A high-density molybdenum target material manufacturing equipment and manufacturing process

Abstract

A high-density molybdenum target material manufacturing equipment includes an upper rotating pressure head and a lower rotating pressure head; a circular pressure groove for holding molybdenum powder is provided on the end surface of the lower rotating pressure head, and a pressure ring corresponding to the pressure groove is provided on the end surface of the upper rotating pressure head; an axial force in opposite directions and a rotational torque in opposite directions are applied between the upper rotating pressure head and the lower rotating pressure head. A molybdenum target material manufacturing process causes thermoplastic deformation of a molybdenum blank through high-pressure and high-speed friction. Microscopically, the thermoplastic deformation can cause the molybdenum atoms to slip, diffuse, and creep, and re-establish bonds between the molybdenum atoms. Macroscopically, the thermoplastic deformation can greatly increase the dislocation density between the molybdenum particles, eliminate the gaps between the molybdenum particles, and greatly increase the density of the molybdenum blank. In addition, the present invention can directly press and sinter the molybdenum powder into a blank that meets the size of the molybdenum target material, which not only saves the hot rolling process, but also does not require trimming, and the utilization rate of the material is greatly improved.

Description

Technical Field

[0001] The invention relates to the field of molybdenum target material preparation, and in particular to a high-density molybdenum target material production device and a production process thereof. Background Art

[0002] At present, molybdenum targets have been widely used in liquid crystal display screens, solar cell back plates, touch screens, glass coating and other fields. For the production of molybdenum targets, density is an important assessment indicator. Generally, the density of molybdenum targets is required to be greater than 99%. However, the density of molybdenum targets produced using existing production processes is generally lower than 99%.

[0003] The existing molybdenum target manufacturing process generally includes cold pressing of billets, sintering, rolling and annealing. For detailed processes, please refer to patents with application numbers 201210260409.8 and 201110337933.6. In the existing molybdenum target manufacturing process, the process that has the greatest impact on density is cold pressing of billets. The maximum water pressure applied by hydraulic equipment to molybdenum billets is about 200MPa, which basically reaches the pressure limit of current hydraulic equipment. Due to the limitation of sealing technology, it is difficult to further increase the water pressure.

[0004] In addition, during the sintering process, we found that after the molybdenum blank was heated, its density would rebound to varying degrees, reducing the density of the molybdenum blank. Summary of the invention

[0005] In order to overcome the deficiencies in the background technology, the present invention discloses a high-density molybdenum target material manufacturing device and a molybdenum target material manufacturing process, the purpose of which is to improve the density of the molybdenum target material to make the density of the molybdenum target material higher than 99%.

[0006] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme:

[0007] A high-density molybdenum target material manufacturing device comprises an upper rotating pressure head and a lower rotating pressure head; a circular pressing groove for containing molybdenum powder is arranged on the end surface of the lower rotating pressure head, and the pressing groove is coaxially arranged with the lower rotating pressure head; a pressing ring corresponding to the pressing groove is arranged on the end surface of the upper rotating pressure head, and the pressing ring is coaxially arranged with the upper rotating pressure head; axial forces in opposite directions and rotational torques in opposite directions are applied between the upper rotating pressure head and the lower rotating pressure head.

[0008] To further improve the technical solution, the molybdenum target material manufacturing equipment also includes a closed box, and the upper rotary pressure head and the lower rotary pressure head are sealed and installed in the closed box.

[0009] To further improve the technical solution, hydrogen is filled into the sealed box.

[0010] To further improve the technical solution, the materials of the pressing groove and the pressing ring are both industrial ceramics, and the pressing ring and the pressing groove are respectively fixed on the upper rotating pressing head and the lower rotating pressing head.

[0011] To further improve the technical solution, an inductive auxiliary heating coil is arranged on the periphery of the upper rotary pressure head or the lower rotary pressure head.

[0012] A process for manufacturing a molybdenum target material comprises the following steps:

[0013] S1: weigh the molybdenum powder, then put the molybdenum powder into the pressing groove, start the molybdenum target material manufacturing equipment, make the pressing ring enter the pressing groove, apply axial pressure to the molybdenum powder, and press the molybdenum powder into a preliminary blank;

[0014] S2: while maintaining the axial pressure, the upper rotating ram rotates in the opposite direction to the lower rotating ram, and the preform is heated by the friction between the pressing ring, the pressing groove and the preform, so that the preform undergoes thermoplastic deformation, and the preform is pressurized and sintered at a temperature of 1340-1450° C. to form a circular ring-shaped intermediate blank;

[0015] S3: cutting the intermediate billet into multiple segments of arc-shaped molybdenum target plates, and straightening and shaping the arc-shaped molybdenum target plates;

[0016] S4: Annealing.

[0017] To further improve the technical solution, in S1, the thickness of the preform is 1.1-1.5 times the thickness of the finished molybdenum target.

[0018] To further improve the technical solution, in S1, the pressure applied by the pressure ring and the pressure groove on the molybdenum powder is 20-30MPa; in S2, the pressure applied by the pressure ring and the pressure groove on the preform is 70-90MPa.

[0019] To further improve the technical solution, in S2, the rotation speed of the upper rotary ram and the lower rotary ram is controlled to heat the preform to 1180-1300°C, so that the preform undergoes thermoplastic deformation, and then the preform is kept warm and pressurized for 1-2 hours; when the preform is pressurized and sintered, the preform is kept warm and pressurized for 2-4 hours.

[0020] Due to the adoption of the above technical solution, compared with the background technology, the present invention has the following beneficial effects:

[0021] The present invention causes thermoplastic deformation of the molybdenum blank by high pressure and high speed friction. Microscopically, the thermoplastic deformation can cause the molybdenum atoms to slip, diffuse and creep, and re-establish bonds between the molybdenum atoms. Macroscopically, the thermoplastic deformation can greatly increase the dislocation density between the molybdenum particles, eliminate the gaps between the molybdenum particles, and greatly increase the density of the molybdenum blank. The density of the molybdenum target plate processed by this process generally reaches above 99.5.

[0022] In addition, the present invention changes the existing molybdenum target material manufacturing process and can directly press and sinter molybdenum powder into a blank that meets the size of the molybdenum target material. It not only eliminates the hot rolling process and shortens the process flow, but also does not require trimming, thereby greatly improving the utilization rate of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is a schematic structural diagram of the molybdenum target material manufacturing equipment.

[0024] Figure 2 The diagram shows the structure of the molybdenum target manufacturing equipment when pressing and sintering molybdenum powder.

[0025] Figure 3 Shown is a schematic diagram of cutting the middle billet.

[0026] Figure 4 Shown is a schematic diagram of thermal correction of a curved molybdenum target plate.

[0027] In the figure: 1. upper rotating pressure head; 11. pressure ring; 2. lower rotating pressure head; 21. pressure groove; 3. induction auxiliary heating coil; 4. molybdenum powder; 5. initial blank; 6. intermediate blank; 7. arc-shaped molybdenum target plate; 8. multi-roller straightening machine. Implementation

[0028] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that in the description of the present invention, the terms "front", "rear", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. It should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal connection of two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. Example

[0029] A high-density molybdenum target material manufacturing equipment, such as Figure 1-2 As shown, it includes an upper rotary pressure head 1 and a lower rotary pressure head 2, and its structure and function are described in detail below.

[0030] The molybdenum target material manufacturing equipment is similar to a metal friction welding machine, which has an upper rotating head 1 and a lower rotating head 2. A circular ring-shaped pressing groove 21 for holding molybdenum powder 4 is fixed on the end face of the lower rotating head 2, and the pressing groove 21 is coaxially arranged with the lower rotating head 2. A pressing ring 11 corresponding to the pressing groove 21 is fixed on the end face of the upper rotating head 1, and the pressing ring 11 is coaxially arranged with the upper rotating head 1. The materials of the pressing ring 11 and the pressing groove 21 are both industrial ceramics. As is known, industrial ceramics are often used for chip cutting tools. Industrial ceramics have high high temperature resistance and hardness, and can maintain high hardness at 1600°C.

[0031] A motor and a hydraulic cylinder (not shown in the figure) are connected to the tail ends of the upper rotary pressing head 1 and the lower rotary pressing head 2. The motor is used to make the upper rotary pressing head 1 and the lower rotary pressing head 2 produce rotational motion in opposite directions. The hydraulic cylinder is used to make the upper rotary pressing head 1 and the lower rotary pressing head 2 produce axial forces in opposite directions, so that the pressing ring 11 enters the pressing groove 21 and applies axial pressure to the molybdenum powder 4.

[0032] After the pressure ring 11 enters the pressure groove 21, a closed compression space is formed for the molybdenum powder 4. In order to further isolate the air, the molybdenum target manufacturing equipment also includes a sealed box (not shown in the figure), and the upper rotary pressure head 1 and the lower rotary pressure head 2 are sealed and installed in the sealed box. The sealed box can be vacuum, or hydrogen can be filled in the sealed box. Vacuum or hydrogen can isolate the air to prevent the molybdenum powder 4 from oxidation.

[0033] In order to assist heating of the molybdenum target, an inductive auxiliary heating coil 3 is arranged on the periphery of the ring groove. Since the pressing groove 21 and the pressing ring 11 are made of non-metallic materials, the inductive auxiliary heating coil 3 can only heat the molybdenum target after being powered on.

[0034] In order to further explain the working process of the molybdenum target material manufacturing equipment, the present invention also discloses a molybdenum target material manufacturing process, which is used to manufacture a molybdenum target plate with a length of 2260 mm, a width of 195 mm, and a thickness of 10 mm, and the molybdenum target plate is used for a sixth-generation flat panel display sputtering machine. In order to match the size of the molybdenum target material, the centerline diameter of the pressing groove 21 is 1445 mm, the groove width of the pressing groove 21 is 195 mm, and the groove depth of the pressing groove 21 is 4 mm.

[0035] The manufacturing process of the molybdenum target material comprises the following steps:

[0036] S1: Figure 1 As shown, the molybdenum powder 4 is first weighed, and then placed into the pressing groove 21 , and then the molybdenum target material manufacturing equipment is started to allow the pressing ring 11 to enter the pressing groove 21 , and axial pressure is applied to the molybdenum powder 4 to press the molybdenum powder 4 into a preliminary blank 5 .

[0037] In this embodiment, the pressure applied by the upper rotary pressing head 1 and the lower rotary pressing head 2 to the molybdenum powder 4 through the pressing ring 11 and the pressing groove 21 is 20 MPa, which can initially compress the gaps between the molybdenum powders 4 and press the molybdenum powders 4 into a preliminary blank 5. After pressing, the thickness of the preliminary blank 5 is 12 mm.

[0038] S2: Figure 2 As shown, while maintaining the axial pressure, the upper rotating ram 1 is rotated in the opposite direction relative to the lower rotating ram 2, and the preform 5 is heated by the friction between the pressure ring 11, the pressure groove 21 and the preform 5, so that the preform 5 undergoes thermoplastic deformation, and the preform 5 is pressure-sintered at a temperature of 1340-1450°C to generate a circular ring-shaped intermediate blank 6.

[0039] In this embodiment, the pressure applied by the upper rotary ram 1 and the lower rotary ram 2 to the blank 5 through the pressure ring 11 and the pressure groove 21 is 70 MPa. Then, by controlling the rotation speed of the upper rotary ram 1 and the lower rotary ram 2, the blank 5 is heated to 1200°C and kept at this temperature and pressure for 1.5 hours, so that the blank 5 undergoes thermoplastic deformation. Practice has proved that the molybdenum blank has forgeability at 1180-1300°C and can undergo thermoplastic deformation under the action of external force. After thermoplastic deformation, the thickness of the intermediate blank 6 is reduced to 10.6 mm.

[0040] The reason why the pressing groove 21 and the pressing ring 11 are made into a circular ring with a large diameter and a small width is that the larger the diameter, the higher the linear speed, the greater the heat generated by friction, and the more uniform the heating degree of each part of the preform 5, which is conducive to the occurrence of thermoplastic deformation. However, the central part of the circular blank has a low temperature rise due to the low linear speed, and thermoplastic deformation cannot occur.

[0041] Different from the existing cold pressing process, the present invention uses high pressure and high speed friction to cause thermoplastic deformation of the preform 5. Microscopically, the thermoplastic deformation can cause the molybdenum atoms to slip, diffuse, and creep, and re-establish bonds between the molybdenum atoms. Macroscopically, the thermoplastic deformation can greatly increase the dislocation density between the molybdenum particles, eliminate the gaps between the molybdenum particles, and greatly increase the density of the intermediate blank 6.

[0042] Then, the axial pressure is kept constant, and the rotation speed of the upper rotary ram 1 and the lower rotary ram 2 is further increased, and the blank 5 is heated to 1300°C, and the temperature and pressure are kept for 3 hours, and the blank 5 is pressure-sintered. After pressure sintering, the gaps between the molybdenum particles are further eliminated, the density of the intermediate blank 6 is increased, and the thickness of the intermediate blank 6 is reduced to 10.2 mm. It is worth noting that after the rotation speed is increased to a certain extent, the temperature rise is difficult to control. At this time, the induction auxiliary heating coil 3 can be used to assist in heating the intermediate blank 6, and the induction auxiliary heating coil 3 is easy to achieve temperature control.

[0043] Different from the existing process, the present invention first weighs the molybdenum powder 4, and then directly presses and sinters the molybdenum powder 4 into a circular molybdenum blank with a width of 195 mm and a thickness of 10.2 mm. The upper and lower surfaces of the molybdenum blank are flat and smooth, and the width and thickness are uniform, and the width and thickness meet the size requirements of the molybdenum target plate. As long as the molybdenum powder 4 is weighed accurately, it is no longer necessary to use a hot rolling process in the subsequent process to reduce the thickness of the molybdenum blank to increase the length and width of the molybdenum blank. The pressing groove 21 and the pressing ring 11 can also be understood as rollers with infinite radius. In the process of thermoplastic deformation and pressure sintering of the molybdenum blank, the rolling of the molybdenum blank has been completed.

[0044] In the existing process, the hot rolling process is generally used to flatten the round molybdenum blank, and then the molybdenum plate is cut to obtain a strip-shaped molybdenum target plate. This method will inevitably produce a large number of useless trimmings, and the material utilization rate is greatly reduced. This process perfectly solves this problem, and there is basically no trimming and waste, and the material utilization rate is greatly improved.

[0045] S3: Figure 3 As shown, the middle billet 6 is cut into two semicircular arc-shaped molybdenum target plates 7, and the arc-shaped molybdenum target plates 7 are straightened and shaped.

[0046] Specifically, after cooling, the middle blank 6 is taken out from the lower rotating press head 2, and then the middle blank 6 is symmetrically cut into two semicircular arc-shaped molybdenum target plates 7. Such a middle blank 6 can be processed into two molybdenum target plates.

[0047] like Figure 4 As shown, under the protection of hydrogen, the arc-shaped molybdenum target plate 7 is heated to 780° C., and then the arc-shaped molybdenum target plate 7 is straightened and shaped by a multi-roll straightening machine 8 to form a long strip of molybdenum target plate.

[0048] S4: annealing the molybdenum target plate to obtain a finished molybdenum target plate.

[0049] After testing, it was found that the density of the finished molybdenum target plates processed by this process generally reached above 99.5. Example

[0050] Different from Example 1, in S1 of the molybdenum target manufacturing process, the pressure applied by the upper rotary pressure head and the lower rotary pressure head to the molybdenum powder through the pressure ring and the pressure groove is 25 MPa.

[0051] In addition, in S2 of the molybdenum target manufacturing process, the pressure applied by the upper rotary pressure head and the lower rotary pressure head to the green sheet through the pressure ring and the pressure groove is 80 MPa, and the heating temperature of the green sheet is 1260°C, and the temperature is kept at this temperature for 1 hour. Then the green sheet is heated to 1410°C, and the temperature is kept at this temperature for 2.5 hours, and the green sheet is pressure-sintered. Example

[0052] Different from Example 1, in S1 of the molybdenum target manufacturing process, the pressure applied by the upper rotary pressure head and the lower rotary pressure head to the molybdenum powder through the pressure ring and the pressure groove is 30 MPa.

[0053] In addition, in S2 of the molybdenum target manufacturing process, the pressure applied by the upper rotary pressure head and the lower rotary pressure head to the green sheet through the pressure ring and the pressure groove is 90 MPa, and the heating temperature of the green sheet is 1300°C, and the temperature is kept at this temperature for 2 hours. Then the green sheet is heated to 1450°C, and the temperature is kept at this temperature for 4 hours, and the green sheet is pressure-sintered.

[0054] As can be seen from the above, the present invention causes thermoplastic deformation and pressure sintering of the molybdenum blank by high pressure and high speed friction, thereby greatly increasing the density of the molybdenum target plate. In addition, the present invention can directly press and sinter the molybdenum powder into a blank that meets the size of the molybdenum target material, eliminating the hot rolling process and shortening the process flow.

[0055] Although the embodiments of the present invention have been shown and described, it is understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the protection scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A high-density molybdenum target material manufacturing process, characterized by: Applicable to a molybdenum target material manufacturing device; the molybdenum target material manufacturing device comprises an upper rotating pressure head and a lower rotating pressure head; a circular pressing groove for containing molybdenum powder is provided on the end surface of the lower rotating pressure head, and the pressing groove is coaxially arranged with the lower rotating pressure head; a pressing ring corresponding to the pressing groove is provided on the end surface of the upper rotating pressure head, and the pressing ring is coaxially arranged with the upper rotating pressure head; an axial force in opposite directions and a rotating torque in opposite directions are applied between the upper rotating pressure head and the lower rotating pressure head; The molybdenum target material manufacturing process comprises the following steps: S1: weigh the molybdenum powder, then put the molybdenum powder into the pressing groove, start the molybdenum target material manufacturing equipment, make the pressing ring enter the pressing groove, apply axial pressure to the molybdenum powder, and press the molybdenum powder into a preliminary blank; S2: while maintaining the axial pressure, the upper rotating ram rotates in the opposite direction to the lower rotating ram, and the preform is heated by the friction between the pressing ring, the pressing groove and the preform, so that the preform undergoes thermoplastic deformation, and the preform is pressurized and sintered at a temperature of 1340-1450° C. to form a circular ring-shaped intermediate blank; S3: cutting the middle billet into multiple segments of arc-shaped molybdenum target plates, and straightening and shaping the arc-shaped molybdenum target plates; S4: Annealing.

2. A high-density molybdenum target manufacturing process as claimed in claim 1, characterized in that: The molybdenum target material manufacturing equipment also includes a sealed box, and the upper rotary pressure head and the lower rotary pressure head are sealed and installed in the sealed box.

3. A high-density molybdenum target manufacturing process as claimed in claim 2, characterized in that: The sealed box is filled with hydrogen.

4. A high-density molybdenum target manufacturing process as claimed in claim 1, characterized in that: The materials of the pressing groove and the pressing ring are both industrial ceramics, and the pressing ring and the pressing groove are respectively fixed on the upper rotating pressing head and the lower rotating pressing head.

5. A high-density molybdenum target manufacturing process as claimed in claim 4, characterized in that: An induction auxiliary heating coil is arranged on the periphery of the upper rotary pressing head or the lower rotary pressing head.

6. A high-density molybdenum target manufacturing process as claimed in claim 1, characterized in that: In S1, the thickness of the blank is 1.1-1.5 times the thickness of the finished molybdenum target.

7. A high-density molybdenum target manufacturing process as claimed in claim 1, characterized in that: In S1, the pressure exerted by the pressure ring and the pressure groove on the molybdenum powder is 20-30MPa; in S2, the pressure exerted by the pressure ring and the pressure groove on the preform is 70-90MPa.

8. A high-density molybdenum target manufacturing process as claimed in claim 1, characterized in that: In S2, the rotation speed of the upper rotary ram and the lower rotary ram is controlled to heat the preform to 1180-1300°C, so that the preform undergoes thermoplastic deformation, and then the preform is kept at this temperature and pressure for 1-2 hours; when the preform is pressurized and sintered, the preform is kept at this temperature and pressure for 2-4 hours.

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