Magnequench powders are produced by a rapid solidification process known as melt spinning.
In the patented Magnequench rapid solidification process (also referred to as jet casting), an ingot of RE-Fe-B alloy is first melted. Then the molten metal is ejected under pressure from a nozzle onto the surface of a water cooled rotating metal wheel. The material solidifies into a thin metal ribbon which is approximately 35 µmm thick and 1-3 mm wide. By carefully controlling process variables such as the metal flow rate and speed of the rotating wheel, the quench rate (and hence microstructure) can be controlled to achieve optimum magnetic properties.
The ribbon is collected and then milled into a platelet, or flake-shaped metal powder, which is heat treated to obtain the desired magnetic properties.
Magnequench also commercialized an alternative rapid solidification process for producing its MQP-S fine, spherical RE-Fe-B powders. In the process, known as centrifugal or spinning cup atomization, molten metal is ejected from a nozzle onto the surface of a rapidly spinning cup. As it leaves the rim of the spinning cup, the molten metal forms droplets which then form into spheres and solidify in flight. The powder is collected and then heat treated to obtain the desired magnetic properties.