Powders

Powders

How can MQP have higher flux and be isotropic?

MQP powders are magnetically isotropic, and most MQP powders are made from the RE2Fe14B single-phase composition region, with typical Br value of about 800-900mT. Higher Br is possible by introducing magnetically soft α-Fe into the RE2Fe14B matrix to form the RE2Fe14B/α-Fe nanocomposite. MQP-15-7 and MQP-16-7 are typical such products, with Br =935mT in MQP-15-7 and 980mT in MQP-16-7 respectively.

Can MQP have higher flux performance?

Higher Br than MQP-16-7 is possible, but it requires the c-axis of all grains within each individual powder to be aligned towards one direction. The development of c-axis alignment can be achieved by applying additional hot deformation process (known as die-upsetting process) to the melt-spun powders. Based on this principle, Magnequench has developed and launched a new class of anisotropic powder products: MQA36-18, MQA37-16, MQA37-11 and MQA38-14, which their Br ranges from 1250 to 1300mT.

What are MQ powder's morphology? PSD?

Magnequench offers MQP powder in a variety of shapes and sizes. Traditionally it has offered products with a -40mesh powder size (i.e. powder particles less than 420 micrometers) and Powder Size Distribution (PSD) that is best illustrated by the graph below:

However, recently new technologies have been developed such that much finer powder (<50 micrometers), more targeted PSDs, and spherical are now available, as illustrated by the SEM micrographs below:

What's the difference between anisotropic (MQA) and isotropic (MQP) powders?

Isotropic MQP powder gives the same magnetic properties is all directions, and therefore this grade of powder does not need to be aligned when being consolidated into a magnet.

Anisotropic MQA powder does have a preferred orientation though. This material has been designed such that it has vastly superior flux density (or remanence) in one particular direction. Therefore, when preparing magnets from anisotropic MQA powder, one has to align it in the preferred direction to take full advantage of its higher magnetic strength potential.
http://www.mqitechnology.com/bonded-neo-powder.jsp

How is MQ powder made?

Magnequench powders are produced by a rapid solidification process known as melt-spinning. In the patented Magnequench rapid solidification process (also referred as jet casting), an ingot of RE-Fe-B alloy is first melted, then the molten metal is ejected from a nozzle under pressure onto the surface of a rotating metal wheel. The material solidifies into a thin metal ribbon which is approximately 35µm thick and 1-3mm wide. The ribbon is collected and milled into a flake-shaped metal powder. The powder is heat treated to obtain the desired magnetic properties.
http://www.mqitechnology.com/bonded-neo-powder-history.jsp