Effects of chromium doping on the insulator properties in vacuum of alumina

Xiang Long Liu, Xiao Yun Li, Jian Yang, Tai Qiu

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Surface flashover phenomena greatly restricts the application of insulating materials under high-voltage in vacuum. Ceramic insulators were prepared with 95wt% alumina powders, doping content of Cr2O3 ranging from 0 to 1.5wt%. The effects of Cr2O3 content on the sintering and insulation properties were investigated. The results show that chromium doping significantly reduced the porosity and the sintering temperature, and improved the property of sintering, therefore Cr-doping alumina ceramic obtained fine-grained microstructure. As the Cr2O3 doping content is 0.5wt%, the ceramic surface flashover voltage in vacuum reached 65 kV/cm, mainly because Cr-doping decreased the porosity and secondary electron emission coefficient of samples. Over-doping of Cr2O3 caused more defects of crystal structure, which reduced the withstand voltage of the ceramic insulator in vacuum instead.

Original languageEnglish
Pages (from-to)857-861
Number of pages5
JournalRengong Jingti Xuebao/Journal of Synthetic Crystals
Volume43
Issue number4
StatePublished - Apr 2014

Keywords

  • Alumina ceramic
  • Chromium oxide
  • Surface flashover

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