Magnetic properties of Mn substituted Nd-Fe-B composite

A study on the magnetic properties of Nd9Fe85-xMnxB6 (x=0-2) melt-spun ribbons has been investigated. Under optimal heating condition, it was found that an appropriate amount of Mn could enhance hard magnetic properties, especially the maximum coercivity, which increases more than about 20%. Higher amounts of Mn addition lead to a loss of coercivity and (BH)max. XRD results indicate that each alloy consists of hard magnetic Nd2Fe14B phase and soft magnetic α-Fe phase. TMA scans indicate that the Curie temperature (Tc) of α-Fe phase rises with the Mn doping content increasing until x=2. For x=2 sample there is a slope between the Nd2Fe14B phase and α-Fe phase peaks in TMA curve. It can be attributed to the formation of the metastable Nd2Fe23B3 phase. The change in magnetic properties and Curie temperature may be attributed to the formation of δ-Mn and R2Fe23B3 phase