Articles
  • Electrical contact properties at the interface between PTCR (positive temperature coefficient of resistance) ceramics and various electrodes suitable for a co-firing process
  • Jun-Kwang Songa, Hyun-Gyoo Shina, Yong-Nam Kima, Min-Seok Jeona, Jin-Sook Leeb and Hee-Soo Leec,*
  • a Material Testing Team, Korea Testing Laboratory, Seoul 152-848, Korea b Department of Chemistry, Yonsei University, Seoul 120-749, Korea c School of Materials Science & Engineering, Pusan National University, Busan 609-735, Korea
Abstract
The electrical contact behavior between various electrodes(Ag, Ni, Au-Ti alloy) and PTCR ceramics was evaluated by a complex impedance analysis and an equivalent circuit conception. PTCR ceramics with ohmic-Ag and Ni electrodes exhibited a very low resistance in normal conditions. Ohmic-Ag and Ni were inappropriate for internal electrodes because ohmic-Ag vaporized above 1,000 oC and Ni oxidized above 400 oC. Au-Ti electrodes were deposited on the surface of PTCR ceramics by a sputtering method and the Au containing 3.00 wt% and 19.56 wt% of Ti showed non-ohmic contact behavior, while the Au containing 5.73 wt%, 10.84 wt% and 13.95 wt% of Ti showed ohmic contact and these Au-Ti electrodes exhibited good thermal stability up to 1300 oC.

Keywords: PTCR ceramics, Inner electrode, Ohmic contact, Co-firing.

This Article

  • 2008; 9(3): 292-295

    Published on Jun 30, 2008