| 摘要 |
PURPOSE:To obtain a permanent magnet of high coercive force and (BH)max by lowering a temperature to 400 deg.C in at most 10 deg.C/minute after formation- sinstering in a magnetic field alloy power of R, B and Fe composed of a kind of rare earth element and Y. CONSTITUTION:After Y and 10-40 weight % of R composed of at least a kind of rare earth element, 0.1-10 weight % of B, and alloy powder of Fe which is the rest are formed in a magnetic field and sinstered in 1000-1200 deg.C, they are cooled down to 400 deg.C in 10 deg.C/minute in succesion. When 70-100 weight % of Nd and Pr in the rare earth element is contained in R, it is proper to obtain a high (BH)max. When a part of B is replaced to a range of 80% of B by such as C, N, Si, P and Ge, degree of sinstering is improved. When a part of Fe is replaced by such a predetermined metal as Co and Ru, temperature stability is increased, and when it is replaced by Cr and Al, corrosion resistivity is increased. A quantity of replacement is in a range of 20% of Fe. In alloy dissolution, an O2 content should be in a range of 0.005-0.03 weight %. When it is formed in the magnetic field, treated in Ar in 1000-1200 deg.C for about one hour, and cooled down to 400 deg.C at most 10 deg.C/minute, an R-Fe-B system permanent magnet of high performance is obtained. |
