Solar Sintering of Ni-Zn Ferrites: Densification and Magnetic Properties.

摘要

The solar sintering of different materials (metals, ceramics and composites) is a good way to improve properties as density and permeability of magnetic materials. In this experimental work we have compared density, microstructure and magnetic properties of NiZn ferrites sintered in a solar furnace and in a conventional electrical furnace. The Ni-Zn ferrites samples (fabricated by uniaxial pressing with a pressure of 100 MPa) were sintered in a Solar Furnace at Plataforma Solar de Almeria (PSA-CIEMAT). The sintering was performed in the temperature ranges of 1150°C to 1300°C. In order to optimize the sintering process, different heating rates (15, 30 and 60°C/min) and dwell times (15, 30 and 60 minutes) where tested. For comparison, similar ferrites samples (with a toroid shape) were sintered in a electric furnace in the same temperature range using standard conditions (3,5°C/min and 120 minutes). A detailed microstructural characterization was performed by means of scanning electron microscopy (SEM). Several improvements of density and magnetic properties (initial permeability) were show in the Solar Furnace samples with short sintering cycles.