| 摘要 |
In a nanocomposite bulk magnet according to the present invention, nanocomposite magnet powder particles, including an Nd2Fe14B crystalline phase and an α-Fe phase, are combined together. The composition of the magnet is represented by T100-x-y-z-n(B1-qCq)xRyTizMn, where T is at least one transition metal element selected from the group consisting of Fe, Co and Ni and always including Fe, R is at least one rare-earth element including substantially no La or Ce, M is an additive metallic element, and x, y, z, n and q satisfy 4 at %≦x≦10 at %, 6 at %≦y≦10 at %, 0.05 at %≦z≦5 at %, 0 at %≦n≦10 at %, and 0≦q≦0.5, respectively. The powder particles have a minor-axis size of less than 40 μm. And powder particles, of which the major-axis size exceeds 53 μm, account for at least 90 mass % of the entire magnet. And those powder particles are directly combined with each other. Consequently, a full-dense magnet, of which the density is 96% or more of the true density of its material alloy, is realized. |
| 主权项 |
1. A method for producing a nanocomposite bulk magnet, the method comprising the steps of:
providing a melt of an alloy having a composition represented by the compositional formula: T100-x-y-z-n(B1-qCq)xRyTizMn, where T is at least one transition metal element that is selected from the group consisting of Fe, Co and Ni and that always includes Fe, R is at least one rare-earth element including substantially no La or Ce, and M is at least one metallic element selected from the group consisting of Al, Si, V, Cr, Mn, Cu, Zn, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au and Pb, and the mole fractions x, y, z, n and q satisfy the inequalities of: 4 at %≦x≦10 at %, 6 at %≦y≦10 at %, 0.05 at %≦z≦5 at %, 0 at %≦n≦10 at %, and 0≦q≦0.5, respectively, quenching the melt to make a rapidly solidified alloy, at least 30 vol % of which is crystalline phases that include an R2T14B phase and an α-Fe phase and that have an average crystal grain size of 100 nm or less and the balance of which is amorphous phases and which has a thickness of less than 40 μm; pulverizing the rapidly solidified alloy, thereby obtaining a powder, at least 90 mass % of which is accounted for by powder particles with a major-axis size of more than 53 μm; and compacting the powder while heating and pressing the powder, thereby making a bulk body in which nanocomposite magnet powder particles including the R2T14B phase and the α-Fe phase are combined together and of which the density is 96% or more of the true density of the alloy. |
