Effect of B2O3 nano-coating on the sintering behaviors and electrical microwave properties of Ba(Nd2-xSmx)Ti4O12 ceramics

Abstract

Ba(Nd0.8Sm0.2)(2)Ti4O12 ceramics prepared by conventional solid-state sintering have a dielectric constant of about 80 and a nearly zero temperature coefficient of resonant frequency; however, the sintering temperature is above 1350degreesC. Doping with B2O3 (up to 5 wt%) promotes the densification and dielectric properties of BNST ceramics. It is found that coating BNST powder with thin B2O3 layer of about 180 nm reduces the sintering temperature to below 1020degreesC. The effects of B2O3 nano-coating on the dielectric microwave properties and the microstructures of BNST ceramics are investigated. Ninety-six percent of theoretical densities is obtained for specimens coated with 2 wt% B2O3 sintered at 960degreesC and the samples exhibit significant (002) preferred orientation and columnar structure.