Fabrication and magnetic properties of LTCC NiZnCu ferrite thick films

Abstract

For appling low temperature co-fired ceramics technology on NiZnCu ferrite with Ag electrode, the synthesis of nano-sized NiZnCu ferrite powders using metal nitrates and the fabrication of ferrite thick films by a doctor blade method were carried out. Microstructural analysis confirmed that nano-sized ferrite powders and fully densified thin films were successively fabricated. At a sintering temperature of 950 °C the magnetic properties of the ferrite thick film with 0.2 -0.3 mol Cu were close to those of bulk materials (permeability > 450, coercivity < 3 Oe).

Magnetic properties and sintering characteristics of NiZn(Ag, Cu) ferrite for LTCC applications

“…For 3 ], were selected as raw materials. After mixing these metal nitrates and ethyl alcohol, the nanopowders were prepared by evaporating ethyl alcohol followed by calcination at 700 1C for 1 h. For preparing thick films, calcined powders were ground by wet ball milling for 10 h and mixed again for 24 h after adding binder, plasticizer, dispersant and solvent.…”

“…Since the melting point of Ag is 961 1C, the sintering temperature of ferrite should be below 950 1C to avoid Ag diffusion and shrinkage [2]. In previous work [3], Ni 0.2 Zn 0.5 Cu 0.3 ferrite thick films sintered at 950 1C for 72 h with a saturation magnetization (4pM s ) of 4.6 kG, a coercive force (H c ) of 2.5 Oe and an initial permeability (m i ) of 500 were obtained. Therefore, we emphasized on enhancing sintering characteristics without reducing magnetic properties in order to develop a feasible co-firing system with ferrite and Ag electrode.…”

Applying the ltcc-technology to obtain hexaferrites for base layers of microstrip shf devices

“…2 and 35ZnO was prepared by the process of melting. The original powders of the BBSZ glass were weighed and mixed in accordance with their ratio in the chemical formula, and then the mixed powders were melted at 1200 °С for 2 hours in the platinum crucible and were hardened in water with the formation of amorphous glass.…”

“…To decrease the dimensions of SHFdevices, it is necessary to examine multilayer devices based on the low-temperature co-fired ceramics (LTCC), which consist of alternating ferrites and internal metal electrodes. As a rule, silver (Ag) is used as the internal metal electrode in multilayer devices because of its low losses and low electrical resistance at high frequencies [1,2]. Since the melting point of Ag is 961 °С, it is necessary to design the LTCC materials that have sintering temperature about 900 °С, in order to avoid diffusion of Ag in ferrites.…”

LTCC-technology for Producing Hexaferrites

“…is small. Therefore, for the manufacture LTCC-multilayer devices, it is important to use ferrites having a sintering temperature below 961 °C to prevent diffusion of Ag and shrinkage [10,20].…”