A high permeability nickel-platinum alloy target and a method of making the same

Abstract

This invention belongs to the field of integrated circuit target manufacturing and discloses a method for preparing a high-permeability nickel-platinum alloy target blank, including the following steps: Step (1): After hot forging, heat treatment, hot rolling and recrystallization annealing of the nickel-platinum alloy ingot, a nickel-platinum alloy billet is obtained; Step (2): The nickel-platinum alloy billet is cold rolled to obtain a nickel-platinum alloy target blank; the cold rolling includes at least three times; each time includes a first rolling and a second rolling; after the first rolling is completed, the nickel-platinum alloy billet is rotated 40-50° and rolled a second time; an annealing is performed between each two cold rollings, and the annealing temperature is based on the recrystallization annealing temperature and gradually decreased by 80-100°. This application optimizes the cold rolling process, after the first rolling is completed, the nickel-platinum alloy billet is rotated 40-45° and rolled a second time, and with the temperature control of the successive annealing, the PTF of the prepared nickel-platinum alloy target blank is >70%. The present invention also discloses a nickel-platinum alloy target blank with high magnetic permeability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of integrated circuit target material manufacturing, in particular to a high magnetic permeability nickel-platinum alloy target blank and a preparation method thereof. BACKGROUND

[0002] Metal silicides have been widely used in semiconductor processes due to their excellent high-temperature oxidation resistance and good electrical and thermal conductivity. Specifically, metal silicides can reduce the contact resistance of transistors at the gate, source, and drain, thereby improving the drive current, reaction time, or circuit operating speed of the entire component.

[0003] As semiconductor components develop towards smaller sizes, they are more significantly affected by resistance, making related research on metal silicides more important. Generally, in complementary metal-oxide-semiconductor (CMOS) processes above 90 nanometers, titanium silicide or cobalt silicide is commonly used. When CMOS processes develop below 65 nanometers, nickel silicide with better properties is selected. In particular, when CMOS processes are below 45 nanometers, to improve the adverse effects of short-channel effects, oxide materials with high dielectric constant (such as hafnium dioxide) are used to replace the silicon dioxide insulating layer, and nickel silicide with low resistance, low silicon consumption, and low process temperature is used. However, nickel silicide has poor thermal stability, and platinum is added to improve its stability. Accordingly, nickel-platinum alloy target material is one of the important sources for making nickel silicide.

[0004] A typical application of nickel-platinum silicide thin films in semiconductor devices is Schottky diodes (discrete devices). Schottky diodes are metal-semiconductor devices that use the contact between metal and N-type semiconductor to form a potential barrier, thereby having rectifying properties, and are widely used in circuits such as switching power supplies, frequency converters, and drivers.

[0005] Nickel-platinum silicide is also widely used in the contact between the source, drain, gate, and metal electrode in very large scale integrated circuit (VLSI) microelectronic devices. Currently, Ni-5at% has been successfully applied in 65nm technology, and Ni-10at% Pt has been applied in 45nm technology. As the line width of semiconductor devices continues to decrease, it is likely that further improvement in the Pt content of nickel-platinum alloy will be needed to prepare NiPtSi contact thin films. The main reason for this is that increasing the Pt content in the alloy can improve the high-temperature stability of the thin film and change the cross-sectional morphology, reducing the occupation defects.

[0006] Nickel platinum alloy target material is a kind of magnetic target material, for high permeability target material, especially Fe, Co, Ni and alloy high saturation magnetic induction intensity target material, because the material has the effect of shielding magnetic field, it is often difficult to sputter. The solution to this fundamental problem is to reduce the magnetic permeability of the material, reduce the magnetic shielding effect of the ferromagnetic material, and increase the magnetic field of the target material surface. The ratio of the magnetic field strength of the same position near the target material surface with the target material to the magnetic field strength without the target material in the sputtering magnetic field is defined as the magnetic permeability (PTF). The higher the magnetic permeability, the higher the magnetic field strength of the target material surface, and the target material is more prone to sputtering.

[0007] Ni and Pt belong to the same transition metal, they can form a stable face-centered cubic structure solid solution in any mixing ratio. Among them, Ni shows ferromagnetic property, Pt shows paramagnetic property, the magnetism of Ni-Pt alloy is derived from the interaction of Ni3d and Pt5d electron orbitals which are not filled by electrons, the magnetic moment of Ni in the alloy is very fragile and easily affected by adjacent atoms. In the face-centered cubic structure, at least 6 Ni atoms are needed to maintain the magnetism of 1 Ni atom, so as the Pt content increases, the magnetism of Ni-Pt alloy weakens, and the ferromagnetic property changes to paramagnetic property, therefore when the Pt content is >10at%, the PTF can be easily improved. But when the Pt content is less, in 1-9at%, the improvement of PTF performance is particularly important.

[0008] CN112808833A provides a method for preparing high-performance ferromagnetic target material containing Ni and NiPt, using 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, the content of platinum in the nickel platinum alloy sputtering target is 0-5at%, the average grain size of the target material is less than 80 microns and the single grain size is not greater than 150 microns, the target material has a uniform distribution of diffraction peak intensity combination, and the diffraction peak intensity in a single direction is not greater than 50%, the magnetic permeability of the target material 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 phenomenon and has a long service life, and the thin film prepared by using the target material has good uniformity.

[0010] 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 disclosed patents, there are many preparation technologies for preparing nickel platinum alloy target material, but the improvement of PTF is not mentioned, and it is difficult to cross the gap to achieve PTF≥70%. Therefore, the technical problem to be solved by the present application is how to improve the PTF of the nickel platinum alloy target to more than 70%. Summary of the Invention

[0012] The purpose of this invention is to provide a method for preparing a high-permeability nickel-platinum alloy target billet. This method refines the grains through hot forging and hot rolling, with a focus on optimizing the cold rolling process. After the first rolling, the nickel-platinum alloy billet is rotated 40-50° and then rolled a second time. Combined with temperature control during successive annealing, the

[100] orientation of the rolled surface of the nickel-platinum alloy target billet is improved, thereby increasing the PTF of the target billet to over 70%. This application also provides a high-permeability nickel-platinum alloy target billet prepared using this method, with a PTF > 70%.

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

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

[0015] Step (1): After hot forging, heat treatment, hot rolling and recrystallization annealing are performed on the nickel-platinum alloy ingot in sequence, nickel-platinum alloy billet is obtained;

[0016] Step (2): Cold roll the nickel-platinum alloy billet to obtain a nickel-platinum alloy target billet;

[0017] Cold rolling involves at least three passes; a single pass includes the first and second rolling processes.

[0018] After the first rolling of the nickel-platinum alloy billet, the billet is rotated 40-50° and rolled a second time. An annealing is performed between each two cold rolling cycles, and the annealing temperature is based on the recrystallization annealing temperature, decreasing by 80-100°C each time.

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

[0020] In some implementations, the annealing temperature between each cold rolling cycle can be reduced by 80°C, 85°C, 90°C, 95°C, or 100°C, but is not limited to the listed values. Other unlisted values ​​are also applicable as long as they are within this range.

[0021] Preferably, in step (1), hot forging specifically involves: holding the nickel-platinum alloy ingot at 900~1100℃ for 60~90min to soften it, and then completing the hot forging by three upsetting and three drawing processes, with each upsetting and three drawing process having a deformation rate of >50%.

[0022] In some embodiments, the holding temperature can be 900℃, 950℃, 1000℃, 1050℃, or 1000℃, but is not limited to the listed values; other unlisted values ​​are applicable as long as they fall within this range. The holding time can be 60min, 65min, 70min, 75min, 80min, 85min, or 90min, but is not limited to the listed values; other unlisted values ​​are applicable as long as they fall within this range.

[0023] Preferably, in step (1), the heat treatment temperature is 850~950℃ and the time is 30~60min, 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. 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℃, the single-pass hot rolling deformation rate is 10~15%, the total hot rolling deformation rate is 75~85%, and the furnace is reheated every 3~4 passes for 10~15 minutes.

[0026] In some embodiments, the hot rolling 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, but is not limited to the listed values. Other unlisted values ​​are applicable as long as they are within this range.

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

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

[0030] Preferably, in step (1), the recrystallization annealing temperature is 850~950℃ and the time is 30~60min.

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

[0032] Preferably, both the first and second rolling processes employ alternating transverse and longitudinal rolling at a 90-degree clockwise angle. The specific rolling methods for the first and second rolling processes are disclosed in Chinese Patent CN104018128B, and therefore will not be elaborated upon in the embodiments of this invention.

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

[0034] Specifically, in conjunction with the rolling method described above, in the first rolling, the transverse rolling and longitudinal rolling alternate clockwise at a 90-degree angle, that is, rolling four points on the nickel-platinum alloy billet. 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 that the positions are completely identical, 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. Other unlisted values ​​are applicable as long as they are within this range.

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

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

[0037] Meanwhile, this application also provides a high-permeability nickel-platinum alloy target blank, which is prepared by a high-permeability nickel-platinum alloy target blank preparation method. In the nickel-platinum alloy target blank, the platinum content is 1~10at%, the grain size is <100um, the hardness is >180HV, the rolling surface

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

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

[0039] This application optimizes the cold rolling process. After the nickel-platinum alloy billet completes the first rolling, it is rotated by 40-45° and then rolled a second time. With the temperature control of successive annealing, the

[100] orientation of the nickel-platinum alloy target billet rolling surface is improved, thereby increasing the PTF of the target billet to more than 70%. Attached Figure Description

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

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

[0042] Figure 3 This is a schematic diagram of the angle between the face-centered cubic structure of the present invention and the plane

[110] and the plane of crystal indices

[100] . Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort 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 will be explained. For details regarding the alternating clockwise rolling of cross and longitudinal rolling at 90-degree angles, please refer to [link to relevant documentation]. Figure 1 In the first rolling, points 1, 2, 3, and 4 are rolled in sequence. Then, the nickel-platinum alloy billet is rotated 40-50° and rolled in the second rolling, with points 5, 6, 7, and 8 rolled in sequence.

[0045] For calculations regarding face-centered cubic structures and angles, please refer to [reference needed]. Figure 2 and Figure 3 .

[0046] In the following examples and comparative examples, the platinum content in the nickel-platinum alloy ingots used was 5 at.

[0047] Example 1

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

[0049] Step (1): Hold the nickel-platinum alloy ingot at 1100℃ for 60 minutes to soften it, and then complete the hot forging by three upsetting and three drawing with a deformation rate of 60% each time. Then, heat treat it at 950℃ for 30 minutes. After the heat treatment, immediately carry out hot rolling at 950℃. The hot rolling deformation rate is 15% per pass and the total hot rolling deformation rate is 85%. It is reheated every 3 passes for 10 minutes. After hot rolling, recrystallization annealing is carried out at 900℃ for 30 minutes to obtain the nickel-platinum alloy billet.

[0050] Step (2): The nickel-platinum alloy billet is cold rolled three times, each time including the first rolling and the second rolling. The rolling is carried out by alternating horizontal and vertical rolling at a 90-degree angle clockwise. After the first rolling is completed with a deformation rate of 3.5% per pass, the nickel-platinum alloy billet is rotated 45° and then rolled in the same way and with the same deformation rate as the first rolling. The total deformation rate of the first cold rolling is 28%. After the first cold rolling is completed, the first annealing is carried out. The annealing temperature is based on the recrystallization annealing temperature and is gradually reduced by 100°. That is, the first annealing temperature is 800° and the time is 30 minutes. After the second cold rolling is completed in the same way, the second annealing is carried out. The second annealing temperature is 700° and the time is 30 minutes. The third cold rolling is completed in the same way to obtain the nickel-platinum alloy target billet.

[0051] Example 2

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

[0053] Step (1): Hold the nickel-platinum alloy ingot at 900℃ for 90 minutes to soften it, and then complete the hot forging by three upsetting and three drawing with a deformation rate of 65% each time. Then, heat treat it at 850℃ for 60 minutes. After the heat treatment, immediately perform hot rolling at 850℃ for 15 minutes. The deformation rate of a single hot rolling pass is 10%, and the total hot rolling deformation rate is 75%. The ingot is reheated every 3 passes. After hot rolling, recrystallization annealing is performed at 850℃ for 60 minutes to obtain the nickel-platinum alloy billet.

[0054] Step (2): The nickel-platinum alloy billet is cold rolled three times, each time including the first rolling and the second rolling. The rolling is carried out by alternating horizontal and vertical rolling at a 90-degree angle clockwise. After the first rolling is completed with a deformation rate of 4.5% per pass, the nickel-platinum alloy billet is rotated 40° and then rolled in the same way and with the same deformation rate as the first rolling. The total deformation rate of the first cold rolling is 36%. After the first cold rolling is completed, the first annealing is carried out. The annealing temperature is based on the recrystallization annealing temperature and is gradually reduced by 80°. That is, the temperature of the first annealing is 770° and the time is 60 minutes. After the second cold rolling is completed in the same way, the second annealing is carried out. The temperature of the second annealing is 690° and the time is 60 minutes. The third cold rolling is completed in the same way to obtain the nickel-platinum alloy target billet.

[0055] Example 3

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

[0057] Step (1): Hold the nickel-platinum alloy ingot at 1000℃ for 75 minutes to soften it, and then complete the hot forging by three upsetting and three drawing with a deformation rate of 55% each time. Then, heat treat it at 900℃ for 45 minutes. After the heat treatment, immediately perform hot rolling at 900℃ for 13 minutes. The deformation rate of a single hot rolling pass is 13%, and the total hot rolling deformation rate is 80%. The ingot is reheated every 4 passes. After hot rolling, recrystallization annealing is performed at 950℃ for 45 minutes to obtain the nickel-platinum alloy billet.

[0058] Step (2): The nickel-platinum alloy billet is cold rolled three times, each time including the first rolling and the second rolling. The rolling is carried out by alternating horizontal and vertical rolling at a 90-degree angle clockwise. After the first rolling of the nickel-platinum alloy billet is completed with a deformation rate of 4% per pass, the nickel-platinum alloy billet is rotated 50° and then rolled in the same way and with the same deformation rate as the first rolling. The total deformation rate of the first cold rolling is 32%. After the first cold rolling is completed, the first annealing is carried out. The annealing temperature is based on the recrystallization annealing temperature and is gradually reduced by 90°. That is, the temperature of the first annealing is 860° and the time is 45min. After the second cold rolling is completed in the same way, the second annealing is carried out. The temperature of the second annealing is 770° and the time is 45min. The third cold rolling is completed in the same way to obtain the nickel-platinum alloy target billet.

[0059] Example 4

[0060] It is basically the same as Example 1, except that the cold rolling is performed four times, and 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 cold rolling is performed five times, and the temperature of the fourth annealing is 500°C for 30 minutes.

[0063] Comparative Example 1

[0064] It is basically the same as Example 1, except that the cold rolling is performed once.

[0065] Comparative Example 2

[0066] It is basically the same as Example 1, except that the cold rolling is performed twice.

[0067] Comparative Example 3

[0068] The process is basically the same as in Example 1, except that the nickel-platinum alloy billets are not rotated 45° before the second rolling.

[0069] Comparative Example 4

[0070] It is basically the same as Example 1, except that the annealing temperature between each cold rolling is 900°C.

[0071] Comparative Example 5

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

[0073] Comparative Example 6

[0074] It is basically the same as Example 1, except that it is not cold rolled after recrystallization annealing.

[0075] Comparative Example 7

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

[0077] Comparative Example 8

[0078] The process is essentially the same as in 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 magnetic permeability nickel-platinum alloy target blanks in Examples 1-5 and Comparative Examples 1-8 were corrected and then wire-cut to take small samples to test the grain size, crystal orientation and target blank hardness. After machining to a finished thickness of 3±0.05mm, the PTF was tested. The test results are shown in Table 1.

[0080] Among them, (1) grain size: the cross-section method disclosed in the national standard GB / T 6394-2017 "Method for Determination of Average Grain Size of Metals" was used for determination;

[0081] (2) Magnetic permeability: The permeability was measured in accordance with YS / T 1124-2016 "Test Method for Magnetic Permeability of Magnetic Sputtering Targets";

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

[100] and

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

[0083] Table 1 Test Results

[0084] Average grain size / um Hardness / HV PTF / %

[100] fraction / %

[110] fraction / % Example 1 49.1 210 71.2 31.6 22.9 Example 2 48.8 210 72.5 32.1 23.0 Example 3 45.4 200 70.8 31.3 24.0 Example 4 43.2 230 73.2 33.3 21.9 Example 5 42.8 244 74.5 34.4 20.3 Comparative Example 1 51.2 195 57.2 20.7 35.1 Comparative Example 2 50.5 200 61.8 22.3 32.9 Comparative Example 3 50.1 201 60.3 21.8 34.2 Comparative Example 4 78.5 188 64.6 25.0 30.8 Comparative Example 5 58.4 190 65.7 25.3 31.5 Comparative Example 6 85.5 110 35.3 10.2 45.0 Comparative Example 7 49.0 205 58.1 21.5 34.8 Comparative Example 8 48.3 211 57.7 22.4 35.6

[0085] Results analysis:

[0086] 1. As can be seen from the results of Examples 1 to 3, the temperature control of cold rolling combined with successive annealing can significantly improve the

[100] orientation of the nickel-platinum alloy target billet rolling surface, and the PTF of the nickel-platinum alloy target billet 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 only 1.7%, indicating that the method has excellent stability, and the average grain size and hardness of the target billet are also very ideal.

[0087] 2. The results of Examples 1, 4, and 5 show that, unlike Example 1, Example 4 involved one more cold rolling cycle, while Example 5 involved two more. However, the PTF of Example 4 increased by 2% compared to Example 1, while the PTF of Example 5 only increased by 1.3%. In reality, during cold rolling, a large number of dislocations are generated within the metal crystal, and the dislocation density increases significantly with increasing deformation. However, once the deformation reaches a certain level, dislocations become entangled, forming dislocation cells or subgrain boundaries, leading to increased resistance to dislocation movement and further limiting their proliferation. The dislocation density then tends towards dynamic equilibrium, which is the main factor causing the PTF to decrease and gradually stabilize with increasing cold rolling cycles.

[0088] 3. The results from Example 1, Comparative Example 1, and Comparative Example 2 show that although Comparative Example 1 and Comparative Example 2 met the temperature control requirements of cold rolling combined with successive annealing, the number of cold rolling operations was less than three. This resulted in the PTF of the nickel-platinum alloy target billets prepared by Comparative Example 1 and Comparative Example 2 being less than ideal, with the largest difference from Example 1 reaching 14%. This further illustrates that multiple cold rolling operations combined with successive annealing are required to stably increase the PTF of the nickel-platinum alloy target billet to over 70%.

[0089] 4. From the results of Examples 1 and Comparative Examples 3 to 5, it can be seen that compared with the conventional process, Comparative Example 3 only has more rolling times and temperature control for successive annealing. It is certain that cold rolling can increase PTF, but after temperature control of 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, normal cold rolling cannot increase the

[100] ratio by reducing the

[110] ratio.

[0090] Comparative Example 4 did not use temperature control for successive annealing. As can be seen from the results of Comparative Example 4, although the PTF can reach 64.6% by simply using directional rolling, which is higher than 60.3% of Comparative Example 3, and the

[100] ratio is also improved, it is still impossible to stably increase the PTF of the nickel-platinum alloy target billet to more than 70% without temperature control for successive annealing.

[0091] Comparative Example 5 used a lower difference in the temperature control of successive annealing. The results of Comparative Example 5 show that the PTF of the nickel-platinum alloy target billet prepared in Comparative Example 5 is better than that of the nickel-platinum alloy target billet in Comparative Example 4. Although the advantage is not obvious, it shows that the result of successively reducing the annealing temperature by 80~100℃ is more ideal. It further shows that the temperature control of cold rolling combined with successive annealing can significantly improve the

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

[0092] 5. As can be seen 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 billet, thereby increasing the PTF of the nickel-platinum alloy target billet. After temperature control by combining cold rolling with orientation and successive annealing, the

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

[0093] 6. From the results of Example 1, Comparative Example 7 and Comparative Example 8, we can see that when the rotation angle exceeds the range of 40° to 50°, it is difficult to reduce the proportion of

[110] , whether it is below or above this range, resulting in a very low proportion of

[100] and the PTF of the nickel-platinum alloy target billet cannot be increased to more than 70%. Therefore, it can be concluded that the optimal rotation angle should be between 40° and 50°. When the rotation angle is below or above this range, it is impossible to increase the proportion of

[100] .

[0094] From a theoretical perspective:

[0095] Both Ni and Pt have a face-centered cubic (fcc) structure. (See reference...) Figure 1The close-packed plane is {111}, and the close-packed direction is... <110> Slip system {111} <110> The initial crystal orientation of the surface is mainly

[110] . Within the range of 0~15°, the proportion of

[110] is >35%, and the proportion of

[111] is <5%. Since

[100] is the hard axis and

[111] is the easy axis, when the

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

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

[0096] In face-centered cubic structures, refer to the attached... Figure 2 and attached Figure 3 Based on crystal orientation theory, Equation 2 is derived from Equation 1:

[0097] Formula 1: ;

[0098] Formula 2: ;

[0099] During the experiment, after the first rolling was completed, turning the nickel-platinum alloy target billet by 45° and scaling the 45° to 40~50° still achieved a very good effect. Therefore, controlling the turning angle within the range of 40~50° can transform

[110] into

[100] . Combined with the annealing temperature control of gradually decreasing by 80~100°, the

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

[0100] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preparing a high-permeability nickel-platinum alloy target blank, characterized in that, Includes the following steps: Step (1): After hot forging, heat treatment, hot rolling and recrystallization annealing are performed on the nickel-platinum alloy ingot in sequence, nickel-platinum alloy billet is obtained; Step (2): Cold roll the nickel-platinum alloy billet to obtain a nickel-platinum alloy target billet; The cold rolling process includes at least three stages; each stage includes a first rolling and a second rolling. After the first rolling of the nickel-platinum alloy billet, the billet is rotated 40-50° and rolled a second time. An annealing is performed between each two cold rolling cycles, and the annealing temperature is based on the recrystallization annealing temperature, decreasing by 80-100°C each time. In step (1), the hot rolling temperature is 850~950℃, the single-pass hot rolling deformation rate is 10~15%, the total hot rolling deformation rate is 75~85%, and the furnace is reheated every 3~4 passes for 10~15 minutes. Both the first and second rolling processes employ a method of alternating horizontal and vertical rolling at a 90-degree angle clockwise. The deformation rate of the first and second rolling passes is 3.5-4.5%, and the total deformation rate of a single cold rolling pass is 28-36%.

2. The method for preparing a high-permeability nickel-platinum alloy target blank according to claim 1, characterized in that, In step (1), hot forging specifically involves: holding the nickel-platinum alloy ingot at 900~1100℃ for 60~90min to soften it, and then completing the hot forging through three upsetting and three drawing processes, with each upsetting and three drawing process having a deformation rate of >50%.

3. The method for preparing a high-permeability nickel-platinum alloy target blank according to claim 1, characterized in that, In step (1), the heat treatment temperature is 850~950℃ and the time is 30~60min, 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 step (1), the recrystallization annealing temperature is 850~950℃ and the time is 30~60min.

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

6. A high-permeability nickel-platinum alloy target blank, characterized in that, The nickel-platinum alloy target blank is prepared by the preparation method of high magnetic permeability nickel-platinum alloy target blank as described in any one of claims 1 to 5. In the nickel-platinum alloy target blank, the platinum content is 1 to 10 at%, the grain size is <100 μm, the hardness is >180 HV, the rolling surface [100] ratio is >30%, and the PTF is >70%.

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