Additive Manufacturing of High-efficient Monolithic Fe6.5Si Electric Sheet Stacks

Energy-efficient electric motors are crucial for the progress of electromobility. Soft magnetic materials with a high silicon content, such as Fe6.5Si, offer the possibility of high electrical resistance, relatively high saturation magnetization and comparatively low power losses. However, due to the brittleness of Fe6.5Si, this material is difficult to process by using conventional manufacturing methods (such as stamping). The 3-D screen printing process enables the production of thin Fe6.5Si electrical sheets in end geometry. However, conventional methods for stacking carry the risk, that those thin brittle sheets crack during their processing. For the first time, we are demonstrating the production of monolithic electrical steel stacks by alternately printing soft magnetic and ceramic layers on top of each other. These stacks are then densified in a joint heat treatment process (co-sintering). The material and magnetic properties of the stacks will be discussed in dependence on the sintering parameters and the powder properties.