UC Riverside

State of the art magnets depend heavily on the use of rare-earth materials and cost 10 to 20 times more than other magnets such as ferrite magnets, per weight. In addition, the global supply of crucial rare-earth elements is uncertain, causing a real threat to the magnetic industry. Effective use of exchange coupling between hard and soft magnetic materials could decrease reliance on rare-earth based magnetic materials and lower the cost of high performance permanent magnets. Despite the promise, engineering a composite permanent magnetic material with enhanced magnetic properties as a result of exchange coupling has been an elusive goal. Research described in this thesis centers on the synthesis and characterization of metal-oxide 3D bulk composite materials for permanent magnetic applications. Samples were densified from powders using the Current Activated Pressure Assisted Densification (CAPAD) apparatus. A range of samples with densities as high as 97% relative density have been synthesized in relatively short times (~10 minutes). Samples have been shown through X-ray diffraction (XRD) to contain desired composition, and are indeed hard and soft magnetic composites. The applied pressure has been shown to play a significant role in increasing density and in turn improving the magnetic properties. Enhanced magnetic saturation of the composite material, as compared to the mass dominant hard phase has been observed.