ความสัมพันธ์ของความเครียดในแลตทิซของผลึกและสมบัติทางไฟฟ้าและแม่เหล็กของวัสดุผสม Mg0.3Zn0.7Fe2O3-Ba0.7Sr0.3TiO3

บทคัดย่อ

In this research is to study the effect of two-stage sintering of composition ceramics between (1-x)Mg0.7Zn0.3Fe2O4-(x)Ba0.7Sr0.3TiO3; (1-x)MZF-(x)BST (x = 0.40, 0.50 and 0.60) on crystal structure, microstructure, mechanical and electrical properties. Sample were sintered under two-stage sintering method with the first sintering temperature (T1) at 1350 ?C different soaking time for 30, 40, 50 and 60 min and cooled down to the second sintering temperature (T2) with varies sintering temperature at 900 ?C and 1100 ?C for 5 hr with heating/cooling rate at 10 ?C/min. 0.40MZF-0.60BST ceramics were revealed highly dense of ceramics and high shrinkage values. It can be found that the densities and shrinkage values tend to slightly increase with increase soaking time. Moreover, ceramics with different T2 sintering temperature between 900 ?C and 1100 ?C is obtained not similarity results of physical properties. XRD patterns showed combination phase between Mg0.7Zn0.3Fe2O4 and Ba0.7Sr0.3TiO3, which are obtained the difference intensities ferrite phase and ferroelectric phase with x contents. The crystallize size and lattice strain were calculated from XRD patterns. It can be found that dwell times of T1 about 40-50 min obtain high the crystallize size and lattice strain values. The EDX technique analysis was used to confirm the element composition percentage of (1-x)MZF-(x)BST. The microstructure of composition ceramics examined by the SEM technique found that grain have round oval shape associate square shape all three ratio for average grain size is not different. The average grain size were in the range of 0.246-0.561 ? m, grain square shape corresponding to the Mg0.7Zn0.3Fe2O4 have average grain size were in the range of 0.489-0.809 ? m, and round oval shape corresponding to the Ba0.7Sr0.3TiO3 have average grain size were in the range of 0.177-0.351 ? m. Fracture toughness which are calculated from vicker and knoop hardness values. 0.60MZF-0.40BST ceramics were showed optimal fracture toughness and found the difference of insignificant fracture toughness values from varies soaking time of T1 and T2 conditions. The dielectric constant and dielectric loss values were characterized the electrical properties of ceramics. The highly dense of 0.50MZF-0.50BST ceramics were obtained the optimal electrical properties from high dielectric constant and lower dielectric loss. Magnetic permeability of medium (?) are obviously increased with highly dense ceramics, high crystallize size and more lattice strains. Finally, the optimal conditions of two stage sintering can be obtained for the soaking time of T1 about 40-50 min and the second sintering temperature of T2 at 900 ?C. Keyword : (1-x)Mg0.7Zn0.3Fe2O4-(x)Ba0.7Sr0.3TiO3; two stage sintering

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