Copper-based alloy gradient heat sink material and induction heating preparation method thereof
By employing local induction heating and copper infiltration, the complexity and performance stability issues of existing tungsten-copper or molybdenum-copper gradient heat sink materials have been resolved. This approach achieves the continuity and diversity of compositional gradients in copper-based alloy gradient heat sink materials, making them suitable for a variety of applications.
Patent Information
- Application Number
- CN202511380078.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-25
- Publication Date
- 2025-12-26
AI Technical Summary
Existing tungsten-copper or molybdenum-copper gradient heat sink materials have complex preparation processes, poor material performance stability, high interfacial thermal resistance, limited structural design diversity, and gradient changes are limited to the upper and lower structures.
A method combining local induction heating with copper infiltration is adopted. The metal billet is locally heated and sintered using a medium-frequency induction heating device to form sintering density differences in different regions. Subsequently, copper infiltration is performed to form a copper-based alloy gradient heat sink material with a composition gradient distribution.
It achieves a continuous and seamless transition of material composition gradient, simplifies the preparation process, improves the performance stability and flexibility of the material, and can realize a variety of gradient distribution forms, making it suitable for chip transition layers and high thermal conductivity sweating materials with different material properties.
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Figure CN121199104A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of copper-based alloy heat sink materials, and particularly to copper-based alloy gradient heat sink materials and their induction heating preparation method. Background Technology
[0002] Gradient alloy heat sinks have unique application value in the field of thermal management. For example, in semiconductor chips and integrated circuits with increasingly higher integration levels, gradient heat sinks can be used to match chips with different coefficients of thermal expansion, thereby improving the lifespan of devices. In chip applications, gradient heat sinks can be designed with a structure that transitions from a high tungsten / molybdenum side (low CTE, close to semiconductor materials such as Si and GaAs) to a high copper side (high CTE, close to metal substrates or heat sinks), reducing thermal stress between the chip and the substrate and preventing solder layer cracking or chip warping. In the aerospace and military fields, the high tungsten / molybdenum side of gradient heat sinks can withstand high temperatures, while the high copper side can quickly conduct heat to reduce device temperature, making them very suitable for use as sweat-generating materials.
[0003] Currently, most commonly used tungsten-copper or molybdenum-copper gradient heat sink materials have layered structures, which have the following drawbacks: multi-layered gradient heat sink materials require rolling bonding, explosive bonding, or hot-press welding, making the preparation process complex and cumbersome; the more layers there are, the more interfaces there are, making it more difficult to control the bonding surfaces, resulting in poor material performance stability and problems such as delamination and increased interface thermal resistance during use; the gradient change is usually limited to the gradient change of the upper and lower structures, which significantly restricts the diversity of structural design. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to propose a novel copper-based alloy gradient heat sink material and its induction heating preparation method. The preparation method is simple, can flexibly meet various design requirements, can realize the gradient structure of the material in multiple directions, and the resulting material can seamlessly transition between different gradient regions without producing obvious bonding interfaces.
[0005] The technical solution of the present invention is as follows: A method for preparing a copper-based alloy gradient heat sink material by induction heating, comprising the following steps: 1. Reduce metal powder under a reducing atmosphere to obtain reduced metal powder; 2. Press the reduced metal powder into a metal blank; 3. Under a reducing atmosphere, the metal billet is locally heated and sintered by the induction heating coil of a medium-frequency induction heating device, so that the heated area and the unheated area and / or the heated area and the heated area have different sintering densities, thus obtaining a locally heated billet; wherein, the heating frequency of the induction heating coil is 2000-20000Hz; and the width of the induction heating coil is 5mm-30mm. 4. Copper is arranged on the surface or inside of the locally heated billet to perform copper infiltration treatment, thereby obtaining a composite billet; 5. Remove excess copper from the composite billet to obtain a copper-based alloy gradient heat sink material with a gradient distribution of composition between the heated and unheated regions and / or between the heated and unheated regions.
[0006] In the above technical solutions of the present invention, the porosity of the region in which the metal billet is locally heated and sintered is lower than that of the unheated region, and less copper is diffused in during the copper diffusion process. The content of other components such as molybdenum and tungsten is higher, thereby forming a copper-based alloy gradient heat sink material with a continuous distribution of components but a gradient composition ratio.
[0007] In the above technical solutions of the present invention, the integrity of the material is ensured by local induction heating, the continuity of the gradient change of the composition is realized, and the transition between different compositions is seamless without obvious bonding interfaces. At the same time, by using local induction heating, the gradient distribution of the material can be flexibly adjusted by simply fixing or moving the blank, and gradient distributions that are difficult to obtain by conventional methods can be obtained.
[0008] In the above technical solutions of the present invention, different sintering densities can be controlled by different local heating sintering temperatures and / or times and / or sintering widths, thicknesses, etc.
[0009] According to some preferred embodiments of the present invention, the metal powder is molybdenum powder and / or tungsten powder with a particle size of 2-10 μm.
[0010] According to some preferred embodiments of the present invention, the reduction process is carried out in a hydrogen atmosphere at a temperature of 800-950°C for 1-2 hours.
[0011] According to some preferred embodiments of the present invention, the compression molding is carried out by molding and / or isostatic pressing, with a pressure of 9-200 MPa.
[0012] According to some preferred embodiments of the present invention, the temperature of the local heating sintering is 1150-2150°C and the time is 5-30 min.
[0013] According to some preferred embodiments of the present invention, the local heating sintering method includes one or more of the following: partitioned heating of the metal billet, spiral moving heating, axial moving heating, and radial moving heating.
[0014] The above preferred embodiments can correspondingly form gradient distribution regions in the form of partitions, spirals, axial distributions, or rings.
[0015] According to some preferred embodiments of the present invention, the copper infiltration treatment is carried out in a hydrogen atmosphere at a temperature of 1250-1450°C for 1-2 hours.
[0016] According to some preferred embodiments of the present invention, the metal blank is one or more of the following: sheet, cuboid, rod, and cylindrical.
[0017] According to some preferred embodiments of the present invention, the induction heating coil is rectangular and / or ring-shaped.
[0018] The present invention further provides a copper-based alloy gradient heat sink material prepared according to the above-described induction heating preparation method.
[0019] The copper-based alloy gradient heat sink material obtained by this invention has a continuous composition gradient distribution, and its distribution pattern is consistent with the distribution pattern of heated and unheated areas in local heating. According to the regional distribution of local heating and sintering of the material, copper-based alloys with different composition ratios are formed. Among them, the region with high heating and sintering temperature forms a relatively low copper content, and the region with low heating and sintering temperature or no heating forms a relatively high copper content.
[0020] The present invention has the following beneficial effects: (1) The preparation method of the present invention has simple procedures and a short production cycle; (2) The preparation method of the present invention can obtain a gradient heat sink material with different component ratios in different regions, but seamless transition between components in each region and no obvious bonding interface by local induction heating and copper infiltration. (3) The preparation method of the present invention is highly flexible and controllable, and the size, shape and heating parameters (such as temperature and time) of the induction heating area can be freely designed according to different design requirements.
[0021] (4) The gradient heat sink material obtained by the present invention can match chips with different material properties in regions with different component ratios, can also be used to reduce the transition layer between the chip and the heat sink, and can also be used as a sweating material with both high temperature resistance and high thermal conductivity, etc., with wide applicability; (5) The preparation method of the present invention can obtain a variety of gradient distribution patterns that are difficult to achieve in conventional methods, including gradient distribution regions with multiple forms such as partitioned variation, axial alternating variation, and thickness or radial alternating variation. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the local induction heating method in Example 1; Figure 2 This is a schematic diagram of the copper plating method in Example 1; Figure 3 This is a schematic diagram of the local induction heating method in Example 2; Figure 4 This is a schematic diagram of the local induction heating method in Example 3; Figure 5 This is a schematic diagram of the copper addition method in Example 3; Figure 6 This is a schematic diagram of the gradient distribution morphology of the gradient heat sink material obtained in Example 3; Figure 7 This is a schematic diagram of the local induction heating method in Example 4; Figure 8 This is a schematic diagram of the gradient distribution morphology of the gradient heat sink material obtained in Example 4; Among them, 1-induction coil, 2-cubic molybdenum billet, 3-pure copper, 4-rod-shaped tungsten billet, 5-cylindrical tungsten billet, 6-rod-shaped molybdenum billet. Detailed Implementation
[0023] The technical solutions of the present invention will be further described below with reference to the embodiments and accompanying drawings. The embodiments described below 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 should fall within the scope of protection of the present invention.
[0024] Example 1: Preparation of a molybdenum-copper alloy partitioned gradient heat sink material by the following steps: (1) Reduced molybdenum powder with a particle size of 5 μm was reduced at 850 °C for 2 h in a hydrogen atmosphere and then cooled to obtain reduced molybdenum powder; (2) Weigh 381 g of reduced molybdenum powder and put it into a rectangular mold with a length × width of 80 mm × 60 mm. Place the mold into the pressure chamber of the hydraulic press and press it under a pressure of 9 MPa to obtain a rectangular molybdenum blank with a thickness of 11.5 mm. (3) Refer to Appendix Figure 1A medium-frequency induction heating device containing a rectangular induction coil 1 with a heating width of 20 mm was used to locally heat a cuboid molybdenum billet 2 in a hydrogen atmosphere and a heating frequency of 3000 Hz. The heating method was to divide the molybdenum billet into four continuous regions of equal area, namely regions A, B, C, and D. Regions A and C were not heated. Region B was heated and sintered at 1800℃ for 8 min, and region D was heated and sintered at 2100℃ for 15 min to obtain a locally sintered molybdenum billet. (4) Refer to Appendix Figure 2 248 g of pure copper 3 was covered on the surface of the obtained partially sintered molybdenum billet, and copper infiltration treatment was carried out in a muffle furnace at 1300℃ under hydrogen atmosphere for 2 hours. After cooling, the composite billet was obtained. (5) Remove excess copper from the surface of the composite billet by machining to obtain a molybdenum-copper alloy gradient heat sink material with a gradient distribution of composition content.
[0025] The compositions of the obtained molybdenum-copper alloy gradient heat sink materials from region A to region D are as follows: region A: Mo70Cu (70 wt% Mo and 30 wt% Cu), region B: Mo75Cu (75 wt% Mo and 25 wt% Cu), region C: Mo70Cu (70 wt% Mo and 30 wt% Cu), and region D: Mo80Cu (80 wt% Mo and 20 wt% Cu).
[0026] Example 2: Preparation of tungsten-copper alloy axially distributed gradient heat sink material through the following steps: (1) Tungsten powder with a particle size of 9 μm was reduced at 950 °C for 2 h in a hydrogen atmosphere and then cooled to obtain reduced tungsten powder; (2) Weigh 1200 g of reduced tungsten powder and put it into a cylindrical rubber mold with an inner diameter of 31 mm. Then seal the rubber mold and fix it with a stainless steel perforated sleeve. Then put it into an isostatic press and gradually increase the pressure to 200 MPa within 10 min. The pressure increase method is: increase the pressure to 70 MPa in 2 min and hold the pressure for 1 min, then increase the pressure from 70 MPa to 140 MPa in 2 min and hold the pressure for 1 min, then increase the pressure from 140 MPa to 200 MPa in 2 min, then hold the pressure for 15 min, and take it out after depressurization to obtain a rod-shaped tungsten billet with a diameter of 25 mm. (3) Refer to Appendix Figure 3A medium-frequency induction heating device containing a ring induction coil 1 with a heating width of 20 mm was used to locally heat the rod-shaped tungsten blank 4 in a hydrogen atmosphere and a heating frequency of 2000 Hz. The heating method was to divide the tungsten blank axially into adjacent E regions and F regions. There were a total of 5 E regions with a width (i.e., the length of the corresponding rod-shaped tungsten blank) of 20 mm, and a total of 4 F regions with a width of 15 mm. The E regions were heated and sintered at 2100℃ for 15 min, while the F regions were not heated, resulting in a locally sintered tungsten blank. (4) Cover the surface of the obtained partially sintered tungsten billet with 295 g of pure copper, and carry out copper diffusion treatment in a muffle furnace at 1400℃ under hydrogen atmosphere for 2 h, and then cool to obtain composite billet; (5) Remove excess copper from the surface of the composite blank by machining to obtain a tungsten-copper alloy gradient heat sink material with a gradient distribution of composition content.
[0027] The resulting tungsten-copper alloy gradient heat sink material has a composition of W90Cu (90 wt% W and 10 wt% Cu) in the heated region and W80Cu (80 wt% W and 20 wt% Cu) in the unheated region.
[0028] Example 3: Preparation of a tungsten-copper alloy spiral gradient heat sink material by the following steps: (1) Tungsten powder with a particle size of 3 μm was reduced at 850 °C for 2 h in a hydrogen atmosphere and then cooled to obtain reduced tungsten powder; (2) Select a cylindrical rubber sleeve with an inner diameter of 50 mm, place a solid cylindrical tool with a diameter of 35 mm in the middle of the cylindrical rubber sleeve to form an assembly mold, so as to ensure that the prepared tungsten blank is cylindrical. Weigh 800 g of reduced tungsten powder and put it into the assembly mold, and then put it into an isostatic press. Gradually increase the pressure to 160 MPa within 10 min. The pressure increase method is: increase the pressure to 60 MPa for 2 min and hold the pressure for 1 min, then increase the pressure from 60 MPa to 120 MPa for 2 min and hold the pressure for 1 min, then increase the pressure from 120 MPa to 160 MPa for 20 min and hold the pressure for 20 min. After depressurization, take it out to obtain a cylindrical tungsten blank with an inner diameter of 28 mm and an outer diameter of 40 mm. (3) Refer to Appendix Figure 4 A medium-frequency induction heating device containing a ring-shaped induction coil 1 with a heating width of 10 mm was used to locally heat a cylindrical tungsten blank 5 for 15 minutes in a hydrogen atmosphere at 2100℃ and a heating frequency of 3000 Hz. The heating method was as follows: the induction coil 1 was moved horizontally at a uniform speed of 8 mm / s (horizontal speed υ in the figure), while the cylindrical tungsten blank 5 was rotated at a uniform speed of 48 rpm (angular velocity ω in the figure) to form a spiral heating area, thereby obtaining a locally sintered tungsten blank. (4) Refer to Appendix Figure 5 The interior of the partially sintered tungsten billet is filled with rod-shaped pure copper 3 with a diameter of 20 mm or the outer surface of the partially sintered tungsten billet is covered with cylindrical pure copper 3 with an outer diameter of 42 mm and a thickness of 1 mm. The billet is then subjected to copper infiltration treatment in a muffle furnace at 1400℃ under a hydrogen atmosphere for 2 h, and then cooled to obtain a composite billet. (5) Remove excess copper from the surface of the composite blank by machining to obtain a tungsten-copper alloy gradient heat sink material with a gradient distribution of composition content.
[0029] See attached document Figure 6 The composition of the obtained tungsten-copper alloy gradient heat sink material exhibits a spiral partitioning consistent with the heating zone. The composition of the heating zone is W85Cu (W content is 85 wt%, Cu content is 15 wt%), while the composition of the unheated zone is W75Cu (W content is 75 wt%, Cu content is 25 wt%).
[0030] Example 4: Preparation of a molybdenum-copper alloy annular gradient heat sink material by the following steps: (1) Molybdenum powder with a particle size of 7 μm was reduced at 950 °C for 2 h in a hydrogen atmosphere and then cooled to obtain reduced molybdenum powder; (2) Weigh 1600 g of reduced molybdenum powder and put it into a cylindrical mold with an inner diameter of 50 mm. Then put it into an isostatic press and gradually increase the pressure to 160 MPa within 10 min. The pressure increase method is as follows: increase the pressure to 60 MPa in 2 min and hold the pressure for 1 min, then increase the pressure from 60 MPa to 120 MPa in 2 min and hold the pressure for 1 min, then increase the pressure from 120 MPa to 160 MPa in 2 min and hold the pressure for 20 min. After depressurization, take it out to obtain a rod-shaped molybdenum billet with a diameter of 40 mm. (3) Refer to Appendix Figure 7 A medium-frequency induction heating device containing a ring-shaped induction coil 1 with a heating width of 10 mm was used. The heating method involved moving the induction coil 1 horizontally at a uniform speed of 4 mm / s (horizontal speed υ as shown in the figure) while simultaneously fixing the rod-shaped molybdenum blank 6. The rod-shaped molybdenum blank 6 was heated for 15 minutes in a hydrogen atmosphere at 2100℃ and a heating frequency of 4300 Hz. (See attached...) Figure 8 Under these conditions, only the annular region (i.e., region H) of the locally sintered molybdenum billet is heated and sintered, while its interior (i.e., region G) is not heated. The annular region that is heated has a ring width of 5 mm. (4) Cover the outer surface of the obtained partially sintered molybdenum billet with 900 g of pure copper, and carry out copper diffusion treatment in a muffle furnace at 1400℃ under hydrogen atmosphere for 3 h, and then cool to obtain composite billet. (5) Remove excess copper from the surface of the composite billet by machining to obtain a molybdenum-copper alloy gradient heat sink material with a gradient distribution of composition content.
[0031] The resulting molybdenum-copper alloy gradient heat sink material has a high-molybdenum composition region H and other low-molybdenum composition regions G that are consistent with the heating zone distribution, as shown in the attached figure. Figure 8 As shown, the composition of the high molybdenum region H is Mo80Cu (Mo content is 80 wt%, Cu content is 20 wt%), and the composition of the low molybdenum region G is Mo70Cu (Mo content is 70 wt%, Cu content is 30 wt%).
[0032] It should be noted that the above descriptions are merely preferred embodiments of the present invention and should not limit the scope of protection of the technical solutions of the present invention. Any modifications made to the technical solutions described in the foregoing embodiments, or equivalent substitutions of technical features, by those skilled in the art within the spirit and principles of the present invention, should be included within the scope of protection of the present invention.
Claims
1. A method for preparing a copper-based alloy gradient heat sink material by induction heating, characterized in that, It includes the following steps:
1. Reduce metal powder under a reducing atmosphere to obtain reduced metal powder; 2. Press the reduced metal powder into a metal blank; 3. Under a reducing atmosphere, the metal billet is locally heated and sintered by the induction heating coil of a medium-frequency induction heating device, so that the heated area and the unheated area and / or the heated area and the heated area have different sintering densities, thus obtaining a locally heated billet; wherein, the heating frequency of the induction heating coil is 2000-20000Hz; and the width of the induction heating coil is 5 mm-30 mm.
4. Copper is arranged on the surface or inside of the locally heated billet to perform copper infiltration treatment, thereby obtaining a composite billet; 5. Remove excess copper from the composite billet to obtain a copper-based alloy gradient heat sink material with a gradient distribution of composition between the heated and unheated regions and / or between the heated and unheated regions.
2. The induction heating preparation method according to claim 1, characterized in that, The metal powder is molybdenum powder and / or tungsten powder with a particle size of 2-10 μm.
3. The induction heating preparation method according to claim 1, characterized in that, The reduction process is carried out in a hydrogen atmosphere at a temperature of 800-950°C for 1-2 hours.
4. The induction heating preparation method according to claim 1, characterized in that, The compression molding process employs die pressing and / or isostatic pressing, with a pressure of 9-200 MPa.
5. The induction heating preparation method according to claim 1, characterized in that, The local heating sintering temperature is 1150-2150℃, and the time is 5-30min.
6. The induction heating preparation method according to claim 1, characterized in that, The local heating sintering method includes one or more of the following: zone heating of the metal billet, spiral moving heating, axial moving heating, and radial moving heating.
7. The induction heating preparation method according to claim 1, characterized in that, The copper diffusion process is carried out in a hydrogen atmosphere at a temperature of 1250-1450℃ for 1-2 hours.
8. The induction heating preparation method according to claim 1, characterized in that, The metal blank is one or more of the following shapes: sheet, cuboid, rod, and cylinder.
9. The induction heating preparation method according to claim 1, characterized in that, The induction heating coil is rectangular and / or ring-shaped.
10. A copper-based alloy gradient heat sink material, characterized in that, It is prepared by the induction heating preparation method according to any one of claims 1-9.