Multiple Non-linear Regression Analysis for Complex Doping of X7R MLCC Ceramics

The multiple non-linear regression analysis method was applied to build up the non-linear regression mathematical model y = b0 + Σbixi + Σbiixi2+ Σbiiixi3,and the complex oxides were used as effective dopants to X7R ceramic powders of multilayer ceramic capacitor (MLCC). The non-linear regression equation regarding the relationship between the dosage of different dopants and the dielectric properties was established based on the testing data. Moreover, the modification mechanism of dopants on the characteristics of the ceramics was explained in this paper. The regression equation suggests that with the increase of Nb and Ce addition to BaTiO3, the dielectric constant decreases, which is consistent with core-shell structure theory. According to the multiple regression equation analysis results, the dosage of different dopants was adjusted to develop the environmental friendly X7R MLCC ceramics. The main features of the BaTiO3 ceramics sintered in air atmosphere at 1140 ＞ are e298K = 2900±50, tgδ ≤1.0%, ρ ≥ 1011Ω·cm, △C/C25℃(-55℃~ +125℃)≤ ±15%.