A high hydrogen content zirconium hydride alloy, and a preparation method and application thereof

Abstract

This invention discloses a high-hydrogen-content zirconium hydride alloy, its preparation method, and its applications, belonging to the field of special alloy technology. The method of using the thermal decomposition of chemical reagents to generate gas for hydrogen charging of zirconium alloys allows for hydrogen charging of zirconium alloys at different hydrogen / water vapor partial pressure ratios, and can obtain samples with varying high / ultra-high hydrogen contents. Compared to traditional methods, the method of this invention can achieve high-hydrogen-content hydrogen charging of zirconium alloys and chromium-coated zirconium alloys under more economical and safer conditions. This provides a reliable technical means for in-depth research on the hydrogenation behavior of zirconium alloys and chromium-coated zirconium alloys at different hydrogen / water vapor partial pressure ratios, and provides solutions for the preparation of high-hydrogen-content zirconium alloy and chromium-coated zirconium alloy samples, as well as hydrogen charging and storage technologies for high / ultra-high hydrogen contents.

Description

Technical Field

[0001] This invention belongs to the field of special alloy technology, specifically relating to a high-hydrogen-content zirconium hydride alloy, its preparation method, and its application. Background Technology

[0002] Zirconium alloys, due to their low thermal neutron absorption cross section, excellent mechanical properties, and good corrosion resistance, are widely used in key structural materials such as fuel cladding tubes and grids in nuclear reactors. During nuclear power plant operation, the zirconium alloy cladding reacts with high-temperature steam, and its hydrogenation behavior directly determines the service life of fuel elements and the safety and reliability of the nuclear reactor. Zirconium has a strong affinity for hydrogen, and the resulting metal hydrides are extremely stable at room temperature, almost never spontaneously releasing hydrogen. This characteristic allows zirconium alloy hydrogen storage to operate under normal or slightly positive pressure, completely avoiding the leakage and explosion risks of high-pressure gaseous hydrogen storage. It is particularly suitable for high-end industries and special fields such as nuclear facilities with stringent safety requirements, life support for manned spaceflight, power supply for deep space probes, backup power for confined spaces, and ultra-high purity hydrogen supply for high-end instruments.

[0003] When a loss-of-coolant accident (LOCA) occurs in a reactor, the failure of the cooling system causes the cladding temperature to rise sharply in a short period of time, reaching as high as 1200~1500℃. At this time, the zirconium alloy undergoes a violent oxidation reaction with the high-temperature steam: Zr + 2H2O → ZrO2 + 2H2↑. This reaction not only releases a large amount of heat, which exacerbates the rise in cladding temperature, but also about 10%~30% of the hydrogen atoms produced during the oxidation reaction are absorbed by the zirconium alloy matrix. When the hydrogen content exceeds its solubility limit, the excess hydrogen will precipitate in the form of zirconium hydride (mainly δ phase or ε phase). The formation of hydrides poses a multi-dimensional threat to the service performance of zirconium alloys. As a brittle second phase with a density lower than the zirconium matrix, the volume expansion generated during hydride precipitation can lead to oxide film cracking, destroying the protective effect and accelerating local oxidation. Furthermore, its poor chemical stability further degrades corrosion resistance. At the same time, the random distribution or aggregation of hydrides along grain boundaries can trigger hydrogen embrittlement, resulting in a significant decrease in alloy plasticity and fracture toughness. Under low temperature or high strain rate conditions, brittle fracture or even delayed hydrogen-induced cracking (DHC) is likely to occur. In addition, the thermal decomposition and re-precipitation process of hydrides can exacerbate mechanical damage to the cladding tube and increase the risk of fracture. Its morphology and distribution play a decisive role in the accident failure mode.

[0004] To simulate and study this process in the laboratory, controlled hydrogen charging of zirconium alloy and chromium-coated zirconium alloy samples is required to achieve high / ultra-high hydrogen content hydrogen storage. Currently, the mainstream laboratory hydrogen charging methods mainly include gas-phase hydrogen charging and water vapor / hydrogen mixed atmosphere methods. Among these, the mixed atmosphere method, which can simulate the coexistence of water vapor and hydrogen in an actual reactor environment, is the focus and challenge of research. The core of this method lies in precisely controlling the hydrogen partial pressure (P0) in the mixed atmosphere. H2) and water vapor partial pressure (P H2O The ratio of ) is crucial because it has a decisive influence on the properties of the oxide film on the zirconium alloy surface, the hydrogen absorption mechanism, and efficiency.

[0005] However, existing methods for transporting a mixture of water vapor and hydrogen through external gas pipelines have the following inherent drawbacks: 1. Low control precision and poor stability: During the transportation process, the steam is very easy to condense in the cold zone of the pipeline, resulting in a large deviation between the actual partial pressure entering the reaction zone and the set value, which seriously affects the repeatability of the experiment and the accuracy of the data.

[0006] 2. Complex system and cumbersome operation: This method usually requires a complex gas mixing, preheating and conveying system, which has high equipment costs and a complicated operation process, and poses certain safety risks.

[0007] 3. Difficulty in achieving accurate low oxygen partial pressure control: In situations requiring simulation of high P... H2 / P H2O At this ratio, achieving precise control by introducing a trace amount of water vapor from the outside is extremely difficult, and oxygen partial pressure often gets out of control due to background impurities or minor leaks.

[0008] Therefore, there is an urgent need in this field for an experimental method that can overcome the above-mentioned shortcomings. This method should be simple to operate, cost-effective, highly safe, and capable of accurately and stably implementing a series of different P values ​​within a closed system. H2 / P H2O The key capability of the ratio provides a reliable technical means for in-depth research on the hydrogenation behavior of zirconium alloys and chromium-coated zirconium alloys under different hydrogen / water vapor partial pressure ratios, and provides solutions for the preparation of high hydrogen content zirconium alloys and chromium-coated zirconium alloys and hydrogen storage technology with high / ultra-high hydrogen content. Summary of the Invention

[0009] In view of the above-mentioned prior art, the present invention provides a high-hydrogen-content zirconium hydride alloy, its preparation method and application, so as to solve the technical problems of high hydrogen charging cost and high risk of existing zirconium alloys.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is to provide a method for preparing a high-hydrogen-content zirconium hydride alloy, comprising the following steps: S1: Wrap the hydrogen source and water source separately in aluminum foil, and place them together with zirconium alloy or zirconium alloy with Cr coating into a tube furnace; the hydrogen source is a chemical reagent that decomposes by heating to produce hydrogen gas, and the water source is a chemical reagent that decomposes by heating to produce water vapor. S2: Evacuate the tubular furnace, then heat it to 500~700℃ and hold it for 18~30h. Use hydrogen and water vapor formed by the thermal decomposition of hydrogen and water sources to hydrogenate the zirconium alloy. S3: After hydrogen charging is completed, furnace cooling or controlled temperature slow cooling to room temperature yields a high-hydrogen-content zirconium hydride alloy.

[0011] Based on the above technical solution, the present invention can be further improved as follows.

[0012] Furthermore, the amount of hydrogen and water used should be based on a hydrogen / water vapor partial pressure ratio of 1 to 10 after pyrolysis.

[0013] Furthermore, the hydrogen source is at least one of titanium hydride, magnesium hydride, sodium aluminum hydride, and calcium hydride; the water source is at least one of copper sulfate pentahydrate, ferrous sulfate heptahydrate, cobalt chloride hexahydrate, potassium aluminum sulfate dodecahydrate, sodium carbonate decahydrate, calcium chloride dihydrate, aluminum hydroxide, ferric hydroxide, basic copper carbonate, boric acid, and magnesium hydroxide.

[0014] Furthermore, the pressure of the S2 tubular furnace after vacuuming is 0.001 Pa.

[0015] Furthermore, the heating rate in S2 is 5~20℃ / min.

[0016] Furthermore, the temperature control and slow cooling method in S3 is to first cool down to 450°C at a cooling rate of 0.3°C / min and hold at that temperature for 60 minutes, and then cool down to room temperature along with the furnace.

[0017] The present invention also discloses a high-hydrogen-content zirconium hydride alloy, which is prepared by the above-described method.

[0018] This invention also discloses the application of the above-mentioned high-hydrogen-content zirconium hydride alloy in the research of zirconium alloy hydrogenation.

[0019] This invention also discloses the application of the above-mentioned high-hydrogen-content zirconium hydride alloy as a hydrogen storage material.

[0020] The beneficial effects of this invention are: This invention utilizes a method for hydrogen charging zirconium alloys using the thermal decomposition of chemical reagents to generate gas. This method enables the hydrogen charging of zirconium alloys at different hydrogen / water vapor partial pressure ratios and yields samples with varying high / ultra-high hydrogen contents. Compared to traditional methods, this invention allows for high-hydrogen-content hydrogen charging of zirconium alloys and chromium-coated zirconium alloys under more economical and safer conditions. It provides a reliable technical means for in-depth research on the hydrogenation behavior of zirconium alloys and chromium-coated zirconium alloys at different hydrogen / water vapor partial pressure ratios, and offers solutions for the preparation of high-hydrogen-content zirconium alloy and chromium-coated zirconium alloy samples, as well as hydrogen charging and storage technologies for high / ultra-high hydrogen contents. Detailed Implementation

[0021] A zirconium hydride alloy is prepared by the following steps: S1: The weight of chemical reagents required for the preparation of zirconium hydride alloy is calculated by the hydrogen / water vapor partial pressure ratio; the zirconium alloy sample and the required hydrogen and water sources are weighed using an analytical balance; the chemical reagents that can be used as water sources are shown in Table 1, and the chemical reagents that can be used as hydrogen sources are shown in Table 2. Table 1 Chemicals that can be used as water sources Table 2 Chemicals that can be used as hydrogen sources S2: Wrap the hydrogen source and water source separately in aluminum foil and place them together with the zirconium alloy sample into a vacuum tube furnace; S3: Evacuate the tubular furnace to 10°C. -3 Pa, then close the valve to seal; S4: Heat the vacuum tube furnace to 500-700℃ at a heating rate of 5-20℃ / min, hold for 18-30h, and use the thermal decomposition properties or chemical reactions of hydrogen and water sources to form hydrogen and water vapor in the sealed vacuum furnace; by adjusting the amount of chemical reagents, different hydrogen / water vapor partial pressure ratios can be obtained and hydrogen filling can be completed. S5: After hydrogen charging is completed, the furnace is cooled or the temperature is controlled and slowly cooled to room temperature. The sample is then removed to complete the preparation of the zirconium hydride alloy.

[0022] The specific embodiments of the present invention will be described in detail below with reference to examples.

[0023] Example 1

[0024] A high-hydrogen-content zirconium hydride alloy is prepared by the following steps: S1: Take a zirconium alloy sample, which is a tube with a length of 10 mm and a diameter of 9.5 mm; weigh TiH2 and Mg(OH)2 as hydrogen source and water source respectively, and weigh 0.1872 g and 0.2195 g of TiH2 and Mg(OH)2 respectively, so as to control the hydrogen / water vapor partial pressure ratio of the generated hydrogen gas and water vapor to be 1; S2: Wrap the hydrogen source and water source separately in aluminum foil and place them together with the zirconium alloy sample into a vacuum tube furnace (vacuum tube furnace model N30 / 85HA). S3: Evacuate the tubular furnace to 10°C. -3 Pa, then close the valve to seal; S4: Heat the vacuum tube furnace to 550℃ at a heating rate of 5℃ / min and hold for 24h; use the thermal decomposition of hydrogen and water sources to form hydrogen and water vapor in the sealed vacuum furnace, obtain a mixed gas with a hydrogen / water vapor partial pressure ratio of 1 and complete the hydrogen filling. S5: After hydrogen charging, the temperature is reduced to 450℃ at a cooling rate of 0.3℃ / min and held for 60min. Then, the sample is cooled to room temperature in the furnace and removed to complete the preparation of zirconium hydride alloy.

[0025] Example 2

[0026] A high-hydrogen-content zirconium hydride alloy is prepared by the following steps: S1: Take a zirconium alloy sample, which is a tube with a length of 10 mm and a diameter of 9.5 mm; weigh TiH2 and Mg(OH)2 as hydrogen source and water source respectively, and weigh 0.1868 g and 0.0439 g of TiH2 and Mg(OH)2 respectively, so as to control the hydrogen / water vapor partial pressure ratio of the generated hydrogen and water vapor to be 5; S2: Wrap the hydrogen source and water source separately in aluminum foil and place them together with the zirconium alloy sample into a vacuum tube furnace (vacuum tube furnace model N30 / 85HA). S3: Evacuate the tubular furnace to 10°C. -3 Pa, then close the valve to seal; S4: Heat the vacuum tube furnace to 550℃ at a heating rate of 5℃ / min and hold for 24h; use the thermal decomposition of hydrogen and water sources to form hydrogen and water vapor in the sealed vacuum furnace, obtain a mixed gas with a hydrogen / water vapor partial pressure ratio of 5 and complete the hydrogen filling. S5: After hydrogen charging, the temperature is reduced to 450℃ at a cooling rate of 0.3℃ / min and held for 60min. Then, the sample is cooled to room temperature in the furnace and removed to complete the preparation of zirconium hydride alloy.

[0027] Example 3

[0028] A high-hydrogen-content zirconium hydride alloy is prepared by the following steps: S1: Take a zirconium alloy sample, which is a tube with a length of 10 mm and a diameter of 9.5 mm; weigh TiH2 and Mg(OH)2 as hydrogen source and water source respectively, and weigh 0.1860 g and 0.0219 g of TiH2 and Mg(OH)2 respectively, so as to control the hydrogen / water vapor partial pressure ratio of the generated hydrogen and water vapor to be 10. S2: Wrap the hydrogen source and water source separately in aluminum foil and place them together with the zirconium alloy sample into a vacuum tube furnace (vacuum tube furnace model N30 / 85HA). S3: Evacuate the tubular furnace to 10°C. -3 Pa, then close the valve to seal; S4: Heat the vacuum tube furnace to 550℃ at a heating rate of 5℃ / min and hold for 24h; use the thermal decomposition of hydrogen and water sources to form hydrogen and water vapor in the sealed vacuum furnace, obtain a mixed gas with a hydrogen / water vapor partial pressure ratio of 10 and complete the hydrogen filling. S5: After hydrogen charging, the temperature is reduced to 450℃ at a cooling rate of 0.3℃ / min and held for 60min. Then, the sample is cooled to room temperature in the furnace and removed to complete the preparation of zirconium hydride alloy.

[0029] Example 4

[0030] A high-hydrogen-content zirconium hydride alloy is prepared by the following steps: S1: Take a zirconium alloy sample with Cr coating. The sample is a tube with a length of 10 mm and a diameter of 9.5 mm. Weigh TiH2 and Mg(OH)2 as hydrogen source and water source, respectively. The weighing amounts of TiH2 and Mg(OH)2 are 0.1896 g and 0.2214 g, respectively, to control the hydrogen / water vapor partial pressure ratio of the generated hydrogen and water vapor to be 1. S2: Wrap the hydrogen source and water source separately in aluminum foil and place them together with the Cr-coated zirconium alloy sample into a vacuum tube furnace (vacuum tube furnace model N30 / 85HA). S3: Evacuate the tubular furnace to 10°C. -3 Pa, then close the valve to seal; S4: Heat the vacuum tube furnace to 550℃ at a heating rate of 20℃ / min and hold for 24h; use the thermal decomposition of hydrogen and water sources to form hydrogen and water vapor in the sealed vacuum furnace, obtain a mixed gas with a hydrogen / water vapor partial pressure ratio of 1 and complete the hydrogen filling. S5: After hydrogen charging, the temperature is reduced to 450℃ at a cooling rate of 0.3℃ / min and held for 60min. Then, the sample is cooled to room temperature in the furnace and removed to complete the preparation of zirconium hydride alloy.

[0031] Example 5

[0032] A high-hydrogen-content zirconium hydride alloy is prepared by the following steps: S1: Take a zirconium alloy sample with Cr coating. The sample is a tube with a length of 10 mm and a diameter of 9.5 mm. Weigh TiH2 and Mg(OH)2 as hydrogen source and water source, respectively. The weighing amounts of TiH2 and Mg(OH)2 are 0.1901 g and 0.0446 g, respectively, to control the hydrogen / water vapor partial pressure ratio of the generated hydrogen and water vapor to be 5. S2: Wrap the hydrogen source and water source separately in aluminum foil and place them together with the Cr-coated zirconium alloy sample into a vacuum tube furnace (vacuum tube furnace model N30 / 85HA). S3: Evacuate the tubular furnace to 10°C. -3 Pa, then close the valve to seal; S4: Heat the vacuum tube furnace to 550℃ at a heating rate of 20℃ / min and hold for 24h; use the thermal decomposition of hydrogen and water sources to form hydrogen and water vapor in the sealed vacuum furnace, obtain a mixed gas with a hydrogen / water vapor partial pressure ratio of 5 and complete the hydrogen filling. S5: After hydrogen charging, the temperature is reduced to 450℃ at a cooling rate of 0.3℃ / min and held for 60min. Then, the sample is cooled to room temperature in the furnace and removed to complete the preparation of zirconium hydride alloy.

[0033] Example 6

[0034] A high-hydrogen-content zirconium hydride alloy is prepared by the following steps: S1: Take a zirconium alloy sample with Cr coating. The sample is a tube with a length of 10 mm and a diameter of 9.5 mm. Weigh TiH2 and Mg(OH)2 as hydrogen source and water source, respectively. The weighing amounts of TiH2 and Mg(OH)2 are 0.1905 g and 0.0227 g, respectively, to control the hydrogen / water vapor partial pressure ratio of the generated hydrogen and water vapor to be 10. S2: Wrap the hydrogen source and water source separately in aluminum foil and place them together with the Cr-coated zirconium alloy sample into a vacuum tube furnace (vacuum tube furnace model N30 / 85HA). S3: Evacuate the tubular furnace to 10°C. -3 Pa, then close the valve to seal; S4: Heat the vacuum tube furnace to 550℃ at a heating rate of 20℃ / min and hold for 24h; use the thermal decomposition of hydrogen and water sources to form hydrogen and water vapor in the sealed vacuum furnace, obtain a mixed gas with a hydrogen / water vapor partial pressure ratio of 10 and complete the hydrogen filling. S5: After hydrogen charging, the temperature is reduced to 450℃ at a cooling rate of 0.3℃ / min and held for 60min. Then, the sample is cooled to room temperature in the furnace and removed to complete the preparation of zirconium hydride alloy.

[0035] Comparative Example 1 Zirconium hydride alloy was prepared by direct hydrogen purging using an argon / hydrogen mixture and water vapor. The zirconium alloy sample used was the same as in Example 1. The experimental parameters were as follows: water vapor flow rate was 0.99 L / min, hydrogen flow rate was 0.99 L / min, argon flow rate was 2 L / min, hydrogen / water vapor partial pressure ratio was 1, argon / hydrogen mixture ratio was 2, heating rate during hydrogen purging was 5 °C / min, hydrogen purging temperature was 550 °C, and hydrogen purging time was 24 h. After hydrogen purging, the temperature was lowered to 450 °C at a cooling rate of 0.3 °C / min and held for 60 min. Then, the furnace was cooled to room temperature, and the sample was removed, thus completing the preparation of zirconium hydride alloy.

[0036] Comparative Example 2 Compared to Comparative Example 1, the hydrogen / water vapor partial pressure ratio will be controlled at 0.63 by adjusting the gas flow rate, and everything else will be exactly the same as Comparative Example 1.

[0037] Comparative Example 3 Compared to Comparative Example 1, the hydrogen / water vapor partial pressure ratio will be controlled at 1.2 by adjusting the gas flow rate, and everything else will be exactly the same as Comparative Example 1.

[0038] Comparative Example 4 Compared to Comparative Example 1, the hydrogen / water vapor partial pressure ratio will be controlled at 2.36 by adjusting the gas flow rate, and everything else will be exactly the same as Comparative Example 1.

[0039] Experimental Example After hydrogen charging, three points were randomly selected on each sample for hydrogen content testing. The instrument used for the test was an ONH836 single-sample hydrogen analyzer, and the method employed was inert gas melting infrared absorption method, referring to standard QB-QT-37-2014. The test results are shown in Table 3.

[0040] Table 3. Hydrogen content test results of hydrogen charging experiment As shown in Table 3, the chemical reagent method allows for hydrogen purging of zirconium alloys and Cr-coated zirconium alloys at different hydrogen / water vapor partial pressure ratios, yielding samples with varying high / ultra-high hydrogen contents. However, using traditional methods, achieving higher hydrogen contents requires: 1. increasing the flow rates of hydrogen and water vapor; 2. increasing the holding temperature; and 3. extending the holding time. Regardless of the method employed, these measures increase experimental costs and risks. Compared to traditional methods, the method described in this invention allows for high hydrogen content purging of zirconium alloys and Cr-coated zirconium alloy samples under more economical and safer conditions.

[0041] Although specific embodiments of the present invention have been described in detail with reference to examples, they should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims are still within the scope of protection of this patent.

Claims

1. A method for preparing a high-hydrogen-content zirconium hydride alloy, characterized in that, Includes the following steps: S1: Wrap the hydrogen source and water source separately in aluminum foil, and place them together with zirconium alloy or zirconium alloy with Cr coating into a tube furnace; the hydrogen source is a chemical reagent that produces hydrogen gas by heating and decomposing, and the water source is a chemical reagent that produces water vapor by heating and decomposing. S2: Evacuate the tubular furnace, then heat it to 500~700℃ and hold it for 18~30h. Use hydrogen and water vapor formed by the thermal decomposition of hydrogen and water sources to hydrogenate the zirconium alloy. S3: After hydrogen charging is completed, furnace cooling or controlled temperature slow cooling to room temperature yields a high-hydrogen-content zirconium hydride alloy.

2. The preparation method according to claim 1, characterized in that: The amounts of hydrogen and water sources used are based on a hydrogen / water vapor partial pressure ratio of 1 to 10 after pyrolysis.

3. The preparation method according to claim 1 or 2, characterized in that: The hydrogen source is at least one of titanium hydride, magnesium hydride, sodium aluminum hydride, and calcium hydride; the water source is at least one of copper sulfate pentahydrate, ferrous sulfate heptahydrate, cobalt chloride hexahydrate, potassium aluminum sulfate dodecahydrate, sodium carbonate decahydrate, calcium chloride dihydrate, aluminum hydroxide, ferric hydroxide, basic copper carbonate, boric acid, and magnesium hydroxide.

4. The preparation method according to claim 1, characterized in that: The pressure of the S2 tubular furnace after vacuuming is 0.001 Pa.

5. The preparation method according to claim 1, characterized in that: The heating rate in S2 is 5~20℃ / min.

6. The preparation method according to claim 1, characterized in that: The temperature control and slow cooling method in S3 is to first cool down to 450℃ at a cooling rate of 0.3℃ / min and hold it at that temperature for 60 minutes, and then cool it down to room temperature along with the furnace.

7. The high-hydrogen-content zirconium hydride alloy prepared by the preparation method according to any one of claims 1 to 6.

8. The application of the high hydrogen content zirconium hydride alloy according to claim 7 in the research of zirconium alloy hydrogenation.

9. The application of the high-hydrogen-content zirconium hydride alloy according to claim 7 as a hydrogen storage material.

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