Abstract: An improvement is proposed in the powder metallurgical method for the preparation of a rare earth-based permanent magnet comprising the steps of compression-molding a magnet alloy powder into a powder compact and sintering the powder compact into a sintered magnet body. The improvement, which has an effect of increasing the density of the sintered body and consequently increased magnetic properties of the magnet product, comprises conducting the sintering heat treatment in two steps consisting of a first partial sintering treatment in vacuum or under a subatmospheric pressure of an inert gas immediately followed by a second partial sintering treatment under a normal to superatmospheric pressure of, for example, up to 20 atmospheres.

Abstract: Disclosed is a novel method for the preparation of a rare earth-based permanent magnet by the so-called two-alloy process in which powders of two kinds of rare earth-containing magnetic alloys each having a different composition from the other are blended together in a specified proportion and the powder blend is shaped in a magnetic field into a green body which is sintered. In the invention, the first magnetic alloy has a composition of the formula R.sub.2 T.sub.14 B, in which R is a rare earth element selected from the group consisting of neodymium, praseodymium, dysprosium and terbium and T is iron or a combination of iron and cobalt, while the second alloy has a composition of the formula R.sub.a Fe.sub.b Co.sub.c B.sub.d M.sub.