Semiconductor ceramic composition and PTC thermistor

摘要

A semiconductor ceramic composition with small resistivity at room temperature and large temperature coefficient of resistance is provided; the composition is represented by formula,
(Ba1-x-y-wBixAyREw)m(Ti1-zTMz)O3  (1),
(wherein, A is at least one element from Na or K, RE is at least one element from the group consisting of Y, La, Ce, Pr, Nd, Sm, Gd, Dy and Er, TM is at least one element from the group consisting of V, Nb and Ta, and w, x, y, z (each in mol) and the mole ratio m of Ba site to Ti site satisfy the following in equations,
0.007≦x≦0.125  (2)xand further includes Sr in a proportion of 0.010 mol or more and 0.050 mol or less relative to 1 mol of Ti site, and the mole ratio u of Sr and the mole ratio x of Bi satisfy the following in equation,
u≦1.8x−0.008  (6).

主权项

1. A semiconductor ceramic composition represented by the following general formula (1),
(Ba1-x-y-wBixAyREw)m(Ti1-zTMz)O3  (1), wherein, in the general formula (1), A is at least one element selected from Na or K, RE is at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Gd, Dy and Er, TM is at least one element selected from the group consisting of V, Nb and Ta, w, x, y, z (each in mol) and m (the mole ratio of Ba site to Ti site) satisfy the following in equations (2) to (5),
0.007≦x≦0.125  (2)xu≦1.8x−0.008  (6).