Preparation method of hydrogen absorption sheet without activation

Abstract

The invention discloses a preparation method of a hydrogen absorption sheet without activation, which comprises the following steps: (1) cleaning: cleaning a titanium foil substrate to remove surface dirt and oxide; (2) coating pretreatment: rapidly transferring the cleaned and blow-dried titanium foil to a cavity of a magnetron sputtering coating machine, vacuumizing until the vacuum degree is superior to 4 * 10 < 14 > Pa, carrying out in-situ heating treatment on a titanium foil substrate, preserving heat at 200-400 DEG C for 0.5-2 hours, and then cooling to room temperature; (3) coating: preparing a Pd film or a Pd-based alloy film with the thickness of 50-300nm on the titanium foil substrate by adopting a magnetron sputtering coating process; and (4) punch forming is conducted, specifically, the titanium foil plated with the Pd film or the Pd-based alloy film is punched, and the hydrogen absorption sheet with the boundary dimension being 1-20 mm and the thickness being 0.1-0.5 mm is obtained. The prepared hydrogen absorption sheet is mainly used for controlling the content of hydrogen in various solid-state microwave devices and assemblies in the field of microelectronic packaging and does not need to be activated before being used, the devices and the assemblies using the hydrogen absorption sheet do not need to be subjected to additional baking hydrogen removal treatment, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to a method for preparing a hydrogen-absorbing sheet without activation, belonging to the technical field of getter materials in microelectronic packaging. Background Technology

[0002] Hydrogen within various solid-state microwave devices and components primarily originates from hydrogen dissolved in the casing and other materials, hydrogen introduced through electroplating, hydrogen generated from the decomposition of organic matter adsorbed on the electroplated casing and cover surfaces due to gas purity issues, and hydrogen permeating in from the external atmosphere. Although prolonged baking before packaging can remove most of the hydrogen, the baking temperature and time cannot be too high due to the presence of heat-sensitive materials, resulting in insufficient hydrogen removal. Furthermore, even after packaging, hydrogen continues to permeate from the metal casing. The residual hydrogen and permeated hydrogen, along with hydrogen released from various components during device use, gradually accumulate, leading to a gradual increase in hydrogen concentration. Controlling the hydrogen content within various solid-state microwave devices and components in the microelectronics packaging field is crucial. Hydrogen poisoning in GaAs chips can cause voltage drift and even device or component failure; therefore, hydrogen-absorbing materials are needed to control the hydrogen concentration within devices and components.

[0003] As devices and components trend towards miniaturization and micro-miniaturization, traditional bulk hydrogen-absorbing materials are too large to be suitable for various solid-state microwave devices and components. Hydrogen-absorbing sheets with dimensions of 1–20 mm and a thickness of 0.1–0.5 mm have become the preferred hydrogen-absorbing material for microelectronic packaging devices. This sheet-like material can be fixed to the inner wall of the device / assembly cap using conductive adhesive, epoxy adhesive, silicone rubber bonding, or spot welding, without occupying additional space.

[0004] Traditional hydrogen-absorbing materials often have high surface activity, forming a passivation film on their surface during atmospheric exposure, which hinders hydrogen absorption. Therefore, unactivated traditional hydrogen-absorbing materials cannot absorb hydrogen at room temperature. Since solid-state microwave devices and components contain heat-sensitive elements and low-melting-point solder, hydrogen-absorbing sheets must selectively absorb hydrogen at room temperature without heating activation; in other words, they must be ready to use immediately.

[0005] Patent document CN110699649A discloses a hydrogen-absorbing material for electronic packaging and its preparation method. The disclosed hydrogen-absorbing material includes a Ti substrate for hydrogen storage and a Pd film with a thickness of 1–50 nm bonded to the Ti substrate for catalytic cracking and permeation. The preparation method includes two processes: pretreatment of the Ti substrate by degreasing, etching, and roughening, and magnetron sputtering of the Pd film layer. Patent document CN110863174A discloses a non-activation titanium-based hydrogen-absorbing material and its preparation method. The disclosed non-activation titanium-based hydrogen-absorbing material includes a 100–500 μm thick getter Ti layer, a 100 nm–1 μm thick dense transition Ti layer, and a 50–500 nm thick dense protective layer of any one of Pd, Ni, and Pd-Ag alloy. The transition layer and the protective layer are symmetrically distributed on both sides of the getter layer. Both the transition layer and the protective layer are prepared by magnetron sputtering. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing a hydrogen-absorbing sheet that does not require activation. The prepared hydrogen-absorbing sheet is mainly used for controlling the hydrogen content inside various solid-state microwave devices and components in the field of microelectronic packaging, and has excellent hydrogen absorption performance without activation.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing a hydrogen absorption sheet without activation includes the following steps:

[0009] (1) Cleaning: Clean the titanium foil substrate to remove surface dirt and oxides;

[0010] (2) Pretreatment before coating: The cleaned and dried titanium foil is quickly transferred to the magnetron sputtering coating machine cavity, and a vacuum is drawn to a vacuum level better than 4×10⁻⁶. -4 Pa, the titanium foil substrate is subjected to in-situ heating treatment, held at 200-400℃ for 0.5-2 hours, and then cooled to room temperature;

[0011] (3) Coating: A Pd film or Pd-based alloy film with a thickness of 80-300 nm is prepared on a titanium foil substrate by magnetron sputtering coating process;

[0012] (4) Stamping: Stamping is performed on titanium foil coated with Pd film or Pd-based alloy film to obtain hydrogen-absorbing sheets with an outer size of 1-20 mm and a thickness of 0.1-0.5 mm.

[0013] Furthermore, in step (1), the specific process for cleaning the titanium foil substrate is as follows: first, ultrasonically clean with acetone for 5-15 minutes, then ultrasonically clean with alcohol for 2-10 minutes to remove surface dirt; then, clean the titanium foil substrate in a 0.5%-3.0% hydrofluoric acid solution for 30 seconds-5 minutes to remove surface oxides, then rinse with flowing deionized water for 1-5 minutes, and then quickly dry with an Ar gas gun.

[0014] Furthermore, in step (3), DC sputtering is used, employing a high-purity Pd target or a Pd-based alloy target. The sputtering gas is high-purity argon (purity > 99.9999%), the sputtering pressure is 0.1–1.0 Pa, and the target sputtering power density is 0.5–6 W / cm². 2 The target-substrate distance is 5-10 cm, and the target material is pre-sputtered for 2-5 minutes to remove surface contaminants. The sputtering time is 2-20 minutes.

[0015] Furthermore, in step (4), the titanium foil is cut into titanium strips 10-25mm wide and stamped. A stamping die made of tungsten steel is used. The tonnage of the stamping machine used to stamp the titanium foil is 30-45 tons, and the stamping speed is 50-120 pieces / minute.

[0016] A hydrogen-absorbing sheet prepared by the above method comprises a titanium foil substrate that performs hydrogen absorption and a dense Pd film or Pd-based alloy film deposited on the titanium foil substrate that catalyzes hydrogen degradation and allows hydrogen to permeate, while protecting the titanium foil substrate from oxidation.

[0017] The Pd-based alloy film is either a Pd-Ag alloy film or a Pd-Cu alloy film.

[0018] The titanium foil substrate has a thickness of 0.1–0.5 mm, a purity greater than 99.5%, and an average grain diameter of less than 50 μm.

[0019] Compared with the prior art, the significant advantages of the present invention are:

[0020] (1) The hydrogen absorption sheet prepared by the present invention has the characteristic of being ready to use immediately, that is, it has excellent hydrogen absorption performance without activation. Therefore, there is no need to perform additional baking and hydrogen removal treatment on the packaging shell and the packaged components.

[0021] (2) The present invention uses a stamping method to prepare hydrogen absorber sheets, which has high production efficiency and high reliability. The hydrogen absorber sheets have high dimensional accuracy and good consistency, thus ensuring the consistency and stability of the hydrogen absorber sheet performance. The size and number of burrs are controllable, which ensures the hydrogen absorber sheet's resistance to the application environment.

[0022] (3) The hydrogen-absorbing sheet prepared by the present invention can control the hydrogen content inside various solid-state microwave devices and components in the field of microelectronic packaging, absorb hydrogen in the sealed device components, and thus prevent the chip in the sealed device components from "hydrogen poisoning" and failure.

[0023] (4) The hydrogen absorption sheet prepared by the present invention has good hydrogen absorption capacity in the range of -65℃ to +150℃, and the material does not become brittle or deteriorate during normal use. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a hydrogen-absorbing sheet prepared according to the present invention.

[0025] Figure 2 This is a morphological diagram of the hydrogen-absorbing sheet prepared in Example 1 of the present invention.

[0026] Figure 3 This is a metallographic diagram representing the average grain size of titanium foil.

[0027] Figure 4 This is a cross-sectional morphology diagram of the Pd membrane used for hydrogen absorption.

[0028] Figure 5 These are XRD patterns of the hydrogen-absorbing sheet with and without hydrogen absorption at different hydrogen absorption rates.

[0029] Figure 6 This is a curve showing the change in hydrogen absorption capacity of the hydrogen-absorbing sheet over time, tested using the constant volume method. It includes a comparative example of a sheet without in-situ baking treatment before titanium foil coating, tested under initial hydrogen pressure of 8 Torr and room temperature conditions.

[0030] Figure 7 This is the XRD pattern of the hydrogen-absorbing sheet obtained in Example 3 after absorbing hydrogen.

[0031] Figure 8 These are images showing the burrs on stamped sheets obtained when using stainless steel and tungsten steel as stamping dies, respectively. Detailed Implementation

[0032] The principles and features of the present invention are described below with reference to the accompanying drawings and embodiments. The embodiments are only used to explain the present invention and do not imply any limitation on the scope of protection of the present invention.

[0033] This invention provides a method for preparing a hydrogen-absorbing sheet without activation. First, the titanium foil substrate is acid-washed, then baked in a coating vacuum chamber before coating, and then a Pd film or Pd-based alloy film such as Pd-Ag or Pd-Cu alloy film is prepared on its surface by magnetron sputtering. Finally, the coated titanium foil is stamped to obtain a hydrogen-absorbing sheet with an external size of 1-20 mm and a thickness of 0.1-0.5 mm.

[0034] In this invention, the baking treatment before coating is as follows: the vacuum degree before heating is better than 4×10⁻⁶. -4 The baking temperature is 200–400℃, and the holding time is 0.5–2 hours. In this invention, the baking treatment before coating is equivalent to activating the titanium foil. Although the oxides on the surface of the titanium foil have been completely removed by acid washing, there is still a short period of exposure to the atmosphere during the process from cleaning to transfer into the vacuum coating machine cavity, resulting in a small amount of surface oxidation. Furthermore, titanium is a good hydrogen absorber; during preparation or storage, hydrogen absorbed and dissolved in the intercrystalline lattice exists within the titanium foil. Heating the titanium foil in a vacuum before coating with a Pd film or Pd-based alloy film is a form of activation treatment. The hydrogen inside the titanium foil diffuses outward, escaping from the titanium foil matrix, and the oxides on the surface of the titanium foil decompose, allowing oxygen atoms to diffuse inward, thus forming a clean titanium foil surface. The coated Pd film or Pd-based alloy film protects the activity of the titanium foil surface and prevents oxidation, significantly improving the hydrogen absorption performance of the hydrogen-absorbing sheet. Verification showed that, according to the constant volume method in GB / T25497, the hydrogen absorption performance of the hydrogen-absorbing sheet with double-sided Pd or Pd-based alloy film, under conditions requiring no activation, and at an initial hydrogen pressure of 8 Torr and a test condition of 298 K, exhibited a hydrogen absorption capacity of >1.56 Torr·L / cm² over 24 hours. 2 .

[0035] In this invention, the preferred coating thickness on the titanium foil substrate is 80–300 nm. On the one hand, if the coating thickness is too thin, defects or lack of density in the film will prevent it from effectively protecting the titanium foil surface from oxidation. On the other hand, controlling the thickness of the Pd film or Pd-based alloy film below 300 nm allows for good hydrogen permeation and excellent film-substrate adhesion, meeting the adhesion requirements without heating. Therefore, the magnetron sputtering coating of the titanium foil substrate in this invention can be performed at room temperature. Excessively thick Pd films or Pd-based alloy films (greater than 300 nm) not only waste precious metals but, more importantly, offer no beneficial effect on hydrogen permeation.

[0036] This invention produces hydrogen-absorbing sheets with high dimensional accuracy through a stamping process, such as dimensional tolerances better than ±0.10 mm and thickness tolerances better than ±0.05 mm, exhibiting good dimensional consistency. Since the hydrogen-absorbing sheets must withstand certain environmental conditions during use, including random vibration, mechanical impact, acceleration, and temperature cycling, the size and distribution of burrs caused by stamping must be strictly limited. For example, loose burrs are not allowed, and hard burrs should not protrude more than 0.03 mm above the surface or extend more than 0.05 mm around the edges of the hydrogen-absorbing sheet to prevent burr breakage and the formation of excess material, which could lead to serious consequences such as contamination and puncture. This invention optimizes the stamping process parameters to control the size, number, and distribution of burrs. The hydrogen-absorbing sheets produced by this invention have high dimensional accuracy and good consistency; the size, number, and distribution of burrs are controllable. The hydrogen-absorbing sheets can be fixed to the inner wall of caps made of materials such as Kovar alloy, 6063 aluminum alloy, and silicon-aluminum alloy using conductive adhesive, epoxy adhesive, silicone rubber bonding, or spot welding.

[0037] Although laser cutting is a method for obtaining sheet metal, the small size of the hydrogen-absorbing sheets (1-20 mm in diameter and 0.1-0.5 mm in thickness) presents challenges. Firstly, large-area titanium foil is laser-cut into smaller pieces to meet these requirements before cleaning and protective film preparation. This leads to problems such as low cleaning efficiency, difficulty in fixing the small titanium foil sheets during coating, and the need for specialized tooling and fixtures. Secondly, if large-area titanium foil is cleaned and coated first, and then laser-cut into smaller hydrogen-absorbing sheets, the edges of the laser-cut sheets may oxidize, affecting hydrogen absorption performance. Even if there are no obvious oxidation marks on the edges, hydrogen absorption performance is still reduced. Sheets with obvious oxidation cannot be cleaned to remove the oxides, affecting aesthetics and product yield. Although laser cutting can be performed under inert gas protection, this increases operational complexity and still cannot guarantee that the edges of the hydrogen-absorbing sheets are completely free from oxidation, reducing the yield. Hydrogen-absorbing sheets are prepared by first cleaning a large area of ​​titanium foil, coating it, and then stamping the titanium foil into shape. This method does not require gas protection, has high production efficiency, and is conducive to large-scale production.

[0038] The existing technology does not mention the stamping process for preparing hydrogen-absorbing sheets. Even if stamping can be used to prepare metal sheets, for titanium foil sheets with a thickness of 0.1–0.5 mm, the titanium foil softens after the heat treatment before coating. Even after cooling to room temperature and coating with a Pd film or Pd-based alloy film, it cannot regain the hardness before the heat treatment. Therefore, the stamping difficulty is increased, and process parameters need to be optimized to obtain hydrogen-absorbing sheets with fewer burrs and higher dimensional accuracy to meet the requirements of practical applications.

[0039] Example 1

[0040] Titanium foil with a purity of 99.88%, an average grain diameter of 22.8 μm, and a thickness of 0.12 mm was used as the substrate. The titanium foil was first ultrasonically cleaned with acetone for 10 min, followed by ultrasonic cleaning with alcohol for 10 min. Then, the titanium foil substrate was cleaned in a 1.5% hydrofluoric acid solution for 90 s, rinsed with flowing deionized water for 3 min, and then rapidly dried with an Ar gas gun before being quickly transferred to a magnetron sputtering deposition chamber. A vacuum was then evacuated to a vacuum level better than 4 × 10⁻⁶. -4 At a pressure of 0.2 Pa, the titanium foil substrate was subjected to in-situ heating treatment at 320℃ for 2 hours, and then cooled to room temperature. Subsequently, a Pd film with a thickness of approximately 120 nm was deposited by magnetron sputtering at a sputtering gas pressure of 0.2 Pa and a target sputtering power density of 1.5 W / cm². 2 The target-substrate distance was 6 cm, and the target was pre-sputtered for 3 minutes to remove surface contaminants. The sputtering time was 1 minute and 40 seconds. After the titanium foil was coated with Pd film on one side, the vacuum of the coating machine was broken, the titanium foil was flipped over, and the vacuum was drawn again. The previous coating operation was repeated. Figure 1 This is a schematic diagram of the structure of the double-sided Pd-coated hydrogen-absorbing sheet in this invention. The titanium foil coated with Pd film is cut into strips with a width of 15mm, and then stamped into hydrogen-absorbing sheets with an outer dimension of 1×1mm. The stamping die is made of tungsten steel, the stamping machine has a tonnage of 45 tons, and the stamping speed is 90 sheets / minute. Figure 2 This is a topographic image of the hydrogen-absorbing sheet stamped out in this embodiment. It can be seen that the hydrogen-absorbing sheet has regular size, clean surface, and uniform Pd film color.

[0041] Example 2

[0042] Using 99.9% purity and an average grain diameter of 18.4 μm (see...) Figure 3 Using a 0.1 mm thick titanium foil as the substrate, the substrate was first ultrasonically cleaned with acetone for 10 min, followed by ultrasonic cleaning with alcohol for 10 min. Then, the titanium foil substrate was cleaned in a 2.0% hydrofluoric acid solution for 70 s, rinsed with flowing deionized water for 4 min, and then rapidly dried with an Ar gas gun before being quickly transferred to a magnetron sputtering deposition chamber. The process was continued until the vacuum level was better than 4 × 10⁻⁶ mm. -4 The titanium foil substrate was heated in situ at 350°C for 1.5 hours, then cooled to room temperature. A Pd film with a thickness of approximately 190 nm was then deposited by magnetron sputtering at a sputtering pressure of 0.1 Pa and a target sputtering power density of 1.5 W / cm². 2 The target-substrate distance was 6 cm, and the target was pre-sputtered for 4 minutes to remove its surface oxides. The sputtering time was 2 minutes and 45 seconds. Titanium foil with a single-sided Pd film was cut into strips with a width of 12 mm, and then stamped into hydrogen-absorbing sheets with an outer dimension of 4×4 mm. The stamping die was made of tungsten steel, the stamping machine had a tonnage of 40 tons, and the stamping speed was 80 sheets / minute. Figure 4The cross-sectional morphology of the Pd film on the hydrogen absorption sheet shows that, under the coating process parameters of this invention, the prepared Pd film is dense and can effectively protect the titanium foil surface from oxidation; the thickness of the Pd film is ~190nm. Figure 5 The image shows the XRD pattern of the hydrogen-absorbing sheet. As can be seen, for the hydrogen-absorbing sheet coated with a Pd film but not yet absorbing hydrogen, in addition to the diffraction peaks of the titanium substrate, there are also obvious diffraction peaks of Pd, indicating that the Pd film has a very good degree of crystallinity.

[0043] like Figure 5 As shown, when the hydrogen-absorbing sheet is not absorbing hydrogen, it consists of α-Ti and Pd phases on its surface. When the hydrogen absorption capacity per square centimeter of the sheet is 0.2 Torr·L, the peak intensity and content of the α-Ti phase decrease, and the titanium hydride phase appears. When the hydrogen absorption capacity increases to 1 Torr·L, the content of the α-Ti phase continues to decrease, and the peak intensity of the titanium hydride phase continues to increase. When the hydrogen absorption capacity increases to 2 Torr·L, the surface α-Ti phase is completely converted into the titanium hydride phase.

[0044] Example 3

[0045] Titanium foil with a purity of 99.995%, an average grain diameter of 7.8 μm, and a thickness of 0.3 mm was used as the substrate. It was first ultrasonically cleaned with acetone for 10 min, followed by ultrasonic cleaning with alcohol for 8 min. The titanium foil substrate was then cleaned in a 1.0% hydrofluoric acid solution for 150 s, rinsed with flowing deionized water for 4 min, and then rapidly dried with an Ar gas gun before being quickly transferred to a magnetron sputtering deposition chamber. The deposition was carried out under a vacuum level better than 4 × 10⁻⁶. -4 The titanium foil substrate was heated in situ at 400℃ for 1 hour, then cooled to room temperature. A Pd film with a thickness of approximately 150 nm was then deposited by magnetron sputtering at a sputtering pressure of 0.1 Pa and a target sputtering power density of 2.5 W / cm². 2 The target-substrate distance was 8 cm, and the target was pre-sputtered for 3 minutes to remove surface oxides. The sputtering time was 2 minutes and 10 seconds. After the titanium foil was coated with Pd film on one side, the vacuum of the coating machine was broken, the titanium foil was flipped over, and the vacuum was drawn again, repeating the previous coating operation. The titanium foil coated with Pd film was cut into strips with a width of 15 mm, and then stamped into hydrogen-absorbing sheets with an outer dimension of 2×2 mm. The stamping die was made of tungsten steel, the stamping machine had a tonnage of 35 tons, and the stamping speed was 100 sheets / minute.

[0046] The hydrogen absorption performance of the hydrogen absorption tablet was tested according to the constant volume method in GB / T25497. Figure 6 The figure shows the hydrogen absorption performance curve of the hydrogen absorption sheet tested by the constant volume method (the red curve shows the pre-coating treatment). Under the conditions of no activation, initial hydrogen pressure of 8 Torr, and test conditions of 298 K, it can be seen that the cumulative hydrogen absorption capacity after 24 hours is >2.40 Torr·L / cm³. 2This is superior to the 1.56 Torr·L / cm reported on the official website of SASE, an Italian company that is a leader in the field of breathable materials. 2 . Figure 7 The XRD pattern of the hydrogen absorption tablet after hydrogen absorption is shown below. Figure 7 It can be seen that at a hydrogen absorption capacity of 2.40 Torr·L / cm 2 At this point, the titanium on the surface has reacted with hydrogen to form hydride TiH2. At this time, the peaks of the titanium foil matrix are basically not visible, indicating that the thickness of the TiH2 formed at this time is also on the order of tens of micrometers.

[0047] Example 4

[0048] Titanium foil with a purity of 99.995%, an average grain diameter of 7.8 μm, and a thickness of 0.3 mm was used as the substrate. It was first ultrasonically cleaned with acetone for 10 min, then ultrasonically cleaned with alcohol for 8 min. Next, the titanium foil substrate was cleaned in a 2.5% hydrofluoric acid solution for 50 s, then rinsed with flowing deionized water for 4 min. Finally, it was rapidly dried with an Ar gas gun and quickly transferred to a magnetron sputtering deposition chamber. The deposition was carried out under a vacuum level better than 4 × 10⁻⁶. -4 The titanium foil substrate was heated in situ at 350°C for 1 hour, then cooled to room temperature. A Pd film with a thickness of approximately 180 nm was then deposited by magnetron sputtering at a sputtering pressure of 0.1 Pa and a target sputtering power density of 2.0 W / cm². 2 The target-substrate distance was 7 cm, and the target was pre-sputtered for 3 minutes to remove surface oxides. The sputtering time was 2 minutes and 30 seconds. After the titanium foil was coated with Pd film on one side, the vacuum of the coating machine was broken, the titanium foil was flipped over, and the vacuum was drawn again, repeating the previous coating operation. The titanium foil coated with Pd film was cut into strips with a width of 15 mm, and then stamped into hydrogen-absorbing sheets with an outer dimension of 3×3 mm. A stamping die made of tungsten steel was used, the stamping machine had a tonnage of 35 tons, and the stamping speed was 110 sheets / minute.

[0049] Comparative Example 1

[0050] For Example 3, the hydrogen-absorbing sheet was prepared without the second process—the titanium foil pretreatment. Under the same preparation process parameters and the same test conditions, the cumulative hydrogen absorption of the hydrogen-absorbing sheet over 24 hours was ~1.40 Torr·L / cm³. 2 (See Figure 6 The black curve in the figure (without pre-coating treatment) is close to the hydrogen absorption performance data of the hydrogen absorption sheet reported on the official website of the Italian company SES, but the hydrogen absorption performance is much lower than that of the hydrogen absorption sheet of this invention that has undergone titanium foil pre-coating treatment.

[0051] Comparative Example 2

[0052] For Example 4, if a stainless steel mold is used, even if the cleaning before stamping, the pre-coating treatment, the coating process and the stamping process remain unchanged, the size and number of burrs on the stamped hydrogen absorber are increased compared to when a tungsten steel mold is used. Figure 8 The image shows the use of tungsten steel (corresponding to...) Figure 8 (a)) and stainless steel (corresponding to Figure 8 (b) Burrs produced by stamping dies.

[0053] The 3×3×0.3mm hydrogen-absorbing sheet prepared in Example 4 of this invention was applied to a solid-state microwave assembly. One hydrogen-absorbing sheet was used in each front-end assembly. After sealing the front-end assembly, the leak rate of the sealed front-end assembly was tested according to "GJB 548C-2021 Method 1014.3 - Sealing". The leak rate was ≤3×10 -3 Pa·cm 3 / s is considered acceptable. Internal gas composition analysis was performed on the acceptable front-end components according to "GJB 548C-2021 Method 1018.2 - Internal Gas Composition Analysis". The results are shown in Table 1, where samples 1-5 are components using hydrogen absorption plates, and C1 and C2 are reference components without hydrogen absorption plates. Table 1 shows that after using the hydrogen absorption plate, the hydrogen content inside the front-end component is less than 100 ppm, below the detection limit of the analyzer, while the H2 content inside the reference component without the hydrogen absorption plate is greater than 300 ppm. This indicates that the hydrogen absorption plate prepared in this invention has excellent hydrogen absorption performance.

[0054] Table 1. Results of hydrogen absorption plate's control over hydrogen content inside front-end components.

[0055] Sample number 1 2 3 4 5 C1 C2 Intraoral pressure Torr 154.9 150.2 150.8 153.7 151.0 155.3 155.5 <![CDATA[N2]]> ％ 98.7 98.8 98.6 98.6 98.7 98.4 98.9 <![CDATA[O2]]> ppm 922 1507 963 1443 1505 2400 1600 Ar ppm 227 219 213 214 241 237 219 <![CDATA[CO2]]> ppm 1164 874 1287 1019 984 971 697 <![CDATA[H2O]]> ％ 1.05 0.92 1.13 1.09 1.04 1.19 0.79 <![CDATA[H2]]> ppm ＜100 ＜100 ＜100 ＜100 ＜100 402 329 He ppm 313 267 202 205 246 200 300

Claims

1. A method for preparing a hydrogen-absorbing sheet without activation, characterized in that, Includes the following steps: (1) Cleaning: Clean the titanium foil substrate to remove surface dirt and oxides; (2) Pretreatment before coating: The cleaned and dried titanium foil is quickly transferred to the magnetron sputtering coating machine cavity, and a vacuum is drawn to a vacuum level better than 4×10⁻⁶. -4 Pa, the titanium foil substrate is subjected to in-situ heating treatment, held at 200-400℃ for 0.5-2 hours, and then cooled to room temperature; (3) Coating: A Pd film or Pd-based alloy film with a thickness of 80-300 nm is prepared on a titanium foil substrate by magnetron sputtering coating process; (4) Stamping: Stamping is performed on titanium foil coated with Pd film or Pd-based alloy film to obtain hydrogen-absorbing sheets with an outer size of 1-20 mm and a thickness of 0.1-0.5 mm.

2. The preparation method of the hydrogen absorption sheet without activation according to claim 1, characterized in that, In step (1), the specific process for cleaning the titanium foil substrate is as follows: first, ultrasonically clean with acetone for 5-15 minutes, then ultrasonically clean with alcohol for 2-10 minutes to remove surface dirt; then, clean the titanium foil substrate in a 0.5%-3.0% hydrofluoric acid solution for 30 seconds to 5 minutes to remove surface oxides, then rinse with flowing deionized water for 1-5 minutes, and then quickly dry with an Ar gas gun.

3. The preparation method of the hydrogen absorption sheet without activation according to claim 1, characterized in that, In step (3), DC sputtering is used, employing a high-purity Pd target or a Pd-based alloy target. The sputtering gas is high-purity argon, the sputtering pressure is 0.1–1.0 Pa, and the target sputtering power density is 0.5–6 W / cm². 2 The target-substrate distance is 5-10 cm, and the target material is pre-sputtered for 2-5 minutes to remove surface contaminants. The sputtering time is 2-20 minutes.

4. The method for preparing the hydrogen absorption sheet without activation according to claim 1, characterized in that, In step (4), the titanium foil is cut into titanium strips 10-25mm wide and stamped. The stamping die is made of tungsten steel. The tonnage of the stamping machine used to stamp the titanium foil is 30-45 tons and the stamping speed is 50-120 pieces / minute.

5. A hydrogen-absorbing sheet, characterized in that, It is prepared using the preparation method described in any one of claims 1 to 4.

6. The hydrogen-absorbing sheet according to claim 5, characterized in that, The Pd-based alloy film is a Pd-Ag alloy film or a Pd-Cu alloy film.

7. The hydrogen-absorbing sheet according to claim 5, characterized in that, The titanium foil substrate has a thickness of 0.1–0.5 mm, a purity greater than 99.5%, and an average grain diameter of less than 50 μm.

Images