Tailored modified ferrimagnetic nano-powders
for micro wave applications
Modern applications with high-frequency electromagnetic fields (satellite-TV, mobile funk, WLAN technologies, radar for traffic and aerial supervision, microwave heating, drying, sintering, up to automotive and medical applications) require novel absorbing materials in order to
• reduce the electromagnetic radiation exposure on biological systems or
• assure the safe operation of instruments and equipments as well as the security (prevention of wireless signal leakages) or
• facilitate the modern applications fundamentally and/ or with larger efficiency.
We can perform such different requirements with tailored modified barium hexaferrite powders made by the “glass crystallization method” in the ternary system BaO-B2O3-Fe2O3.
One way to modify the properties is to substitute the iron oxide in the raw materials mixture by pairs of other metal oxides (e.g. CoO/TiO2, CoO/RuO2, MnO/TiO2, FeO/TiO2). Thereby the original hard magnetic behaviour of the barium hexaferrite powder is shifted to „soft magnetic behaviour“ without change the crystallographic structure and consequently the powders can absorb micro wave selective at different frequencies in range 1 to « 48 GHz.
The other way for modification is the adjustment of the melting and crystallization conditions. That is primarily changed the crystal morphology and size due to the influencing the nucleation and crystal growth.
With the powders can fabricate
composites for microwave induced curing/ bonding,
coatings or composites for microwave defectoscopy,
magnetic carriers for agent transport,
magnetic carriers for microwave hyperthermia and or
coatings or composites to reduce the radiation exposure at humans and/or to minimize the noise level of electronic devices.
