A preparation method of rare earth alloy target for improving the performance of NdFeB

Abstract

The present invention discloses a preparation method of a rare earth alloy target for improving the performance of neodymium iron boron, comprising the following steps: preparing a rare earth alloy rotating target from a rare earth rotating target and a preset metal target tube, wherein the material of the rare earth rotating target is one of terbium, dysprosium, holmium, and gadolinium, and the preset metal target tube comprises at least one of aluminum, copper, nickel, iron, etc.; welding the rare earth alloy rotating target and the backing tube together; installing the rare earth alloy rotating target and the backing tube on a coating production line; performing heat treatment and tempering treatment on the magnet to obtain the treated rare earth alloy target. In order to improve the utilization rate of the rare earth target, the sputtering efficiency and achieve precise control of the composition, and at the same time shorten the grain boundary diffusion time or reduce the diffusion temperature, the rare earth and the preset metal elements are combined to prepare an alloy rotating target, and the utilization rate of the target can reach more than 85%. The rare earths such as terbium / dysprosium and the preset metal elements are simultaneously attached to the surface of the neodymium iron boron, which helps to improve the grain boundary diffusion and optimize the magnet performance.

Description

Technical Field

[0001] The present invention relates to the technical field of rare earth magnetic material coating grain boundary diffusion, and particularly relates to a method for preparing a rare earth alloy target for improving the performance of neodymium iron boron. Background Art

[0002] Adding terbium / dysprosium to magnetic materials such as neodymium iron boron is beneficial to improving their magnetic properties. Adding a preset metal element during the process of grain boundary diffusion infiltration of terbium / dysprosium is beneficial to improving grain boundary diffusion and optimizing the properties of the magnet. The methods for depositing thin films include coating method, electrophoresis method, dipping method, magnetron sputtering, etc. Among them, magnetron sputtering coating is one of the mainstream methods for neodymium iron boron grain boundary diffusion. Compared with other methods, this method has a high binding force between the obtained thin film and the magnet, controllable film thickness, and less consumption of heavy rare earths. There is no need to prepare powders to eliminate the risk of explosion and combustion, especially for metal powders or alloy powders with high chemical activity. Sputtering with elemental rare earth targets and rare earth targets of beneficial elements in sequence has problems of low sputtering efficiency and difficult composition control. In addition, the utilization rate of rare earth planar targets is generally 30%-50%, and the target utilization rate is low. Summary of the Invention

[0003] The purpose of the embodiment of the present invention is to provide a method for preparing a rare earth alloy target for improving the performance of neodymium iron boron. To improve the utilization rate of rare earth targets, sputtering efficiency and achieve precise composition control, and at the same time shorten the grain boundary diffusion time or reduce the diffusion temperature, rare earths and preset metal elements are combined to prepare an alloy rotating target, so that rare earths such as terbium / dysprosium and preset metal elements are simultaneously attached to the surface of neodymium iron boron, which helps subsequent grain boundary diffusion.

[0004] To solve the above technical problems, the embodiment of the present invention provides a method for preparing a rare earth alloy target for improving the performance of neodymium iron boron, including the following steps:

[0005] (1) Prepare a rare earth alloy rotating target from a rare earth rotating target and a preset metal target tube. The material of the rare earth rotating target is one of terbium, dysprosium, holmium, and gadolinium, and the preset metal target tube includes at least one of aluminum, copper, nickel, iron, etc.;

[0006] (2) Weld the rare earth alloy rotating target and the back tube together;

[0007] (3) Install the rare earth alloy rotating target and the back tube on a coating production line, with the target power density being 0.5 W / cm 2 -6 W / cm 2 , and the magnet weight gain is controlled within 0.2%-0.6%;

[0008] (4) Perform heat treatment and tempering treatment on the magnet to obtain the treated rare earth alloy target.

[0009] Further, in step (1), the rare earth alloy rotary target is prepared by a casting method or a powder metallurgy method using the rare earth rotary target and the preset metal target tube.

[0010] Further, the material of the rare earth rotary target is terbium or dysprosium.

[0011] Further, the preset metal target tube includes aluminum and / or copper.

[0012] Further, in step (1), the rare earth content in the rare earth alloy rotary target is 80%-95%, and the rest is the content of the preset metal.

[0013] Further, in step (3), the target power density is 3 W / cm 2 -5 W / cm 2 。

[0014] Further, in step (4), the temperature of the heat treatment is 600°C - 950°C, and the duration of the heat treatment is 5 h - 10 h.

[0015] Further, the temperature of the heat treatment is 800°C - 900°C.

[0016] Further, in step (4), the temperature of the tempering treatment is 400°C - 600°C, and the duration of the tempering treatment is 2 h - 6 h.

[0017] The above technical solution of the embodiment of the present invention has the following beneficial technical effects:

[0018] To improve the utilization rate of rare earth targets, sputtering efficiency and achieve precise control of composition, while shortening the grain boundary diffusion time or reducing the diffusion temperature, rare earths are combined with beneficial elements such as aluminum and copper to prepare an alloy rotary target. The utilization rate of the target can reach more than 85%, realizing the simultaneous deposition of rare earths such as terbium / dysprosium and beneficial elements on the surface of NdFeB, which helps to improve grain boundary diffusion and optimize the magnetic properties of the magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flowchart of a method for preparing a rare earth alloy target for improving the performance of NdFeB provided by an embodiment of the present invention;

[0020] Figure 2 is an overall structural schematic diagram of a rare earth alloy rotary target provided by an embodiment of the present invention.

[0021] Reference Signs:

[0022] 1. Back tube, 2. Non-rare earth target tube, A. Rare earth alloy target tube, OD1. Outer diameter of non-rare earth target tube at both ends of rotating target, OD2, OD3. Outer diameters of dog bone section A1 near target tubes at both ends, where OD2 > OD3, OD4. Outer diameter of target tube in middle region. Detailed implementation manners

[0023] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the specific implementation manners and with reference to the accompanying drawings. It should be understood that these descriptions are exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0024] Please refer to Figure 1 、 Figure 2 , an embodiment of the present invention provides a method for preparing a rare earth alloy target for improving the performance of neodymium iron boron, including the following steps:

[0025] Step (1): Prepare a rare earth alloy rotating target from a rare earth rotating target and a preset metal target tube. The material of the rare earth rotating target is one of terbium, dysprosium, holmium, and gadolinium, and the preset metal target tube includes at least one of aluminum, copper, nickel, iron, etc.

[0026] Specifically, in step (1), the rare earth rotating target and the preset metal target tube are prepared into a rare earth alloy rotating target by a casting method or a powder metallurgy method.

[0027] Preferably, the material of the rare earth rotating target is terbium or dysprosium.

[0028] Preferably, the preset metal target tube includes aluminum and / or copper.

[0029] Specifically, in step (1), the rare earth content in the rare earth alloy rotating target is 80% - 95%, and the rest is the content of the preset metal.

[0030] Step (2): Weld the rare earth alloy rotating target to the back tube.

[0031] 1) Preferably, the materials at both ends of the rotating target are non-rare earth, and the length is 20 mm - 35 mm.

[0032] 2) Except for both ends, the diameter (OD2) of the target material in the middle region near both ends is 2 mm - 6 mm larger than the diameter (OD3) of the middle section, and it presents a dog bone shape (A1), with a length within 300 mm;

[0033] Step (3): Install the rare earth alloy rotating target and the back tube on a coating production line, with the target power density being 0.5 W / cm 2 -6 W / cm 2 , and the weight gain of the magnet is controlled within 0.2% - 0.6%.

[0034] Preferably, the target power density is 3 W / cm 2 - 5 W / cm 2 .

[0035] Step (4): Heat-treat and temper the magnet to obtain the heat-treated rare earth alloy target.

[0036] As Figure 2 shown, OD1 is the outer diameter of the non-rare earth target tubes at both ends of the rotating target; OD2 and OD3 are the outer diameters of the dog bone section A1 near the target tubes at both ends, where OD2 > OD3; OD4 is the outer diameter of the target tube in the middle region.

[0037] Optionally, the heat treatment temperature is 600°C - 950°C, and the heat treatment duration is 5 h - 10 h.

[0038] Preferably, the heat treatment temperature is 800°C - 900°C.

[0039] Optionally, the tempering temperature is 400°C - 600°C, and the tempering duration is 2 h - 6 h.

[0040] The application of rare earth targets in the fields of magnetic material coating grain boundary diffusion, storage, and electronic information is increasing day by day. The rotating target with a utilization rate of over 70% is increasingly sought after. To improve the utilization rate of rare earth targets, sputtering efficiency, achieve precise composition control, and at the same time shorten the grain boundary diffusion time or reduce the diffusion temperature of the magnet, the present invention combines rare earths with beneficial elements such as aluminum and copper to prepare a rotating target, enabling rare earths such as terbium / dysprosium and beneficial elements to be simultaneously attached to the surface of neodymium iron boron through magnetron sputtering, which is beneficial to improving grain boundary diffusion and optimizing the magnet performance.

[0041] Example

[0042] Example 1: Prepare a terbium-aluminum alloy rotating target by the casting method. The aluminum content is 10%. The total length of the rotating target is 1600 mm. The gap between the two target tubes is 0.25 mm. It is composed of 11 joints. OD1 is 165 mm, OD2 is 165 mm, OD3 = OD4 = 158 mm. The material of the non-rare earth target tube 2 is stainless steel, and the lengths of both ends are 30 mm each; A1 presents a dog bone. Neodymium iron boron with a thickness of 6 mm is placed in the coating production line. The target power density is 4 W / cm2, the magnet weight gain ratio is 0.4%, the heat treatment temperature is 900°C, the heat treatment time is 10 h, and the tempering temperature and time are 500°C and 2 h respectively.

[0043] Comparative Example 1: A pure terbium rotating target with a weight gain ratio of 0.35%, and the other conditions are the same as those in Example 1.

[0044] Example 2: The heat treatment temperature is 850°C, and the other conditions are the same as those in Example 1.

[0045] Example 3: The heat treatment time is 8 h, and the other conditions are the same as those in Example 1.

[0046] Example 4: The aluminum content in the terbium alloy rotating target is 15%, the heat treatment temperature is 850 °C, the time is 10 h, and the weight gain ratio is 0.41%. The other conditions are the same as those in Example 1.

[0047] Comparative Example 2: The aluminum content in the terbium alloy rotating target is 25%, the heat treatment temperature is 850 °C, the time is 10 h, and the weight gain ratio is 0.47%. The other conditions are the same as those in Example 1.

[0048] Comparative Example 3: The aluminum content in the terbium alloy rotating target is 7.6%, the heat treatment temperature is 850 °C, the time is 10 h, and the weight gain ratio is 0.38%. The other conditions are the same as those in Example 1.

[0049] Example 5: The copper content in the terbium alloy rotating target is 10%, and the other conditions are the same as those in Example 2.

[0050] Example 6: The copper content in the terbium alloy rotating target is 15%, and the weight gain ratio is 0.41%. The other conditions are the same as those in Example 2.

[0051] Comparative Example 4: The copper content in the terbium alloy rotating target is 18%, and the weight gain ratio is 0.43%. The other conditions are the same as those in Example 2.

[0052] Comparative Example 5: The copper content in the terbium alloy rotating target is 4%, and the weight gain ratio is 0.36%. The other conditions are the same as those in Example 2.

[0053] Example 7: The aluminum and copper contents in the terbium alloy rotating target are both 5%, and the other conditions are the same as those in Example 2.

[0054] Example 8: The aluminum content in the dysprosium alloy rotating target is 15%, and the weight gain ratio is 0.41%. The other conditions are the same as those in Example 2.

[0055] Example 9: The copper content in the dysprosium alloy rotating target is 10%, and the weight gain ratio is 0.4%. The other conditions are the same as those in Example 2.

[0056] Comparative Example 6: The sputtering target is a pure dysprosium target, and the weight gain ratio is 0.35%. The other conditions are the same as those in Example 2.

[0057] Comparative Example 7: LA1 and LA6 are not dog-bone shaped, OD2 = OD3 = 165 mm, and the heat treatment temperature is 850 °C. The other conditions are the same as those in Example 1.

[0058] Comparative Example 8: The materials of the non-rare earth target tubes 2 and 3 are terbium, and the heat treatment temperature is 850 °C. The other conditions are the same as those in Example 1.

[0059] Example 10

[0060] In the dysprosium alloy rotary target, the copper content is 10%, the weight gain ratio is 0.4%, the heat treatment temperature is 950 °C, and the time is 5 h. The other conditions are the same as those in Example 2.

[0061] Example 11

[0062] In the dysprosium alloy rotary target, the copper content is 10%, the weight gain ratio is 0.4%, the heat treatment temperature is 800 °C, and the time is 8 h. The other conditions are the same as those in Example 2.

[0063] Example 12

[0064] In the terbium alloy rotary target, the copper content is 10%, the weight gain ratio is 0.4%, the heat treatment temperature is 600 °C, and the time is 10 h. The other conditions are the same as those in Example 2.

[0065] Table 1 Performance parameter table of each example and comparative example

[0066]

[0067]

[0068] As can be seen from the data in Table 1 above, the co-sputtering rare earth rotary target provided by the embodiments of the present invention can simultaneously achieve the co-sputtering of rare earth and co-sputtering elements on one target by controlling the length ratio of the rare earth target tube and the co-sputtering target tube and controlling the target structure, which can improve the sputtering efficiency, shorten the diffusion temperature or reduce the diffusion temperature, and can improve the grain boundary diffusion and optimize the magnet performance:

[0069] (1) Under the condition that the terbium content in the magnet increases by the same content, adding a certain content of beneficial elements aluminum and copper is beneficial to optimizing the magnet performance. After adding 10% and 15% of aluminum to the terbium target, the coercivity is increased by 0.7 KOe and 0.4 KOe compared with adding pure terbium. After adding 10% and 15% of copper to the terbium target, the coercivity is increased by 0.5 KOe and 0.3 KOe compared with adding pure terbium.

[0070] (2) Compared with adding pure terbium, adding an appropriate amount of beneficial elements can reduce the diffusion temperature or shorten the diffusion time under the condition of achieving the same coercivity. For example, under the conditions of the heat treatment temperature of 850 °C - heat treatment time of 10 h and heat treatment temperature of 900 °C - heat treatment time of 8 h for adding co-sputtering elements and the heat treatment temperature of 900 °C - heat treatment time of 10 h for adding pure terbium, the coercivity of the magnet reaches more than 41 KOe.

[0071] (3) Replacing the two ends of the target with non-rare earth target tubes, or processing the target tube A1 near the two ends of the target into a dog bone shape is beneficial to improving the target utilization rate. When both are adopted at the same time, the target utilization rate is as high as 88%.

[0072] An embodiment of the present invention aims to protect a method for preparing a rare earth alloy target for improving the performance of neodymium iron boron, which includes the following steps: (1) preparing a rare earth alloy rotating target from a rare earth rotating target and a preset metal target tube, where the material of the rare earth rotating target is one of terbium, dysprosium, holmium, and gadolinium, and the preset metal target tube includes at least one of aluminum, copper, nickel, iron, etc.; (2) welding the rare earth alloy rotating target and the backing tube together; (3) installing the rare earth alloy rotating target and the backing tube on a coating production line, with the target power density being 0.5 W / cm 2 - 6 W / cm 2 , and controlling the magnet weight gain to be within 0.2% - 0.6%; (4) performing heat treatment and tempering treatment on the magnet to obtain the treated rare earth alloy target. The above technical solution has the following effects:

[0073] To improve the utilization rate of rare earth targets, sputtering efficiency, and achieve precise control of composition, while shortening the grain boundary diffusion time or reducing the diffusion temperature, rare earths are combined with beneficial elements such as aluminum and copper to prepare an alloy rotating target. The utilization rate of the target can reach over 85%, enabling rare earths such as terbium / dysprosium and beneficial elements to be simultaneously deposited on the surface of neodymium iron boron, which helps to improve grain boundary diffusion and optimize the magnet performance.

[0074] It should be understood that the above specific embodiments of the present invention are only used for exemplary illustration or explanation of the principle of the present invention, and do not constitute a limitation to the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all variations and modification examples falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A method for preparing a rare earth alloy target for improving the performance of neodymium iron boron, characterized in that, it comprises the following steps: (1) Prepare a rare earth alloy rotating target from a rare earth rotating target and a preset metal target tube. The material of the rare earth rotating target is one of terbium, dysprosium, holmium, and gadolinium, and the preset metal target tube includes aluminum and copper; (2) Weld the rare earth alloy rotating target and the back tube together. The diameters of both ends of the rare earth alloy rotating target are larger than the diameter at the middle position, and both ends of the rare earth alloy rotating target are made of non-rare earth materials; (3) The rare earth alloy rotating target and the back tube are installed on the coating production line, and the target power density is 0.5W / cm 2 -6W / cm 2 , the weight gain of magnet is controlled at 0.2%-0.6%; (4) Perform heat treatment and tempering treatment on the magnet to obtain a treated rare earth alloy target; In step (1), the rare earth content in the rare earth alloy rotating target is 85%-90%, and the rest is the content of the preset metal; In step (4), the temperature of the heat treatment is 800°C-900°C, and the duration of the heat treatment is 5h-10h.

2. The method for preparing a rare earth alloy target for improving the performance of neodymium iron boron according to claim 1, characterized in that, in step (1), the rare earth rotating target and the preset metal target tube are prepared into the rare earth alloy rotating target by a casting method or a powder metallurgy method.

3. The method for preparing a rare earth alloy target for improving the performance of neodymium iron boron according to claim 1 or 2, characterized in that, the material of the rare earth rotating target is terbium or dysprosium.

4. The method for preparing a rare earth alloy target for improving the performance of neodymium iron boron according to claim 1 or 2, characterized in that, In step (3), the target power density is 3 W / cm 2 - 5 W / cm 2 .

5. The method for preparing a rare earth alloy target for improving the performance of neodymium iron boron according to claim 1 or 2, characterized in that, in step (4), the temperature of the tempering treatment is 400°C-600°C, and the duration of the tempering treatment is 2h-6h.

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