A method for preparing high-performance thin-walled molybdenum rings for MPCVD equipment using molybdenum residual targets.

Abstract

This invention discloses a method for preparing high-performance thin-walled molybdenum rings for MPCVD equipment using a molybdenum residual target. The method uses a sputtered molybdenum residual target as raw material. First, the molybdenum residual target is milled to ensure flatness on both sides, and then re-rolled to a certain thickness to form the required molybdenum ring. The precision-machined molybdenum rings produced by this method have high density, good machinability, and long service life, meeting the application requirements of the MPCVD method for preparing diamond films. Furthermore, it avoids the waste caused by repeated sintering of slabs, significantly reducing costs, and is particularly suitable for the production of thin-walled molybdenum rings.

Description

Technical Field

[0001] This invention relates to the field of high-performance thin-walled molybdenum ring preparation, specifically a method for preparing high-performance thin-walled molybdenum rings for MPCVD equipment using a molybdenum residual target. Background Technology

[0002] Diamond possesses unique properties such as the highest hardness, low coefficient of friction, high elastic modulus, high thermal conductivity, high insulation, wide bandgap, high sound propagation speed, and excellent chemical stability. However, natural diamond exists only in the form of gemstones, and its variability and rarity greatly limit its applications. Synthetic diamond films, on the other hand, combine these excellent physicochemical properties at a lower cost than natural diamonds. They can be fabricated into various geometries, theoretically without size limitations, and have broad application prospects in electronics, optics, and mechanical industries.

[0003] Existing technologies primarily utilize microwave plasma chemical vapor deposition (MPCVD) to prepare diamond films. This method can produce high-quality diamond films with large areas, good uniformity, high purity, and excellent crystal morphology. It is particularly suitable for coating diamond films on various curved surfaces (irregular surfaces) and can prepare diamond film products with diverse needs. Molybdenum rings, as crucial components in MPCVD equipment, work in conjunction with the diamond substrate to ensure the uniformity and stability of the diamond film production rate and to fix the substrate to prevent movement. They can operate stably for extended periods under high temperature and high pressure conditions.

[0004] Traditional molybdenum rings often employ a process route of "molybdenum powder-molding-sintering-machining" or "molybdenum powder-powder loading-sintering-forging-machining". Molded and sintered molybdenum rings, which only undergo sintering without plastic deformation, have low density, and their performance and lifespan are insufficient to meet the requirements of MPCVD equipment. Forged molybdenum rings, although undergoing plastic deformation, suffer from thin walls that make it difficult to guarantee sufficient forging deformation, and are prone to uneven deformation during forging, resulting in poor machinability and frequent cracking during subsequent machining. Neither method is suitable for mass production. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing high-performance thin-walled molybdenum rings for MPCVD equipment using a molybdenum residual target. This method uses a sputtered molybdenum residual target as raw material. First, the molybdenum residual target is milled to ensure flatness on both sides, and then re-rolled to a certain thickness to form the desired molybdenum ring. The precision-machined molybdenum rings produced by this method have high density, good machinability, and long service life, meeting the application requirements of the MPCVD method for preparing diamond films. Furthermore, it avoids the waste caused by repeated sintering of slabs, significantly reducing costs, and is particularly suitable for the production of thin-walled molybdenum rings.

[0006] To achieve the above objectives, the specific solution adopted by the present invention is as follows:

[0007] The method for preparing high-performance thin-walled molybdenum rings for MPCVD equipment using molybdenum residual targets mainly includes the following steps:

[0008] (1) Select the molybdenum residual target returned after magnetron sputtering coating and pre-treat the molybdenum residual target into a molybdenum block with a flat and clean surface;

[0009] (2) The molybdenum block is rolled to obtain a molybdenum plate;

[0010] (3) Annealing and leveling the molybdenum plate;

[0011] (4) The leveled molybdenum plate is cut by water jet cutting to obtain a blank molybdenum ring;

[0012] (5) The blank molybdenum ring is precision machined to obtain a molybdenum ring with a wall thickness of less than 10 mm.

[0013] Furthermore, in step (1), the purity of the molybdenum residual target is 99.95%, and the density is ≥10.19 g / cm³. 3 .

[0014] Further, in step (1), the specific method for pre-treating the molybdenum residual target is as follows: first, the molybdenum residual target is milled, and the thickness of the molybdenum residual target after milling is 10mm and the surface is flat; then, the milled molybdenum residual target is cut into several molybdenum blocks, and then the molybdenum blocks are cleaned with molten NaOH solution at 400℃.

[0015] Further, in step (2), the molybdenum block is heated to 1050-1150℃ and held for 0.5-1.5h. A two-pass rolling process is adopted, with the deformation amount of the first pass being 15-30% and the deformation amount of the second pass being 10-20%.

[0016] Furthermore, in step (3), the specific parameters for the annealing treatment are: to keep the molybdenum plate at a temperature of 800-900℃ for 0.5-1.5h.

[0017] Further, in step (3), the annealed molybdenum plate is placed on a nine-roll leveling machine and repeatedly leveled until the flatness is ≤0.5mm.

[0018] Furthermore, in step (5), the blank molybdenum ring is precision machined to the size of the molybdenum plate using a CNC lathe.

[0019] In this invention, a molybdenum residual target is selected for two reasons: first, the residual molybdenum target itself has a high density after rolling, and secondary processing can ensure that the density of the finished molybdenum ring is close to the theoretical density, which is better than rolling performance of re-sintered billets; second, it eliminates the need for re-sintering the slab, saving the sintering process, reducing costs and improving efficiency. Pretreatment of the molybdenum residual target is necessary because the surface of the target material after use is wavy and uneven, such as… Figure 1 As shown, direct rolling results in uneven deformation, leading to more cracks and a low yield. Milling reduces the difficulty of rolling and improves the yield. Alkali washing is used to remove the surface oxide layer and impurities, ensuring purity and the quality of the rolled surface.

[0020] Compared to existing technologies where sintered billets need to be rolled at a high temperature (1300℃), this invention uses a molybdenum residual target for rolling. Because it has undergone plastic processing and has a high density, it does not require billet preparation. The rolling temperature can be appropriately reduced to 1050-1150℃, and the deformation per rolling pass can be appropriately increased without worrying about risks such as delamination and cracking (up to about 30%). This saves energy and improves the yield.

[0021] This invention requires water jet cutting and precision turning after rolling. Leveling ensures the flatness of the molybdenum plate, reduces the machining allowance required for thickness dimensions, and improves material utilization. Annealing fully releases the internal stress generated during plastic deformation, preventing machining cracks.

[0022] Beneficial effects:

[0023] This invention employs a molybdenum target-milling-rolling-machining process to produce thin-walled molybdenum rings. Due to the high density of the molybdenum target, rolling requires less high a temperature compared to sintered billets. This secondary processing ensures the molybdenum ring density is close to the theoretical density of 10.2 g / cm³, improving its performance and lifespan. Furthermore, compared to the sintered molybdenum tube-forging-machining process, it avoids repeated sintering of the billet, resulting in greater and more uniform deformation during rolling. Subsequent machining exhibits virtually no cracking, achieving a 100% pass rate. This method is particularly suitable for the large-scale production of thin-walled molybdenum rings, enabling the recycling of molybdenum targets at low cost. It is of great significance for breaking the foreign market monopoly in this industry and promoting the localization of related equipment and products. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the cross-section of the raw material for the molybdenum residual target. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0026] This invention provides a method for preparing high-performance thin-walled molybdenum rings for MPCVD equipment using a molybdenum residual target, mainly comprising the following steps:

[0027] (1) The molybdenum residual target returned after magnetron sputtering coating is selected. The purity of the molybdenum residual target is 99.95% and the density is ≥10.19 g / cm³. 3 The molybdenum target residue is pretreated into a molybdenum block with a smooth and clean surface;

[0028] (2) Rolling process: heat the molybdenum block to 1050-1150℃ and hold for 0.5-1.5h. Use a one-fire two-pass rolling method. The deformation amount of the first pass is 15-30% and the deformation amount of the second pass is 10-20% to obtain molybdenum plate.

[0029] (3) Compared with the sintered billet, the molybdenum residual target has a high density. The rolling heating temperature can be set above the recrystallization temperature, and it does not need to be too high. The molybdenum plate is annealed at 800-900℃ for 0.5-1.5h. Then the annealed molybdenum plate is placed on a nine-roll leveling machine and repeatedly leveled until the flatness is ≤0.5mm.

[0030] (4) The leveled molybdenum plate is cut by water jet cutting to obtain a blank molybdenum ring;

[0031] (5) The blank molybdenum ring is precision machined to the size of the molybdenum plate using a CNC lathe, that is, a molybdenum ring with a wall thickness of less than 10mm is obtained.

[0032] In detail, in step (1), the pretreatment of the molybdenum target residue includes milling and alkaline washing. Because the molybdenum target residue has been used, its surface is uneven, with a difference of 4 mm between the thickest and thinnest parts. Before rolling, the surface needs to be milled flat to ensure uniform deformation during subsequent rolling. The specific method is as follows: first, the molybdenum target residue is milled, and after milling, the thickness of the molybdenum target residue is 10 mm and the surface is flat; then, the milled molybdenum target residue is cut into several molybdenum blocks, and then the molybdenum blocks are cleaned with molten NaOH solution at 400℃.

[0033] The technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0034] Example 1

[0035] (1) Raw materials: The molybdenum target residue returned after magnetron sputtering coating was selected as the raw material. The purity of the molybdenum target residue was 99.95%, and the density was 10.19 g / cm³. 3 ;

[0036] (2) Milling: The molybdenum target is milled to a thickness of about 10 mm and the surface is flat.

[0037] (3) Alkali washing: The molybdenum target after milling is divided into molybdenum blocks with a size of 10*200*200mm by water jet, and then the molybdenum blocks are cleaned with molten NaOH solution at 400℃ to remove surface oxides and impurities;

[0038] (4) Rolling: The molybdenum block is heated to 1100℃ and held for 60 minutes. It is then rolled in two passes with a deformation of 20% and 15% per pass, respectively.

[0039] (5) Annealing and leveling: After rolling, the molybdenum plate is annealed at 850℃ for 60 minutes to eliminate internal stress, and then repeatedly leveled on a nine-roll leveling machine until the flatness is ≤0.5mm;

[0040] (6) Waterjet cutting: After leveling, the molybdenum plate is cut by waterjet cutting to obtain a molybdenum ring blank with OD93.6*ID72.3*6.8mm, leaving enough allowance for subsequent machining;

[0041] (7) Machining: The blank molybdenum ring is precision machined by CNC lathe to obtain a molybdenum ring with dimensions of OD90.6*ID75.3*5mm.

[0042] Using the method described in this embodiment, 50 molybdenum rings were prepared, and the density of the prepared molybdenum rings was ≥10.2 g / cm³. 3 No cracking occurred during the rolling and blank molybdenum ring machining process, with a pass rate of 100%.

[0043] Example 2

[0044] The only difference between Example 2 and Example 1 is that in step (4), the molybdenum block is heated to 1050°C and kept at that temperature for 0.5 hours.

[0045] Using the method of this embodiment, 50 molybdenum rings were prepared. The density of the prepared molybdenum rings was 10.19-10.2 g / cm3. No cracking occurred during the rolling and machining of the blank molybdenum rings, and the pass rate was 100%.

[0046] Comparative Example 1

[0047] The only difference between Comparative Example 1 and Example 1 is that in step (1), sintered slabs are used instead of molybdenum residual targets as raw materials, and in step (4), two-pass rolling is required. The initial rolling temperature is 1300℃, the holding time is 2h, and the deformation per pass is 15% and 10%. The secondary rolling temperature is 1250℃, the holding time is 1h, and the deformation per pass is 15% and 10%.

[0048] Using the method described in this comparative example, 50 molybdenum rings were prepared, with densities ranging from 10.17 to 10.19 g / cm³. 3 No cracking occurred during the machining process, but the sintering process was added, and the rolling temperature and holding time needed to be extended, resulting in a reduction in deformation per pass, a longer production cycle, and a decrease in efficiency.

[0049] Comparative Example 2

[0050] The only difference between Comparative Example 2 and Example 1 is that it does not include step (2).

[0051] Fifty molybdenum rings were prepared using the method described in this comparative example. The density of the prepared molybdenum rings was ≥10.2 g / cm³. 3 However, because the residual targets were not treated and the surface was uneven, there were many cracks due to uneven deformation during the rolling process, and the pass rate was only about 50%.

[0052] Comparative Example 3

[0053] The method described in patent CN115007866B for preparing molybdenum rings with dimensions of OD90.6*ID75.3*5mm mainly includes the steps of "molybdenum powder - molding - sintering - processing".

[0054] Using the method described in this comparative example, 50 molybdenum rings were prepared, and the density of the prepared molybdenum rings was only 9.8-10.0 g / cm³. 3 The wall is thin and the density is low, making it difficult to machine. After machining, there are many pores on the surface, which cannot meet the requirements of MPCVD equipment.

[0055] Comparative Example 4

[0056] The method described in steps one to four of patent CN116590672A is used to prepare molybdenum rings with dimensions of OD90.6*ID75.3*5mm, which mainly includes "molybdenum powder-powder loading-sintering-forging-processing".

[0057] Fifty molybdenum rings were prepared using the method described in this comparative example. The density of the prepared molybdenum rings was 10.1-10.12 g / cm³. 3 Due to the difficulty in forging the tube blank, the small amount of deformation, and the uneven internal and external deformation, multiple cracking phenomena occurred during the machining process, resulting in a pass rate of only about 40% and a short service life for the prepared products.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention in any way. All equivalent transformations or modifications made in accordance with the essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a high-performance thin-wall molybdenum ring for an MPCVD device using a molybdenum residue target, characterized in that, The method mainly comprises the following steps: (1) selecting a molybdenum residual target after magnetron sputtering coating and returning, and pretreating the molybdenum residual target into a molybdenum block with a smooth and clean surface; (2) performing rolling treatment on the molybdenum block to obtain a molybdenum plate; (3) performing annealing and leveling treatment on the molybdenum plate; (4) performing water cutting on the leveled molybdenum plate to obtain a molybdenum blank ring; (5) performing finish machining on the molybdenum blank ring to obtain a molybdenum ring with a wall thickness less than 10 mm; In step (2), the molybdenum block is heated to 1050-1150℃ and kept for 0.5-1.5 h, and a one-fire two-pass rolling method is adopted, with a first-pass deformation of 15-30% and a second-pass deformation of 10-20%. In step (3), the specific parameters of the annealing treatment are as follows: the molybdenum plate is kept at a temperature of 800-900℃ for 0.5-1.5 h.

2. The method for preparing high-performance thin-wall molybdenum rings for MPCVD equipment by using molybdenum residual targets according to claim 1, characterized in that, In step (1), the purity of the molybdenum residue target is 99.95%, and the density is ≥10.19 g / cm 3 .

3. The method for preparing high-performance thin-wall molybdenum ring for MPCVD equipment by using molybdenum residual target according to claim 1, characterized in that, In step (1), the specific method for pretreating the molybdenum residual target is as follows: first, performing milling processing on the molybdenum residual target, so that the thickness of the molybdenum residual target after milling processing is 10 mm and the surface is smooth; then, cutting the molybdenum residual target after milling processing into a plurality of molybdenum blocks, and then cleaning the molybdenum blocks using a 400℃ molten NaOH solution.

4. The method for preparing high-performance thin-wall molybdenum ring for MPCVD equipment by using molybdenum residual target according to claim 1, characterized in that, In step (3), the molybdenum plate after annealing treatment is repeatedly leveled on a nine-roll leveling machine until the flatness is ≤0.5 mm.

5. The method for preparing high-performance thin-wall molybdenum ring for MPCVD equipment by using molybdenum residual target according to claim 1, characterized in that, In step (5), the molybdenum blank ring is finish machined to the size of the molybdenum plate by using a numerical control lathe.

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