Strontium titanate ceramic material, grain boundary layer ceramic substrate and preparation method and application of grain boundary layer ceramic substrate

The invention discloses a strontium titanate ceramic material, a grain boundary layer ceramic substrate and a preparation method and application of the grain boundary layer ceramic substrate. The preparation method comprises the following steps: mixing SrTiO3 powder and a dopant, firing, grinding and sieving to obtain a raw material A; the doping substance is one or more of Nb2O5 powder, La2O3 powder, MgO powder and Nd2O3 powder, and the doping substance is one or more of Nb2O5 powder, La2O3 powder, MgO powder and Mixing SrTiO3 powder and glass powder, firing, grinding and sieving to obtain a raw material B; mixing the raw material A, the raw material B, an adhesive and an organic solvent, and molding to obtain a diaphragm; and carrying out glue removal and reductive firing on the membrane to obtain the strontium titanate ceramic material. The strontium titanate ceramic material disclosed by the invention has the advantages of large crystal grains, uniform growth, stable electrical properties and the like, is