Disclosure of Invention
The invention aims to overcome the defect that the consistency of the performance of a magnet is poor when B in an R-T-B series magnet is less than 5.88 at% in the prior art, and provides a neodymium iron boron material and a preparation method and application thereof.
The invention provides an R-T-B series permanent magnetic material, which comprises the following components: r, Cu, B, Al and Fe, and also comprises one or more of Ti, Zr and Nb, and the content is as follows in percentage by weight:
r: 28.1-33.1 wt%; r is a rare earth element at least containing Nd;
Cu:≥0.4wt%;
Al:0.08-0.125wt%;
B:0.84-0.945wt%;
fe: 64.6 to 70.1 weight percent; wherein:
when the R-T-B series permanent magnet material contains Ti, the content of the Ti is 0.15-0.255 wt%;
when the R-T-B series permanent magnet material contains Zr, the content of Zr is 0.19-0.355 wt%;
when the R-T-B series permanent magnet material contains Nb, the content of Nb is 0.19-0.51 wt%;
the R-T-B series permanent magnet material does not contain Co;
the R-T-B series permanent magnetic material comprises R2T14A main phase B, a grain boundary phase and a rare earth-rich phase, wherein the grain boundary phase contains R6Fe13Cu phase, said R6Fe13The volume fraction of the Cu phase is more than or equal to 3.5 percent, and the percentage refers to the R6Fe13Volume of Cu phase in the grain boundary phase and R phase2T14The sum of the volumes of the B main phase and the rare earth-rich phase is a percentage.
In the present invention, preferably, R is6Fe13The volume fraction of the Cu phase is 4.6-8.4%, e.g. 4.6%, 4.7%, 4.8%, 4.9%, 5.1%, 5.3%, 5.6%, 6.7%, 7.6%, 7.8% or 8.4%, the percentages referring to said R6Fe13Volume of Cu phase in the grain boundary phase and R phase2T14The sum of the volumes of the B main phase and the rare earth-rich phase is a percentage.
In the present invention, the content of said R is preferably 28.495-33.006wt%, for example 28.495 wt%, 28.497 wt%, 28.507 wt%, 29.497 wt%, 29.500 wt%, 29.505 wt%, 29.987 wt%, 30.017 wt%, 30.018 wt%, 30.489 wt%, 30.492 wt%, 30.493 wt%, 30.496 wt%, 30.501 wt%, 30.505 wt%, 31.002 wt%, 31.003 wt%, 31.004 wt%, 31.005 wt%, 31.006 wt%, 31.008 wt%, 31.879 wt%, 31.991 wt%, 32.001 wt%, 32.984 wt%, 33.004 wt% or 33.006wt%, the percentage referring to the weight percentage in said R-T-B system permanent magnetic material.
In the present invention, the content of Nd is preferably 21.372 to 24.753 wt%, for example, 21.372 wt%, 21.374 wt%, 21.378 wt%, 21.382 wt%, 22.126 wt%, 22.127 wt%, 22.495 wt%, 22.508 wt%, 22.509 wt%, 22.871 wt%, 22.872 wt%, 22.874 wt%, 22.876 wt%, 23.251 wt%, 23.252 wt%, 23.253 wt%, 23.254 wt%, 23.892 wt%, 23.968 wt%, 24.014 wt%, 24.752 wt% or 24.753 wt%, and the percentage refers to the weight percentage in the R-T-B system permanent magnetic material.
In the invention, the R can also comprise Pr and/or heavy rare earth RH.
Wherein, the content of Pr can be less than 0.2 at% or more than 8 at%, and the percentage refers to the atomic percentage in the R-T-B series permanent magnetic material.
Wherein, the content of Pr is preferably 5.0-18.0 wt%, such as 7.121-8.253 wt%, such as 7.121 wt%, 7.125 wt%, 7.371 wt%, 7.373 wt%, 7.378 wt%, 7.492 wt%, 7.509 wt%, 7.619 wt%, 7.621 wt%, 7.625 wt%, 7.629 wt%, 7.750 wt%, 7.752 wt%, 7.753 wt%, 7.756 wt%, 7.987 wt%, 8.023 wt%, 8.252 wt% or 8.253 wt%, the percentage refers to the weight percentage in the R-T-B series permanent magnetic material.
Wherein, when said R further comprises Pr, the atomic percentage of B/(Pr + Nd) is preferably ≧ 0.405, such as 0.405, 0.414, 0.424, 0.426 or 0.428.
Wherein, the RH can be Tb or Dy.
Wherein the RH content may be 1.5-6.0 wt%, such as 1.978 wt% or 1.986 wt%, the percentage referring to the weight percentage in the R-T-B series permanent magnetic material.
In the present invention, the Cu content is preferably 0.4 to 2.05 wt%, for example, 0.402 wt%, 0.409 wt%, 0.452 wt%, 0.453 wt%, 0.503 wt%, 0.504 wt%, 0.552 wt%, 0.553 wt%, 0.605 wt%, 0.652 wt%, 0.705 wt%, 0.709 wt%, 0.793 wt%, 0.805 wt%, 0.808 wt%, 0.809 wt%, 0.987 wt%, 0.989 wt%, 1.012 wt%, 1.402 wt%, 1.404 wt%, 1.509 wt%, 1.804 wt%, 1.987 wt%, or 2.012 wt%, and the percentage means the weight percentage in the R-T-B series permanent magnetic material.
In the present invention, it is preferable that the Cu content is 0.45wt% or more, for example, 0.45wt% or more and less than 0.65wt% or Cu 0.65wt% or more, and the percentage means the weight percentage in the R-T-B series permanent magnetic material.
In the present invention, it is preferable that the R-T-B based permanent magnetic material does not contain Ga.
In the present invention, the content of Al is preferably 0.081 to 0.124 wt%, for example, 0.081 wt%, 0.082 wt%, 0.083 wt%, 0.089 wt%, 0.091 wt%, 0.092 wt%, 0.093 wt%, 0.1 wt%, 0.101 wt%, 0.103 wt%, 0.104 wt%, 0.106 wt%, 0.111 wt%, 0.112 wt%, 0.113 wt%, 0.115 wt%, 0.122 wt%, or 0.124 wt%, and the percentage refers to the weight percentage in the R-T-B system permanent magnetic material.
In the present invention, the content of B is preferably 0.842 to 0.943 wt%, for example, 0.842 wt%, 0.843 wt%, 0.863 wt%, 0.883 wt%, 0.884 wt%, 0.892 wt%, 0.893wt%, 0.902 wt%, 0.909 wt%, 0.911 wt%, 0.914 wt%, 0.915 wt%, 0.916 wt%, 0.919 wt%, 0.922 wt%, 0.923 wt%, 0.925 wt%, 0.939 wt%, 0.942 wt%, or 0.943 wt%, and the percentage means the weight percentage in the R-T-B series permanent magnetic material.
In the invention, the content of B is preferably not less than 0.915 wt% or not less than 5.55 at%; more preferably, the content of B is greater than 0.915 wt% and 5.55 at%; wt% means a weight percentage in the R-T-B system permanent magnetic material, and at% means an atomic percentage in the R-T-B system permanent magnetic material.
In the present invention, preferably, the ratio of the atomic percentages of B and TRE is not less than 0.38, such as 0.38, 0.39, 0.40, 0.41 or 0.42; wherein, TRE is total rare earth amount; for example, when the R comprises Nd and Pr, the TRE is the sum of the contents of the Nd and the Pr, and when the R comprises Nd, Pr and heavy rare earth RH, the TRE is the sum of the contents of the Nd, the Pr and the heavy rare earth RH.
In the present invention, the content of Fe is preferably 64.641 to 70.007 wt%, for example, 64.641 wt%, 64.833 wt%, 64.977 wt%, 65.022 wt%, 65.454 wt%, 65.883 wt%, 65.891 wt%, 65.925 wt%, 66.016 wt%, 66.557 wt%, 66.829 wt%, 66.844 wt%, 66.899 wt%, 66.9 wt%, 67.008 wt%, 67.027 wt%, 67.416 wt%, 67.608 wt%, 67.675 wt%, 67.723 wt%, 67.8 wt%, 67.907 wt%, 68.094 wt%, 68.243 wt%, 68.252 wt%, 68.366 wt%, 68.888 wt%, 68.938 wt%, 69.148 wt% or 70.007 wt%, and the percentage means the weight percentage in the R-T-B system permanent magnetic material.
In the present invention, when the R-T-B based permanent magnetic material contains Ti, the content of Ti is preferably 0.152 to 0.253 wt%, for example, 0.152 wt%, 0.154 wt%, 0.197 wt%, 0.204 wt%, 0.205 wt%, 0.206 wt%, or 0.253 wt%, which means a weight percentage in the R-T-B based permanent magnetic material.
In the present invention, when the R-T-B based permanent magnetic material contains Zr, the content of Zr is preferably 0.193 to 0.352 wt%, such as 0.193 wt%, 0.197 wt%, 0.262 wt%, 0.264 wt%, 0.281 wt%, 0.283 wt%, 0.297 wt%, 0.308 wt%, 0.309 wt%, 0.344 wt%, 0.348 wt%, or 0.352 wt%, and the percentage refers to the weight percentage in the R-T-B based permanent magnetic material.
In the present invention, when the R-T-B based permanent magnetic material contains Nb, the content of Nb is preferably 0.197 to 0.505 wt%, for example, 0.197 wt%, 0.198 wt%, 0.200 wt%, 0.203 wt%, 0.297 wt%, 0.298 wt%, 0.397 wt%, 0.398 wt%, or 0.505 wt%, which means the weight percentage in the R-T-B based permanent magnetic material.
In the present invention, when the R-T-B series permanent magnetic material contains Zr, the Zr content is preferably 0.20wt% Zr ≦ (3.48B-2.67) wt%, for example 0.26wt% Zr ≦ (3.48B-2.67) wt%, wherein B is the weight percentage of B in the R-T-B series permanent magnetic material; the percentage refers to the weight percentage in the R-T-B series permanent magnet material.
In a preferred embodiment of the present invention, the R-T-B based permanent magnetic material comprises the following components: r: 28.1-33.1 wt%, Al: 0.08 to 0.125 wt%, Cu: not less than 0.45wt%, B: 0.84-0.945 wt%, Fe: 64.6-70.1 wt%, Ti: 0.15-0.255 wt%, the percentage refers to the weight percentage in the R-T-B series permanent magnetic material.
In a preferred embodiment of the present invention, the R-T-B based permanent magnetic material comprises the following components: r: 28.1-33.1 wt%, Al: 0.08 to 0.125 wt%, Cu: 0.45-0.65 wt%, B: 0.84-0.945 wt%, Fe: 64.6 to 70.1 wt%, Zr: 0.19-0.355 wt%; wherein, preferably, the Zr content is more than or equal to 0.26 percent and less than (3.48B-2.67 percent) by weight; the percentage refers to the weight percentage in the R-T-B series permanent magnet material.
In a preferred embodiment of the present invention, the R-T-B based permanent magnetic material comprises the following components: r: 28.1-33.1 wt%, Al: 0.08 to 0.125 wt%, Cu: not less than 0.65wt%, B: 0.84-0.945 wt%, Fe: 64.6 to 70.1 wt%, Zr: 0.19-0.355 wt%; wherein, preferably, the content of Zr is more than or equal to 0.20 percent and less than (3.48B-2.67 percent) percent by weight; the percentage refers to the weight percentage in the R-T-B series permanent magnet material.
The invention provides a raw material composition of an R-T-B series permanent magnetic material, which comprises the following components: r, Cu, B, Al and Fe, and also comprises one or more of Ti, Zr and Nb, and the content is as follows in percentage by weight:
r: 28.0-33.0 wt%; r is a rare earth element at least containing Nd;
Cu:≥0.4wt%;
Al:0.05-0.07wt%;
B:0.84-0.94wt%;
fe: 64.6 to 70.1 weight percent; wherein:
when the R-T-B series permanent magnet material contains Ti, the content of the Ti is 0.15-0.25 wt%;
when the R-T-B series permanent magnet material contains Zr, the content of Zr is 0.2-0.35 wt%;
when the R-T-B series permanent magnet material contains Nb, the content of Nb is 0.2-0.5 wt%;
the R-T-B series permanent magnet material does not contain Co.
As known to those skilled in the art, the raw material composition of the R-T-B series permanent magnetic material generally refers to raw materials actively added in the preparation process of the permanent magnetic material, and does not include components and/or contents introduced in the preparation process or impurities.
In the present invention, the content of R is preferably 28.5 to 33.0 wt%, for example 28.5 wt%, 29.5 wt%, 30.0 wt%, 30.5 wt%, 31.0 wt%, 32.0 wt%, or 33.0 wt%, which is a weight percentage in the raw material composition of the R-T-B-based permanent magnetic material.
In the present invention, the content of Nd is preferably 17.5 to 26.0 wt%, for example 21.375 wt%, 22.125 wt%, 22.5 wt%, 22.875 wt%, 23.25 wt%, 24.0 wt%, or 24.75 wt%, which is a weight percentage in the raw material composition of the R-T-B-based permanent magnetic material.
In the invention, the R can also comprise Pr and/or heavy rare earth RH.
Wherein, the content of Pr can be less than 0.2 at% or more than 8 at%, and the percentage refers to the atomic percentage in the raw material composition of the R-T-B series permanent magnetic material.
Wherein, the content of Pr is preferably 2.5-12.0 wt%, such as 7.125 wt%, 7.375 wt%, 7.5 wt%, 7.625 wt%, 7.75 wt%, 8.0 wt% or 8.25 wt%, which is the weight percentage in the raw material composition of the R-T-B series permanent magnetic material.
Wherein, when the R also comprises Pr, the atomic percentage of B/(Pr + Nd) is preferably more than or equal to 0.405.
Wherein, the RH can be Tb or Dy.
Wherein the RH may be present in an amount of 1.5-6.0 wt.%, for example 2.0 wt.%, percentages referring to weight percentages in the raw material composition of the R-T-B based permanent magnetic material.
In the present invention, it is preferable that the raw material composition of the R-T-B based permanent magnetic material does not contain Ga.
In the present invention, the content of Al is preferably 0.06 to 0.07 wt%, for example, 0.06 wt% or 0.07 wt%, which is a weight percentage in the raw material composition of the R-T-B based permanent magnetic material.
In the present invention, the content of Cu is preferably 0.4 to 2.0 wt%, for example, 0.4 wt%, 0.45wt%, 0.5 wt%, 0.55 wt%, 0.6 wt%, 0.65wt%, 0.7 wt%, 0.8 wt%, 1.0 wt%, 1.4 wt%, 1.5 wt%, 1.8 wt%, or 2.0 wt%, and the percentage means the weight percentage in the raw material composition of the R-T-B-based permanent magnetic material.
In the present invention, it is preferable that the Cu content is 0.4 wt% or more, for example, 0.45wt% or more and less than 0.65wt% or Cu 0.65wt% or more, and the percentage means the weight percentage in the raw material composition of the R-T-B system permanent magnetic material.
In the present invention, the content of B is preferably 0.86 to 0.94 wt%, for example, 0.86 wt%, 0.88 wt%, 0.9 wt%, 0.915 wt%, 0.92 wt%, or 0.94 wt%, which is a weight percentage in the raw material composition of the R-T-B-based permanent magnetic material.
In the invention, the content of B is preferably not less than 0.915 wt% or not less than 5.55 at%; more preferably, the content of B is greater than 0.915 wt% and 5.55 at%; wt% means a weight percentage in the raw material composition of the R-T-B based permanent magnetic material, and at% means an atomic percentage in the raw material composition of the R-T-B based permanent magnetic material.
In the invention, preferably, the atomic percentage ratio of B to TRE is more than or equal to 0.38; wherein, TRE is total rare earth amount; for example, when Nd and Pr are included in the R, the TRE is the sum of the contents of the Nd and the Pr.
In the present invention, the content of Fe is preferably 64.675 to 70.06 wt%, for example, 64.675 wt%, 64.885 wt%, 64.99 wt%, 65.07 wt%, 65.51 wt%, 65.93 wt%, 65.955 wt%, 65.96 wt%, 66.615 wt%, 66.855 wt%, 66.9 wt%, 66.925 wt%, 66.96 wt%, 67.055 wt%, 67.1 wt%, 67.46 wt%, 67.65 wt%, 67.71 wt%, 67.78 wt%, 67.84 wt%, 67.94 wt%, 68.135 wt%, 68.28 wt%, 68.315 wt%, 68.43 wt%, 68.93 wt%, 68.97 wt%, 69.165 wt% or 70.06 wt%, which is a weight percentage in a raw material composition of the R-T-B system permanent magnetic material.
In the present invention, when the R-T-B based permanent magnetic material contains Ti, the content of Ti is preferably 0.2 to 0.25 wt%, for example, 0.2 wt% or 0.25 wt%, and the percentage refers to the weight percentage in the raw material composition of the R-T-B based permanent magnetic material.
In the present invention, when the R-T-B based permanent magnetic material contains Zr, the content of Zr is preferably 0.26 to 0.35 wt%, for example, 0.26wt%, 0.28 wt%, 0.3 wt%, 0.34 wt%, or 0.35 wt%, and the percentage refers to the weight percentage in the raw material composition of the R-T-B based permanent magnetic material.
In the present invention, when the R-T-B based permanent magnetic material contains Nb, the content of Nb is preferably 0.3 to 0.5 wt%, for example, 0.30 wt%, 0.40 wt%, or 0.5 wt%, and the percentage refers to the weight percentage in the raw material composition of the R-T-B based permanent magnetic material.
In the present invention, when Zr is contained in the raw material composition of the R-T-B series permanent magnetic material, the Zr content is preferably 0.20wt% or more and less than (3.48B-2.67) wt%, for example 0.26wt% or less and less than (3.48B-2.67) wt%, wherein B is the weight percentage of B in the raw material composition of the R-T-B series permanent magnetic material; the percentage refers to the weight percentage in the raw material composition of the R-T-B series permanent magnet material.
In a preferred embodiment of the present invention, the raw material composition of the R-T-B series permanent magnetic material comprises the following components: r: 28.0-33.0 wt%, Al: 0.05 to 0.07 wt%, Cu: not less than 0.45wt%, B: 0.84-0.94 wt%, Fe: 64.6-70.1 wt%, Ti: 0.15-0.25 wt%, the percentage refers to the weight percentage in the raw material composition of the R-T-B series permanent magnetic material.
In a preferred embodiment of the present invention, the raw material composition of the R-T-B series permanent magnetic material comprises the following components: r: 28.0-33.0 wt%, Al: 0.05 to 0.07 wt%, Cu: 0.45-0.65 wt%, B: 0.84-0.94 wt%, Fe: 64.6 to 70.1 wt%, Zr: 0.20-0.35 wt%; wherein, preferably, the Zr content is more than or equal to 0.26 percent and less than (3.48B-2.67 percent) by weight; the percentage refers to the weight percentage in the raw material composition of the R-T-B series permanent magnet material.
In a preferred embodiment of the present invention, the raw material composition of the R-T-B series permanent magnetic material comprises the following components: r: 28.0-33.0 wt%, Al: 0.05 to 0.07 wt%, Cu: not less than 0.65wt%, B: 0.84-0.94 wt%, Fe: 64.6 to 70.1 wt%, Zr: 0.20-0.35 wt%; wherein, preferably, the content of Zr is more than or equal to 0.20 percent and less than (3.48B-2.67 percent) percent by weight; the percentage refers to the weight percentage in the raw material composition of the R-T-B series permanent magnet material.
The invention also provides a preparation method of the R-T-B series permanent magnetic material, which comprises the following steps:
performing casting, hydrogen fracturing, forming, sintering and aging treatment on the molten liquid of the raw material composition of the R-T-B series permanent magnet material; wherein:
the aging treatment comprises primary aging treatment and secondary aging treatment, wherein the temperature of the primary aging treatment is 830-870 ℃.
Wherein, the melting liquid of the raw material composition of the R-T-B series permanent magnetic material can be prepared by the conventional method in the field, such as: smelting in a high-frequency vacuum induction smelting furnace. The vacuum degree of the smelting furnace can be 5 multiplied by 10-2Pa. The temperature of the smelting can be below 1500 ℃.
Wherein the casting process may be a casting process conventional in the art, such as: in Ar atmosphere (e.g. 5.5 prepared)104Pa Ar atmosphere), passing the melt of the raw material composition of the R-T-B permanent magnetic material through a rotating roller at 10 deg.C2DEG C/sec-104Cooling at a rate of DEG C/sec.
The cooling can be realized by introducing cooling water into the roller.
The roller may be a copper roller.
Preferably, the water inlet temperature of the roller is less than or equal to 25 ℃, such as 23.1 ℃, 23.4 ℃, 23.6 ℃, 23.7 ℃, 23.9 ℃, 24.2 ℃ or 24.5 ℃.
The hydrogen breaking process can be a hydrogen breaking process conventional in the art, and can be performed through hydrogen absorption, dehydrogenation and cooling treatment.
The hydrogen absorption can be carried out under the condition that the hydrogen pressure is 0.15 MPa.
The dehydrogenation can be carried out under the condition of vacuum pumping and temperature rise.
Wherein, after the hydrogen is broken, the raw materials can be crushed by the conventional method in the field. The comminution process may be a comminution process conventional in the art, such as jet milling.
The jet mill pulverization may be performed in a nitrogen atmosphere having an oxidizing gas content of 120ppm or less. The oxidizing gas refers to oxygen or moisture content.
The pressure of the crushing chamber for crushing by the jet mill can be 0.38 MPa.
The jet mill pulverizing time may be 3 hours.
After the pulverization, a lubricant, such as zinc stearate, may be added to the powder as is conventional in the art. The lubricant may be added in an amount of 0.10 to 0.15%, for example 0.12% by weight of the mixed powder.
The forming process may be a forming process conventional in the art, such as magnetic field forming or hot press hot deformation.
Wherein the sintering process may be a sintering process conventional in the art, for example, under vacuum conditions (e.g., at 5 × 10)-3Pa, vacuum), preheating, sintering and cooling.
The temperature of the preheating may be 300-600 ℃. The preheating time can be 1-2 h. Preferably, the preheating is for 1h each at a temperature of 300 ℃ and 600 ℃.
The sintering temperature may be a sintering temperature conventional in the art, such as 1040-.
The sintering time may be a sintering time as conventional in the art, such as 5-10h, for example, further 8 h.
Before cooling, Ar gas can be introduced to ensure that the gas pressure reaches 0.1 MPa.
Wherein, the temperature of the primary aging treatment is preferably 840 ℃ to 870 ℃, such as 840 ℃, 845 ℃, 850 ℃, 860 ℃ or 870 ℃.
In the primary aging treatment, the rate of temperature rise to the temperature of the primary aging treatment is preferably 3to 5 ℃/min. The starting point of the warming may be room temperature.
Wherein the treatment time of the primary aging can be 1-6h, such as 3 h.
Wherein, the temperature of the secondary aging treatment is preferably 430-560 ℃, such as 440-465 ℃, and further such as 440 ℃, 450 ℃, 455 ℃, 460 ℃ or 465 ℃.
In the secondary aging, the heating rate of heating to 430-560 ℃ is preferably 3-5 ℃/min. The starting point of the warming may be room temperature.
The treatment time for the secondary ageing may be 1 to 6 hours, for example 3 hours.
The invention also provides the R-T-B series permanent magnetic material prepared by the method.
The invention also provides application of the R-T-B series permanent magnetic material as an electronic component.
The application field can be the automobile driving field, the wind power field, the servo motor field and the household appliance field (such as an air conditioner).
In the present invention, the room temperature means 25 ℃. + -. 5 ℃.
On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.
The reagents and starting materials used in the present invention are commercially available.
The positive progress effects of the invention are as follows:
(1) excellent magnetic performance: the R-T-B series permanent magnetic material Br is more than or equal to 12.54kGs, Hcj is more than or equal to 17.05kOe, and after heavy rare earth elements are added, the Hcj can reach 27.01kOe (Tb) and 23.69kOe (Dy); the magnet has good temperature stability, and the absolute value of the Br temperature coefficient alpha%/DEG C at 20-80 ℃ is less than 0.108.
(2) The demagnetization curve is smooth, no step exists, the relative magnetic conductivity is low, the same-batch range of the coercive force is less than or equal to 1.5kOe, and the consistency of the magnet performance is good.