| After the zinc oxide varistor, a kind of a new varistor material ceramic presents. It can be used as capacitor and varistor. Compared to ZnO varistor ceramics, SrTiO3 ceramic varistor has the advantage of low sensing-voltage. In the low-pressure area, SrTiO3 ceramic varistor has been widely used.In this experiment, we used the traditional solid-phase sintering and second-step synthesization. First, put the samples in to the vaccum furace which can be used to creat reducing atmosphere, after that, these samples will be placed in a muffle furnace in order to complete the second sintering. Compared with the previous method of H2+N2, this experiment has a higher security. Also, this experiment has created SrTiO3 ceramic varistors with excellent electrical properties.A series experiment results indicate that, under the same condition, when doping Ti/Sr=1.02, the SrTiO3 sample has the higest dielectric constant and less pores. This showed that excessive Ti will promote the groth of SrTiO3 grain; Doping lanthanum oxide and niobium pentxoxide as donors, will promote their semiconductivity; Under the same sintering, as contrasted with nickel oxide, doping manganous carbonate as accepter can decrease nonlinear coefficient; Compared with silicon dioxide and aluminium oxide, doping lithium carbonate as sintering additives can obtained the highest nonlinear coefficient. This indicates that lithium carbonate can be used both as acceptor and sintering additive. The SrTiO3 ceramic varistors which obtained from this experiment have the following properties, breakdown voltage is between 20～200V/mm, nonlinear coefficient is between 5～12, dielectric constant is between 104～107. |
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