Enhanced coercivity in Nd–Fe–C alloys prepared by a re-milling process

In order to obtain a single phase Nd2Fe14C and reduce the formation of the Nd2C3 and Nd2Fe17Cx phases in the mechanically alloyed Nd–Fe–C alloys, a process of re-milling and subsequent annealing is carried out. Enhanced coercivity as large as iHc = 13.2 kOe has been achieved for Nd16Fe76C8 alloy, which mainly originates from the formation of Nd2Fe14C phase. The effect of carbon content on the structure, phase transformation and magnetic properties of Nd16Fe84−xCx (6 ≤ x ≤ 12) alloys prepared by this way is investigated. The intrinsic coercivities of the Nd16Fe84−xCx (6 ≤ x ≤ 12) alloys by two-step mechanical alloying are higher those of the samples by direct mechanical alloying.