Fig. 4 shows the microwave dielectric properties of the Li2ZnTi3O8 ceramics as a function of theBi2O3 addition and sintering temperature .It is noticed that the variation of dielectric constant(εr) is very similar to that of the density .The εr values of Li2ZnTi3O8 ceramics both increase initially and then reduce with increasing of Bi2O3 contentand sintering temperature .The dielectric constant is dependent on the density , molecular volume, ionic polarizability , second phase and structural characteristics such as the distortion and tilting spaces of oxygen octahedron in the unit cell [18]. In present study ,the density and second phase are the two main factors that may change the εr value. According to the Lichtenecker law [19], the Li2ZnTi3O8 ceramics with 1.0wt% Bi2O3 addition have lower εr values, which is caused by the lower density(the dielectric constant of pore equals 1.0).The maxi mum εr value(27.8) of Li2ZnTi3O8 ceramic with 2.0 wt%Bi2O3 addition sintered at950 1C Is larger than the εr value(25.6)of pure Li2ZnTi3O8 ceramic ,which is related to the large εr value (125.5)of the second phase Bi2Ti2O7
Addition sintered at 950 C is larger than the εr value(25.6)of pure Li2ZnTi3O8 ceramic ,which is related to the large εr value (125.5)of the second phase Bi2Ti2O7 [