Synthesis of nanocomposite ceramics for magnetic remote sensing and actuating

Oxide ceramics based nanocomposites including ferromagnetic dispersoids were fabricated by ordinary sintering and hot pressing of composite powders obtained by chemical and metallurgical synthetic routes. The microstructure of nanocomposite was affected by the composite structure of powders and sintering condition for temperature and reducing atmosphere. Nanocomposite of ferromagnetic metals, alloys, intermetallic compounds and oxides with oxide ceramics such as Ni/alumina were successfully fabricated. Magnetization response to applied uni-axial stress in the nanocomposite was observed. Results on the relationship between particle size of ferromagnetic dispersoids and magnetization change for permeability were explained as the reverse magnetostriction effect of nano-dispersoids. Amplified magnetization sensitive to applied stress on ceramics indicates the possibility of remote sensing of applied stress on the structural ceramics. Combining with the fracture mechanics, this phenomena will contribute to the enhancement of reliability of ceramics by controlling the operating condition.