Development of PTCR Characteristic in Vacuum-Sintered BaTiO3-Based Ceramics by Addition of Partially Oxidized Ti Powder.

• Kim Jun-Gyu

  Institute of Industrial Science, The University of Tokyo

• Hayashi Koji

  Institute of Industrial Science, The University of Tokyo

Bibliographic Information

Other Title

• 部分酸化Ｔｉ粉添加によるＢａＴｉＯ３基セラミックス真空焼結体におけるＰＴＣＲ特性の発現
• ブブン サンカ Tiフン テンカ ニ ヨル BaTiO3キ セラミックス シンクウ ショウケツタイ ニ オケル PTCR トクセイ ノ ハツゲン

Abstract

The compact of the mixture composed of (Ba, Sr)TiO₃ ceramics powder and partially oxidized Ti powder (5.0mass% O) which was named TiO₂(Ti) powder was found to show PTCR characteristic, when the compact was sintered in vacuum at 1623 K for 3.6 ks, and then heated in air at 853 K for 0.3 ks. Some properties of the sintered compacts were investigated.<BR>The results obtained were as follows; (1)Obvious PTCR characteristic developed at TiO₂(Ti) contents of 5-7vol%. (2)The transformation from tetragonal structure (ferroelectric phase) to cubic structure (paraelectric phase) of (Ba, Sr)TiO₃ phase in the sintered and then annealed compact was suggested to occur only near the grain boundary and surface of the (Ba, Sr)TiO₃ grains. (3)The dielectric constant ratio of ε _{?? .540K}/ε _{?? t} was 1/8, which was below the value (1/3) of (Ba, Sr)TiO₃ air-sintered compact without TiO₂(Ti), (4)The oxygen content of (Ba, Sr)TiO₃ phase fairly decreased with increasing TiO₂(Ti) content. (5)The densification and grain growth of the compact with 5-7vol% TiO₂(Ti) hardly occured by the sintering. (6)The mechanism for the development of PTCR characteristic by the addition of TiO₂(Ti) was discussed, based on Heywang-Jonker's model.

Journal

• Journal of the Japan Society of Powder and Powder Metallurgy

  Journal of the Japan Society of Powder and Powder Metallurgy 46 (4), 348-357, 1999

  Japan Society of Powder and Powder Metallurgy

Keywords

• PTCR
• BaTiO<SUB>3</SUB>
• barium titanate
• thermistor
• titanium
• powder
• specific resistivity
• dielectric constant
• vacuum sintering

Details

• CRID: 1390001206309312128
• NII Article ID: 10002262236
• NII Article ID: 10003590793
• NII Book ID: AN00222724
• DOI: 10.2497/jjspm.46.348
• ISSN: 18809014
• ISSN: 05328799
• NDL BIB ID: 4701480
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4701480
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed