| Popis: |
Soft magnetic composites based on Fe powder and phenol-formaldehyde resins modified with tetraethylorthosilicate and 3-glycidoxypropyltrimethoxysilane are investigated in detail. The chemical synthesis of phenolic resin, its modification with nanometer-sized SiO 2 particles created by sol-gel method and subsequent coating, enables a preparation of insulating layer on the surface of Fe particles. Thermal degradation of native and modified resins with different amount of SiO 2 was examined in order to suggest the appropriate curing temperature and schedule. Mechanical, magnetic and electrical properties of a novel family of SMC materials were substantially improved by using silane coupling agents. The hybride insulating layer results in a defectless structure of prepared green compacts, which consequently exhibit a higher permeability and lower eddy current losses. |
