Preparation method of high-quality EB evaporation target material
By using spark plasma sintering technology, the problems of target density and production efficiency in existing technologies have been solved, and high-quality EB evaporation targets have been prepared, which are suitable for EBPVD coatings and bulk materials, achieving efficient production and high-performance coatings.
Patent Information
- Application Number
- CN202511836021.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-08
- Publication Date
- 2026-02-06
AI Technical Summary
Existing technologies for preparing high-quality targets suffer from problems such as insufficient density, numerous pores, long production cycles, high costs, difficulty in preparing multi-component targets, and significant loss of volatile components. In particular, the melting method is inefficient when dealing with volatile components.
The discharge plasma sintering method is adopted. After pre-compacting the powder raw material, auxiliary heating, pulse current sintering and staged controlled cooling are carried out in the discharge plasma sintering equipment. Combined with particle size optimization and cleaning treatment, the densification and uniformity of the powder are achieved.
High density, low porosity, and high mechanical strength target materials were prepared, shortening production time, expanding the application range of volatile component target materials, improving material utilization, and forming a dense coating with high hardness and high adhesion.
Smart Images
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of target material preparation, in particular to a preparation method of high-quality EB evaporation target material. BACKGROUND
[0002] Coating preparation is of great significance in many engineering and industries such as the semiconductor field, high-temperature thermal insulation, cutting tools, etc. As a method for preparing high-crystallinity and high-density coatings, electron beam physical vapor deposition (EBPVD) can deposit a coating on a substrate by evaporating a target material heated by an electron beam. The deposition rate can be adjusted according to the structure and composition of the coating. In addition to making coatings, EB evaporation can also synthesize bulk materials that cannot be synthesized by ordinary methods. Through high-energy evaporation, the materials are fully mixed in molecular form, and the cooling speed is fast. The synthesized materials are uniform in composition and excellent in performance. In application scenarios such as coating preparation and bulk material synthesis, high-quality target materials are the key to obtaining high-quality products. Therefore, the preparation technology of target materials has always been the focus of research in this field.
[0003] To solve the problem of preparing high-quality target materials, conventional methods include direct sintering, cold isostatic pressing sintering, and melting-crystallization and breaking. Direct sintering is a relatively basic preparation method that directly sinters raw materials into a desired shape. Cold isostatic pressing sintering adds an isostatic pressing step to direct sintering to improve the density of the target material. The melting-crystallization and breaking method first melts the raw materials, then crystallizes them, and finally breaks them into the desired target material. These methods can prepare target materials that meet some needs to some extent and have been widely used in fields such as coating preparation and bulk material synthesis.
[0004] However, these conventional methods in the prior art have obvious defects. The density of the target material prepared by direct sintering is not high enough, and there are a large number of pores. Even if cold isostatic pressing is used, it is difficult to completely remove the micro-bubbles. Although the target material prepared by melting and recrystallization has high crystallinity, the production cycle is long and the cost is high. Moreover, when preparing multi-component target materials, especially those containing volatile and decomposable components, the above methods cannot be used to prepare them. In addition, many existing target materials have a large amount of volatile loss during melting, and the melting time is long, so there is room for improvement. SUMMARY
[0005] To solve the above problems, the present application provides a preparation method of high-quality EB evaporation target material.
[0006] The preparation method of high-quality EB evaporation target material provided by the present application adopts the following technical scheme: A preparation method of high-quality EB evaporation target material, comprising the following steps: S1, loading the powder raw material into the cleaned crucible, and pre-compacting to obtain a pre-compacted crucible; S2. Place the pre-compacted crucible into the spark plasma sintering equipment, evacuate and pressurize it, turn on the auxiliary heating to raise the temperature to the thermal shock buffer temperature, then stop the auxiliary heating, apply current to raise the temperature to the sintering densification temperature, hold it at that temperature, then stop applying the current, turn on the auxiliary heating to control the cooling rate, cool it to the stress safety cooling threshold, then switch to the program-controlled cooling system for cooling, remove the crucible, clean and dry it to obtain a high-quality EB evaporation target.
[0007] Spark plasma sintering generates a local discharge effect between powder particles by applying pulsed current. On the one hand, it effectively cleans and activates the particle surface, enhancing its diffusion and migration capabilities. On the other hand, under the action of a strong electric field and plasma, the synergistic effect with axial pressure causes evaporation and melting on the grain surface, achieving rapid sintering and densification between particles without the formation of pores, thus ensuring the density of the target material. By pre-compacting the powder raw material and placing it in a spark plasma sintering (SPSS) apparatus, and subjecting it to the synergistic effects of auxiliary heating preheating, pulsed current rapid sintering, and staged programmed cooling, the energy barrier on the surface of the powder particles is effectively reduced, promoting grain boundary diffusion and particle rearrangement. This achieves full densification of the green body, resulting in a target material with a uniform internal structure and low porosity. Simultaneously, this method utilizes a gradual heating followed by rapid cooling process to help release the thermal stress accumulated during sintering, improve the overall strength of the target material, and reduce internal defects. The resulting target material exhibits high density and mechanical strength, with reduced internal stress. It demonstrates good evaporation stability and film uniformity during electron beam physical vapor deposition, and the final coating structure is dense, with high hardness and high adhesion. The above preparation method makes it possible to prepare target materials containing volatile and easily decomposed components, greatly expanding the scope of new materials and coatings produced by EB evaporation. The target materials synthesized by this method can be directly used for the production of EBPVD coatings or bulk materials, eliminating the target material melting stage, reducing production time by more than half, and increasing material utilization by more than 60%.
[0008] Preferably, in step S1, the powder raw material is dried in a Class 1000 cleanroom environment; the median particle size D50 of the powder raw material is 0.3-2μm.
[0009] By drying the powder raw materials in a Class 1000 cleanroom environment and optimizing the control of the median particle size of the powder raw materials, the risk of surface contamination of the powder is effectively reduced and the uniformity of powder packing is improved. The powder has high surface activity and diffusion ability during sintering, which helps to promote material migration and grain boundary formation between particles, thereby improving the densification degree and microstructure uniformity of the sintered body. At the same time, the uniform powder distribution helps to alleviate the concentration of local stress during sintering, laying the foundation for obtaining a target material with a dense structure and low internal stress. This allows the target material to form a dense and well-bonded coating during the evaporation deposition process, exhibiting high hardness and high adhesion.
[0010] Preferably, the crucible in step S1 includes one of a glass graphite crucible and a carbon fiber reinforced graphite crucible; the cleaning process in step S1 includes acid washing, plasma cleaning, and drying of the crucible.
[0011] Using a graphite crucible with good thermal stability can adapt to the thermal cycling changes during rapid heating and cooling, helping to reduce residual stress inside the sintered body and ultimately obtaining a target material with uniform microstructure and dense structure. By performing a combined treatment of acid washing and plasma cleaning on the graphite crucible, surface impurities can be effectively removed and the inner wall of the crucible can be activated to form a clean and stable powder carrying environment, promoting uniform temperature transfer and stress distribution, thereby improving the density and uniformity of the target material.
[0012] Preferably, the pre-compaction pressure in step S1 is 40-60 MPa.
[0013] By employing appropriate pressure for pre-compaction, the powder particles achieve a preliminary close arrangement, which helps to promote uniform current conduction and stable heat distribution during sintering. This improves material migration efficiency and reduces the risk of local overheating, allowing grains to grow in a coordinated manner during sintering and forming a sintered body with fewer defects and a complete structure. This enhances the density and mechanical strength of the target material, enabling it to form a dense and well-bonded coating during evaporation deposition.
[0014] Preferably, in step S2, the vacuum is drawn to 0.01-0.05 Pa, the pressure is increased to 95-105 MPa, and the auxiliary heating is turned on.
[0015] By applying axial pressure in a high vacuum environment in conjunction with auxiliary heating, a clean and stable thermodynamic environment is created for the sintering process. Vacuum conditions effectively inhibit powder oxidation and promote gas desorption, thereby promoting particle surface activation. The application of moderate pressure helps to enhance interparticle contact and plastic flow, providing a continuous driving force for material densification. Auxiliary heating reduces the thermal shock of the material during the rapid sintering stage through a smooth temperature transition, promotes coordinated grain growth and stress relaxation, and thus synergistically improves the density and structural integrity of the target material, thereby enhancing the hardness and adhesion of the prepared coating.
[0016] Preferably, the thermal shock buffer temperature is 1150-1250℃.
[0017] By setting a thermal shock buffer temperature range, the powder material is fully and uniformly preheated before sintering, promoting the migration and rearrangement of activated substances on the particle surface. This step-by-step heating method helps to alleviate the thermal stress concentration phenomenon generated during subsequent rapid sintering, thereby promoting the coordinated growth of grains. The initial sintering neck formed by the preheating treatment can improve the current conduction path, enhance the sintering driving force, promote the complete densification process of the material, and reduce the tendency of micro-defect formation. In the end, a target material with uniform structure and low internal stress is obtained, which in turn improves the density, hardness and bonding strength with the substrate of the coating formed during the evaporation deposition process.
[0018] Preferably, the heating rate after the current is applied in step S2 is 100-300℃ / min.
[0019] By controlling the heating rate after energization, the powder material can form a balanced thermal conduction and mass migration condition during sintering. Appropriate rapid heating helps maintain a highly activated state on the particle surface, promotes the dynamic process of grain boundary diffusion and particle rearrangement, and at the same time suppresses the grain coarsening phenomenon dominated by surface diffusion, so that the material can be fully densified in a short time to form a sintered body with uniform grain size and dense structure.
[0020] Preferably, the sintering densification temperature in step S2 is 1580-2000℃, and the holding time is 10-30 min.
[0021] By controlling the sintering densification temperature and holding time, the atoms on the surface of the powder particles acquire sufficient migration ability, and the pore structure is effectively filled through the grain boundary diffusion mechanism. At the same time, the holding process creates balanced conditions for the coordinated growth of grains, so that the crystal structure maintains a uniform microstructure while achieving high densification. This helps to form a sintered body with a complete structure and few internal defects, providing an ideal target material for the subsequent preparation of a dense and stable coating, thereby promoting the formation of a strong bonding interface between the coating and the substrate.
[0022] Preferably, in step S2, the current is stopped and the auxiliary heating is turned on to control the cooling rate at 3-7℃ / min, and the stress safety cooling threshold is 750-850℃.
[0023] By controlling the cooling rate to maintain slow cooling above a specific temperature threshold, the sintered body can undergo sufficient grain boundary relaxation and stress release at high temperatures. This controlled cooling process helps avoid microcracks and residual stress concentration caused by rapid temperature changes, while promoting grain structure stabilization. Implementing a slow cooling strategy within the temperature range where the material has good plasticity can coordinate strain mismatch caused by different coefficients of thermal expansion, maintaining the integrity and continuity of the sintered body structure. The target material obtained under this cooling regime has low stress and high density, and can form a dense coating with good interfacial bonding during subsequent evaporation deposition, thus exhibiting high hardness and good adhesion performance.
[0024] Preferably, the program-controlled cooling system in step S2 includes an annealing furnace.
[0025] By employing an annealing furnace as a programmed cooling system, a stable and controlled cooling environment is provided for the sintered body after the rapid cooling phase. This slow cooling method helps the material maintain thermal equilibrium in the phase transition sensitive temperature range, promotes the orderly adjustment of the crystal structure and further releases internal stress. The uniform thermal field distribution of the annealing furnace can avoid micro-stress concentration caused by uneven local cooling, maintain the integrity and continuity of the sintered body structure, and the resulting target material has low stress and high structural integrity. In the subsequent electron beam evaporation process, it can form a coating with uniform structure and good interfacial bonding, thus exhibiting high hardness and good adhesion performance.
[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. By pre-compacting the powder raw material and placing it in a spark plasma sintering (SPSS) apparatus, the powder undergoes a series of synergistic processes including auxiliary heating preheating, pulsed current rapid sintering, and staged programmed cooling. This effectively reduces the energy barrier on the surface of the powder particles, promotes grain boundary diffusion and particle rearrangement, and achieves full densification of the green body. The resulting target material has a uniform internal structure and low porosity. Simultaneously, this method utilizes a gradual heating followed by rapid cooling process to help release the thermal stress accumulated during sintering, improve the overall strength of the target material, and reduce internal defects. The resulting target material exhibits high density and mechanical strength, with reduced internal stress. It demonstrates good evaporation stability and film uniformity during electron beam physical vapor deposition, and the final coating structure is dense with high hardness and high adhesion.
[0027] 2. The above preparation method provides the possibility for the preparation of target materials containing volatile and easily decomposed components, greatly expanding the scope of new materials and coatings produced by EB evaporation. The target materials synthesized by this method can be directly used for the production of EBPVD coatings or bulk materials, eliminating the target material melting stage, reducing production time by more than half, and increasing material utilization by more than 60%. Attached Figure Description
[0028] Figure 1 This is a SEM image of the high-quality EB evaporation target prepared in Example 1 of this application.
[0029] Figure 2 This is a SEM image of the EBPVD yttrium oxide coating prepared from the high-quality EB evaporation target prepared in Example 1 of this application. Detailed Implementation
[0030] This application discloses a method for preparing a high-quality EB evaporation target. Unless otherwise specified, all raw materials used in this application can be obtained from commercially available sources. The following detailed description, in conjunction with embodiments, further illustrates this application: Example 1 The raw material is 300g of yttrium oxide powder (self-made) with a median particle size D50 of 1-2μm. The crucible is a glass-graphite crucible. The spark plasma sintering equipment is a spark plasma sintering furnace with a thermal shock buffer temperature of 1200℃, a sintering densification temperature of 1580℃, a stress safety cooling threshold of 800℃, and a programmable cooling system of an annealing furnace.
[0031] S1. Dry the powder raw material at 100℃ for 3 hours in a Class 1000 cleanroom to obtain the dried powder raw material; immerse the crucible in 10% dilute nitric acid for ultrasonic cleaning for 30 minutes, rinse with deionized water until neutral, place it in a plasma cleaner, treat it at 300W power and argon atmosphere for 10 minutes, and dry it at 150℃ for 1 hour to obtain the cleaned crucible; load the dried powder raw material into the cleaned crucible, place it in a press, and pre-compact it under 50MPa pressure for 2 minutes to obtain the pre-compacted crucible; S2. Place the pre-compacted crucible into the spark plasma sintering equipment, evacuate and pressurize to 100 MPa. When the vacuum degree of the chamber reaches below 0.03 Pa, turn on the auxiliary heating and heat to 1200℃ at a rate of 20℃ / min. Stop the auxiliary heating, apply current to control the heating rate at 150℃ / min, heat to 1580℃, hold for 10 min, stop the current, turn on the auxiliary heating to control the cooling rate at 5℃ / min, and then transfer to the annealing furnace to continue cooling to room temperature. After removing the glass-graphite crucible, ultrasonically clean the sintered ingot three times each with anhydrous ethanol and deionized water, and dry at 80℃ for 2 h to obtain a high-quality EB evaporation target.
[0032] Example 2 The powder raw material is 500g of zirconium carbide powder (Heeger Materials) with a median particle size D50 of 300nm. The crucible is a glass-graphite crucible. The spark plasma sintering equipment is a spark plasma sintering furnace with a thermal shock buffer temperature of 1200℃, a sintering densification temperature of 1958℃, a stress safety cooling threshold of 800℃, and a programmable cooling system of an annealing furnace.
[0033] S1. Dry the powder raw material at 100℃ for 3 hours in a Class 1000 cleanroom to obtain the dried powder raw material; immerse the crucible in 10% dilute nitric acid for ultrasonic cleaning for 30 minutes, rinse with deionized water until neutral, place it in a plasma cleaner, treat it at 300W power and argon atmosphere for 10 minutes, and dry it at 150℃ for 1 hour to obtain the cleaned crucible; load the dried powder raw material into the cleaned crucible, place it in a press, and pre-compact it under 50MPa pressure for 2 minutes to obtain the pre-compacted crucible; S2. Place the pre-compacted crucible into the spark plasma sintering equipment, evacuate and pressurize to 100 MPa. When the vacuum degree of the chamber reaches below 0.03 Pa, turn on the auxiliary heating and raise the temperature to 1200℃ at a rate of 20℃ / min. Stop the auxiliary heating and apply current to control the heating rate at 150℃ / min. Raise the temperature to 1958℃, hold for 13 min, stop the current, turn on the auxiliary heating to control the cooling rate at 5℃ / min to 800℃. Then transfer it to the annealing furnace to continue cooling to room temperature. After removing the glass-graphite crucible, ultrasonically clean the sintered ingot three times each with anhydrous ethanol and deionized water, and dry it at 80℃ for 2 h to obtain a high-quality EB evaporation target.
[0034] Example 3 The powder raw material is 500g of zirconium carbide powder (Heeger Materials) with a median particle size D50 of 300nm. The crucible is a glass-graphite crucible. The spark plasma sintering equipment is a spark plasma sintering furnace with a thermal shock buffer temperature of 1150℃, a sintering densification temperature of 1958℃, a stress safety cooling threshold of 750℃, and a programmable cooling system of an annealing furnace.
[0035] S1. Dry the powder raw material at 100℃ for 3 hours in a Class 1000 cleanroom to obtain the dried powder raw material; immerse the crucible in 10% dilute nitric acid for ultrasonic cleaning for 30 minutes, rinse with deionized water until neutral, place it in a plasma cleaner, treat it at 300W power and argon atmosphere for 10 minutes, and dry it at 150℃ for 1 hour to obtain the cleaned crucible; load the dried powder raw material into the cleaned crucible, place it in a press, and pre-compact it under 40MPa pressure for 3 minutes to obtain the pre-compacted crucible; S2. Place the pre-compacted crucible into the spark plasma sintering equipment, evacuate and pressurize to 95 MPa. When the vacuum degree of the chamber reaches below 0.03 Pa, turn on the auxiliary heating and raise the temperature to 1150°C at a rate of 20°C / min. Stop the auxiliary heating and apply current to control the heating rate at 100°C / min. Raise the temperature to 1958°C and hold for 13 min. Stop the current and turn on the auxiliary heating to control the cooling rate at 3°C / min. After cooling to 750°C, transfer it to the annealing furnace and continue to cool to room temperature. After removing the glass-graphite crucible, ultrasonically clean the sintered ingot three times each with anhydrous ethanol and deionized water, and dry it at 80°C for 2 h to obtain a high-quality EB evaporation target.
[0036] Example 4 The powder raw material is 500g of zirconium carbide powder (Heeger Materials) with a median particle size D50 of 300nm. The crucible is a carbon fiber reinforced graphite crucible. The spark plasma sintering equipment is a spark plasma sintering furnace with a thermal shock buffer temperature of 1250℃, a sintering densification temperature of 1958℃, a stress safety cooling threshold of 850℃, and a programmable cooling system of an annealing furnace.
[0037] S1. Dry the powder raw material at 100℃ for 3 hours in a Class 1000 cleanroom to obtain the dried powder raw material; immerse the crucible in 10% dilute nitric acid for ultrasonic cleaning for 30 minutes, rinse with deionized water until neutral, place it in a plasma cleaner, treat it at 300W power and argon atmosphere for 10 minutes, and dry it at 150℃ for 1 hour to obtain the cleaned crucible; load the dried powder raw material into the cleaned crucible, place it in a press, and pre-compact it under 60MPa pressure for 1 minute to obtain the pre-compacted crucible; S2. Place the pre-compacted crucible into the spark plasma sintering equipment, evacuate and pressurize to 105 MPa. When the vacuum degree of the chamber reaches below 0.03 Pa, turn on the auxiliary heating and raise the temperature to 1250°C at a rate of 20°C / min. Stop the auxiliary heating and apply current to control the heating rate at 300°C / min. Raise the temperature to 1958°C and hold for 13 min. Stop the current and turn on the auxiliary heating to control the cooling rate at 7°C / min. After cooling to 850°C, transfer it to the annealing furnace and continue to cool to room temperature. After removing the glass-graphite crucible, ultrasonically clean the sintered ingot three times each with anhydrous ethanol and deionized water, and dry it at 80°C for 2 h to obtain a high-quality EB evaporation target.
[0038] Comparative Example 1 Comparative Example 1 was sintered by directly heating to the densification temperature.
[0039] The powder raw material is 500g of zirconium carbide powder (Heeger Materials) with a median particle size D50 of 300nm. The crucible is a glass-graphite crucible. The spark plasma sintering equipment is a spark plasma sintering furnace. The sintering densification temperature is 1958℃, the stress safety cooling threshold is 800℃, and the programmable cooling system is an annealing furnace.
[0040] S1. Dry the powder raw material at 100℃ for 3 hours in a Class 1000 cleanroom to obtain the dried powder raw material; immerse the crucible in 10% dilute nitric acid for ultrasonic cleaning for 30 minutes, rinse with deionized water until neutral, place it in a plasma cleaner, treat it at 300W power and argon atmosphere for 10 minutes, and dry it at 150℃ for 1 hour to obtain the cleaned crucible; load the dried powder raw material into the cleaned crucible, place it in a press, and pre-compact it under 50MPa pressure for 2 minutes to obtain the pre-compacted crucible; S2. Place the pre-compacted crucible into the spark plasma sintering equipment, evacuate and pressurize to 100 MPa. When the vacuum degree of the chamber reaches below 0.03 Pa, apply current to control the heating rate at 150 °C / min, heat to 1958 °C, hold for 13 min, then stop applying current and turn on auxiliary heating to control the cooling rate at 5 °C / min to 800 °C. Transfer to an annealing furnace and continue to cool to room temperature with the furnace. After removing the glass-graphite crucible, ultrasonically clean the sintered ingot three times each with anhydrous ethanol and deionized water, and dry at 80 °C for 2 h to obtain a high-quality EB evaporation target.
[0041] Comparative Example 2 In Comparative Example 2, no temperature control or cooling was performed.
[0042] The powder raw material is 500g of zirconium carbide powder (Heeger Materials) with a median particle size D50 of 300nm. The crucible is a glass-graphite crucible. The spark plasma sintering equipment is a spark plasma sintering furnace with a thermal shock buffer temperature of 1200℃ and a sintering densification temperature of 1958℃.
[0043] S1. Dry the powder raw material at 100℃ for 3 hours in a Class 1000 cleanroom to obtain the dried powder raw material; immerse the crucible in 10% dilute nitric acid for ultrasonic cleaning for 30 minutes, rinse with deionized water until neutral, place it in a plasma cleaner, treat it at 300W power and argon atmosphere for 10 minutes, and dry it at 150℃ for 1 hour to obtain the cleaned crucible; load the dried powder raw material into the cleaned crucible, place it in a press, and pre-compact it under 50MPa pressure for 2 minutes to obtain the pre-compacted crucible; S2. Place the pre-compacted crucible into the spark plasma sintering equipment, evacuate and pressurize to 100 MPa. When the vacuum degree of the chamber reaches below 0.03 Pa, turn on the auxiliary heating and heat to 1200℃ at a rate of 20℃ / min. Stop the auxiliary heating, apply current to control the heating rate at 150℃ / min, heat to 1958℃, hold for 13 min, then stop the current and cool to room temperature with the furnace. After removing the glass-graphite crucible, ultrasonically clean the sintered ingot three times each with anhydrous ethanol and deionized water, and dry at 80℃ for 2 h to obtain a high-quality EB evaporation target.
[0044] Performance testing The density of the high-quality EB evaporation target prepared in Example 1 was tested. A 10 μm thick EBPVD yttrium oxide coating was prepared on an alumina ceramic substrate using this target. The coating condition was observed, and the coating hardness and adhesion were tested. The results are recorded in Table 1.
[0045] Table 1. Test results of coating quality The density of the high-quality EB evaporation targets prepared in Examples 2-4 and Comparative Examples 1-2 was tested. A 5 μm thick zirconium carbide coating was prepared using tungsten steel as the substrate by EBPVD method. The hardness and adhesion of the coating were tested, and the results are recorded in Table 2.
[0046] Table 2. Test results of coating quality As shown in Table 1, the target material density in Example 1 is 5.01 g / cm³. 3 The prepared coating is dense and non-porous, with a hardness (HV) exceeding 1000 MPa and an adhesion exceeding 45 MPa; Figure 1 , 2It can be seen that the target material prepared in Example 1 has a dense structure, and the coating prepared using the target material is dense and free of pores; the target material in Examples 2-4 has a density greater than 6.71 g / cm³. 3 The prepared coating is dense and free of pores, with a coating hardness (HV) greater than 30 GPa and an adhesion greater than 34 MPa. This shows that the target material prepared in this application has high density, high strength and low stress, and the prepared coating has excellent quality, with high hardness and high adhesion.
[0047] As shown in Table 2, the only difference between Comparative Example 1 and Example 2 is that Comparative Example 1 did not use auxiliary heating to slowly raise the temperature to the thermal shock buffer temperature, which led to the occurrence of thermal shock, introduced structural defects, increased the internal stress of the target material, and thus reduced the coating hardness and adhesion.
[0048] As shown in Table 2, the only difference between Comparative Example 2 and Example 2 is that temperature control cooling was not performed in Comparative Example 2. Cooling with the furnace caused thermal stress to be generated inside the target material, which in turn led to a decrease in the adhesion of the coating and affected the hardness of the coating.
[0049] This specific embodiment is merely an explanation of this application and is not intended to limit it. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of this application. The technical scope of this application is not limited to the contents of the specification but must be determined according to the scope of the claims.
Claims
1. A method for preparing a high-quality EB evaporation target, characterized in that: Includes the following steps: S1. The powder raw material is loaded into the cleaned crucible and pre-compacted to obtain the pre-compacted crucible. S2. Place the pre-compacted crucible into the spark plasma sintering equipment, evacuate and pressurize it, turn on the auxiliary heating to raise the temperature to the thermal shock buffer temperature, then stop the auxiliary heating, apply current to raise the temperature to the sintering densification temperature, hold it at that temperature, then stop applying the current, turn on the auxiliary heating to control the cooling rate, cool it to the stress safety cooling threshold, then switch to the program-controlled cooling system for cooling, remove the crucible, clean and dry it to obtain a high-quality EB evaporation target.
2. The method for preparing a high-quality EB evaporation target according to claim 1, characterized in that: In step S1, the powder raw material is dried in a Class 1000 cleanroom environment; the median particle size D50 of the powder raw material is 0.3-2μm.
3. The method for preparing a high-quality EB evaporation target according to claim 1, characterized in that: The crucible in step S1 includes one of a glass graphite crucible and a carbon fiber reinforced graphite crucible; the cleaning process in step S1 includes acid washing, plasma cleaning, and drying of the crucible.
4. The method for preparing a high-quality EB evaporation target according to claim 1, characterized in that: The pre-compaction pressure in step S1 is 40-60 MPa.
5. The method for preparing a high-quality EB evaporation target according to claim 1, characterized in that: In step S2, the vacuum is evacuated to 0.01-0.05 Pa, the pressure is increased to 95-105 MPa, and auxiliary heating is turned on.
6. The method for preparing a high-quality EB evaporation target according to claim 5, characterized in that: The thermal shock buffer temperature is 1150-1250℃.
7. The method for preparing a high-quality EB evaporation target according to claim 6, characterized in that: The heating rate after the current is applied in step S2 is 100-300℃ / min.
8. The method for preparing a high-quality EB evaporation target according to claim 7, characterized in that: In step S2, the sintering densification temperature is 1580-2000℃, and the holding time is 10-30min.
9. The method for preparing a high-quality EB evaporation target according to claim 1, characterized in that: In step S2, the current is stopped, and the auxiliary heating is turned on to control the cooling rate at 3-7℃ / min. The stress safety cooling threshold is 750-850℃.
10. The method for preparing a high-quality EB evaporation target according to claim 9, characterized in that: The program-controlled cooling system in step S2 includes an annealing furnace.