LTCC processed CoTi substituted M-type barium ferrite composite with BBSZ glass powder additives for microwave device applications

Abstract

Hexagonal magnetoplumbite ferrites typically have sintering temperatures above 1100∘C in order to stabilize a single phase compound, which is much higher than the melting point of silver leading to device fabrication challenges. Application of low temperature co-fired ceramics (LTCC) technologies may prove effective in decreasing the sintering temperature of hexagonal ferrites. Ferrite powders combined with glass frit powder is an effective pathway to lowering the sintering temperature. Here, hexagonal M-type barium ferrite (i.e., Ba(CoTi)1.5Fe9O19) ceramics, combined with BBSZ glass powder as a sintering aid were synthesized. Co and Ti ions where used to substitute for Fe cations in order to modify the magnetic anisotropy field. The density, microstructure, magnetic properties and complex permeability are reported. The BBSZ glass addition was shown to improve the densification and magnetic properties of the barium ferrite. The densification of the BaM ferrite Ba(CoTi)1.5Fe9O19 was further enhanced by the glass additive at low firing temperatures of below 900∘C because of the formation of a liquid phase. Complex permeability of ferrites sintered at 900∘C was also influenced by the BBSZ addition and the resonance frequency was shown to decrease with increased amounts of the glass modifier.

Synthesis and Microwave Dielectric Properties of BBSZ-Zinc Silicate Based Material for LTCC Applications

“…During sintering, the molten liquid phase wets and flows between the grains, causing their rearrangement. In many cases, such as reported by Wang et al, 34 the dissolution of grains into liquid causes transportation and grain coarsening. 35 In the present case, however, while there is good evidence of liquid- Fig.…”

Characterization of Zr-Al Substituted M-Type Barium Hexaferrite Synthesized by Co-Precipitation Method

“…Average cell volume of pure hexaferrites must be about 690 Å 3 (Ashraf, Zhang, Abbas, & Murtaza, 2018). The average crystallite size D must be in the range 15 nm-60 nm (Almessiere et al, 2019;Gunanto et al, 2016;Mahmood & Bsoul, 2017;Wang et al, 2016). In all the samples, the crystallite size is found in the range of 9.43 nm-18.86 nm, the average cell volume of all the samples is in the range of 539.77(Å 3 ) to 502.51(Å 3 ).…”