High-permeability nickel-platinum alloy target blank and preparation method thereof

Abstract

The invention belongs to the field of integrated circuit target manufacturing, and discloses a high-permeability nickel-platinum alloy target blank preparation method, which comprises: (1) sequentially carrying out hot forging, heat treatment, hot rolling and recrystallization annealing on a nickel-platinum alloy ingot to obtain a nickel-platinum alloy blank; (2) the nickel-platinum alloy blank is subjected to cold rolling, and a nickel-platinum alloy target blank is obtained; cold rolling comprises at least three times; the single rolling comprises first rolling and second rolling; after the nickel-platinum alloy blank is rolled for the first time, the nickel-platinum alloy blank is rotated by 40-50 degrees to be rolled for the second time; one time of annealing is carried out between every two times of cold rolling, and the annealing temperature is gradually reduced by 80-100 DEG C by taking the recrystallization annealing temperature as a reference. The cold rolling process is optimized, after the nickel-platinum alloy blank is rolled for the first time, the nickel-platinum alloy blank is rotated by 40-45 degrees, then the nickel-platinum alloy blank is rolled for the second time, temperature control of successive annealing is matched, and the PTF of the prepared nickel-platinum alloy target blank is larger than 70%. The invention further discloses the nickel-platinum alloy target blank with the high magnetic permeability.

Description

Technical Field

[0001] The invention belongs to the field of integrated circuit target material manufacturing, and specifically relates to a high-permeability nickel-platinum alloy target blank and a preparation method thereof. Background Art

[0002] Metal silicide has been widely used in semiconductor technology due to its excellent high-temperature oxidation resistance and good electrical and thermal conductivity. Specifically, metal silicide can reduce the contact resistance of transistors at the gate, source and drain, thereby increasing the driving current, response time or circuit operation speed of the entire component.

[0003] As semiconductor components develop towards smaller sizes, they are more significantly affected by resistance, so the research on metal silicide has attracted attention. Generally speaking, titanium silicide or cobalt silicide is usually used as the main material in complementary metal-oxide-semiconductor (CMOS) above 90 nanometers; when the CMOS process develops to below 65 nanometers, nickel silicide with better properties is selected instead. In particular, when the CMOS process is below 45 nanometers, in order to improve the adverse effects of the short-channel effects that occur, oxide materials with high dielectric constants (such as hafnium dioxide) are usually selected to replace the silicon dioxide insulating layer, and nickel silicide with characteristics such as low resistance, low silicon consumption and low process temperature is used. However, nickel silicide has poor thermal stability and needs to be improved by adding platinum elements. Therefore, nickel-platinum alloy targets are one of the important sources for making nickel silicide.

[0004] A typical application of nickel platinum silicide film in semiconductor devices is Schottky diode (discrete device). Schottky diode is a metal-semiconductor device that uses metal and N-type semiconductor to form a potential barrier, thus having rectification characteristics. It is widely used in switching power supplies, inverters, drivers and other circuits.

[0005] Nickel platinum silicide is also widely used in the contact between source, drain, gate and metal electrodes in very large scale integrated circuit (VLSI) microelectronic devices. At present, Ni-5at% has been successfully applied to 65nm technology, and Ni-10at%Pt has been applied to 45nm technology. With the further reduction of the line width of semiconductor devices, it is very likely that the Pt content in the nickel platinum alloy will need to be further increased to prepare the NiPtSi contact film. The main reason is that the increase in the Pt content in the alloy can improve the high temperature stability of the film and change the cross-sectional morphology, reducing the encroachment defects.

[0006] Nickel-platinum alloy target is a magnetic target. For high magnetic permeability targets, especially targets with high saturation magnetic induction intensity such as Fe, Co, Ni and alloys, it is often difficult to sputter because the material has the function of shielding the magnetic field. The solution to this fundamental problem is to reduce the magnetic permeability of the material, reduce the magnetic shielding effect of ferromagnetic materials, and increase the magnetic field on the target surface. The ratio of the magnetic field intensity when there is a target and the magnetic field intensity when there is no target at the same position near the target surface in the sputtering magnetic field is usually defined as the magnetic permeability (PTF). The higher the magnetic permeability, the higher the magnetic field intensity on the target surface, and the easier it is for the target to be sputtered.

[0007] Ni and Pt are both transition metals. They can form a stable face-centered cubic structure solid solution in any mixing ratio. Among them, Ni exhibits ferromagnetism and Pt exhibits paramagnetism. The magnetism of Ni-Pt alloy originates from the interaction between Ni3d and Pt5d electron orbitals that are not filled with electrons. The magnetic moment of Ni in the alloy is very fragile and easily affected by neighboring atoms. In the face-centered cubic structure, one Ni atom must have at least 6 Ni atoms in its vicinity to maintain its magnetism. Therefore, with the increase of Pt content, the magnetism of Ni-Pt alloy weakens and changes from ferromagnetism to paramagnetism. Therefore, when the Pt content is greater than 10at%, PTF is easy to improve. However, when the Pt content is low, at 1-9at%, it is particularly important to improve PTF performance.

[0008] CN112808833A provides a method for preparing a high-performance ferromagnetic target material, which contains Ni and NiPt, and uses a spinning method to improve the magnetic permeability of the target blank, but the final PTF can only reach 42%;

[0009] CN104018128B discloses a nickel-platinum alloy sputtering target and a preparation method thereof. In the nickel-platinum alloy sputtering target, the platinum content is 0-5at%, the average grain size of the target is less than 80 microns and the single grain size is not more than 150 microns, the target has a uniformly distributed diffraction peak intensity combination, and the diffraction peak intensity in a single direction is not more than 50%, the magnetic permeability of the target is greater than 40%, and the difference in the values ​​measured in different directions is within 5%. The nickel-platinum alloy sputtering target can reduce the occurrence of sputtering, has a long service life, and the film prepared using the target has good uniformity.

[0010] The above technical solution records the target material performance evaluation in paragraph 0049 of the specification. The PTF of the nickel-platinum alloy target material prepared by the method of the above technical solution can only reach 60% at most.

[0011] In addition to the above two public patents, there are many preparation technologies for nickel-platinum alloy target preparation, but none of them mention the improvement of PTF. It is an insurmountable gap to achieve PTF ≥ 70%. Therefore, the technical problem to be solved by the present invention is how to improve the PTF of nickel-platinum alloy target to more than 70%. Summary of the invention

[0012] The purpose of the present invention is to provide a method for preparing a high-permeability nickel-platinum alloy target blank. The method refines the grains by hot forging and hot rolling, and focuses on optimizing the cold rolling process. After the nickel-platinum alloy blank is rolled for the first time, the nickel-platinum alloy blank is rotated 40 to 50 degrees, and then rolled for the second time. The temperature of the nickel-platinum alloy target blank is controlled by the successive annealing to improve the

[100] orientation of the rolled surface, thereby improving the PTF of the target blank to more than 70%. At the same time, the present application also provides a high-permeability nickel-platinum alloy target blank prepared by the method, and the PTF of the nickel-platinum alloy target blank is greater than 70%.

[0013] To achieve the above objectives, this application provides the following technical solutions:

[0014] A method for preparing a high magnetic permeability nickel-platinum alloy target blank comprises the following steps:

[0015] Step (1): subjecting a nickel-platinum alloy ingot to hot forging, heat treatment, hot rolling and recrystallization annealing in sequence to obtain a nickel-platinum alloy billet;

[0016] Step (2): cold rolling the nickel-platinum alloy blank to obtain a nickel-platinum alloy target blank;

[0017] Cold rolling includes at least three times; a single cold rolling includes a first rolling and a second rolling;

[0018] After the nickel-platinum alloy billet is rolled for the first time, the nickel-platinum alloy billet is rotated 40-50 degrees and rolled for the second time; annealing is performed between each two cold rollings, and the annealing temperature is gradually reduced by 80-100°C based on the temperature of recrystallization annealing.

[0019] In some embodiments, after the first rolling, the rotation angle of the nickel-platinum alloy billet can be 40°, 41°, 42°, 43°, 44°, or 45°, but is not limited to the listed values, and other unlisted values ​​are applicable as long as they are within this range.

[0020] In some embodiments, the annealing temperature between each two cold rollings can be successively reduced by 80°C, 85°C, 90°C, 95°C, and 100°C, but is not limited to the listed values, and other unlisted values ​​are applicable as long as they are within this range.

[0021] Preferably, in step (1), hot forging specifically comprises: keeping the nickel-platinum alloy ingot at 900-1100° C. for 60-90 minutes to soften it, and then completing hot forging by three upsetting and three drawing, and the deformation rate of each three upsetting and three drawing is greater than 50%.

[0022] In some embodiments, the insulation temperature may be 900°C, 950°C, 1000°C, 1050°C, 1000°C, but is not limited to the listed values, and other values ​​not listed are applicable as long as they are within this range. The insulation time may be 60min, 65min, 70min, 75min, 80min, 85min, 90min, but is not limited to the listed values, and other values ​​not listed are applicable as long as they are within this range.

[0023] Preferably, in step (1), the heat treatment temperature is 850-950° C., the time is 30-60 min, and hot rolling is performed immediately after the heat treatment is completed.

[0024] In some embodiments, the heat treatment temperature can be 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C, or 950°C, and the time can be 30 min, 40 min, 50 min, or 60 min, but is not limited to the listed values, and other unlisted values ​​are applicable as long as they are within this range.

[0025] Preferably, in step (1), the hot rolling temperature is 850-950°C, the single hot rolling deformation rate is 10-15%, the total hot rolling deformation rate is 75-85%, and the steel is re-melted every 3-4 passes for 10-15 minutes.

[0026] In some embodiments, the hot rolling temperature may be 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C, 950°C, but is not limited to the listed values, and other values ​​not listed are applicable as long as they are within this range;

[0027] The melting time can be 10min, 11min, 12min, 13min, 14min, 15min, but is not limited to the listed values. Other values ​​not listed are applicable as long as they are within this range.

[0028] The deformation rate of a single hot rolling pass can be 10%, 11%, 12%, 13%, 14%, 15%, but is not limited to the listed values. Other values ​​not listed are applicable as long as they are within this range;

[0029] The total hot rolling deformation rate can be 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, or 85%, but is not limited to the listed values. Other values ​​not listed are applicable as long as they are within this range.

[0030] Preferably, in step (1), the temperature of the recrystallization annealing is 850-950° C., and the time is 30-60 min.

[0031] Specifically, the temperature of recrystallization annealing can be 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C, and 950°C, and the time can be 30 min, 40 min, 50 min, and 60 min, but is not limited to the listed values, and other unlisted values ​​are applicable as long as they are within this range.

[0032] Preferably, the first rolling and the second rolling are both performed by alternating the horizontal rolling and the vertical rolling at an angle of 90 degrees clockwise. The first rolling and the second rolling methods have been disclosed in Chinese patent CN104018128B, so they are not described in detail in the embodiments of the present invention.

[0033] Preferably, the deformation rates of the first rolling and the second rolling are both 3.5-4.5%, and the total deformation rate of a single cold rolling is 28-36%.

[0034] Specifically, in combination with the above-mentioned rolling method, in the first rolling, transverse rolling and longitudinal rolling are alternately rolled clockwise at an angle of 90 degrees, that is, four points are rolled on the nickel-platinum alloy billet, and the deformation rate of each point can be 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, and 4.5%; the second rolling is exactly the same as the first rolling except for the position, and the total deformation rate of a single cold rolling can be 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, and 36%, but is not limited to the listed values, and other values ​​not listed are applicable as long as they are within this range.

[0035] Preferably, the annealing time is 30 to 60 minutes.

[0036] Specifically, if the number of cold rolling is three times, then after the first time, the annealing temperature can be 750℃~870℃, specifically 750℃, 760℃, 770℃, 780℃, 790℃, 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃; after the second time, the annealing temperature can be 650℃~790℃, specifically 650℃, 660℃, 670℃, 680℃, 690℃, 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, 760℃, 770℃, 780℃, 790℃; the annealing time can be 30min, 40min, 50min, 60min, but is not limited to the listed values, and other values ​​not listed are applicable as long as they are within this range.

[0037] At the same time, the present application also provides a high magnetic permeability nickel-platinum alloy target blank, which is prepared by the preparation method of a high magnetic permeability nickel-platinum alloy target blank as claimed in any one of claims 1 to 8. In the nickel-platinum alloy target blank, the platinum content is 1 to 10 at%, the grain is <100 um, the hardness is >180 HV, the rolling surface

[100] accounts for >30%, and the PTF is >70%.

[0038] Compared with the prior art, the beneficial effects of this application are:

[0039] The present application optimizes the cold rolling process. After the nickel-platinum alloy billet completes the first rolling, the nickel-platinum alloy billet is rotated 40 to 45 degrees and then rolled for the second time. The temperature of the successive annealing is controlled to improve the

[100] orientation of the rolled surface of the nickel-platinum alloy target billet, thereby increasing the PTF of the target billet to more than 70%. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the first rolling and the second rolling of the present invention;

[0041] Figure 2 is a schematic diagram of a face-centered cubic structure of the present invention;

[0042] Figure 3 It is a schematic diagram of the angle between the plane

[110] and the plane index

[100] of the face-centered cubic structure of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0044] Before describing the embodiments of the present invention, the rotation of the nickel-platinum alloy billet is first described. For details, refer to Figure 1 During the first rolling, points 1, 2, 3, and 4 are rolled in sequence, and then the nickel-platinum alloy billet is rotated 40 to 50 degrees and then rolled for the second time, and points 5, 6, 7, and 8 are rolled in sequence.

[0045] For the calculation of face-centered cubic structure and angle, please refer to Figure 2 and Figure 3 .

[0046] In the following examples and comparative examples, the nickel-platinum alloy ingot used has a platinum content of 5 at %.

[0047] Example 1

[0048] A method for preparing a high magnetic permeability nickel-platinum alloy target blank comprises the following steps:

[0049] Step (1): keeping the nickel-platinum alloy ingot at 1100° C. for 60 minutes to soften it, performing hot forging by three upsetting and three drawing processes with a deformation rate of 60% each time, and then performing heat treatment at 950° C. for 30 minutes. After the heat treatment is completed, hot rolling is immediately performed, the hot rolling temperature is 950° C., the single hot rolling deformation rate is 15%, the total hot rolling deformation rate is 85%, and the ingot is returned to the furnace once every three passes for 10 minutes. After the hot rolling is completed, recrystallization annealing is performed at 900° C. for 30 minutes to obtain a nickel-platinum alloy billet;

[0050] Step (2): cold rolling the nickel-platinum alloy billet three times, each time including a first rolling and a second rolling, adopting a method of alternating horizontal rolling and vertical rolling at an angle of 90 degrees clockwise, after the nickel-platinum alloy billet is rolled for the first time at a deformation rate of 3.5% per pass, the nickel-platinum alloy billet is rotated 45°, and then rolled for the second time in the same manner and deformation rate as the first rolling, the total deformation rate of the first cold rolling is 28%, and after the first cold rolling is completed, the first annealing is performed, the annealing temperature is based on the temperature of recrystallization annealing, and is gradually reduced by 100°C, that is, the temperature of the first annealing is 800°C, and the time is 30 minutes, and then the second cold rolling is completed in the same cold rolling manner, and then the second annealing is performed, the temperature of the second annealing is 700°C, and the time is 30 minutes, and then the third cold rolling is completed in the same cold rolling manner to obtain a nickel-platinum alloy target billet.

[0051] Example 2

[0052] A method for preparing a high magnetic permeability nickel-platinum alloy target blank comprises the following steps:

[0053] Step (1): keeping the nickel-platinum alloy ingot at 900° C. for 90 minutes to soften it, and then performing hot forging by three upsetting and three drawing processes with a deformation rate of 65% each time, and then performing heat treatment at a temperature of 850° C. for 60 minutes. After the heat treatment is completed, hot rolling is immediately performed, the hot rolling temperature is 850° C., the time is 15 minutes, the single-pass hot rolling deformation rate is 10%, the total hot rolling deformation rate is 75%, and the ingot is returned to the furnace once every three passes. After the hot rolling is completed, recrystallization annealing is performed at a temperature of 850° C. for 60 minutes to obtain a nickel-platinum alloy billet;

[0054] Step (2): cold rolling the nickel-platinum alloy billet three times, each time including a first rolling and a second rolling, adopting a method of alternating horizontal rolling and longitudinal rolling at an angle of 90 degrees in a clockwise direction, after the nickel-platinum alloy billet is rolled for the first time at a deformation rate of 4.5% per pass, the nickel-platinum alloy billet is rotated 40°, and then rolled for the second time in the same manner and deformation rate as the first rolling, the total deformation rate of the first cold rolling is 36%, and after the first cold rolling is completed, the first annealing is performed, and the annealing temperature is based on the temperature of recrystallization annealing, and is gradually reduced by 80°C, that is, the temperature of the first annealing is 770°C, and the time is 60 minutes, and then the second cold rolling is completed in the same cold rolling method, and then the second annealing is performed, and the temperature of the second annealing is 690°C, and the time is 60 minutes, and then the third cold rolling is completed in the same cold rolling method to obtain a nickel-platinum alloy target billet.

[0055] Example 3

[0056] A method for preparing a high magnetic permeability nickel-platinum alloy target blank comprises the following steps:

[0057] Step (1): keeping the nickel-platinum alloy ingot at 1000° C. for 75 minutes to soften it, performing hot forging by three upsetting and three drawing processes with a deformation rate of 55% each time, and then performing heat treatment at 900° C. for 45 minutes. After the heat treatment is completed, hot rolling is immediately performed, the hot rolling temperature is 900° C., the time is 13 minutes, the single-pass hot rolling deformation rate is 13%, the total hot rolling deformation rate is 80%, and the ingot is returned to the furnace once every 4 passes. After the hot rolling is completed, recrystallization annealing is performed at 950° C. for 45 minutes to obtain a nickel-platinum alloy billet;

[0058] Step (2): cold rolling the nickel-platinum alloy billet three times, each time including a first rolling and a second rolling, adopting a method of alternating horizontal rolling and longitudinal rolling at an angle of 90 degrees in a clockwise direction, after the nickel-platinum alloy billet is rolled for the first time at a deformation rate of 4% per pass, the nickel-platinum alloy billet is rotated 50°, and then rolled for the second time in the same manner and deformation rate as the first rolling, the total deformation rate of the first cold rolling is 32%, and after the first cold rolling is completed, the first annealing is performed, and the annealing temperature is based on the temperature of recrystallization annealing, and is gradually reduced by 90°C, that is, the temperature of the first annealing is 860°C, and the time is 45 minutes, and then the second cold rolling is completed in the same cold rolling manner, and then the second annealing is performed, the temperature of the second annealing is 770°C, and the time is 45 minutes, and then the third cold rolling is completed in the same cold rolling manner to obtain a nickel-platinum alloy target billet.

[0059] Example 4

[0060] It is basically the same as Example 1, except that the number of cold rolling is four times, the temperature of the third annealing is 600° C., and the time is 30 minutes.

[0061] Example 5

[0062] It is basically the same as Example 1, except that the number of cold rolling is five times, the temperature of the fourth annealing is 500° C., and the time is 30 minutes.

[0063] Comparative Example 1

[0064] It is basically the same as Example 1, except that the number of cold rolling times is one.

[0065] Comparative Example 2

[0066] It is basically the same as Example 1, except that the number of cold rolling is two.

[0067] Comparative Example 3

[0068] It is basically the same as Example 1, except that the nickel-platinum alloy billet is not rotated 45° before the second rolling.

[0069] Comparative Example 4

[0070] The method is basically the same as Example 1, except that the annealing temperature between each two cold rollings is 900°C.

[0071] Comparative Example 5

[0072] It is basically the same as Example 1, except that the annealing temperature is gradually reduced by 50°C.

[0073] Comparative Example 6

[0074] It is basically the same as Example 1, except that there is no cold rolling after recrystallization annealing.

[0075] Comparative Example 7

[0076] It is basically the same as Example 1, except that before the second rolling, the nickel-platinum alloy billet is rotated 30°.

[0077] Comparative Example 8

[0078] The method is basically the same as Example 1, except that the nickel-platinum alloy billet is rotated 60° before the second rolling.

[0079] Test method: The nickel-platinum alloy target blanks prepared by the preparation methods of high permeability nickel-platinum alloy target blanks of Examples 1 to 5 and Comparative Examples 1 to 8 were calibrated and then wire-cut to take small samples to detect grain size, crystal orientation and target blank hardness. After machining to a finished product thickness of 3±0.05 mm, PTF was tested. The test results are shown in Table 1.

[0080] Wherein, (1) grain size: measured by the cross-section method disclosed in the national standard GB / T 6394-2017 “Method for determination of average grain size of metals”;

[0081] (2) Magnetic permeability: measured in accordance with YS / T 1124-2016 “Test method for magnetic permeability of magnetic sputtering target”;

[0082] (3) The proportion of grains with crystal orientations

[100] and

[110] was measured by electron backscattered diffraction (EBSD) mounted on a scanning electron microscope (SEM);

[0083] Table 1 Test results

[0084]

[0085]

[0086] Result analysis:

[0087] 1. From the results of Examples 1 to 3, it can be seen that the use of temperature control of steering cold rolling combined with successive annealing can significantly improve the

[100] orientation of the rolled surface of the nickel-platinum alloy target blank, and the PTF of the nickel-platinum alloy target blank is stably increased to more than 70%, with the highest being 72.5% in Example 2 and the lowest being 70.8% in Example 3, with a difference of nearly 1.7%, indicating that the present method has excellent stability, and the average grain size and hardness of the target blank are very ideal.

[0088] 2. From the results of Example 1, Example 4, and Example 5, it can be seen that, unlike Example 1, Example 4 has one more cold rolling times than Example 1, while Example 5 has two more cold rolling times than Example 1. However, in terms of results, the PTF of Example 4 is 2% higher than that of Example 1, while the PTF of Example 5 is only 1.3% higher than that of Example 4. In fact, during the cold rolling process, a large number of dislocations are generated in the metal crystals, and the dislocation density increases significantly with the increase in deformation. However, when the deformation reaches a certain extent, the dislocations are entangled with each other, forming dislocation cells or subgrain boundaries, resulting in increased resistance to dislocation movement, further limited proliferation, and a tendency of dislocation density to dynamic equilibrium. This is also the main factor that causes the PTF to decrease with the increase in the number of cold rolling times and gradually stabilize.

[0089] 3. From the results of Example 1, Comparative Example 1 and Comparative Example 2, it can be seen that although Comparative Example 1 and Comparative Example 2 meet the temperature control of cold rolling combined with successive annealing, the number of cold rolling is less than three times, resulting in the PTF of the nickel-platinum alloy target blanks prepared in Comparative Example 1 and Comparative Example 2 being less than ideal, with the maximum difference from Example 1 reaching 14%, further illustrating that multiple cold rolling combined with successive annealing temperature control are required to stably increase the PTF of the nickel-platinum alloy target blank to more than 70%.

[0090] 4. From the results of Example 1 and Comparative Examples 3 to 5, it can be seen that, compared with the conventional process, Comparative Example 3 only has the additional number of rolling times and temperature control of successive annealing. It is certain that cold rolling can improve PTF, but after temperature control of step-by-step successive annealing, PTF can only reach 60.3%. Combining the

[100] ratio and

[110] ratio of Comparative Example 3, it can be found that the

[110] ratio in Comparative Example 3 is significantly higher than the

[100] ratio, that is, it is difficult to increase the

[100] ratio by reducing the

[110] ratio in normal cold rolling;

[0091] Comparative Example 4 does not use temperature control of successive annealing. From the results of Comparative Example 4, it can be seen that although the PTF can reach 64.6% by only using steering rolling, which is higher than 60.3% of Comparative Example 3, and the

[100] ratio is also improved, the PTF of the nickel-platinum alloy target blank cannot be stably increased to more than 70% without temperature control of successive annealing;

[0092] Comparative Example 5, on the other hand, uses a lower difference in the temperature control of successive annealing. From the results of Comparative Example 5, it can be seen that the PTF of the nickel-platinum alloy target blank prepared in Comparative Example 5 is better than the PTF of the nickel-platinum alloy target blank in Comparative Example 4. Although the advantage is not obvious, it shows that the result of successively reducing the annealing temperature by 80 to 100°C is more ideal. It further shows that the use of steering cold rolling combined with successive annealing temperature control can significantly improve the

[100] orientation of the rolled surface of the nickel-platinum alloy target blank, and the PTF of the nickel-platinum alloy target blank is stably increased to more than 70%.

[0093] 5. From the results of Example 1 and Comparative Example 6, it can be determined that cold rolling can improve the

[100] orientation of the rolled surface of the nickel-platinum alloy target blank, thereby improving the PTF of the nickel-platinum alloy target blank. By combining cold rolling with turning and successive annealing temperature control, the

[100] orientation of the rolled surface of the nickel-platinum alloy target blank can be significantly improved, and the PTF of the nickel-platinum alloy target blank is stably increased to more than 70%.

[0094] 6. From the results of Example 1, Comparative Example 7 and Comparative Example 8, we noticed that when the rotation angle exceeds the range of 40° to 50°, it is difficult to reduce the

[110] ratio, whether it is lower or higher than this range, resulting in the

[100] ratio being still very low, and the PTF of the nickel-platinum alloy target blank cannot be increased to more than 70%. Therefore,

[0095] It can be concluded that the optimal rotation angle should be between 40° and 50°. When the rotation angle is lower or higher than this range, the proportion of

[100] cannot be increased.

[0096] From the principle analysis:

[0097] Both Ni and Pt have face-centered cubic (fcc) structures. Figure 1 , the close-packed plane is {111}, and the close-packed direction <110> , slip system {111} <110> The initial crystal orientation of the surface is mainly

[110] , and within 0-15°,

[110] accounts for more than 35%, and

[111] accounts for less than 5%. Because

[100] is the difficult magnetization axis and

[111] is the easy magnetization axis, when the

[100] preferred orientation is presented, the crystal orientation is exactly consistent with the direction of the difficult magnetization axis, and the alloy is difficult to magnetize. Therefore, the

[100] orientation is very beneficial for improving the PTF of the target material.

[0098] In the face-centered cubic structure, refer to the attached Figure 2 and attached Figure 3 , according to the crystal orientation theory, equation 2 is derived from equation 1:

[0099] Formula 1:

[0100] Formula 2:

[0101] During the experiment, after the first rolling, the nickel-platinum alloy target blank was turned 45° and scaled from 45° to 40-50° to achieve a very ideal effect. Therefore, by controlling the turning angle within the range of 40-50°,

[110] can be transformed into

[100] . Combined with the annealing temperature control of gradually reducing 80-100°C, the

[100] orientation of the rolled surface of the nickel-platinum alloy target blank can be significantly improved, and the PTF of the nickel-platinum alloy target blank can be stably increased to more than 70%.

[0102] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for preparing a high magnetic permeability nickel-platinum alloy target blank, characterized in that: The steps include: Step (1): subjecting a nickel-platinum alloy ingot to hot forging, heat treatment, hot rolling and recrystallization annealing in sequence to obtain a nickel-platinum alloy billet; Step (2): cold rolling the nickel-platinum alloy blank to obtain a nickel-platinum alloy target blank; The cold rolling includes at least three times; a single cold rolling includes a first rolling and a second rolling; After the nickel-platinum alloy billet is rolled for the first time, the nickel-platinum alloy billet is rotated 40-50 degrees and rolled for the second time; annealing is performed between each two cold rollings, and the annealing temperature is gradually reduced by 80-100°C based on the temperature of recrystallization annealing.

2. The method for preparing a high permeability nickel-platinum alloy target blank according to claim 1, characterized in that: In the step (1), the hot forging is specifically as follows: keeping the nickel-platinum alloy ingot at 900-1100° C. for 60-90 minutes to soften it, and then completing the hot forging by three upsetting and three drawing, wherein the deformation rate of each upsetting and three drawing is greater than 50%.

3. The method for preparing a high permeability nickel-platinum alloy target blank according to claim 1, characterized in that: In the step (1), the heat treatment temperature is 850-950° C., the time is 30-60 min, and hot rolling is performed immediately after the heat treatment is completed.

4. The method for preparing a high permeability nickel-platinum alloy target blank according to claim 1, characterized in that: In the step (1), the hot rolling temperature is 850-950°C, the single hot rolling deformation rate is 10-15%, the total hot rolling deformation rate is 75-85%, and the furnace is re-melted every 3-4 passes for 10-15 minutes.

5. The method for preparing a high permeability nickel-platinum alloy target blank according to claim 1, characterized in that: In the step (1), the temperature of the recrystallization annealing is 850-950° C. and the time is 30-60 min.

6. The method for preparing a high permeability nickel-platinum alloy target blank according to claim 1, characterized in that: The first rolling and the second rolling are both performed by alternating horizontal rolling and vertical rolling at an angle of 90 degrees in a clockwise direction.

7. The method for preparing a high permeability nickel-platinum alloy target blank according to claim 6, characterized in that: The deformation rates of the first rolling and the second rolling are both 3.5-4.5%, and the total deformation rate of a single cold rolling is 28-36%.

8. The method for preparing a high permeability nickel-platinum alloy target blank according to claim 1, characterized in that: The annealing time is 30 to 60 minutes.

9. A high magnetic permeability nickel-platinum alloy target blank, characterized in that: The nickel-platinum alloy target blank is prepared by the preparation method of the high magnetic permeability nickel-platinum alloy target blank as described in any one of claims 1 to 8, wherein the platinum content of the nickel-platinum alloy target blank is 1 to 10 at%, the grain size is <100 um, the hardness is >180 HV, the rolling surface [100] accounts for >30%, and the PTF is >70%.

Images