HIGH-COERCIVITY SINTERED ND14.5DY1.5FE68CO5AL1.5CR2B7.5 PERMANENT-MAGNET

Effect of 1.5 at.% Al and 2.0 at.% Cr additions on microstructure, mag netic properties, thermal stability and corrosion resistance of (Nd,Dy )-(Fe,Co)-B sintered magnet have been studied. It is shown that simult aneous substitution of these elements for Fe in (Nd,Dy)-(Fe,Co)-B magn et causes significant improvement in coercivity and thermal stability; maximum operating temperature up to 473 K may be possible. The corros ion resistance in acid solution and atmospheric environment is also si gnificantly improved by blocking the selective oxidation of the Nd-ric h phase owing to the formation of (Nd,Dy)-(Co,Al,Fe)and (Nd,Dy))-(Fe,C r,Co) phases. (C) 1998 Elsevier Science S.A.