Ceramic target material based on organic pore-forming agent gradient design and preparation method thereof

Abstract

The invention provides a ceramic target material based on organic pore-forming agent gradient design and a preparation method thereof.The ceramic target material is divided into four layers of structures, organic pore-forming agents with different concentrations and different particle sizes are added, an isostatic pressing forming method is combined, after the target material is sintered at high temperature, circular pores with gradient changes are reserved in the ceramic target material, and the ceramic target material is prepared. The ceramic target material with the porosity gradient can not be broken under a rapid temperature difference caused by high-energy electron beam irradiation. The introduction of the circular pores can disperse crack propagation during thermal stress impact, the gradient design can change the internal stress distribution of the target material and release stress concentration, the thermal shock resistance of the ceramic target material is greatly improved, and the service stability of the target material is improved.

Description

Technical Field

[0001] This invention belongs to the field of ceramic target preparation technology, and in particular relates to a ceramic target based on the gradient design of organic pore-forming agents and its preparation method. Background Technology

[0002] The working principle of electron beam physical vapor deposition (EB-PVD) technology is as follows: First, a vacuum chamber is evacuated using a vacuum pump to achieve a certain vacuum level. Then, an electron gun emits an electron beam that directly irradiates the target material in a water-cooled crucible. The energy of the electron beam heats and vaporizes the target material, and the target vapor is deposited onto the substrate in the form of atoms or molecules to form a coating. When the electron beam begins to irradiate the target surface, thermal stress damage is triggered by the temperature gradient. When the ceramic surface is rapidly heated, the heated surface shrinks significantly, while the unheated parts remain at a lower temperature and shrink less. This uneven shrinkage creates stress accumulation within the material. Because ceramics are brittle materials with poor ductility, they cannot disperse stress through plastic deformation. When the thermal stress exceeds the tensile strength, cracks form from the high-stress area and propagate rapidly, ultimately causing the target material to shatter.

[0003] Existing ceramic target preparation technology generally involves granulating single-size ceramic powder with a binder, followed by two-step pressing and high-temperature sintering to produce a ceramic target with uniform pores. However, when ceramic targets prepared by this method are used in electron beam physical vapor deposition equipment, the surface temperature of the target will rise sharply due to functional electron beam irradiation, causing the target surface to crack, which is not conducive to the use of the target.

[0004] Therefore, it is necessary to conduct research on the structural design and supporting preparation technology of ceramic targets to improve the thermal shock resistance of ceramic targets in order to meet the usage requirements of electron beam physical vapor deposition equipment. Summary of the Invention

[0005] In view of this, the present invention aims to propose a ceramic target material based on the gradient design of organic pore-forming agents and its preparation method. This method divides the ceramic target material into four parts, adding organic pore-forming agents of different concentrations and particle sizes to each part. Combined with isostatic pressing, after high-temperature sintering, the target material is left with circular pores exhibiting a gradient. This ceramic target material with a porosity gradient can withstand rapid temperature differences caused by high-energy electron beam irradiation without fracturing. The introduction of these circular pores can disperse crack propagation during thermal stress impact, and the gradient design can alter the internal stress distribution of the target material, releasing stress concentration and greatly improving the thermal shock resistance of the ceramic target material.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] A method for preparing a ceramic target based on an organic pore-forming agent gradient design, the method comprising the following steps:

[0008] S1. Zirconia is mixed with an oxide stabilizer and then ball-milled and calcined to obtain raw material powder;

[0009] S2. Add deionized water to a mixer, then add raw material powder and 1.5-2μm PMMA (polymethyl methacrylate) or PS (polystyrene) microspheres and PVA (polyvinyl alcohol) aqueous solution to prepare raw material ①. Add raw material powder and 0.9-1.2μm PMMA or PS microspheres and PVA aqueous solution to prepare raw material ②. Add raw material powder and 0.5-0.7μm PMMA or PS microspheres and PVA aqueous solution to prepare raw material ③. Add PVA aqueous solution to prepare raw material ④. Then, spray granulate the four raw materials separately to obtain four granulated powders.

[0010] S3. According to the height ratio of 2:3:4:11, put powder No. ④, powder No. ③, powder No. ② and powder No. ① into the isostatic pressing polyurethane mold in sequence, and obtain the target blank by isostatic pressing.

[0011] S4. The target blank is sintered to obtain the final ceramic target.

[0012] Further, the specific steps of S1 are as follows: Zirconia and oxide stabilizer are mixed and ball-milled in a ball mill jar, with deionized water as the dispersant. After ball milling for 8-10 hours, the mixture is sintered at 1500-1600℃ for 9-10 hours to allow the zirconia and oxide stabilizer to undergo a solid-phase reaction. Then, the sintered block raw material is crushed and ball-milled again with water as the dispersant for 10-15 hours to obtain the raw material powder.

[0013] Furthermore, the material-to-ball mass ratio was 1:1 and the material-to-water mass ratio was 3:1 in both ball milling processes.

[0014] Furthermore, in S1, by weight percentage, there is 91-94 wt% zirconium oxide and 6-9 wt% oxide stabilizer.

[0015] Furthermore, the oxide stabilizer is a rare earth oxide, specifically any one of the following five: Y2O3, CeO2, La2O3, Yb2O3, Sc2O3, and Nb2O.

[0016] Furthermore, in S2, the mass fraction of the raw material powder is 97-99 wt%;

[0017] In raw material ①, the mass fraction of PMMA or PS microspheres is 1.5-1.8 wt%, and the mass fraction of PVA aqueous solution is 0.2-0.5 wt%.

[0018] In raw material No. ②, the mass fraction of PMMA or PS microspheres is 0.8-1.2 wt%, and the mass fraction of PVA aqueous solution is 0.3-0.7 wt%.

[0019] In raw material No. ③, the mass fraction of PMMA or PS microspheres is 0.4-0.7 wt%, and the mass fraction of PVA aqueous solution is 0.3-0.6 wt%.

[0020] In raw material No. ④, the mass fraction of PVA aqueous solution is 0.8-1.5 wt%.

[0021] Furthermore, in S2, when mixing the raw materials, the mixer speed is 800-1200 rpm and the mixture is dispersed for 0.5-2 hours until it is completely mixed; the inlet temperature of the spray granulation is 150-250℃ and the outlet temperature is 150-200℃.

[0022] Furthermore, in S3, the isostatic pressing conditions are: holding pressure at 100-250MPa for 3-5 minutes.

[0023] Furthermore, in S4, the sintering conditions are: sintering at 1000-1450℃ for 20-25 hours.

[0024] The present invention also provides a ceramic target material based on an organic pore-forming agent gradient design prepared by the preparation method described above.

[0025] Compared with existing technologies, the ceramic target material and its preparation method based on the gradient design of organic pore-forming agents described in this invention have the following advantages:

[0026] (1) The ceramic target material based on the gradient design of organic pore-forming agents described in this invention is divided into four parts, each with different concentrations and particle sizes of organic pore-forming agents added. Combined with isostatic pressing, after high-temperature sintering, the target material leaves circular pores with gradient changes. This ceramic target material with a porosity gradient can withstand rapid temperature differences caused by high-energy electron beam irradiation without cracking. The introduction of circular pores can disperse crack propagation during thermal stress impact, and the gradient design can change the internal stress distribution of the target material, release stress concentration, greatly improve the thermal shock resistance of the ceramic target material, and enhance the service stability of the target material.

[0027] (2) The organic pore-forming agent used in the ceramic target material based on the gradient design of organic pore-forming agent described in this invention is discharged along with the pores during the sintering process, leaving uniformly sized and diffusely distributed circular pores. When irradiated by a high-energy electron beam gun, the inner walls of the circular pores help to disperse stress, thereby improving the thermal shock resistance of the material and preventing the target material from breaking. This method introduces a pore-forming agent with a high concentration and relatively large particle size on the surface of the target material, which can effectively resist the rapid temperature rise during the initial irradiation of the electron beam.

[0028] (3) The ceramic target material based on the gradient design of organic pore-forming agent described in this invention can change the stress distribution inside the material from top to bottom, alleviate the thermal stress of the interlayer material, and generate multiple cracks when the gradient material is subjected to thermal shock. The crack density increases, the stress concentration is released, and the thermal shock resistance is effectively improved. At the same time, this pore gradient design also avoids the problem of faster melting speed and reduced utilization rate of the target material caused by high porosity. In addition, during the isostatic pressing process, the particles in each layer will have a small amount of relative flow at the interlayer interface, which further makes the porosity at the interface too gradual. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 This is a schematic diagram of the structure of the ceramic target material based on the gradient design of organic pore-forming agent as described in an embodiment of the present invention. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 scope of protection of the present invention.

[0033] Example 1

[0034] A method for preparing a ceramic target based on an organic pore-forming agent gradient design, the method comprising the following steps:

[0035] S1. Zirconia and oxide stabilizer Y2O3 are mixed and ball-milled in a ball mill jar with deionized water as the dispersant. The material-to-ball ratio is 1:1 and the material-to-water ratio is 3:1. After 8 hours, the mixture is sintered at 1550℃ for 9 hours to allow the zirconia and oxide stabilizer to undergo a solid-phase reaction. The sintered block raw material is then crushed and ball-milled again with water as the dispersant for 12 hours with the material-to-ball ratio being 1:1 and the material-to-water ratio being 3:1 to obtain the raw material powder.

[0036] S2. Add deionized water to a mixer, add 98-99 wt% of the raw material powder, add 1.8 wt% of 1.5 μm PMMA microspheres and 0.2 wt% of PVA aqueous solution as raw material ①, add 1 wt% of 1 μm PMMA microspheres and 0.5 wt% of PVA aqueous solution as raw material ②, add 0.5 wt% of 0.5 μm PMMA microspheres and 0.5 wt% of PVA aqueous solution as raw material ③, and add 1 wt% of PVA aqueous solution as raw material ④. Disperse the mixture at 1000 rpm for 1 hour until completely mixed. Spray granulate the slurries of the four raw materials separately at an inlet temperature of 150℃ and an outlet temperature of 150℃ to obtain four granulated powders.

[0037] S3. According to the height ratio of 2:3:4:11, powder No. ④, powder No. ③, powder No. ②, and powder No. ① are placed into an isostatic pressing polyurethane mold in sequence, and the target blank is obtained by isostatic pressing at 200MPa for 5 minutes. The distribution of the four powders is as follows. Figure 1 As shown.

[0038] S4. Sinter the target blank at 1400℃ for 24h to obtain the final ceramic target material at room temperature.

[0039] The prepared ceramic target was subjected to service life testing. The target cracked after three electron beam evaporation tests, and the overall average porosity of the target was 39.6%.

[0040] Example 2

[0041] A method for preparing a ceramic target based on an organic pore-forming agent gradient design, the method comprising the following steps:

[0042] S1. Zirconia and oxide stabilizer Y2O3 are mixed and ball-milled in a ball mill jar with deionized water as the dispersant. The material-to-ball ratio is 1:1 and the material-to-water ratio is 3:1. After 8 hours, the mixture is sintered at 1550℃ for 9 hours to allow the zirconia and oxide stabilizer to undergo a solid-phase reaction. The sintered block raw material is then crushed and ball-milled again with water as the dispersant for 12 hours with the material-to-ball ratio being 1:1 and the material-to-water ratio being 3:1 to obtain the raw material powder.

[0043] S2. Add deionized water to a mixer, then add 98-99 wt% of the raw material powder, 1.5 wt% of 2 μm PMMA microspheres and 0.5 wt% of PVA aqueous solution as raw material ①; add 1.2 wt% of 1.2 μm PMMA microspheres and 0.3 wt% of PVA aqueous solution as raw material ②; add 0.6 wt% of 0.6 μm PMMA microspheres and 0.4 wt% of PVA aqueous solution as raw material ③; add 1.2 wt% of PVA aqueous solution as raw material ④. Disperse the mixture at 1100 rpm for 1.5 hours until completely mixed. Spray granulate the slurries of the four raw materials separately at an inlet temperature of 150℃ and an outlet temperature of 150℃ to obtain four granulated powders.

[0044] S3. According to the height ratio of 2:3:4:11, powder No. ④, powder No. ③, powder No. ②, and powder No. ① are placed into an isostatic pressing polyurethane mold in sequence, and the target blank is obtained by isostatic pressing at 250MPa for 5 minutes. The distribution of the four powders is as follows: Figure 1 As shown.

[0045] S4. Sinter the ceramic target blank at 1450℃ for 25 hours to obtain the final ceramic target product at room temperature.

[0046] The prepared ceramic target was subjected to service life testing. The target cracked after four electron beam evaporation tests, and the overall average porosity of the target was 42.3%.

[0047] Example 3

[0048] A method for preparing a ceramic target based on an organic pore-forming agent gradient design, the method comprising the following steps:

[0049] S1. Zirconia and oxide stabilizer Y2O3 are mixed and ball-milled in a ball mill jar with deionized water as the dispersant. The material-to-ball ratio is 1:1 and the material-to-water ratio is 3:1. After 8 hours, the mixture is sintered at 1550℃ for 9 hours to allow the zirconia and oxide stabilizer to undergo a solid-phase reaction. The sintered block raw material is then crushed and ball-milled again with water as the dispersant for 12 hours with the material-to-ball ratio being 1:1 and the material-to-water ratio being 3:1 to obtain the raw material powder.

[0050] S2. Add deionized water to a mixer, add 98-99 wt% of the raw material powder, add 1.8 wt% of 1.5 μm PS microspheres and 0.2 wt% of PVA aqueous solution as raw material ①, add 1 wt% of 1 μm PS microspheres and 0.5 wt% of PVA aqueous solution as raw material ②, add 0.5 wt% of 0.5 μm PS microspheres and 0.5 wt% of PVA aqueous solution as raw material ③, and add 1 wt% of PVA aqueous solution as raw material ④. Disperse the mixture at 1000 rpm for 1 hour until completely mixed. Spray granulate the slurries of the four raw materials separately at an inlet temperature of 150℃ and an outlet temperature of 150℃ to obtain four granulated powders.

[0051] S3. According to the height ratio of 2:3:4:11, powder No. ④, powder No. ③, powder No. ②, and powder No. ① are placed into an isostatic pressing polyurethane mold in sequence, and the target blank is obtained by isostatic pressing at 200MPa for 5 minutes. The distribution of the four powders is as follows. Figure 1 As shown.

[0052] S4. Sinter the ceramic target blank at 1400℃ for 24 hours to obtain the final ceramic target product at room temperature.

[0053] The prepared zirconia-based ceramic target was subjected to service life testing. The target cracked after three electron beam evaporation tests, and the overall average porosity of the target was 38.4%.

[0054] Comparative Example 1 has only two types of stratification

[0055] The difference from Example 1 is that in step S2, only raw material ① and raw material ④, which are the same as those in Example 1, are prepared. Raw material ① and raw material ④ are placed into an isostatic pressing polyurethane mold in a height ratio of 9:11 in the order of ④→①. The target blank is obtained by isostatic pressing at 200MPa for 5 minutes. The target blank is then sintered at 1400℃ for 24 hours to obtain a ceramic target.

[0056] The prepared zirconia-based ceramic target with no gradient porosity was subjected to service life testing. After one electron beam evaporation test, the target showed delamination and cracking, and the overall average porosity of the target was 45.7%.

[0057] Comparative Example 2: The order of the four raw materials is different.

[0058] The difference from Example 1 is that the order in which the four raw materials are added in step S3 is different. Specifically, the powders No. ④, No. ①, No. ②, and No. ③ are added to the isostatic pressing polyurethane mold in a height ratio of 2:3:4:11. The target blank is formed by isostatic pressing at 200MPa for 5 minutes. The target blank is then sintered at 1400℃ for 24 hours to obtain the ceramic target.

[0059] The prepared zirconia-based ceramic target with anti-gradient porosity was subjected to service process testing. After one electron beam evaporation test, the target showed delamination and cracking, and the overall average porosity of the target was 40.8%.

[0060] Comparative Example 3: Single-layer structure

[0061] The difference from Example 1 is that in step S2, only raw material No. ④, the same as in Example 1, is prepared, that is, 99 wt% of the raw material powder and 1 wt% of PVA aqueous solution are added as pressing raw materials. In step S3, only raw material No. ④ powder is placed into an isostatic pressing polyurethane mold and isostatically pressed at 200 MPa for 5 min to obtain a target blank. The target blank is then sintered at 1400℃ for 24 h to obtain a ceramic target.

[0062] The prepared zirconia-based ceramic target without pore design was tested in service. The target cracked after one electron beam evaporation test, and the overall average porosity of the target was 33.4%.

[0063] Comparative Example 4: Particle size does not meet requirements

[0064] The difference from Example 1 is that in step S2, 1.8 wt% of 5 μm PMMA microspheres and 0.2 wt% of PVA aqueous solution are added to raw material ①, while the rest is the same as in Example 1.

[0065] The zirconia-based ceramic target material prepared with large-particle-size PMMA microspheres as pore-forming agent No. 1 was tested during service. Due to the excessively large surface pores, the early consumption rate of the target material increased. In addition, the particle size difference between No. 1 and No. 2 in the lower layer was large, which caused interlayer cracking to occur in the target material at the beginning of service. The overall average porosity of the target material was 38.8%.

[0066] Comparative Example 5: Raw Material Height Different

[0067] The difference from Example 1 is that in step S3, powder No. ④, powder No. ③, powder No. ②, and powder No. ① are placed into the isostatic polyurethane mold in sequence according to a height ratio of 1:1:1:17, and the rest is the same as in Example 1.

[0068] The prepared ceramic targets with different raw material heights were tested in service. The targets cracked after one electron beam evaporation test, and the overall average porosity of the targets was 34.8%.

[0069] A comparison of the above embodiments and comparative examples reveals that the comparative examples exhibit varying degrees of defects when conditions such as lack of stratification, different raw material placement order, insufficient particle size, and different raw material heights are present. Only the ceramic target material prepared according to this invention possesses superior performance, improving its thermal shock resistance and service stability.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a ceramic target based on a gradient design of an organic pore former, characterized by: The method comprises the following steps: S1, mixing zirconia and an oxide stabilizer, then ball milling and calcining to obtain a raw material powder; S2, adding deionized water in a blender, then adding the raw material powder and 1.5-2 μm PMMA or PS microspheres and PVA aqueous solution to prepare No. 1 raw material, adding the raw material powder and 0.9-1.2 μm PMMA or PS microspheres and PVA aqueous solution to prepare No. 2 raw material, adding the raw material powder and 0.5-0.7 μm PMMA or PS microspheres and PVA aqueous solution to prepare No. 3 raw material, and adding PVA aqueous solution to prepare No. 4 raw material; then spray granulating the four obtained raw materials to obtain four granulated powders; S3, according to a height ratio of 2:3:4:11, sequentially placing No. 4 powder, No. 3 powder, No. 2 powder and No. 1 powder into an isostatic pressing polyurethane mold, and isostatic pressing to obtain a target blank; S4, sintering the target blank to obtain a final ceramic target.

2. The method of claim 1, wherein the method is characterized by: The specific steps of S1 are as follows: placing zirconia and an oxide stabilizer into a ball mill tank for mixing and ball milling, using deionized water as a dispersant, ball milling for 8-10 h, and then sintering at 1500-1600 ℃ for 9-10 h to make the zirconia and the oxide stabilizer undergo solid phase reaction; then crushing the sintered bulk raw material; again ball milling for 10-15 h with water as a dispersant to obtain a raw material powder.

3. The method of claim 2, wherein the method further comprises: The mass ratio of the milling balls in the two ball milling processes is 1:1, and the mass ratio of the material to water is 3:

1.

4. The method of claim 1, wherein the method is characterized by: In S1, the zirconia accounts for 91-94 wt%, and the oxide stabilizer accounts for 6-9 wt% according to the weight percentage.

5. The method of claim 1, wherein the method further comprises: The oxide stabilizer is a rare earth oxide, specifically any one of Y2O3, CeO2, La2O3, Yb2O3, Sc2O3 and Nb2O5.

6. The method of claim 1, wherein the method further comprises: In S2, the mass fraction of the raw material powder is 97-99 wt%; In No. 1 raw material, the mass fraction of PMMA or PS microspheres is 1.5-1.8 wt%, and the mass fraction of PVA aqueous solution is 0.2-0.5 wt%; In No. 2 raw material, the mass fraction of PMMA or PS microspheres is 0.8-1.2 wt%, and the mass fraction of PVA aqueous solution is 0.3-0.7 wt%; In No. 3 raw material, the mass fraction of PMMA or PS microspheres is 0.4-0.7 wt%, and the mass fraction of PVA aqueous solution is 0.3-0.6 wt%; In No. 4 raw material, the mass fraction of PVA aqueous solution is 0.8-1.5 wt%.

7. The method of claim 1, wherein the method further comprises: In S2, the stirring speed of the blender is 800-1200 rpm during mixing of the raw materials, and the dispersion time is 0.5-2 h until complete mixing; the inlet temperature of the spray granulation is 150-250 ℃, and the outlet temperature is 150-200 ℃.

8. The method of claim 1, wherein the method further comprises: In S3, the isostatic pressing conditions are: 100-250 MPa for 3-5 min.

9. The method of claim 1, wherein the method further comprises: In S4, the sintering conditions are: 1000-1450 ℃ for 20-25 h.

10. A ceramic target based on an organic pore-forming agent gradient design, prepared by the preparation method of any one of claims 1-9.

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