CN109909465B - Method for inhibiting high-temperature ordering of high-iron-concentration samarium-cobalt alloy - Google Patents
Method for inhibiting high-temperature ordering of high-iron-concentration samarium-cobalt alloy Download PDFInfo
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Abstract
The invention relates to a method for inhibiting high-temperature ordering of high-iron-concentration samarium cobalt alloy, which mainly comprises the following steps: the method comprises two steps of mother alloy preparation and mother alloy post-treatment, melt rapid quenching and high-temperature stabilization treatment are adopted, a 1:7H structure is obtained in a main phase of the high-iron-concentration samarium-cobalt mother alloy, and generation of a 2:17 ordered phase is successfully inhibited. The method can be applied to the preparation process of the high-iron-concentration samarium cobalt magnet, has low improvement consumption on the conventional process, and is beneficial to large-scale application.
Description
Technical Field
The invention relates to the technical field of rare earth permanent magnet material preparation, in particular to a preparation method of a high-iron-concentration 2:17 type samarium cobalt permanent magnet material.
Background
The 2:17 type samarium cobalt permanent magnet material has been widely used in devices with complicated thermal and magnetic environments, such as an electronic traveling wave tube, a magnetic bearing, an engine, a generator, an ion thruster and the like, due to the excellent temperature characteristics of the material. Research on high iron 2:17 type samarium cobalt permanent magnet materials has been implicated in recent journal literature as a compositionIs Sm (Co)1-u-v-wFeuCuvZrw)zFor example, it is generally believed that when the iron concentration exceeds 25 at% (or the subscript u > 0.32), the cell structure of the magnet is destroyed, and a complete cell structure cannot be formed, and the existing improvement method mainly comprises: the adjustment process inhibits the precipitation of the second phase or adjusts the composition to obtain the optimal single-phase composition, thereby preparing the high-iron concentration magnet. Taking the research results of toshiba corporation as an example, the process for preparing samarium cobalt permanent magnet material with high iron concentration (Fe content subscript u is 0.35 or the atomic concentration ratio is 31 at%) is the traditional powder metallurgy process, wherein the alloy preparation is induction melting, and the result shows that even if the precise control of the heat treatment process is adopted, the single-phase 1:7H structure is still difficult to obtain in the main phase of the magnet, and the 2:17R ordered phase always exists, which affects the performance of the magnet. The magnet composition adjusted by institute of new Ningbo materials of Chinese academy of sciences can inhibit the existence of the 2:17R ordered phase at a lower Fe concentration (subscript u is 0.28, and the atomic concentration ratio is 25%), but the method is not beneficial to popularization and preparation of magnets with higher Fe concentration.
According to the invention, through analysis, the 2:17R ordered phase exists in the master alloy ingot with high-iron concentration components, in order to inhibit the generation of the 2:17 ordered phase in the high-iron concentration permanent magnet material, the master alloy ingot is subjected to melt rapid quenching to obtain the 2:17 type samarium cobalt permanent magnet rapid quenching sheet, the 2:17R ordered phase is successfully inhibited from being generated, and the alloy is converted into a single-phase 1:7H structure through subsequent high-temperature stabilization treatment, so that the 2:17R ordered phase rapid quenching sheet can be used for preparing a high-performance magnet through subsequent crushing and powder preparation.
Disclosure of Invention
The technical problem to be solved is as follows:
aiming at the defects in the prior art, the invention provides a method for inhibiting the high-temperature phase ordering of a 2:17 type samarium-cobalt magnet with high iron concentration, so that a high-temperature single-phase 1:7H structure is obtained. Specifically, the post-treatment process for the alloy cast ingot in the powder metallurgy process comprises the steps of solidifying the alloy cast ingot at a very high cooling speed by a solution rapid quenching method to inhibit the occurrence of ordered alloy in the alloy cast ingot, and then stabilizing a metastable solidification phase into a high-temperature phase 1:7H by high-temperature stabilization treatment. The alloy treated by this method suppresses the generation of ordered 2:17 phases, and can provide the high temperature 1:7H solid solution phase required for magnet production.
A method for inhibiting high-temperature ordering of high-iron-concentration samarium-cobalt alloy comprises the following specific steps:
1) preparation of master alloy
Mixing Sm, Co, Cu, Fe and Zr according to the chemical formula proportion, wherein the chemical formula composition is represented as Sm (Co)1-u-v- wFeuCuvZrw)zWherein u is 0.32-0.40, v is 0.05-0.08, w is 0.01-0.03, z is 7.4-8.0, then placing the crucible in a water-cooled copper crucible of a vacuum melting furnace, placing Sm easy to burn into the bottom of the crucible, and vacuumizing to 2 x 10-3～5×10-3Pa, filling high-purity argon into the furnace body, and increasing the vacuum degree in the furnace to 0.8 multiplied by 105Stopping inflating after Pa, repeatedly smelting for 3-4 times under the conditions of working voltage of 30-45V and working current of 600-800A, and cooling to obtain the alloy ingot.
Sm (Co) as defined above1-u-v-wFeuCuvZrw)zIn the preparation of the alloy, the actual amount of the Sm content is 3-5% more than the theoretical addition amount.
The vacuum smelting furnace is an electric arc smelting furnace or an induction smelting furnace.
2) Post-treatment of master alloy
Melt rapid quenching: putting the alloy ingot into a quartz tube with a flat nozzle of 0.1-0.5 mm, putting the quartz tube into a furnace body, connecting the quartz tube with a spray gun, and vacuumizing to 3 multiplied by 10-3Pa, then filling high-purity argon to the pressure of-0.04 Pa in the furnace body, repeatedly pumping and washing for three times, filling the high-purity argon of 0.03Pa into the spray gun, filling the high-purity argon in the furnace body to the pressure of-0.04 Pa in the furnace body, keeping the pressure difference of 0.07Pa between the spray gun and the furnace body, opening the water-cooling copper wheel to keep the speed of the water-cooling copper wheel at 3-25 m/s, carrying out induction heating on the alloy cast ingot to 1300-1500 ℃, after the alloy is completely melted and stabilized, quickly opening an air valve of the spray gun to quickly spray the alloy melt onto the surface of the rolling copper wheel, and quickly solidifying the alloy melt into a quick-setting sheet with the thickness of 0..
High-temperature stabilizing treatment: placing the rapid hardening sheet obtained in the melt rapid quenching step into a high vacuum furnace with the vacuum of the furnace body being 2 multiplied by 10-3～5×10-3Pa, filling argon, pumping to 2X 10-3～5×10-3Pa, heating to a solid solution temperature TstAnd (3) carrying out solid solution at 1120-1145 ℃ for 2-8 h, and then quenching to obtain the high-iron-concentration samarium cobalt alloy.
Further, when the melt in the step 2) is quenched, the induction heating temperature of the alloy ingot is 1350-1400 ℃.
Further, when the melt in the step 2) is quenched quickly, the speed of the water-cooling copper wheel is controlled to be 3-10 m/s.
Further, during the high-temperature stabilizing treatment in the step 2), the solution treatment time is 4-6 h.
Further, the high-iron-concentration samarium cobalt alloy has a 1:7H structure as a main phase, and the volume percentage of 2:17 phases in the ordered phase is 0-0.3%.
Further, the width of a disordered 1:7H twin crystal in the high-iron-concentration samarium cobalt alloy is 2.0-2.4 nm.
According to the invention, a single-phase 1:7H phase structure can be obtained by a mother alloy post-treatment mode, and 2:17 phases existing in a high-temperature phase of the high-iron-concentration samarium-cobalt magnet are inhibited. The process has two advantages, namely, the samarium cobalt main phase with high iron concentration can be prepared, and each alloy element has the highest solid solubility in the main phase and basically has no precipitation; and secondly, the extremely fast cooling speed of the melt rapid quenching method can inhibit the ordering of atoms (especially Co-Co and Fe-Fe atom pairs) in the main phase 1:7H, inhibit the formation of the 2:17R phase and avoid the incompleteness of the cellular structure of the magnet. The invention needs to control the rotating speed of the copper wheel to obtain extremely fast cooling speed, the too slow cooling speed can cause insufficient cooling speed, and the aim of inhibiting the formation of 2:17R phase can not be achieved, and the speed of the water-cooled copper wheel is 3-25 m/s. Meanwhile, high-temperature stabilization treatment is required in the process. The alloy structure after melt rapid quenching is actually an ordered phase of 2:17H, although the ordered phase 2:17R does not exist, the 2:17H is not a high-temperature solid solution 1:7H phase required subsequently, so that the high-temperature solid solution 1:7H phase needs to be obtained through a high-temperature stabilizing treatment mode, different cooling parts of an ingot have solidification form differences due to the cooling rate differences, the solidification structure homogenization is facilitated through the high-temperature stabilizing treatment, and the powder crushing in the later magnet preparation process is facilitated.
Compared with the prior art, the invention has the following beneficial effects:
the invention obtains the main phase of the single-phase 1:7H alloy with high iron concentration by technical innovation, and inhibits the unnecessary 2:17 phase. The method can be applied to the preparation process of the high-iron-concentration samarium-cobalt magnet, has low improvement consumption on the conventional process, and is beneficial to large-scale application.
Drawings
Figure 1 is an XRD pattern of the alloy of example 1.
Fig. 2 is an XRD pattern of the alloy of comparative example 1.
FIG. 3 is a micrograph of the alloy of example 1.
FIG. 4 is a micrograph of the alloy of comparative example 1.
Fig. 5 is an XRD pattern of the alloy of comparative example 2.
FIG. 6 is the morphology of the main phase TEM micro-regions of example 1.
FIG. 7 is the morphology of the main phase TEM micro-region of comparative example 2.
Fig. 8 is an alloy XRD pattern of comparative example 3.
Detailed Description
Example 1
1) Preparation of master alloy
Sm, Co, Cu, Fe and Zr according to Sm (Co)0.58Fe0.34Cu0.06Zr0.02)7.8Mixing the components according to the chemical formula proportion, placing the mixture in a water-cooled copper crucible of a vacuum smelting furnace, placing Sm which is easy to burn out at the bottom of the crucible, and vacuumizing to 2 multiplied by 10-3～5×10-3Pa, filling high-purity argon into the furnace body, and increasing the vacuum degree in the furnace to 0.8 multiplied by 105Stopping inflating after Pa, repeatedly smelting for 3-4 times under the conditions of working voltage of 30-45V and working current of 600-800A, and cooling to obtain the alloy ingot.
2) Post-treatment of master alloy
Melt rapid quenching: and putting the alloy ingot into a quartz tube with a 0.5mm wide nozzle, and placing the quartz tube into a furnace body to be connected with a spray gun. Vacuum pumping to 3 × 10-3Pa, then filling high-purity argon to the pressure of-0.04 Pa in the furnace body, repeatedly pumping and washing for three times, and filling high-purity argon of 0.03Pa into the spray gunAnd introducing high-purity argon into the furnace body until the pressure of the furnace body is-0.04 Pa, keeping the pressure difference of 0.07Pa between the spray gun and the furnace body, opening the water-cooled copper wheel to keep the speed of the water-cooled copper wheel at 5m/s, carrying out induction heating on the alloy cast ingot to 1400 ℃, quickly opening a spray gun air valve after the alloy is completely melted and stabilized, quickly spraying the alloy melt to the surface of the rolling copper wheel, and quickly solidifying the alloy melt into a quick-setting sheet with the thickness of 0.1 mm.
High-temperature stabilizing treatment: putting the quick-setting sheet obtained in the step 2) into a high vacuum furnace with the vacuum of the furnace body being 4 multiplied by 10-3Pa, filling argon, pumping to 4X 10-3Pa, heating to a solid solution temperature TstAnd (4) carrying out solid solution for 6h at 1145 ℃, and then quenching.
Comparative example 1
In comparison with example 1, comparative example 1 was prepared using only the master alloy of step 1), and the master alloy post-treatment process of step 2) was not performed.
Comparative example 2
Compared with the embodiment 1, the comparative example 2 omits the solution rapid quenching step in the post-treatment of the master alloy in the process step 2) of the embodiment 1, and adopts the same components and processes as the embodiment 1.
Comparative example 3
In comparison with example 1, comparative example 3 omits the high temperature stabilization step in the post-treatment of the master alloy in the process step 2) of example 1, and adopts the same components and processes as those of example 1.
The comparison of the alloy obtained in example 1 with that obtained in comparative example 1, comparative example 2 and comparative example 3 can be illustrated by FIGS. 1 to 8. As can be seen from fig. 1 and 2, the master alloy prepared by the process of example 1 has no second phase 2:17R in the main phase (volume fraction 0), but if the alloy is not treated, 8% (volume fraction) of 2:17R ordered phase will be present in the master alloy as shown in comparative example 1, and if the subsequent magnet preparation is performed using the master alloy in comparative example 1, the ordered 2:17R phase will inevitably remain in the magnet, resulting in a decrease in the magnet performance.
From the microscopic morphology observations of fig. 3 and 4, the major phase in the alloy treated in example 1 was the 1:7H phase, but the major phase in comparative example 1 was present in the ratio of 2:17R, while the component segregation is more severe, such component segregation affects the powder quality for magnet powder crushing.
FIG. 5 is an XRD pattern analysis of the alloy of comparative example 2, from which it can be seen that about 20% of the 2:17R ordered phase is present in the alloy. It is shown that the 1:7H phase can be obtained only by adopting the solution rapid quenching and the high-temperature stabilizing treatment at the same time. In comparative example 2, since the 2:17R phase is present in the master alloy, the diffusion of the 2:17R phase is accelerated after the high-temperature stabilization treatment, resulting in the increased ordering. FIG. 6 is a high resolution of the 1:7H phase in example 1, and it can be seen that the twin width of the 1:7H phase as the main phase is 2.0-2.4 nm wide. FIG. 7 shows that the twin width of the main phase 1:7H in comparative example 2 is 10nm or more, and the width of the partial region is 20nm or more, indicating that the disorder degree of the main phase in example 1 is higher than that in comparative example 2.
FIG. 8 is an XRD pattern analysis of the alloy of comparative example 3, from which it can be seen that without the high temperature stabilization treatment, the 2:17R phase is not present in the alloy, but a portion of the 2:17H phase is present at a level of 22%. Indicating that the high temperature stabilization treatment can further convert the ordered 2:17H structure to the major phase 1: 7H.
Examples 2 to 4
Examples 2-4 were conducted in the same manner as in example 1 except that magnet components of the formula Sm (Co)1-u-v- wFeuCuvZrw)zU in (A) is different from each other, and the specific composition is shown in Table 1.
TABLE 1
The above examples fully demonstrate the ability of the process of the present invention to inhibit the formation of the 2:17R ordered phase in high iron concentration samarium cobalt alloys. According to the results in the literature, when the magnet has a 2:17R ordered phase, an incomplete cell structure is formed after the magnet is aged, and the coercive force is rapidly reduced. The ingot treated by the process of the invention has been inhibited from generating 2:17, which illustrates the advantage of the process in preparing high Fe concentration magnets.
Although exemplary embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions, substitutions and the like can be made in form and detail without departing from the scope and spirit of the invention as disclosed in the accompanying claims, all of which are intended to fall within the scope of the claims, and that various steps in the various sections and methods of the claimed product can be combined together in any combination. Therefore, the description of the embodiments disclosed in the present invention is not intended to limit the scope of the present invention, but to describe the present invention. Accordingly, the scope of the present invention is not limited by the above embodiments, but is defined by the claims or their equivalents.
Claims (6)
1. A method for inhibiting high-temperature ordering of high-iron-concentration samarium-cobalt alloy comprises the following specific steps:
1) preparation of master alloy
Mixing Sm, Co, Cu, Fe and Zr according to the formula proportion, and the chemical formula composition is represented as Sm (Co)1-u-v-wFeuCuvZrw)zWherein u is 0.32-0.40, v is 0.05-0.08, w is 0.01-0.03, z is 7.4-8.0, then placing the crucible in a water-cooled copper crucible of a vacuum melting furnace, placing Sm easy to burn into the bottom of the crucible, and vacuumizing to 2 x 10-3～5×10-3Pa, filling high-purity argon into the furnace body, and increasing the vacuum degree in the furnace to 0.8 multiplied by 105Stopping inflating after Pa, repeatedly smelting for 3-4 times under the conditions of working voltage of 30-45V and working current of 600-800A, and cooling to obtain an alloy ingot;
when the raw materials are mixed, the actual addition amount of Sm is 3-5% more than the theoretical addition amount;
the vacuum smelting furnace is an electric arc smelting furnace or an induction smelting furnace;
2) post-treatment of master alloy
Melt rapid quenching: putting the alloy cast ingot into a quartz tube with a flat nozzle with the seam width of 0.1-0.5 mmIs arranged in a furnace body and connected with a spray gun, and is vacuumized to 3 multiplied by 10-3Pa, then filling high-purity argon until the pressure of the furnace body is-0.04 Pa, repeatedly pumping and washing for three times, filling high-purity argon of 0.03Pa into the spray gun, filling high-purity argon into the furnace body until the pressure of the furnace body is-0.04 Pa, keeping the pressure difference of 0.07Pa between the spray gun and the furnace body, opening the water-cooling copper wheel to keep the speed of the water-cooling copper wheel at 3-25 m/s, carrying out induction heating on the alloy cast ingot to 1300-1500 ℃, after the alloy is completely melted and stabilized, quickly opening an air valve of the spray gun to quickly spray the alloy melt onto the surface of the rolling copper wheel, and quickly solidifying the alloy melt into a quick-setting sheet with the thickness of 0.1-0.;
high-temperature stabilizing treatment: putting the rapid hardening sheet obtained in the melt rapid quenching step into a high vacuum furnace with the vacuum of the furnace body being 2 multiplied by 10-3～5×10-3Pa, filling argon, pumping to 2X 10-3～5×10-3Pa, heating to a solid solution temperature TstAnd (3) quenching after solid solution at 1120-1145 ℃ for 2-8 h to obtain the high-iron-concentration samarium cobalt alloy.
2. The method of claim 1, wherein: and during melt rapid quenching in the step 2), the induction heating temperature of the alloy ingot is 1350-1400 ℃.
3. The method of claim 1, wherein: and in the step 2), during melt rapid quenching, the speed of the water-cooling copper wheel is controlled to be 3-10 m/s.
4. The method of claim 1, wherein: and in the step 2), during high-temperature stabilization treatment, the solution treatment time is 4-6 h.
5. The method of claim 1, wherein: the high-iron-concentration samarium cobalt alloy has a 1:7H structure as a main phase, and the volume percentage of 2:17 phases in an ordered phase is 0-0.3%.
6. The method of claim 1, wherein: the width of the disordered 1:7H twin crystal in the high-iron-concentration samarium cobalt alloy is 2.0-2.4 nm.
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| JPH05295489A (en) * | 1992-04-21 | 1993-11-09 | Seiko Epson Corp | Alloy for bond magnet and its manufacture |
| JP3505261B2 (en) * | 1995-03-17 | 2004-03-08 | 株式会社三徳 | Sm-Co permanent magnet material, permanent magnet and method for producing the same |
| CN1198292C (en) * | 1998-10-30 | 2005-04-20 | 株式会社三德 | Sm(Co, Fe, Cu, Zr, C) compositions and methods of producing same |
| JP4832856B2 (en) * | 2005-10-31 | 2011-12-07 | 昭和電工株式会社 | Method for producing RTB-based alloy and RTB-based alloy flakes, fine powder for RTB-based rare earth permanent magnet, RTB-based rare earth permanent magnet |
| CN101620928B (en) * | 2009-06-15 | 2011-03-30 | 河北工业大学 | Sm (Co, cu, fe, zr)ztype alloy strip magnet preparation method |
| CN102403117B (en) * | 2011-10-09 | 2016-02-03 | 河北工业大学 | The preparation method of Sm-Co based amorphous nano thin strip magnet |
| CN102543340B (en) * | 2011-12-30 | 2015-06-10 | 北矿磁材科技股份有限公司 | High-performance samarium-cobalt magnetic powder and preparation method thereof |
| CN102650004B (en) * | 2012-05-24 | 2014-01-01 | 宁波科星材料科技有限公司 | Method for producing samarium-cobalt series sintered materials |
| CN105405554A (en) * | 2015-11-26 | 2016-03-16 | 宁波科星材料科技有限公司 | High-iron content and high-performance SmCo magnet |
| JP2018103211A (en) * | 2016-12-26 | 2018-07-05 | 日立金属株式会社 | Method for producing rare earth-transition metal based ferromagnetic alloy, and rare earth-transition metal based ferromagnetic alloy |
| CN107895620B (en) * | 2017-11-30 | 2019-09-13 | 北京航空航天大学 | A kind of high Fe content samarium-cobalt permanent-magnetic material and preparation method |
| CN108039258B (en) * | 2017-12-01 | 2019-04-02 | 北京航空航天大学 | A kind of high temperature high-coercive force samarium-cobalt permanent-magnetic material and preparation method |
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