Effect of Ni Electrode on the Characteristics of BaTiO₃ Based PTCR Ceramics

Abstract:

In order to achieve cost-effective inner electrodes for the multilayer BaTiO₃-based ceramics having a positive temperature coefficient of resistivity (PTCR), we fabricated Ni paste based on Ni powder and investigated the effect of Ni electrode on the performance of semiconducting BaTiO₃ ceramics. We adjusted the particle size of Ni powder (0.2μm, 0.6μm and 1μm) and incorporated them as the electrodes into both single-layer and laminated BaTiO₃ PTCR devices. The device samples were sintered at 1200oC for 30min in reducing atmosphere consisting of N₂ and H₂ (97:3 by volume ratio), and went through a post-sintering in-air heat treatment at 700-900oC in air which is necessary for the PTCR effect. The results indicate that Ni powder with lager particle size are more stable against post-sintering heat treatment, and the heating temperature needs to be optimized to overcome the trade-off between ohmic behaviors of Ni electrodes and the PTCR effect of BaTiO₃-based semiconducting ceramics.

• Periodical: Advanced Materials Research (Volumes 415-417)
• Pages: 1000-1004
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.415-417.1000
• Online since: December 2011
• Authors: Huan Liu, Rong Zhu, Zhi Ping Zheng, Dong Xiang Zhou, Qiu Yun Fu
• Keywords: Ni Paste, Ohmic Contact, Particle Size, PTCR

References

[1] Sasaki K and Niimi H, U.S. Patent 5,493,266. (1996)

[2] Seiter H and Heywang W J: Journal of Materials Science. 6(1971), pp.1214-1223

[3] Turner D R and Sauer H A: Journal of the Electrochemical Society. 107(3) (1960), pp.250-251

[4] Zhou D X and Gong S P: PTCR Materials and Their Applications (HuaZhong University of Science and Technology Press, 1989) (In Chinese)

[5] Ueyama R, Ueyama T, Koumoto K and Kuribayashi K: Journal of the Ceramic Society of Japan. 109(8) (2001), pp.661-666

DOI: 10.2109/jcersj.109.1272_661

[6] Kanda A, Tashiro S and Igarashi H: Japanese Journal of Applied Physics. 33(1994), pp.5431-5434