Abstract: A permanent magnet material is prepared by cooling with a chill roll a molten alloy containing R wherein R is at least one rare earth element inclusive of Y, Fe or Fe and Co, and B. The chill roll has a plurality of circumferentially extending grooves in a circumferential surface, the distance between two adjacent ones of the grooves at least in a region with which the molten alloy comes in contact being 100 to 300 .mu.m on average in an arbitrary cross section containing a roll axis. Permanent magnet material of stable performance is obtained since the variation of cooling rate caused by a change in the circumferential speed of the chill roll is small. The variation of cooling rate is small even when it is desired to change the thickness of the magnet by altering the circumferential speed. The equalized groove pitch results in a minimized variation in crystal grain diameter.

Abstract: An object of the invention is to provide an inexpensive magnet having a high coercivity, high squareness ratio and high maximum energy product. According to the invention, a magnet containing R, T, N, and M wherein R is at least one rare earth element with essential samarium, T is iron or iron and cobalt, and M is at least one element of Ti, V, Cr, Nb, Hf, Ta, Mo, W, Al, C, and P, with essential zirconium, in amounts of 4-8 at % of R, 10-20 at % of N, 2-10 at % of M, and having a hard magnetic phase (TbCu.sub.7 type crystalline phase) and a soft magnetic phase (which is a bcc structured T phase, has an average grain diameter of 5-60 nm, and accounts for 10 to 60% by volume of the entirety), the atomic ratio (R+M)/(R+T+M) in the hard magnetic phase being in excess of 12.5%, is prepared utilizing a single roll technique. In the single roll technique, the peripheral speed of a chill roll is at least 50 m/s, and the discharge pressure of the molten alloy is 0.3-2 kgf/cm.sup.2.

Abstract: A magnet consists essentially of 4-8 at % of R, 10-20 at % of N, 2-10 at % of M, and the balance of T wherein R is at least one rare earth element, Sm being present in R in a proportion of at least 50 at %, T is Fe or Fe and Co, M is Zr with or without partial replacement by at least one element of Ti, V, Cr, Nb, Hf, Ta, Mo, W, Al, C, and P. Contained in the magnet are a hard magnetic phase based on R, T, and N and containing at least one crystalline phase selected from TbCu.sub.7, Th.sub.2 Zn.sub.17, and Th.sub.2 Ni.sub.17 types and a soft magnetic phase consisting of a T phase having a bcc structure, the soft magnetic phase having a mean grain size of 5-60 nm and being present in a proportion of 10-60% by volume. This construction ensures high coercivity, high squareness ratio, and high maximum energy product.

Abstract: A permanent magnet material is prepared by cooling with a chill roll a molten alloy containing R wherein R is at least one rare earth element inclusive of Y, Fe or Fe and Co, and B. The chill roll has a plurality of circumferentially extending grooves in a circumferential surface, the distance between two adjacent ones of the grooves at least in a region with which the molten alloy comes in contact being 100 to 300 .mu.m average in an arbitrary cross section containing a roll axis. Permanent magnet material of stable performance is obtained since the variation of cooling rate caused by a change in the circumferential speed of the chill roll is small. The variation of cooling rate is small even when it is desired to change the thickness of the magnet by altering the circumferential speed. The equalized groove pitch results in a minimized variation in crystal grain diameter.

Abstract: A melt of Nd-Fe-B alloy is injected in an inert gas atmosphere through a nozzle against a chill roll or a pair of chill rolls rotating relative to the nozzle for contacting the melt with the circumference of the chill roll or rolls, thereby quenching the melt. The chill roll has a low heat conductivity surface layer around a base or has a predetermined surface roughness on its circumference. The contact time of the melt with the chill roll can be increased by blowing an inert gas flow. Further the melt is quenched in an inert gas atmosphere of up to 1 Torr. A wind shield is disposed in proximity to the chill roll circumference for preventing a wind of the ambient gas induced by rotation of the chill roll from reaching a paddle of the melt. With these means, there is obtained a permanent magnet material having a grain diameter with a reduced variation.

Abstract: According to the invention, a magnetic recording medium is formed by using magnetic powder having a composition of the following formula:MeO.multidot.n[Fe.sub.2-x-y-z Ga.sub.x Cr.sub.y Al.sub.z O.sub.3 ]wherein Me is at least on element selected from the group consisting of Ba, Sr, Pb, and Ca,4.5.ltoreq.n.ltoreq.6, x.gtoreq.0, y.gtoreq.0, z.gtoreq.0,x/3+y/4+z/6.gtoreq.1/6, andx/6+y/10+z/11.ltoreq.1/6,preferably the number of those particles having a particle size of from 0.5d to 1.5d being at least 65% of the entire particles wherein is an average particle size, and the Fe content on the particle surface being substantially equal to the Fe content in the particle interior, and blending the powder with a binder. Thermomagnetic recording and thermomagnetic duplication are carried out using the medium. There results a magnetic layer which has high Hc, is not easily erased once recorded, has high squareness ratio, and enables thermomagnetic recording and thermomagnetic duplication at 100.degree. to 180.degree. C.

Abstract: A melt of Nd-Fe-B alloy is injected in an inert gas atmosphere through a nozzle against a chill roll or a pair of chill rolls rotating relative to the nozzle for contacting the melt with the circumference of the chill roll or rolls, thereby quenching the melt. The chill roll has a low heat conductivity surface layer around a base or has a predetermined surface roughness on its circumference. The contact time of the melt with the chill roll can be increased by blowing an inert gas flow. Further the melt is quenched in an inert gas atmosphere of up to 1 Torr. A wind shield is disposed in proximity to the chill roll circumference for preventing a wind of the ambient gas induced by rotation of the chill roll from reaching a paddle of the melt. With these means, there is obtained a permanent magnet material having a grain diameter with a reduced variation.

Abstract: A permanent magnet having high coercivity and energy product contains rare earth elements, boron, at least one element of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W, and a blance of Fe or Fe and Co, and consists of a primary phase of substantially tetragonal grain structure, or a mixture of such a primary phase and an amorphous or crystalline rare earth element-poor auxiliary phase wherein the volume ratio of auxiliary phase to primary phase is smaller than a specific value.

Abstract: A permanent magnet material having high coercivity and energy product is provided which contains rare earth elements, boron, at least one element of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W, optional nickel, and a balance of Fe or Fe and Co, and consists of a primary phase of substantially tetragonal grain structure, or a mixture of such a primary phase and an amorphous or crystalline rare earth element-poor auxiliary phase wherein the volume ratio of auxiliary phase to primary phase has a specific relationship to other parameters.

Abstract: In an R-Fe-B permanent magnet produced by a process including a rapid cooling, a composition of{R.sub.a (Ce.sub.b La.sub.1-b).sub.1-a }x(Fe.sub.1-z Co.sub.z).sub.100-x-y-w B.sub.y M.sub.w(R is at least one rare earth element except for La and Ce but including Y, 5.5.ltoreq.x<12, 2.ltoreq.y<15, 0.ltoreq.z.ltoreq.0.7, 0<w.ltoreq.10, 0.80.ltoreq.a.ltoreq.1.00, 0.ltoreq.b.ltoreq.1, M is Zr, Nb, Mo, Hf, Ta, W, Ti, and/or V) is proposed. The presence of the M element increases a ((BH)max) to a value higher than that of a composition wherein x is higher than 12 and makes the magnet more easily magnetizable.

Abstract: Disclosed is the addition of at least two elements of Nb, V, Ta and Zr to the ternary alloy of R (rare earth)-Co-Cu for permanent magnet materials, to thereby provide the permanent magnets with increased coercive force, residual magnetization and energy product. The additional elements enable employment of such Cu and Fe contents of the alloy as less than 10% and more than 6%, respectively. These percentages were avoided in the prior art to prevent the reduction of Br and Hc, respectively.

Abstract: Disclosed is the addition of Nb, V, Ta or Zr to the ternary alloy of R (rare earth)-Co-Cu for permanent magnet materials, to thereby provide the permanent magnets with increased coercive force, residual magnetization and energy product. The additional elements enables employment of such Cu and Fe contents of the alloy as less than 10% and more than 6%, respectively. These percentages were avoided in the prior art to prevent the reduction of Br and Hc, respectively.