| 摘要 |
PURPOSE:To obtain economical and high-performance R-Fe-B-based magnet by sintering a powder compact of the (Pr-Nd)Fe-B-based alloy formed by raw material of didymium mainly composed of Pr, Nd, then gradually cooling it at the particular cooling rate and then quickly cooling it through heat treatment at a specified temperature. CONSTITUTION:In manufacturing the R2T14B-based magnet (R is yttrium and rare earth element, T is a transition metal) by the powder metallurgical method, the powder compact of (Pr-Nd)Fe-B-based alloy using the raw material of didymium mainly composed of Pr, Nd is sintered, then gradually cooled at the cooling rate of 500 deg.C/hr or less and then it is quickly cooled through heat treatment at a temperature range of 350 deg.C-650 deg.C. Using didymium with a ratio of Pr and Nd of 3:7 and purity of 90% or more, Fe and ferroboron, an ingot of (Pr-Nd)Fe-B-based alloy consisting of R35wt%, B1.1wt% and Fe (remainder) is formed. Then it is ground and molded under the magnetic field, in order to form a compact. This compact is kept under the vacuum condition for 1hr at 1,060 deg.C. Thereafter, it is kept for 1hr under the Ar atmosphere for sintering. Thereafter, it is cooled gradually at the cooling rate of 100 deg.C/hr and then heat-treated for 1hr at a temperature range of 300 deg.C-700 deg.C. Finally, it is cooled again quickly. |
