantation and deposition on the surface of alumina ceramic and surface flashover characteristics[D]. Harbin: Harbin Institute of Technology, 2020: 53-77
[7]	姚舜. 体掺杂Al₂O₃陶瓷的制备及沿面闪络性能的研究[D]. 武汉: 武汉理工大学, 2020: 21-55 Yao Shun. Preparation and surface flashover properties of bulk doped Al₂O₃ ceramics[D]. Wuhan: Wuhan University of Technology, 2020: 21-55
[8]	Feng Dandan, Wang Xiaojing, Zhao Shike, et al. Study of TiO₂ on the voltage holdoff capacity of Cr/Mn-doped Al₂O₃ ceramic in vacuum[J]. Materials, 2023, 16: 5048. doi: 10.3390/ma16145048
[9]	Yu Weixin, Kong Fei, Dong Pan, et al. Depositing chromium oxide film on alumina ceramics enhances the surface flashover performance in vacuum via PECVD[J]. Surface and Coatings Technology, 2021, 405: 126509. doi: 10.1016/j.surfcoat.2020.126509
[10]	Hamada K, Asari N, Tateyama C. The influence of chromium oxide coating of alumina surface on partial discharge in vacuum[J]. IEEE Transactions on Plasma Science, 2024, 52(9): 4378-4381. doi: 10.1109/TPS.2024.3360989
[11]	Sudarshan T S, Cross J D. The effect of chromium oxide coatings on surface flashover of alumina spacers in vacuum[J]. IEEE Transactions on Electrical Insulation, 1976, EI-11(1): 32-35.
[12]	Khilla M A, Hanafi Z M, Mohamed A K. The electrical conductivity of chromium trioxide and its suboxides[J]. Thermochimica Acta, 1982, 56(3): 291-298. doi: 10.1016/0040-6031(82)87037-8
[13]	Asari N, Sakaguchi W, Shioiri T, et al. Influence of coating to surface flashover characteristics of alumina ceramics in vacuum[C]//Proceedings of the 2016 27th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV). 2016: 1-4.
[14]	Sun Xiaoliang, Xun Tao, Zhong Huihuang, et al. Improved surface flashover characteristics of ceramic vacuum interface by surface treatment[C]//Proceedings of the 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV). 2018: 151-154.
[15]	He Jialong, Yang Jie, Peng Yufei, et al. Measurement of yield and spectrum of secondary electron emission and their characteristics under modification of conductive materials[J]. Review of Scientific Instruments, 2019, 90: 063304. doi: 10.1063/1.5053965
[16]	杨洁, 陈欣, 李晨, 等. 高温烧结Cr₂O₃涂层对Al₂O₃陶瓷真空沿面耐压性能的影响[J]. 强激光与粒子束, 2025, 37: 055003 doi: 10.11884/HPLPB202537.240275 Yang Jie, Chen Xin, Li Chen, et al. Effect of Cr₂O₃ coating sintered at high temperature on the vacuum surface hold-off voltage performance of Al₂O₃ ceramic[J]. High Power Laser and Particle Beams, 2025, 37: 055003 doi: 10.11884/HPLPB202537.240275
[17]	曾智江, 杨秋红, 徐军. Cr³⁺: Al₂O₃透明多晶陶瓷光谱特性分析[J]. 物理学报, 2005, 54(11): 5445-5449 doi: 10.7498/aps.54.5445 Zeng Zhijiang, Yang Qiuhong, Xu Jun. Spectroscopic characteristics of Cr³⁺: Al₂O₃ polycrystalline transparent alumina ceramics[J]. Acta Physica Sinica, 2005, 54(11): 5445-5449 doi: 10.7498/aps.54.5445
[18]	姚舜, 王友法. 钛镁掺杂对氧化铝陶瓷的相组成、微观形貌及沿面闪络特性的影响[J]. 硅酸盐通报, 2020, 39(9): 2964-2969,2986 Yao Shun, Wang Youfa. Effect of titanium-magnesium doping on phase composition, microstructure and surface flashover characteristics of alumina ceramics[J]. Bulletin of the Chinese Ceramic Society, 2020, 39(9): 2964-2969,2986
[19]	Yoon B K, Choi S Y, Yamamoto T, et al. Grain boundary mobility and grain growth behavior in polycrystals with faceted wet and dry boundaries[J]. Acta Materialia, 2009, 57(7): 2128-2135. doi: 10.1016/j.actamat.2009.01.005
[20]	Fukuda H, Yamano Y, Kobayashi S, et al. Relationship between vacuum surface flashover and charging characteristics for alumina ceramics of lowered resistivity[C]//Proceedings of the 2013 2nd International Conference on Electric Power Equipment - Switching Technology (ICEPE-ST). 2013: 1-4.
[21]	Sun Guangyu, Song Baipeng, Guo Baohong, et al. Estimation of surface flashover threshold in vacuum: from multipactor to discharge plasma[J]. Journal of Physics D: Applied Physics, 2018, 51: 295201. doi: 10.1088/1361-6463/aacccf
[22]	Kato H, Kato K, Morita A, et al. Influence of surface charges on alumina dielectrics on impulse flashover characteristics in vacuum[C]//Proceedings of the 2008 23rd International Symposium on Discharges and Electrical Insulation in Vacuum. 2008: 58-61.