| 摘要 |
PURPOSE:To obtain alloy powder for magnet with high residual magnetic flux density by changing an Fe-Co-B-R system alloy molten metal of specific composition, having low content of rare-earth element, into an amorphous structure by a super quenching method and applying a specific heat treatment thereafter. CONSTITUTION:A rare-earth magnet is represented by the composition formula: Fe100-x-y-zCoxByRz (R is either or both kinds of Pr and Nd), whereas the symbols (x, y, z) defining the composition range satisfy respectively the conditions, 0.05<=x<=15at.%, 16<=y<=22at.%, and 3<=z<=6at.%. Its main phase is an Fe3B type compound, and it holds a magnetic phase having an Nd2Fe14B type crystal structure and is composed of microcrystalline aggregated body with its average particle dia. of 0.01-0.1mum. Further, the alloy powder used for the rare-metal magnet is a resultant product through such steps as changing the alloy molten metal represented by the composition formula into an amorphous structure by a super quenching method, raising temperature at a temperature rise rate of 1-10 deg.C/min from 500 deg.C, holding the range of 550-700 deg.C for 5min to 6 hours and crushing. Thus, a bond magnet having a residual flux density of 5kg or more can be obtained. |
