Effect of glass phase in coatings on the vacuum insulation performance of alumina ceramics
-
摘要: Al2O3陶瓷在电真空器件中常被用来作为绝缘部件，但在高电压加载下，其表面由于电荷积累容易产生沿面闪络现象，严重降低了整个器件的绝缘性能，影响器件的正常运行，因此，提升Al2O3陶瓷的真空绝缘性能具有十分重要的意义。本研究在Al2O3陶瓷表面制备了Cr2O3基涂层，并系统性地研究了涂层中的玻璃相对涂层陶瓷相结构、表面形貌、二次电子发射系数、表面电阻率和真空绝缘性能的影响。结果表明：陶瓷基体中的Al元素在高温下会向涂层中进行迁移。随着玻璃相含量的提高，涂层中的Cr2O3相含量逐渐降低直至完全消失，使其全部与陶瓷基体反应形成Al2-xCrxO3 (0＜x＜2)、Mg(Al2-yCry)O4 (0＜y＜2)及少量的ZnAl2O4和(Na,Ca)Al(Si,Al)3O8。涂层可以提高陶瓷表面晶粒均匀性和致密度，但玻璃相含量的变化对其微观形貌影响较小。Cr2O3涂层可以降低Al2O3陶瓷的二次电子发射系数和表面电阻率，这使得所有配方涂层陶瓷的真空绝缘性能均优于Al2O3陶瓷。随着涂层中玻璃相含量的增大，涂层陶瓷的二次电子发射系数和表面电阻率也逐渐增大。当玻璃相质量分数为20%时，涂层陶瓷绝缘性能最佳，其真空沿面耐压强度达到119.63 kV/cm。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 Al2-xCrxO3 (0＜x＜2)、Mg(Al2-yCry)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.-
Key words:
- glass phase /
- Cr2O3 coating /
- alumina /
- vacuum surface hold-off voltage performance
-
图 1 玻璃粉的(a) SEM图及其(b)成分
Figure 1. (a) SEM micrograph and (b) ingredient of the glass powder
图 3 Al2O3陶瓷及涂层陶瓷样品的XRD图谱
Figure 3. XRD patterns of Al2O3 ceramic and coated ceramic samples
图 5 Al2O3陶瓷及涂层陶瓷样品的(a)二次电子发射系数变化，(b)最大二次电子发射系数与加入玻璃相的关系图
Figure 5. (a) Variation diagram of the secondary electron emission yield, and (b) the maximum value of the secondary electron emission yield for Al2O3 ceramic and coated ceramic samples
图 6 Al2O3陶瓷及涂层陶瓷样品的表面电阻率对比图
Figure 6. Surface resistivity for Al2O3 ceramic and coated ceramic samples
图 7 Al2O3陶瓷及涂层陶瓷样品在脉冲电压下的耐压强度对比图
Figure 7. Contrast diagram of hold-off electric field strength for Al2O3 ceramic and coated ceramic samples under pulsed voltage
表 1 涂层配方
Table 1. Recipe of the coatings
mass fraction/% 10G90Cr 20G80Cr 40G60Cr 60G40Cr 80G20Cr glass powder 10 20 40 60 80 Cr2O3 90 80 60 40 20 
下载: 导出CSV
表 2 陶瓷样品表面的Al/Cr比例
Table 2. Al/Cr ratio of ceramic samples
mass fraction/% Al2O3 10G90Cr 20G80Cr 40G60Cr 60G40Cr 80G20Cr Al 100 33.01 44.4 57.37 70.65 83.71 Cr 0 66.99 55.6 42.63 29.35 16.29
下载: 导出CSV
-
[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/HPLPB20142604.45049Li 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: 53-77Zhu 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: 21-55Yao 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/HPLPB202537.240275Yang 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.54.5445Zeng 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): 2964-2969,2986Yao 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. -
点击查看大图
图(7) / 表(2)
计量
- 文章访问数: 22
- HTML全文浏览量: 15
- PDF下载量: 0
- 被引次数: 0
