Phase transformation at high temperature and coercivity of Sm(Co,Cu,Fe,Zr)7-9 magnet alloys

The phase diagram near compositions of magnet alloys, that is, Sm-Co-13.0at%Cu-10.0at%Fe, Sm-Co-7.0at%Cu-22.0at%Fe and Sm-Co-7.0at%Cu-22.0at%Fe-2.0 at%Zr sections of the phase diagram were determined in the Sm content range from 6 to 16 at%. Furthermore, relationships between phase transformation at high temperature and coercivity were investigated. The Sm <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (Co,Cu,Fe,Zr) <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">17</inf> (Zr=0 and 2.0at%) intermetallic compound (2/17 phase) has the hexagonal TbCu <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</inf> , hexagonal Th <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> Ni <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">17</inf> or rhombohedral Th <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> Zn <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">17</inf> structure depending on the quantity of Cu, Fe and Zr, and temperature. The alloys quenched after homogenizing treatment, by which the 2/17 phase with TbCu <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</inf> structure is obtained, can possess high coercivity after the aging treatment.