| In this paper, the conductive Barium metaplumbate (BaPbO3) doped with various contents of rare earth (La, Y) was prepared by powder metallurgy method using mechanical milling and liquid-state co-precipitation method (LSCM). The prepared process, micrograph, mechanical and electrical properties of the BaPbO3 with doping rare earth were investigated systemically by using modern instruments. Furthermore, the effect of the rare earth on conductive mechanism and PTC characteristics of BaPbO3 were discussed in detail. It is shown that the formation temperature of BaPbO3 was decreased significantly, about 700 and 650, respectively, as well as the various properties of BaPbO3 were improved by using mechanical milling and LSCM. With the increase of the rare earth content, the parabola-shaped mechanical and electrical behavior has been observed. When the content of the rare earth is about 1.0%, the properties of the BaPbO3 powder were optimal, and it has a higher purity and finer particle size, the additives of the rare earth increases remarkably the density, hardness and the bending strength, decreases the room resistivity significantly, and improves the PTC characteristics of the sintered BaPbO3. The room resistivity of the additive La and Y is about 0.33445 and 0.4648cm, Rmax/R25 is about 2500and 1800, respectively. However, the effect of the rare earth on the curie temperature of the BaPbO3 is not obvious, about 750 . The decrease of the room resistivity can be explained by the phenomenon of the more overlap or gap formation between the Pb(6s) and 0(2p) orbitals and the increase of the carrier, probably due to a increase the tilt of the PbO6 octahedra by additives of the rare earth. The improvement of the PTC characteristics was induced by the more oxide of the grain boundary of the refiner particle size and an increase of the Barium vacancy. Meanwhile, the solubility limit of the rare earth La and Y in the BaPbO3 was found to be about 10% and 5%, respectively. |
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