TiO₂(Ti)粉添加(Ba,Sr)TiO₃真空焼結体のPTCR特性に及ぼす焼結およびペースト焼き付け条件の影響

抄録

The effects of sintering temperature (T_s; 1573-1748K) and time (t_s; 0.6-14.4ks) and paste-baking-temperature or heating temperature (T_b or T_h; 673-1273K; t_b is 0.3ks) on PTCR characteristic were investigated for (Ba, Sr)Ti0₃ vacuum-sintered compact added with 3.9mass% TiO₂(Ti) powder of 12.5mass% TiO₂.
The results obtained were as follows; (1)PTCR characteristic developed at all T_S (t_s=3.6ks, T_b=853K). The electrical resistivity at room temperature (ρ_rt) showed a minimum value of 1.8x 10²Ω⋅cm and the ρ_max/ρ_rt showed a maximum value of about 10⁶ at 1723K. (2)For all t_s(T_s=1623K, T_b=853K), PTCR characteristic developed. The ρ_rt showed a minimum value of 2.6x 10³Ω.cm at 7.2ks. (3) At T_b above 823K (T_s=1623K, t_s=3.6ks), PTCR characteristic developed. The ρ_rt showed a minimum value of 1.0x l0³Ω⋅cm. (4)The ρ-T curve of (Ba, Sr)Ti0₃+TiO₂(Ti) vacuum-sintered compact was affected more largely by T_S, t_s and T_b than that of (Ba, Sr)Ti0₃ air-sintered compact. This was considered to be mainly due to the porous and fine grained microstructure in the former compact.