ABSTRACT
Economic uncertainty in the rare earth permanent magnet marketplace, as well as an expanding electric drive vehicle market that favors permanent magnet alternating current (AC) synchronous drive motors, has motivated renewed research in rare earth–free permanent magnets like "alnico," an Al–Ni–Co–Fe alloy. Standard commercial processing of alnico magnets with the highest second quadrant squareness and energy product utilizes directionally solidified casting and significant final machining, which leads to higher costs and considerable material waste. Powder-processed, sintered alnico magnets have inferior energy product due to their randomly oriented fine-grained microstructure and are currently typically used only for low-energy density applications. Recent advancements in net-shape powder-processing alnico magnets have shown considerable increase in coercivity, remanence, and energy product, showing great promise for use in traction drive motors and other green energy technologies.
