Patent Application
20240412902
The present invention relates, generally, to rare earth-based permanent magnets, and more particularly, to such magnets containing cerium, which may be in combination with lanthanum, and more particularly, where neodymium or dysprosium is in a minor amount or excluded. The present invention also relates to methods for producing such magnets.
To date, permanent magnets can be roughly considered to fall into three groups: the Nd2Fe14B and Sm—Co-based high performance rare-earth magnets, the relatively low performance ferrite magnet, and the alnico-represented intermediate gap magnet. A large percentage of present day rare earth magnets suffer from a high percentage, as much as 32 weight percent, of the critical rare earth elements Nd and Dy, which are very costly and in limited supply. This amounts to a significant hindrance for domestic energy-relevant applications, such as electric vehicle traction motors and direct-drive wind turbines.
Considering the low availability of critical expensive elements, such as Nd, Sm, and Dy, there has been an ongoing effort to find more abundant and lower cost high performance magnets. However, efforts in achieving permanent magnets relying on lower cost elements and which exhibit similar or same energy product (BHmax) and high Curie points as the currently known permanent magnets in widespread use have been largely unsuccessful. Thus, the provision of such a magnet would be a significant advance in the field of permanent magnets.
The present disclosure is foremost directed to permanent (hard) cerium-based ferromagnetic alloy magnetic compositions that rely more on lower cost elements (e.g., Ce and La), and conversely, rely less on more costly elements such as Nd and Dy. In some embodiments, higher cost elements, such as Nd or Dy, are excluded. In some embodiments, the magnetic compositions have exceptional Curie points (e.g., above the 585 K Curie point of commercial Nd2Fe14B) without relying on incorporation of Dy or Nd, and in some instances, with a substantially lower amount of Co than used in SmCo5. The permanent magnet may include at least cerium (Ce), iron (Fe), cobalt (Co), and boron (B), and optionally, one or more of lanthanum (La), bismuth (Bi), and zirconium (Zr).
More particularly, the permanent magnet has the composition (Ce1-xM1x)2.7-(v+w)M2v(Fe14-yCoy)1-zM3zB, denoted as Formula (1), wherein 0≤x<1; 0≤v≤1; 0≤y≤3; 0≤w≤0.8; and 0≤z≤1, wherein M1 represents one or more lanthanide elements other than Ce; M2 represents at least one element selected from the group consisting of Sn, Sb, Bi Pb, Ca, Sr, and Zr; and M3 represents at least one element selected from the group consisting of Ti, Cr, Mn, Ni, Cu, Zn, Zr, Nb, Mo, W, Ta, or Hf. In further or alternative embodiments, the permanent magnet has the composition (Ce1-xM1x)2-vM2v(Fe14-yCoy)1-zM3zB, or more particularly, (Ce1-xM1x)2-vM2v(Fe14-yCoy)B. In particular embodiments of any of these or other formulas disclosed in this application, any one or more of the following ranges may be selected: 0<x<1, 0.1≤x<1, 0.1≤x≤0.8, 0<y≤3, 0≤y≤2, 0<y≤2, 0.01≤v≤1, 0.1≤v≤1, 0≤v≤1, 0≤v≤0.4, 0≤v≤0.2, 0≤z≤1, 0.1≤z≤1, and 0.01≤z≤1. In some embodiments, in any of the foregoing formulas, where applicable, any one or more of the following conditions may apply: 0.01≤v≤1, 0≤v≤1, 0≤v≤0.4, 0≤v≤0.2, 0.1≤v≤1, 0≤z≤1, 0.01≤z≤1, or 0.1≤z≤1. In some embodiments, the permanent magnet excludes Nd, Dy, or both.
The magnetic composition described herein substantially reduces expensive, critical rare earth content in high performance magnets while maintaining room temperature magnetic properties. The permanent magnet may have some of the following exemplary properties: 300 K Magnetization of 1.5 Tesla or higher; Curie point of 700 K or higher; 300 K Anisotropy Field of 5.5 Tesla or higher. The energy product may be 5-55 MG-Oe, or in some cases, about 5-20 MG-Oe, with coercivities as high as 6 kOe or higher. Each of these properties is important in a permanent magnet: i.e., the magnetization sets an upper limit on BHmax, the Curie point (or ferromagnetic ordering point) determines the usable temperature range of the magnet, and a sufficient anisotropy field (generally a minimum of three times the magnetization) permits subsequent development of sufficient coercivity to prevent demagnetization.
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In one aspect, the present disclosure is directed to a bulk permanent magnet (“magnet”) having the formula (Ce1-xM1x)2.7-(v+w)M2v(Fe14-yCoy)1-zM3zB, which may denoted herein as Formula (1). In a particular sub-formula of Formula (1), the permanent magnet has the formula (Ce1-xM1x)2-vM2v(Fe14-yCoy)1-zM3zB, which may be denoted here as Formula (1a). In a further sub-formula of Formula (1a), the permanent magnet has the formula (Ce1-xM1x)2-vM2v(Fe14-yCoy)B (i.e., when z is 0), which may be denoted here as Formula (1b). Notably, all subscript values correspond to molar amounts.
The variable M1 represents at least one lanthanide element (or at least two or more lanthanide elements) other than Ce. The term “lanthanide element” refers to any of the elements (other than Ce) having an atomic number of 57-71, e.g., lanthanum (La), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). In some embodiments, M1 is or includes La and/or Pr. In some embodiments, one or both of Nd and Dy are excluded from M1, or Nd and/or Dy are independently or in sum present in a trace amount, which may be a molar amount of no more than or below, for example, 0.1, 0.05, or 0.01 by total molar amount of Ce and M1. In some embodiments, M1 is not present (i.e., when x is 0).
The variable M2 represents at least one element (or at least two or more elements) selected from Sn, Sb, Bi, Pb, Ca, Sr, and Zr. In a first embodiment, M2 is or includes Sn. In a second embodiment, M2 is or includes Sb. In a third embodiment, M2 is or includes Bi. In a fourth embodiment, M2 is or includes Pb. In a fifth embodiment, M2 is or includes Ca. In a sixth embodiment, M2 is or includes Sr. In a seventh embodiment, M2 is or includes Zr. In other embodiments, any two or more of the above first through seventh embodiments are combined, e.g., M2 may represent at least Bi and/or Zr, and may or may not include (or may exclude) one or more other elements selected from Sn, Sb, Bi Pb, Ca, Sr, and Zr. In some embodiments, any one or more of the above elements for M2 is/are excluded or present independently or in sum in a trace amount. In some embodiments, M2 is not present (i.e., when v is 0).
The variable M3 represents at least one element (or at least two or more elements) selected from Ti, Cr, Mn, Ni, Cu, Zn, Zr, Nb, Mo, W, Ta, and Hf. In a first embodiment, M3 is or includes Ti. In a second embodiment, M3 is or includes Cr. In a third embodiment, M3 is or includes Mn. In a fourth embodiment, M3 is or includes Ni. In a fifth embodiment, M3 is or includes Cu. In a sixth embodiment, M3 is or includes Zn. In a seventh embodiment, M3 is or includes Zr. In an eighth embodiment, M3 is or includes Nb. In a ninth embodiment, M3 is or includes Mo. In a tenth embodiment, M3 is or includes W. In an eleventh embodiment, M3 is or includes Ta. In a twelfth embodiment, M3 is or includes Hf. In other embodiments, any two or more of the above first through twelfth embodiments are combined. In some embodiments, any one or more of the above elements for M3 is/are excluded or present independently or in sum in a trace amount. In some embodiments, M3 is not present (i.e., when z is 0).
The variable x represents the stoichiometric (molar) amount of M1, i.e., at least one lanthanide other than cerium, present in the magnetic composition. In different embodiments, x can be, for example, 0, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, or 0.95, or x may have a value within a range bounded by any two of the foregoing values. Any of the foregoing values may be combined to form a range in which one of the values represents a lower bound (minimum) and the other value represents an upper bound (maximum) for x, wherein the lower or upper bound value may be included or excluded from the range. As an example, x having a lower bound of at least 0.25 and an upper bound of up to 0.75 is expressed as 0.25≤x≤0.75, while x having a lower bound of at least 0.25 and an upper bound of less than 0.75 is expressed as 0.25≤x<0.75, while x having a lower bound above 0.25 and an upper bound of up to 0.75 is expressed as 0.25<x≤0.75, while x having a lower bound above 0.25 and an upper bound of less than 0.75 is expressed as 0.25<x<0.75.
A number of exemplary ranges for x in which x has an upper bound less than 1 are provided as follows: 0≤x<1, 0≤x<1, 0.1≤x<1, 0.1≤x<1, 0.15≤x<1, 0.15≤x<1, 0.2≤x<1, 0.2≤x<1, 0.25≤x<1, 0.25≤x<1, 0.3≤x<1, 0.3≤x<1, 0.35≤x<1, 0.35≤x<1, 0.4≤x<1, 0.4≤x<1, 0.45≤x<1, 0.45≤x<1, 0.5≤x<1, 0.5≤x<1, 0.55 x<1, 0.55≤x<1, 0.6 x<1, 0.6≤x<1, 0.65 x<1, 0.65≤x<1, 0.7 x<1, 0.7<x<1, 0.75≤x<1, 0.75≤x<1, 0.8≤x<1, 0.8≤x<1, 0.85≤x<1, 0.85<x<1, 0.9≤x<1, 0.9≤x<1, 0.95≤x<1, and 0.95<x<1.
A number of exemplary ranges for x in which x has an upper bound of up to or less than 0.8 are provided as follows: 0≤x<0.8, 0≤x<0.8, 0≤x≤0.8, 0≤x≤0.8, 0.1≤x<0.8, 0.1<x≤0.8, 0.1≤x≤0.8, 0.1≤x≤0.8, 0.15≤x≤0.8, 0.15≤x≤0.8, 0.15≤x≤0.8, 0.15≤x≤0.8, 0.2≤x≤0.8, 0.2≤x≤0.8, 0.2≤x≤0.8, 0.2≤x≤0.8, 0.25≤x≤0.8, 0.25<x≤0.8, 0.25≤x≤0.8, 0.25≤x≤0.8, 0.3≤x≤0.8, 0.3≤x≤0.8, 0.3≤x≤0.8, 0.3≤x≤0.8, 0.35≤x≤0.8, 0.35<x≤0.8, 0.35≤x≤0.8, 0.35≤x≤0.8, 0.4≤x≤0.8, 0.4<x≤0.8, 0.4≤x≤0.8, 0.4≤x≤0.8, 0.45≤x≤0.8, 0.45≤x≤0.8, 0.45≤x≤0.8, 0.45≤x≤0.8, 0.5≤x≤0.8, 0.5≤x≤0.8, 0.5≤x≤0.8, 0.5<x≤0.8, 0.55≤x≤0.8, 0.55≤x≤0.8, 0.55≤x≤0.8, 0.55≤x≤0.8, 0.6≤x≤0.8, 0.6<x<0.8, 0.6≤x≤0.8, 0.6<x≤0.8, 0.65≤x≤0.8, 0.65<x<0.8, 0.65≤x≤0.8, and 0.65<x≤0.8.
A number of exemplary ranges for x in which x has an upper bound of up to or less than 0.6 are provided as follows: 0≤x<0.6, 0≤x<0.6, 0≤x≤0.6, 0<x≤0.6, 0.1≤x<0.6, 0.1<x<0.6, 0.1≤x≤0.6, 0.1≤x≤0.6, 0.15≤x≤0.6, 0.15≤x≤0.6, 0.15≤x≤0.6, 0.15≤x≤0.6, 0.2≤x≤0.6, 0.2≤x≤0.6, 0.2≤x≤0.6, 0.2≤x≤0.6, 0.25≤x≤0.6, 0.25<x<0.6, 0.25≤x≤0.6, 0.25≤x≤0.6, 0.3≤x≤0.6, 0.3≤x≤0.6, 0.3≤x≤0.6, 0.3<x≤0.6, 0.35≤x≤0.6, 0.35<x≤0.6, 0.35≤x≤0.6, 0.35≤x≤0.6, 0.4≤x≤0.6, 0.4<x<0.6, 0.4≤x≤0.6, and 0.4<x≤0.6.
A number of exemplary ranges for x in which x has an upper bound of up to or less than 0.5 are provided as follows: 0≤x<0.5, 0≤x<0.5, 0≤x≤0.5, 0<x≤0.5, 0.1 x<0.5, 0.1<x<0.5, 0.1≤x≤0.5, 0.1≤x≤0.5, 0.15≤x≤0.5, 0.15≤x≤0.5, 0.15≤x≤0.5, 0.15<x≤0.5, 0.2≤x≤0.5, 0.2≤x≤0.5, 0.2≤x≤0.5, 0.2≤x≤0.5, 0.25≤x≤0.5, 0.25<x<0.5, 0.25≤x≤0.5, 0.25≤x≤0.5, 0.3≤x≤0.5, 0.3≤x≤0.5, 0.3≤x≤0.5, 0.3<x≤0.5, 0.35≤x<0.5, 0.35<x<0.5, 0.35≤x<0.5, 0.35≤x≤0.5, 0.4≤x<0.5, 0.4<x<0.5, 0.4≤x≤0.5, and 0.4<x≤0.5.
A number of exemplary ranges for x in which x has an upper bound of up to or less than 0.3 are provided as follows: 0≤x<0.3, 0<x<0.3, 0≤x≤0.3, 0≤x≤0.3, 0.1≤x<0.3, 0.1<x≤0.3, 0.1≤x≤0.3, 0.1≤x≤0.3, 0.15≤x<0.3, 0.15<x<0.3, 0.15≤x≤0.3, and 0.15<x≤0.3.
The variable y represents the stoichiometric (molar) amount of cobalt present in the magnetic composition. In different embodiments, y can be, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.5 1.8, 2, 2.2, 2.5, 2.8, or 3, or y may have a value within a range bounded by any two of the foregoing values.
A number of exemplary ranges for y in which y has an upper bound of up to or less than 3 are provided as follows: 0≤y≤3, 0≤y≤3, 0≤y≤3, 0≤y≤3, 0.1≤y≤3, 0.1<y≤3, 0.1≤y≤3, 0.1<y<3, 0.2≤y≤3, 0.2≤y≤3, 0.2≤y≤2, 0.2≤y≤3, 0.3≤y≤3, 0.3≤y≤3, 0.3≤y≤3, 0.3≤y≤3, 0.4≤y≤3, 0.4≤y≤3, 0.4≤y≤3, 0.4≤y≤3, 0.5≤y≤3, 0.5≤y≤3, 0.5≤y≤3, 0.5≤y≤3, 0.6≤y≤3, 0.6≤y≤3, 0.6≤y≤3, 0.6≤y≤3, 0.7≤y≤3, 0.7≤y≤3, 0.7≤y≤3, 0.7≤y≤3, 0.8≤y≤3, 0.8≤y≤3, 0.8≤y≤3, 0.8≤y≤3, 0.9≤y≤3, 0.9≤y≤3, 0.9≤y≤3, 0.9≤y≤3, 1≤y≤3, 1≤y≤3, 1≤y≤3, 1≤y≤3, 1.2≤y≤3, 0.21y≤3, 0.21y≤3, 0.21y≤3, 0.5≤y≤3≤1.5≤y≤3≤1.5≤y≤3, 1.5≤y≤3, 1.8≤y≤3, 1.8≤y≤3, 1.8≤y≤3, 1.8≤y≤3, 2≤y≤3, 2≤y≤3, 2≤y≤3, 2<y<3, 2.2≤y≤3, 2.2≤y≤3, 2.2≤y≤3, 2.2≤y<3, 2.5≤y≤3, 2.5<y≤3, 2.5≤y<3, 2.5<y<3, 2.8≤y≤3, 2.8<y≤3, 2.8≤y<3, and 2.8<y<3. Moreover, any of the ranges or specific values provided above for y can be combined with any of the ranges or specific values provided earlier above for x.
A number of exemplary ranges for y in which y has an upper bound of up to or less than 2 are provided as follows: 0≤y≤2, 0≤y≤2, 0≤y≤2, 0≤y≤2, 0.1≤y≤2, 0.1<y≤2, 0.1≤y<2, 0.1<y<2, 0.2≤y≤2, 0.2≤y≤2, 0.2≤y≤2, 0.2≤y≤2, 0.3≤y≤2, 0.3≤y≤2, 0.3≤y≤2, 0.3≤y≤2, 0.4≤y≤2, 0.4≤y≤2, 0.4≤y≤2, 0.4≤y≤2, 0.5≤y≤2, 0.5≤y≤2, 0.5≤y≤2, 0.5≤y≤2, 0.6≤y≤2, 0.6≤y≤2, 0.6≤y≤2, 0.6≤y≤2, 0.7≤y≤2, 0.7≤y≤2, 0.7≤y≤2, 0.7≤y≤2, 0.8≤y≤2, 0.8≤y≤2, 0.8≤y≤2, 0.8≤y≤2, 0.9≤y≤2, 0.9<y≤2, 0.9≤y≤2, 0.9≤y≤2, 1≤y≤2, 1≤y≤2, 1≤y≤2, 1<y<2, 1.2≤y≤2, 1.2≤y≤2, 1.2≤y<2, 1.2≤y≤2, 1.5≤y≤2, 1.5≤y≤2, 1.5≤y≤2, 1.5<y<2, 1.8≤y≤2, 1.8<y≤2, 1.8≤y<2, and 1.8<y<2. Moreover, any of the ranges or specific values provided above for y can be combined with any of the ranges or specific values provided earlier above for x.
A number of exemplary ranges for y in which y has an upper bound of up to or less than 1 are provided as follows: 0≤y≤1, 0≤y≤1, 0≤y≤1, 0≤y≤1, 0.1≤y≤1, 0.1<y≤1, 0.1≤y≤1, 0.1≤y≤1, 0.2≤y≤1, 0.2≤y≤1, 0.2≤y≤1, 0.2≤y≤1, 0.3≤y≤1, 0.3≤y≤1, 0.3≤y≤1, 0.3≤y≤1, 0.4y≤1, 0.4≤y≤1, 0.4≤y≤1, 0.4≤y≤1, 0.5≤y≤1, 0.5≤y≤1, 0.5≤y≤1, 0.5≤y≤1, 0.6≤y≤1, 0.6≤y≤1, 0.6≤y≤1, 0.6≤y≤1, 0.7≤y≤1, 0.7≤y≤1, 0.7<y≤1, 0.7<y<1, 0.8≤y≤1, 0.8<y≤1, 0.8≤y<1, and 0.8<y<1. Moreover, any of the ranges or specific values provided above for y can be combined with any of the ranges or specific values provided earlier above for x.
The variable v represents the stoichiometric (molar) amount of M2, i.e., at least one element selected from Sn, Sb, Bi, Pb, Ca, Sr, and Zr, present in the magnetic composition. In different embodiments, v can be, for example, 0, 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1, or v may have a value within a range bounded by any two of the foregoing values.
A number of exemplary ranges for v in which v has an upper bound of up to or less than 1 are provided as follows: 0≤v≤1, 0≤v≤1, 0≤v≤1, 0≤v≤1, 0.01≤v≤1, 0.01≤v≤1, 0.01≤v≤1, 0.01≤v≤1, 0.1≤v≤1, 0.1≤v≤1, 0.1≤v≤1, 0.1≤v≤1, 0.2≤v≤1, 0.2≤v≤1, 0.2≤v≤1, 0.2≤v≤1, 0.3≤v≤1, 0.3≤v≤1, 0.3≤v≤1, 0.3≤v≤1, 0.4≤v≤1, 0.4≤v≤1, 0.4≤v≤1, 0.4≤v≤1, 0.5≤v≤1, 0.5≤v≤1, 0.5≤5 v≤1, 0.5<v<1, 0≤v≤10.6≤v≤1, 0.6 v≤1, 0.6≤v≤1, 0.7≤v≤1, 0.7≤v≤1, 0.7≤v≤1, 0.7<v<1, 0.8≤v≤1, 0.8<v≤1, 0.8≤v≤1, 0.8≤v≤1, 0.9≤v≤1, 0.9≤v≤1, and 0.9≤v<1. Moreover, any of the ranges or specific values provided above for v can be combined with any of the ranges or specific values provided earlier above for x and y.
A number of exemplary ranges for v in which v has an upper bound of up to or less than 0.8 are provided as follows: 0≤v≤0.8, 0≤v≤0.8, 0≤v≤0.8, 0≤v≤0.8, 0.01≤v≤0.8, 0.01≤v≤0.8, 0.01≤y≤0.8, 0.01≤v≤0.8, 0.1≤v≤0.8, 0.1≤v≤0.8, 0.1≤0.8, 0.1<v≤0.8, 0.2≤v≤0.8, 0.2≤v≤0.8, 0.2≤v≤0.8, 0.2≤v≤0.8, 0.3≤v≤0.8, 0.3<v≤0.8, 0.3≤v≤0.8, 0.3<v≤0.8, 0.4≤v≤0.8, 0.4≤v≤0.8, 0.4≤y≤0.8, 0.4≤v≤0.8, 0.5≤v≤0.8, 0.5≤v≤0.8, 0.5 v≤0.8, 0.5≤v≤0.8, 0.6≤v≤0.8, 0.6<v≤0.8, 0.6≤v<0.8, and 0.6<v<0.8. Moreover, any of the ranges or specific values provided above for v can be combined with any of the ranges or specific values provided earlier above for x and y.
A number of exemplary ranges for v in which v has an upper bound of up to or less than 0.5 are provided as follows: 0≤v≤0.5, 0≤v≤0.5, 0≤v<0.5, 0≤v≤0.5, 0.01≤v≤0.5, 0.01<v<0.5, 0.01≤v≤0.5, 0.01≤v≤0.5, 0.1≤v≤0.5, 0.1<v≤0.5, 0.1≤v≤0.5, 0.1<v<0.5, 0.2≤v≤0.5, 0.2≤v≤0.5, 0.2≤v≤0.5, 0.2≤v≤0.5, 0.3≤v≤0.5, 0.3<v≤0.5, 0.3≤v<0.5, and 0.3<v<0.5. Moreover, any of the ranges or specific values provided above for v can be combined with any of the ranges or specific values provided earlier above for x and y.
A number of exemplary ranges for v in which v has an upper bound of up to or less than 0.4 are provided as follows: 0≤v≤0.4, 0≤v≤0.4, 0≤v≤0.4, 0≤v≤0.4, 0.01≤v≤0.4, 0.01<v≤0.4, 0.01≤v≤0.4, 0.01≤v≤0.4, 0.1≤v≤0.4, 0.1≤v≤0.4, 0.1≤v≤0.4, 0.1≤v≤0.4, 0.2≤v≤0.4, 0.2≤v≤0.4, 0.2≤v≤0.4, 0.2≤v≤0.4, 0.3≤y≤0.4, 0.3<v≤0.4, 0.3≤v≤0.4, and 0.3<v<0.4. Moreover, any of the ranges or specific values provided above for v can be combined with any of the ranges or specific values provided earlier above for x and y.
A number of exemplary ranges for v in which v has an upper bound of up to or less than 0.3 are provided as follows: 0≤v≤0.3, 0<v≤0.3, 0≤v≤0.3, 0≤v≤0.3, 0.01≤v≤0.3, 0.01<v≤0.3, 0.01≤v≤0.3, 0.01≤v≤0.3, 0.1≤v≤0.3, 0.1≤v≤0.3, 0.1≤v<0.3, 0.1<v<0.3, 0.2≤v≤0.3, 0.2<v≤0.3, 0.2 v<0.3, and 0.2<v<0.3. Moreover, any of the ranges or specific values provided above for v can be combined with any of the ranges or specific values provided earlier above for x and y.
A number of exemplary ranges for v in which v has an upper bound of up to or less than 0.2 are provided as follows: 0≤v≤0.2, 0<v≤0.2, 0≤v≤0.2, 0<v<0.2, 0.01≤v≤0.2, 0.01<v≤0.2, 0.01≤v≤0.2, 0.01≤v≤0.2, 0.1≤y≤0.2, 0.1<v≤0.2, 0.1≤v≤0.2, and 0.1<v<0.2. Moreover, any of the ranges or specific values provided above for v can be combined with any of the ranges or specific values provided earlier above for x and y.
The variable z represents the stoichiometric (molar) amount of M3, i.e., at least one element selected from Ti, Cr, Mn, Ni, Cu, Zn, Zr, Nb, Mo, W, Ta, and Hf, present in the magnetic composition. In different embodiments, z can be, for example, 0, 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1, or z may have a value within a range bounded by any two of the foregoing values.
A number of exemplary ranges for z in which z has an upper bound of up to or less than 1 are provided as follows: 0≤z≤1, 0≤z<1, 0<z<1, 0≤z≤1, 0.01≤z≤1, 0.01<z≤1, 0.01≤z≤1, 0.01≤z≤1, 0.1≤z≤1, 0.1≤z≤1, 0.1≤z≤1, 0.1≤z≤1, 0.2≤z≤1, 0.2<z≤1, 0.2≤z≤1, 0.2≤z≤1, 0.3≤z≤1, 0.3≤z≤1, 0.3≤z≤1, 0.3≤z≤1, 0.4≤z≤1, 0.4≤z≤1, 0.4≤z≤1, 0.4<z<1, 0.5≤z≤1, 0.5≤z≤1, 0.5≤z≤1, 0.5≤z≤1, 0.6≤z≤51, 0.6≤z≤51, 0.6≤5z≤1, 0.6≤z≤1, 0.7≤5z≤51, 0.7≤z≤51, 0.7≤5z≤1, 0.7<z<1, 0.8≤z≤1, 0.8≤z≤1, 0.8≤z≤1, 0.8≤z≤1, 0.9≤z≤1, 0.9≤z≤1, and 0.9≤z<1. Moreover, any of the ranges or specific values provided above for z can be combined with any of the ranges or specific values provided earlier above for x, y, and v.
A number of exemplary ranges for z in which z has an upper bound of up to or less than 0.8 are provided as follows: 0≤z≤0.8, 0≤z≤0.8, 0≤z≤0.8, 0≤z≤0.8, 0.01≤z≤0.8, 0.01<z≤0.8, 0.01≤z≤0.8, 0.01≤z≤0.8, 0.1≤z≤0.8, 0.1≤z≤0.8, 0.1≤z<0.8, 0.1<z<0.8, 0.2≤z≤0.8, 0.2≤z≤0.8, 0.2≤z≤0.8, 0.2≤z≤0.8, 0.3≤z≤0.8, 0.3≤z≤0.8, 0.3≤z<0.8, 0.3<z<0.8, 0.4≤z≤0.8, 0.4≤z≤0.8, 0.4≤z≤0.8, 0.4≤z≤0.8, 0.5≤z≤0.8, 0.5≤z≤0.8, 0.5≤z≤0.8, 0.5≤z≤0.8, 0.6≤z≤0.8, 0.6≤z≤0.8, 0.6≤z<0.8, and 0.6<z<0.8. Moreover, any of the ranges or specific values provided above for z can be combined with any of the ranges or specific values provided earlier above for x, y, and v.
A number of exemplary ranges for z in which z has an upper bound of up to or less than 0.5 are provided as follows: 0≤z≤0.5, 0≤z≤0.5, 0≤z≤0.5, 0<z≤0.5, 0.01≤z≤0.5, 0.01<z≤0.5, 0.01≤z<0.5, 0.01≤z≤0.5, 0.1≤z≤0.5, 0.1<z≤0.5, 0.1≤z<0.5, 0.1<z<0.5, 0.2≤z≤0.5, 0.2≤z≤0.5, 0.2≤z≤0.5, 0.2≤z≤0.5, 0.3≤z≤0.5, 0.3<z≤0.5, 0.3≤z<0.5, and 0.3<z<0.5. Moreover, any of the ranges or specific values provided above for z can be combined with any of the ranges or specific values provided earlier above for x, y, and v.
A number of exemplary ranges for z in which z has an upper bound of up to or less than 0.4 are provided as follows: 0≤z≤0.4, 0≤z≤0.4, 0≤z≤0.4, 0≤z≤0.4, 0.01≤z≤0.4, 0.01<z≤0.4, 0.01≤z≤0.4, 0.01<z<0.4, 0.1≤z≤0.4, 0.1<z≤0.4, 0.1≤z<0.4, 0.1<z<0.4, 0.2≤z≤0.4, 0.2≤z≤0.4, 0.2≤z<0.4, 0.2≤z≤0.4, 0.3≤z≤0.4, 0.3<z≤0.4, 0.3≤z<0.4, and 0.3<z<0.4. Moreover, any of the ranges or specific values provided above for z can be combined with any of the ranges or specific values provided earlier above for x, y, and v.
A number of exemplary ranges for z in which z has an upper bound of up to or less than 0.3 are provided as follows: 0≤z≤0.3, 0≤z≤0.3, 0≤z≤0.3, 0≤z≤0.3, 0.01≤z≤0.3, 0.01≤z≤0.3, 0.01≤z≤0.3, 0.01≤z≤0.3, 0.1≤z≤0.3, 0.1≤z≤0.3, 0.1≤z<0.3, 0.1<z<0.3, 02z≤03.2≤z≤0.3, 0.2 z<0.3, and 0.2<z<0.3. Moreover, any of the ranges or specific values provided above for z can be combined with any of the ranges or specific values provided earlier above for x, y, and v.
A number of exemplary ranges for z in which z has an upper bound of up to or less than 0.2 are provided as follows: 0≤z≤0.2, 0z≤0.2, 0 z≤0.2, 0<z<0.2, 0.01≤z≤0.2, 0.01<z≤0.2, 0.01≤z≤0.2, 0.01≤z≤0.2, 0.1≤z≤0.2, 0.1≤z≤0.2, 0.1≤z<0.2, and 0.1<z<0.2. Moreover, any of the ranges or specific values provided above for z can be combined with any of the ranges or specific values provided earlier above for x, y, and v.
A number of exemplary ranges for z in which z has an upper bound of up to or less than 0.1 are provided as follows: 0≤z≤0.1, 0≤z≤0.1, 0≤z≤0.1, 0≤z≤0.1, 0.01≤z≤0.1, 0.01<z≤0.1, 0.01≤z≤0.1, 0.01≤z≤0.1, 0.05≤z≤0.1, 0.05≤z≤0.1, 0.05≤z<0.1, and 0.05<z<0.1. Moreover, any of the ranges or specific values provided above for z can be combined with any of the ranges or specific values provided earlier above for x, y, and v.
The variable w adds to the value of v, thereby serving as a possible adjustment in the amount of lanthanide present in the magnetic composition. In different embodiments, w can be, for example, 0, 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8, or w may have a value within a range bounded by any two of the foregoing values.
A number of exemplary ranges for w in which w has an upper bound of up to or less than 0.8 are provided as follows: 0≤w≤0.8, 0≤w≤0.8, 0≤w≤0.8, 0<w<0.8, 0.01≤w≤0.8, 0.01<w≤0.8, 0.01≤w<0.8, 0.01<w<0.8, 0.1≤w≤0.8, 0.1≤w≤0.8, 0.1≤w<0.8, 0.1<w<0.8, 0.2≤w≤0.8, 0.2≤w≤0.8, 0.2≤w≤0.8, 0.2<w≤0.8, 0.3≤w≤0.8, 0.3≤w≤0.8, 0.3≤w≤0.8, 0.3≤w≤0.8, 0.4≤w≤0.8, 0.4≤w≤0.8, 0.4≤w<0.8, 0.4<w<0.8, 0.5≤w≤0.8, 0.5<w≤0.8, 0.5≤w≤0.8, 0.5≤w<0.8, 0.6≤w≤0.8, 0.6<w≤0.8, 0.6≤w<0.8, and 0.6<w<0.8. Moreover, any of the ranges or specific values provided above for w can be combined with any of the ranges or specific values provided earlier above for x, y, v, and z.
A number of exemplary ranges for w in which w has an upper bound of up to or less than 0.5 are provided as follows: 0≤w≤0.5, 0≤w≤0.5, 0≤w<0.5, 0≤w≤0.5, 0.01≤w≤0.5, 0.01≤w≤0.5, 0.01≤w<0.5, 0.01≤w<0.5, 0.1≤w≤0.5, 0.1<w≤0.5, 0.1≤w<0.5, 0.1≤w<0.5, 0.2≤w≤0.5, 0.2≤w≤0.5, 0.2≤w≤0.5, 0.2≤w≤0.5, 0.3≤w≤0.5, 0.3<w≤0.5, 0.3≤w<0.5, and 0.3<w<0.5. Moreover, any of the ranges or specific values provided above for w can be combined with any of the ranges or specific values provided earlier above for x, y, v, and z.
A number of exemplary ranges for w in which w has an upper bound of up to or less than 0.4 are provided as follows: 0≤w≤0.4, 0≤w≤0.4, 0≤w≤0.4, 0≤w≤0.4, 0.01≤w≤0.4, 0.01≤w≤0.4, 0.01≤w≤0.4, 0.01≤w≤0.4, 0.1≤w≤0.4, 0.1<w≤0.4, 0.1≤w<0.4, 0.1<w<0.4, 0.2≤w≤0.4, 0.2<w≤0.4, 0.2≤w≤0.4, 0.2<w<0.4, 0.3≤w≤0.4, 0.3<w≤0.4, 0.3≤w<0.4, and 0.3<w<0.4. Moreover, any of the ranges or specific values provided above for w can be combined with any of the ranges or specific values provided earlier above for x, y, v, and z.
A number of exemplary ranges for w in which w has an upper bound of up to or less than 0.3 are provided as follows: 0≤w≤0.3, 0<w≤0.3, 0≤w≤0.3, 0<w<0.3, 0.01≤w≤0.3, 0.01<w≤0.3, 0.01≤w<0.3, 0.01<w<0.3, 0.1≤w≤0.3, 0.1<w≤0.3, 0.1≤w<0.3, 0.1<w<0.3, 0.2≤w≤0.3, 0.2<w≤0.3, 0.2≤w<0.3, and 0.2<w<0.3. Moreover, any of the ranges or specific values provided above for w can be combined with any of the ranges or specific values provided earlier above for x, y, v, and z.
A number of exemplary ranges for w in which w has an upper bound of up to or less than 0.2 are provided as follows: 0≤w≤0.2, 0<w≤0.2, 0≤w<0.2, 0<w<0.2, 0.01≤w≤0.2, 0.01<w≤0.2, 0.01≤w≤0.2, 0.01≤w≤0.2, 0.1≤w≤0.2, 0.1<w≤0.2, 0.1≤w<0.2, and 0.1<w<0.2. Moreover, any of the ranges or specific values provided above for w can be combined with any of the ranges or specific values provided earlier above for x, y, v, and z.
A number of exemplary ranges for w in which w has an upper bound of up to or less than 0.1 are provided as follows: 0≤w≤0.1, 0<w≤0.1, 0≤w≤0.1, 0<w<0.1, 0.01≤w≤0.1, 0.01≤w≤0.1, 0.01≤w≤0.1, 0.01<w<0.1, 0.05≤w≤0.1, 0.05<w≤0.1, 0.05≤w<0.1, and 0.05<w<0.1. Moreover, any of the ranges or specific values provided above for w can be combined with any of the ranges or specific values provided earlier above for x, y, v, and z.
In some embodiments of Formula (1), x is 0, which results in Formula (1) having the following formula: Ce2.7-(v+w)M2v(Fe14-yCoy)1-zM3zB, or alternatively, Ce2-vM2v(Fe14-yCoy)1-zM3zB. In further embodiments, v is 0, which may result in the following formula: Ce2.7-w(Fe14-yCoy)1-zM3zB, or alternatively, Ce2(Fe14-yCoy)1-zM3zB. Alternatively, v may be 1, which may result in any of the following formulas: Ce2.7-(v+w)M2(Fe14-y Coy)1-zM3zB, or alternatively, CeM2(Fe14-yCoy)1-zM3zB. Alternatively, y may be 0, which may result in any of the following formulas: Ce2.7-(v+w)M2v(Fe14)1-zM3zB, or alternatively, Ce2-vM2v(Fe14)1-zM3zB, Ce2.7-w(Fe14)1-zM3zB, or Ce2(Fe14)1-zM3zB. Alternatively, w may be 0, which may result in any of the following formulas: Ce2.7-vM2v(Fe14-y Coy)1-zM3zB, Ce2.7(Fe14-yCoy)1-zM3zB, or Ce2.7(Fe14)1-zM3zB. Alternatively, z may be 0, which may result in any of the following formulas: Ce2.7-(v+w)M2v(Fe14-yCoy)B, or alternatively, Ce2-vM2v(Fe14-yCoy)B, Ce2.7-w(Fe14-yCoy)B, Ce2(Fe14-yCoy)B, Ce2.7-(v+w)M2v(Fe14)B, Ce2-wM2vFe14B, Ce2.7-wFe14B, Ce2Fe14B, Ce2.7-vM2v(Fe14-yCoy)B, Ce2.7(Fe14-yCoy)B, or Ce2.7Fe14B. Alternatively, z may be 1, which may result in any of the following formulas: Ce2.7-wM3B, or alternatively, Ce2M3B, Ce2.7-(1+w)M2M3B, CeM2M3B, Ce2.7-(v+w)M2vM3B, Ce2-wM2vM3B, Ce2.7-wM3B, Ce2.7-VM2vM3B, or Ce2.7M3B.
In embodiments of Formula (1), v is 0, which results in Formula (1) having the following formula: (Ce1-xM1x)2.7-wM2v(Fe14-yCoy)1-zM3zB, or alternatively, (Ce1-xM1x)2(Fe14-y Coy)1-zM3zB. In further embodiments, x is 0, which results in the following formulas: Ce2.7-wM2v(Fe14-yCoy)1-zM3zB, or alternatively, Ce2(Fe14-yCoy)1-zM3zB. In other embodiments, y is 0, which results in the following formulas: (Ce1-xM1x)2.7-wM2v(Fe14)1-zM3zB, or alternatively, (Ce1-xM1x)2(Fe14)1-zM3zB, Ce2.7-wM2v(Fe14)1-zM3zB, or Ce2(Fe14)1-zM3zB. In other embodiments, w is 0, which results in the following formulas: (Ce1-xM1x)2.7M2v(Fe14-yCoy)1-zM3zB, Ce2.7M2v(Fe14-yCoy)1-zM3zB, (Ce1-xM1x)2.7M2(Fe14)1-zM3zB, or Ce2.7M2v(Fe14)1-zM3zB. In other embodiments, z is 0, which results in the following formulas: (Ce1-xM1x)2.7-wM2(Fe14-yCoy)B, (Ce1-xM1x)2(Fe14-yCoy)B, Ce2.7-wM2v(Fe14-yCoy)B, Ce2(Fe14-yCoy)B, (Ce1-xM1x)2.7-wM2vFe14B, (Ce1-xM1x)2Fe14B, Ce2.7-wM2vFe14B, (Ce1-xM1x)2.7M2v(Fe14-yCoy)B, Ce2.7M2v(Fe14-yCoy)B, (Ce1-xM1x)2.7M2Fe14B, or Ce2.7M2vFe14B.
In other embodiments of Formula (1), v is 1, which results in Formula (1) having the following formula: (Ce1-xM1x)2.7-(1+w)M2(Fe14-yCoy)1-zM3zB, or alternatively, (Ce1-xM1x)2M2(Fe14-yCoy)1-zM3zB. In further embodiments, x is 0, which results in the following formulas: Ce2.7-(1+w)M2(Fe14-yCoy)1-zM3zB, or alternatively, Ce2M2(Fe14-yCoy)1-zM3zB. In other embodiments, y is 0, which results in the following formulas: (Ce1-xM1x)2.7-(1+w)M2(Fe14)1-zM3zB, or alternatively, (Ce1-xM1x)2M2(Fe14)1-zM3zB, Ce2.7-(1+w)M2(Fe14)1-z M3zB, or Ce2M2(Fe14)1-zM3zB. In other embodiments, w is 0, which results in the following formulas: (Ce1-xM1x)1.7M2(Fe14-yCoy)1-zM3zB, Ce1.7M2(Fe14-yCoy)1-zM3zB, (Ce1-xM1x)1.7M2(Fe14)1-zM3zB, or Ce1.7M2(Fe14)1-zM3zB. In other embodiments, z is 0, which results in the following formulas: (Ce1-xM1x)2.7-(1+w)M2(Fe14-yCoy)B, (Ce1-xM1x)2M2(Fe14-y Coy)B, Ce2.7-(1+w)M2(Fe14-yCoy)B, Ce2M2(Fe14-yCoy)B, (Ce1-xM1x)2.7-(1+w)M2Fe14B, (Ce1-xM1x)2M2Fe14B, Ce2.7-(1+w)M2Fe14B, Ce2M2Fe14B, (Ce1-xM1x)1.7M2Fe14-yCoyB, Ce1.7M2Fe14-y CoyB, (Ce1-xM1x)1.7M2Fe14B, or Ce1.7M2Fe14B.
In embodiments of Formula (1), y is 0, which results in Formula (1) having the following formula: (Ce1-xM1x)2.7-(v+w)M2v(Fe14)1-zM3zB, or alternatively, (Ce1-xM1x)2-v M2v(Fe14)1-zM3zB. In further embodiments, x is 0, which results in the following formulas: (Ce)2.7-(v+w)M2v(Fe14)1-zM3zB, or alternatively, (Ce)2-vM2v(Fe14)1-zM3zB. In other embodiments, w is 0, which results in the following formulas: (Ce1-xM1x)2.7-vM2v(Fe14)1-zM3zB or (Ce)2.7-vM2v(Fe14)1-zM3zB. In other embodiments, z is 0, which results in the following formulas: (Ce1-xM1x)2.7-(v+w)M2vFe14B, (Ce1-xM1x)2-vM2vFe14B, (Ce)2.7-(v+w)M2vFe14B, (Ce)2-vM2vFe14B, (Ce1-xM1x)2.7-vM2vFe14B, or (Ce)2.7-vM2vFe14B.
In embodiments of Formula (1), z is 0, which results in Formula (1) having the following formula: (Ce1-xM1x)2.7-(v+w)M2(Fe14-yCoy)B, or alternatively, (Ce1-xM1x)2-vM2v(Fe14-yCoy)B. In further embodiments, x is 0, which results in the following formulas: (Ce)2.7-(v+w)M2v(Fe14-yCoy)B, or alternatively, (Ce)2-vM2v(Fe14-yCoy)B. In other embodiments, w is 0, which results in the following formulas: (Ce1-xM1x)2.7-vM2v(Fe14-y Coy)B or (Ce)2.7-vM2v(Fe14-yCoy)B. In other embodiments, y is 0, which results in the following formulas: (Ce1-xM1x)2.7-(v+w)M2vFe14B, (Ce1-xM1x)2-vM2vFe14B, (Ce)2.7-(v+w)-M2vFe14B, (Ce)2-vM2vFe14B, (Ce1-xM1x)2.7-vM2vFe14B, or (Ce)2.7-vM2vFe14B.
In embodiments of Formula (1), z is 1, which results in Formula (1) having the following formula: (Ce1-xM1x)2.7-(v+w)M2vM3B, or alternatively, (Ce1-xM1x)2-vM2vM3B. In further embodiments, x is 0, which results in the following formulas: (Ce)2.7-(v+w)M2vM3B, or alternatively, (Ce)2-vM2vM3B. In other embodiments, w is 0, which results in the following formulas: (Ce1-xM1x)2.7-vM2vM3B or (Ce)2.7-vM2vM3B.
Notably, any of the various and alternative formulas provided in this application may have x, y, z, v, and w variables independently selected from among any of the ranges or specific values provided anywhere in this application.
In further particular embodiments, the magnetic composition may have one of following formulas: Ce2-xLax(Fe14-yCoy)1-zM3zB, or more particularly Ce2-xLaxFe14-yCoyB, preferably wherein 0≤x≤2, 0≤y≤3, and 0≤z≤1. In other particular embodiments, the magnetic composition may have one of the following formulas: Ce2-xZrx(Fe14-yCoy)1-zM3zB, Ce2-xZrx(Fe14-yCoy)B, Ce2-xZrxFe12Co2B, or Ce2-xZrx(Fe12Co2)1-zM3zB. In other particular embodiments, the magnetic composition may have one of the following formulas: (Ce1-xXx)2(Fe14-yCoy)1-zM3zB, or more particularly, (Ce1-xXx)2(Fe14-yCoy)B, or more particularly, (Ce1-xXx)2Fe14B, or more particularly, (Ce0.75X0.25)2Fe14B or (Ce0.5Bi0.5)2Fe14B (X=Sn, Sb, Pb, Bi, La or Zr or more particularly X=Sn, Sb and Bi) and 0≤x<1, or any of the particular x values provided anywhere else in this disclosure. In other particular embodiments, the magnetic composition may have one of the following formulas: LaCeFe12.7Co1.3B, (La0.5Ce0.5)1.9Zr0.1Fe12Co2B, or Ce2Fe12.7Co1.3B. All variables x, y, and z in any of the above formulas can independently be any of the ranges or specific values provided anywhere in this application.
The permanent magnet may, in some embodiments, be denoted as a bulk or macroscopic object, which is larger than a microscopic or nanoscopic object. The permanent magnet considered herein typically has a size of at least 1 millimeter (mm) for at least one of the dimensions of the permanent magnet. In some embodiments, the permanent magnet may have a size of at least 1 centimeter (cm) for at least one of its dimensions. In other embodiments, the permanent magnet may have a size in the micron range, such as obtained by grinding a larger object of the same magnetic composition. The micron-sized magnetic object may be precisely, at least, or more than, for example, 1, 2, 5, 10, 20, 50, or 100 microns.
In some embodiments, the permanent magnet has a planar (layer) shape, generally with a thickness of up to or less than 10 mm, e.g., up to or less than 5, 4, 3, 2, or 1 mm. The magnet may, in one embodiment, have no edges or corners, such as in a smoothened disk or sphere. In other embodiments, the magnet has at least one edge and no corners, such as in an edged disk. In yet other embodiments, the magnet has at least one corner, such as in a parallelepiped, such as a cube, block, or layer shape, or other polyhedral shape.
The magnetic composition according to Formula (1) or sub-formula or alternative formula thereof may have one or more acceptable or exceptional magnetic properties. Some examples of magnetic properties include Curie point, energy product, coercivity, magnetization, and anisotropy field. The magnetic composition may exhibit a Curie point greater than 585 K, and in some embodiments, the Curie point may be at least or above 600 K, 650 K, 700 K, 725 K, or 750 K. The magnetic composition may exhibit an energy product (magnetic strength) of at least or above 5, 10, or 15 MG-Oe (where MG-Oe=Megagauss-Oersted), and in some embodiments, the energy product is at least or above 20, 25, 30, 35, 40, 45, 50, or 55 MG-Oe. The magnetic composition may exhibit a coercivity of at least or above 2, 3, 4, or 5 kOe, and in some embodiments, the coercivity may be at least or above 6, 8, 10, 12, 15, 20, 25, 30, 35, or 40 kOe. The magnetic composition may exhibit a magnetization of at least or above 0.8 or 0.9 T (where T=Tesla), and in some embodiments, the magnetization may be at least or above 1, 1.1, 1.2, 1.3, 1.4, 1.5, or 1.6 T (room temperature values). To convert T to kilogauss (kG), multiply by the foregoing values by 10. The magnetic composition may exhibit an anisotropy field of at least 0.5 or 1 T, and in some embodiments, the anisotropy field is at least or above 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 T (or 5-120 kOe).
In another aspect, the present disclosure is directed to a method for producing the above-described permanent magnet. Any of the known methods for producing alloys containing a combination of lanthanide and transition metal elements can be used for producing compositions according to Formula (1) or sub-formula or alternative formula thereof. In a typical method, stoichiometric quantities of all elements to be included in the formula are melted together (e.g., by arc-melting, vacuum melting, or plasma melting) followed by annealing the melt, typically under a low-oxygen or completely inert gas atmosphere. The inert gas may be, e.g., argon or nitrogen. The annealing step may employ a temperature of, typically, at least 700° C., 800° C., 900° C., or 1000° C., for a period of at least 24 hours, 48 hours, 72 hours, or a week.
Examples have been set forth below for the purpose of illustration and to describe certain specific embodiments of the invention. However, the scope of this invention is not to be in any way limited by the examples set forth herein.
The following experimental work examines magnetic compositions based on Ce2Fe14B with Co, La of Zr substitutions. Along with the Co substitutions on Fe, partial Zr substitution increases the impurity phase and has little effect on the Curie point and Ms. While, without the loss of anisotropy field, the substitution of La on Ce increases the Curie temperature and saturation magnetization, which may produce an estimated energy product of 48 MG-Oe. For example, LaCeFe12.7Co1.3B can function as a critical-element-free, high-performance permanent magnet. While neither La nor Zr substitution improves the magnetic anisotropy of Ce2Fe14B, first principles calculations can be used to study the origin of magnetic anisotropy in Ce2Fe14B. These findings suggest that, contrary to the prevailing view of cerium in Ce2Fe14B as non-magnetic and therefore not contributing to magnetic anisotropy, the magnetic anisotropy in Ce2Fe14B is comparably contributed by the Ce and Fe atoms, where the Ce-projected magnetic anisotropy is predominately provided by the Ce atoms in 4g site.
By providing the atom substitution on the “non-contributing” 4f-site Ce atoms (the energetically favorable site for Bi), a considerable (almost three times) promotion of magnetic anisotropy in Bi-substituted Ce2Fe14B was found while slightly increasing the already strong magnetization. These experimental results reveal the great potential of La—Co co-substitution and Bi substitution on developing Ce2Fe14B-based low-cost and critical-element-free permanent magnet.
Accordingly, in one aspect, the technologies described herein provides a magnet composition comprising Ce2-xLaxFe14-yCoyB wherein 0≤x≤2 and 0≤y≤3.
In the present work, additional elements were added to enhance properties, such as, for example, yield coercivity and a square hysteresis loop. Additions may include, for example, of up to 6 weight percent of any of the following elements, which could also be used in combination:
In another aspect, the above elements can substitute for Fe and Co. In particular aspects, the magnet composition has the formula Ce2-xLax(Fe14-yCoy)1-zAzB, where the variable A represents A1, A2 and/or A3, as shown above, and wherein 0≤x≤2 and 0≤y≤3, and 0≤z≤1. In some embodiments, the magnets described herein can further comprise sintering aids. Sintering aids include, but are not limited to, for example, gallium. The sintering aids can be used, typically in concentrations under 1% wt. In some embodiments, sintering aids are excluded.
The Ce2Fe14B-based materials were prepared by conventional arc melting and post annealing process. The starting materials were La, Ce, Zr (99.8%), Fe pieces (99.999%), Co ingots (99.999%), and B pieces (99.5%). The starting materials in the desired ratio were arc melted in an argon-arc furnace with a water-cooled hearth and a non-consumable tungsten electrode. The ingot was melted four or five times to ensure homogeneity and then sealed in a quartz tube under vacuum. The ampoule was then kept in a box furnace at 920° C. for 15 days. The above annealing temperature and time were found to yield samples with the highest fraction of 2-14-1 phase. After the long-term annealing, the ampoule was quenched in ice water. Room temperature x-ray powder diffraction measurements were performed using a diffractometer and a position sensitive detector using monochromated Cu Kα1 radiation.
The field dependence of magnetization was measured at room temperature for both aligned powder and a small piece of annealed polycrystalline ingot. Fine powder was aligned with epoxy inside of a capsule using a procedure described previously (B. C. Sales, Sci. Rep. 4, 7024 (2014)). The magnetic ordering temperature was determined using a Perkin-Elmer 7 series thermogravimetric analyzer (TGA) with a permanent magnet positioned right above the sample. A dramatic mass change is expected at the Curie temperature because the force exerted on the sample by the magnet disappears above the Curie temperature.
The calculations were performed by using the all-electron-density functional code WIEN2k (E. Sjöstedt et al., Solid State Commun., 114, 15 (2000)) with the generalized-gradient approximation of Perdew, Burke and Ernzerhof (J. P. Perdew et al., Phys. Rev.
Lett., 77, 3865, 1996). The formation enthalpies and decomposition enthalpies of substituted Ce2Fe14B were calculated according to the Vienna Ab initio Simulation Package (G. Kresse et al., Comput. Mater. Sci., 6, 15, 1996).
Experimental analysis on Ce2Fe14B with Co, La and Zr substitution. In general, the Curie point of R2Fe14B can be improved by Co substitution for Fe. The effect of partial substitution of Ce by La and Zr in Ce2Fe14-xCoxB with x=1.3 or 2.0 was also studied.
According to the X-ray powder diffraction of Ce2-xZrxFe12Co2B collected at room temperature, for x=0, Ce2Fe12Co2B is the majority phase with a small fraction of Ce2Fe17 that could be barely resolved by the diffraction measurement. The lattice parameters determined from Rietveld refinement are a=8.7509(10) Å and c=12.0824(16) Å, consistent with previous reports (T. Wang et al., J. Magn. Magn. Mater. 460, 95, 2018). Partial substitution of Ce by Zr significantly increases the fraction of Ce2Fe17. The fraction of Ce2Fe17 increases from 13% wt for Ce1.9Zr01Fe12Co2B to 64% wt for Ce1.8Zr0.2Fe12Co2B. The lattice parameters for the 2-14-1 phase are a=8.7481(4) Å and c=12.0692(6) Å for both x=0.1 and 0.2.
Replacing half of Ce by La seems to stabilize the desired 2-14-1 phase. As shown in the X-ray powder diffraction of (LaCe)2-xZrxFe12.7Co1.3B (x=0.0. 0.1 or 0.2) in
The magnetic ordering temperature, i.e., the Curie temperature, was determined by measuring the magnetic thermogravimetric analyses. The Curie temperature for Ce2-x ZrxFe12Co2B is at 285° C. and the partial substitution of Ce by Zr has little effect on Curie temperature. With half of Ce replaced by La, the Curie point is increased to 315° C. for (La0.5Ce0.5)1.9Zr0.1Fe12Co2B, which is higher than the achieved highest Curie point of ˜490 K in Ce2Fe14B substituted just by La (Z. Li et al., J. Magn. Magn. Mater. 505, 166747, 2020). This 315° C. value is in fact equivalent to that of Nd2Fe14B.
The anisotropy field for these La- and Zr-substituted compounds was also studied.
Origin of magnetic anisotropy in Ce2Fe14B. Although the permanent magnetic properties in Ce2Fe14B was achieved with La and Co co-substitution, it should be noted that neither La nor Zr substitution improves the magnetic anisotropy of Ce2Fe14B. Only the Zr substitution on Ce has ever been reported to enhance the anisotropy of Ce2Fe14B and other R2Fe14B compounds (e.g., T. Capehart et al., J. Appl. Phys. 73, 6476, 1993), which is contrary to our experimental results. These experimental results reflect the challenge of modulating the magnetic anisotropy of Ce2Fe14B. Here, theoretical calculations were employed to further elucidate Ce2Fe14B.
In order to confirm the magnetic calculations in Ce2Fe14B, the magnetization and magnetic anisotropy were first calculated, and this was compared with the experimental results. The calculated magnetization was 1.53 T and magnetic anisotropy was found to be 1.42 MJ/m3. On this basis, an anisotropy field HA of 2.34 T was obtained from the relationship of μ0HA=2μ0K1/Ms. In previously reported experiments (J. F. Herbst et al., Rev. Mod. Phys., 63, 819, 1991), the magnetization of 1.47 T and anisotropy field of 2.6 T are measured at 4 K in Ce2Fe14B. It can be seen that the calculated magnetization of 1.53 T and anisotropy field of 2.34 T are relatively close to the related experimental values. Thus, the present calculations should be reliable for further elucidating the origin of magnetic anisotropy in Ce2Fe14B.
As shown in the side-view geometry structures of Ce2Fe14B in
Given the inequivalent sites and dramatically different MAE contribution of Ce-4f and Ce-4g atoms, the partial DOS projected on the two kinds of Ce atoms can be further calculated, with the results shown in
In
For checking the B—Ce interaction, the charge density for Ce2Fe14B can be plotted, as shown in
Magnetic anisotropy improved by 4f-site atom substitution. According to the atom-projected MAE in
Next, the magnetic properties of (Ce0.75X0.25)2Fe14B (X=Sn, Sb, Pb, Bi, La or Zr) were explored, where X atoms, except the La atom, occupy the 4f site. As shown in
It should be noted that atom substitution in the rare earth 4f site does not decrease the magnetization in Ce2Fe14B. On the contrary, the introduced Bi atoms slightly increase the magnetization of Fe atoms. Table I below lists the atomic spin and orbital moments of (Ce0.5Bi0.5)2Fe14B and Ce2Fe14B. The magnetic moment differences of the atomic spin (orbital) moment in (Ce0.5Bi0.5)2Fe14B and Ce2Fe14B are defined as Δμs and ΔμL, as displayed in
Given the promising magnetic properties in (Ce1-xBix)2Fe14B, further Bi-substituted compounds were fabricated. Notably, significant impediments were encountered for synthesizing Bi-doped Ce2Fe12.7Co1.3B via conventional arc melting and post annealing process due to phase separation. Here, we estimate the thermodynamic stability of (Ce0.5Bi0.5)2Fe14B by the enthalpies of formation ΔHf and potential decomposition enthalpies ΔHd by the grand canonical linear programming method (A. R. Akbarzadeh et al., Adv. Mater. 19, 3233, 2007).
The ΔHf, on a per-atom basis, is calculated based on the elementary substances as follows:
where the applied enthalpy denotes the total enthalpy of related materials. The enthalpies of Ce, Bi, Fe and B were calculated in their stable phases in the Materials Project data base (e.g., A. R. Akbarzadeh et al., Ibid.). As listed in Table II below, the calculated ΔHf of 0.028 eV/atom in (Ce0.5Bi0.5)2Fe14B is higher than that in Ce2Fe14B. Given that a system with a lower formation enthalpy will be more stable at high temperatures, the (Ce0.5Bi0.5)2Fe14B seems unstable with respect to the formation of Ce2Fe14B. However, the R2Fe14B structure could be formed with R=Y, Th and all the lanthanide elements except Eu and Pm. The formation enthalpies of these R2Fe14B materials range from −0.125 eV/atom (in Lu2Fe14B) and 0.727 eV/atom (in Gd2Fe14B). Parts of R2Fe14B are listed in Table II. Thus, it is entirely possible that the (Ce0.5Bi0.5)2Fe14B with ΔHf of 0.028 eV/atom may form under appropriate synthesis conditions.
Moreover, except the magnetic anisotropy and saturation magnetization, Curie point is an indispensable property for permanent magnet application. Co substitution may be employed in (Ce0.75Bi0.25)2Fe14B and (Ce0.5Bi0.5)2Fe14B to achieve a higher Curie point. The magnetization and anisotropy for the two Bi cases with the Co content of 10% and 15% were calculated by employing the virtual crystal approximation to treat the Fe/Co substitution. It was herein found that the magnetizations of the two Bi cases were nearly unaffected by the introduced Co. The magnetic anisotropy of 2.48 MJ/m3 in (Ce0.75Bi0.25)2Fe14B decreases to 1.80 MJ/m3 (with 10% Co) and 2.18 MJ/m3 (with 15% Co). In (Ce0.5Bi0.5)2Fe14B, the magnetic anisotropy of 4.24 MJ/m3 decreased to 3.77 MJ/m3 (with 10% Co) and 3.82 MJ/m3 (with 15% Co). It can be roughly assessed that the magnetic anisotropies of the two Bi cases decrease 10%-12% by proper Co substitution. Thus, although the Co substitution decreases the magnetic anisotropy in the two Bi cases, it remains possible to control the magnetic anisotropy by optimizing the content of Co. These results lay the foundation for low-cost Ce2Fe14B-based permanent magnet applications.
Notably, even for magnetic anisotropy fields in the ˜3 Tesla room-temperature values found experimentally, it should still be feasible to make high-performance magnets in this class. Relying on the time-tested Brown paradox in which experimentally realizable coercivities can be as high as 30% of the anisotropy field results in estimated coercivities as high as 0.9 T or 9 kOe, which exceeds half the approximate 1.4 Tesla room-temperature magnetization of these alloys. This would thus permit these magnets to be made in any shape free of demagnetization effects, and obtain the full energy product as high as 48 MG-Oe. Although not studied here, previous work (J. F. Herbst, Rev. Mod. Phys., 63, 819, 1991) also finds that in Ce2Fe14B and La2Fe14B, anisotropy fields are nearly constant in the technologically important range just above room temperature, rather than falling off quickly with temperature as in Nd2Fe14B. It is this latter property that has largely necessitated the unfavorable usage of the extremely critical Dy in conventional magnet compositions. In contrast, the presently described Ce2Fe14B-based magnets do not require Dy, which substantially reduces room-temperature energy products.
Commercial grade (>99.9 wt % purity) Mischmetal (“MM”), Fe, Co, Fe—B, Cu, and Ga were used to prepare the master alloy with a nominal composition of (MM)2.6Fe11.9Co2Ga0.1B. The approximate composition of the Mischmetal is given in Table 3 below:
The alloys were first arc-melted, then strip-cast to flakes (˜125 mm thickness) with the wheel speed set at 1.5 m/s. The flakes were further treated with hydrogen decrepitation process and ground into coarse powders (200-400 μm). The powder of the grain boundary modifier alloy Pr68Cu32 (mole ratio) or Pr34Dy34Cu32 were prepared by arc-melting, melt-spinning, and pre-ball-milling processes. The obtained coarse Pr—Cu or Pr—Dy—Cu powder (˜75 μm) was added to the master MM-FeCoGa-B coarse powder at a ratio of 7.5 wt. %. The mixture was ball-milled to finer powder (˜3.5 μm), then aligned with a 9 T pulsed field in a rubber die, and cold isostatic pressed with a hydrostatic pressure of 500 MPa. These processes are shown in
Room-temperature hysteresis loops for alloys, employing the indicated grain boundary modifiers, are depicted in
In summary, the magnetic properties of Ce2Fe14B with Co, La and Zr substitutions were examined. Together with the Co substitutions on Fe, partial Zr substitution increases the impurity phase and has little effect on the Curie point and Ms. Without the loss of anisotropy field, substitution of La improves the Curie temperature and Ms, which may produce an estimated energy product as high as 48 MG-Ge. These properties indicate LaCeFe12.7Co1.3B as a particularly high performance permanent magnet which is advantageously critical-element-free. Moreover, the results indicate that the magnetic anisotropy of Ce2Fe14B is comparably contributed by the Ce and Fe atoms. Then the Ce-projected magnetic anisotropy is predominately provided by the Ce atoms in 4g site. In particular, employing the Bi substitution on the Ce atoms in the 4g site can increase the magnetic anisotropy energy to 4.24 MJ/m3 in (Ce0.5Bi0.5)2Fe14B, which is almost three times of that in Ce2Fe14B. Meanwhile, (Ce0.5Bi0.5)2Fe14B exhibits a strong magnetization of 1.64 T and a magnetic hardness parameter of 1.41. These magnetic criteria also imply the potential of Bi substitution for making Ce2Fe14B a low-cost, high-performance permanent magnet. These experimental and theoretical results provide a foundation for developing Ce2Fe14B-based critical-element-free, high performance, low-cost permanent magnets.
While there have been shown and described what are at present considered the preferred embodiments of the invention, those skilled in the art may make various changes and modifications which remain within the scope of the invention defined by the appended claims.
The present application claims benefit of U.S. Provisional Application No. 63/460,914, filed on Apr. 21, 2023, all of the contents of which are incorporated herein by reference.
This invention was made with government support under Prime Contract No. DE-AC05-000R22725 and DE-AC02-07CH11358, both awarded by the U.S. Department of Energy. The government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 63460914 | Apr 2023 | US |
