Zirconium alloy surface controllable plasma hydrogen permeation method and hydrogen permeation piece

Abstract

The invention belongs to the technical field of zirconium alloy materials, and relates to a zirconium alloy surface controllable plasma hydrogen permeation method and a hydrogen permeation piece. The hydrogen permeation method comprises the steps that hydrogen and argon mixed gas is introduced into a vacuum cavity and adjusted to set hydrogen partial pressure, pulse negative electricity bias voltage is applied to the surface of a sample to generate plasma after the temperature is increased, and hydrogen permeation is carried out on the surface of the sample; hydrogen ions accelerate to move towards a cathode workpiece under the action of an electric field so as to permeate into the material at a high speed; by regulating and controlling parameters such as hydrogen partial pressure, bias voltage, duty ratio, temperature and time and combining real-time monitoring current signals, accurate control over the hydrogen content and the hydride morphology is achieved; according to the method, quantitative, controllable and safe hydrogen permeation can be achieved, and the problems that an existing electrolytic hydrogen permeation method, an existing gas-phase hydrogen permeation method and an existing liquid-phase hydrogen permeation method are poor in control precision, low in efficiency and large in pollution are solved; the method has the advantages of simplicity and convenience in operation, good hydrogen permeation uniformity, high safety and the like.

Description

Technical Field

[0001] This invention belongs to the field of zirconium alloy material technology, specifically relating to a controllable plasma hydrogen permeation method for zirconium alloy surfaces and a hydrogen permeation component. Background Technology

[0002] Zirconium alloys are widely used as cladding and core structural materials for reactors due to their low thermal neutron capture cross-section, good thermal conductivity, strong resistance to water-side corrosion, and excellent mechanical properties. Because zirconium alloys are extensively used in water-cooled reactors, the hydrogen released during the high-temperature reaction with steam (Zr + 2H₂O → ZrO₂ + 2H₂) is partially retained in the water and partially absorbed by zirconium—this is the phenomenon of "hydrogen absorption." Since the solid solubility of hydrogen in zirconium is limited, excess hydrogen beyond this solubility will precipitate as hydrides. As shown in the Zr-H phase diagram, there are two types of stable hydrides formed between zirconium alloys and H: fcc-structured δ-hydrides (ZrH₂). 1.5～1.66 ) and fct-structured ε-hydrides (ZrH 1.8～2 These hydrides have a certain compositional width and are all brittle phases, which are prone to microcracks, reducing the toughness and strength of the material, making it brittle, and increasing its susceptibility to hydrogen-induced delayed cracking (DHC), thus limiting the service life of the zirconium alloy cladding.

[0003] With the development of nuclear energy utilization towards high burnup, high safety, and low consumption, the burnup of fuel rods has increased from 30 GWd / tMH to 50 GWd / tMH, and the service life of nuclear fuel cladding tubes in the reactor has increased from 3 years to 5 years. This places higher demands on their performance, and the hydrogen embrittlement problem caused by hydrogen absorption is becoming increasingly prominent in restricting material properties. Therefore, it is crucial to study the formation mechanism, microstructure, and mechanical properties of hydrides, but this requires a controllable and stable hydrogen permeation process in the early stages to obtain samples with a certain hydrogen content and hydride state.

[0004] Currently, there are three main methods for hydrogen permeation testing of zirconium alloys in China: electrolytic hydrogen permeation, liquid-phase hydrogen permeation, and gas-phase hydrogen permeation. Electrolytic hydrogen permeation involves using the zirconium alloy as the cathode in an acidic electrolyte (0.1-1 mol / L H₂SO₄) to allow the evolved hydrogen atoms to permeate into the material surface. Its biggest advantage is that it can reduce surface oxidation, and the prepared samples can be further used to test mechanical properties. However, its disadvantages include a complex preparation process, requiring further heat treatment after hydrogen permeation to ensure the hydrogen enriched on the surface is evenly distributed throughout the matrix, and a tendency to cause corrosion or electrochemical side reactions. Gas-phase hydrogen permeation involves placing the zirconium alloy in a hydrogen-argon mixed atmosphere (the recommended hydrogen component is 1.8%-2.2%), applying a certain temperature to the mixed atmosphere under a certain pressure to promote H diffusion and achieve hydrogen permeation. However, the open structure of gas-phase hydrogen permeation results in poor furnace temperature uniformity and hydrogen distribution uniformity, leading to poor hydrogen permeation uniformity and reproducibility of test results. Liquid-phase hydrogen permeation is a commonly used method, in which the zirconium alloy sample is immersed in an autoclave containing a lithium hydroxide solution of a certain concentration and left to stand for several hours to hundreds of hours under specific temperature and pressure. However, this method is slow, highly polluting, and difficult to control precisely. In summary, existing hydrogen permeation methods cannot achieve precise and controllable adjustment of hydrogen content and have shortcomings in terms of hydrogen permeation uniformity and safety.

[0005] Therefore, there is an urgent need to develop a novel hydrogen permeation method that is controllable in hydrogen content, uniform in hydrogen permeation, highly efficient, and safe, so as to provide reliable support for subsequent hydride research and engineering applications. Summary of the Invention

[0006] This invention provides the following technical solution: a method for controllable plasma hydrogen permeation on the surface of a zirconium alloy, comprising the following steps:

[0007] a. After placing zirconium or zirconium alloy in a vacuum chamber, introduce a hydrogen-argon mixture and adjust it to the target hydrogen partial pressure before heating.

[0008] b. Apply a controllable negative bias voltage to the surface of a zirconium or zirconium alloy matrix and generate plasma in a pulse mode to accelerate the penetration of hydrogen ions into the zirconium or zirconium alloy matrix under the action of an external electric field.

[0009] c. By adjusting one or more parameters among bias voltage, temperature, and plasma hydrogen permeation time, combined with real-time monitoring signals, the hydrogen content and hydride morphology can be controlled; where hydrogen content ∝ hydrogen gas integral number × chamber pressure × negative bias voltage.

[0010] d. After hydrogen permeation is complete, turn off the plasma source, convert the chamber atmosphere to high-purity argon, and cool it down using a pressure-controlled method.

[0011] The hydrogen gas integral number determines the number of hydrogen atoms and ions in the plasma, which is the basis for effective hydrogen permeation. A larger hydrogen gas integral number can provide more hydrogen particle sources, thereby increasing the hydrogen content. Increasing the chamber pressure can increase the hydrogen particle density, promote diffusion, and increase the number of hydrogen particles impacting the material surface per unit time, thus increasing the hydrogen content. The negative bias voltage directly affects the energy and flux of hydrogen ions. The higher the bias voltage, the stronger the acceleration of hydrogen ions, and at the same time, it regulates the hydrogen ion injection rate, thereby increasing the hydrogen content. Therefore, hydrogen content ∝ hydrogen gas integral number × chamber pressure × negative bias voltage.

[0012] Preferably, in step a, the vacuum condition inside the vacuum chamber is: 1.0 × 10⁻⁶ -4 ~1.0×10 -3 Pa.

[0013] Preferably, in step a, the volume ratio of hydrogen to argon in the hydrogen-argon mixture is 10 to 8:1.

[0014] Preferably, in step a, the target hydrogen partial pressure is 20–45 Pa.

[0015] Preferably, in step a, the temperature range for heating is 200–400°C.

[0016] Preferably, in step b, the negative bias voltage range is 500–1000V.

[0017] Preferably, in step b, the duty cycle of the pulse mode is 18-22%. When the duty cycle is within this range, the hydrogen permeation is optimal. When the duty cycle is greater than this range, the time proportion of plasma energy input per unit time increases, leading to increased heat accumulation on the sample surface, a rise in temperature, and an increase in the hydrogen diffusion coefficient. However, desorption / escape also increases simultaneously, thus reducing the hydrogen content. When the duty cycle is less than this range, insufficient dosage leads to a decrease in hydrogen content.

[0018] Preferably, in step c, the real-time monitoring signal is a current signal.

[0019] Preferably, in step d, the air pressure in the chamber is 20 Pa when the pressure is controlled to cool down.

[0020] The present invention also discloses a zirconium alloy surface controllable plasma hydrogen permeation part, which is prepared by the above-mentioned zirconium alloy surface controllable plasma hydrogen permeation method.

[0021] The beneficial effects of this invention are:

[0022] This invention achieves precise control of hydrogen content through the synergistic regulation of various factors during plasma hydrogen permeation treatment. The operation steps of this invention are simple, fast, efficient, and highly safe. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the steps of a controllable plasma hydrogen permeation method for zirconium alloy surfaces and a hydrogen-permeated component according to the present invention. Detailed Implementation

[0024] The related technologies of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figure 1 As shown, in this embodiment, the controllable plasma hydrogen permeation method for zirconium alloy surfaces includes the following steps:

[0026] a. Place the zirconium or zirconium alloy sample under certain vacuum conditions, introduce a hydrogen-argon mixture into the vacuum chamber and adjust it to the target hydrogen partial pressure, then heat it to the set temperature.

[0027] b. Apply an adjustable negative bias voltage to the surface of a zirconium or zirconium alloy substrate and generate plasma in a pulse mode to accelerate the penetration of hydrogen ions into the sample under the action of an external electric field.

[0028] c. By adjusting one or more parameters among bias voltage, temperature, and plasma hydrogen permeation time, combined with real-time monitoring signals, the hydrogen content and hydride morphology can be controlled.

[0029] d. After hydrogen permeation is complete, turn off the plasma source, convert the chamber atmosphere to high-purity argon, and cool it down using a pressure-controlled method.

[0030] Furthermore, in step a, the vacuum condition is 1.0 × 10⁻⁶. -4 ~1.0×10 -3 Pa.

[0031] Furthermore, in step a, the volume fraction ratio of hydrogen to argon in the hydrogen-argon mixture is 9:1.

[0032] Furthermore, in step a, the target hydrogen partial pressure is 20–45 Pa.

[0033] Furthermore, in step a, the set temperature is 200–400°C.

[0034] Furthermore, in step b, the adjustable negative bias voltage is 500–1000V.

[0035] Furthermore, in step b, the duty cycle of the pulse mode is 20%.

[0036] Furthermore, in step c, the real-time monitoring signal is a current signal.

[0037] Furthermore, in step d, the chamber pressure for cooling by the pressure control method is 20 Pa.

[0038] Secondly, the present invention provides a zirconium alloy surface controllable plasma hydrogen permeation part prepared by the method proposed in the first aspect above.

[0039] Example

[0040] The method and its effects of the present invention will be illustrated below through specific examples. In the following examples, the hydrogen content was tested using a hydrogen, oxygen, and nitrogen analyzer N36 (LECO, USA).

[0041] Example 1

[0042] The target hydrogen content was 0.022 wt%. The sample was a CZ2 alloy, weighing 4 g. The CZ alloy sample was placed in the sample chamber of the hydrogen permeation apparatus, and the vacuum degree in the sample chamber was controlled to be ≤1.0×10-3 Pa. Then, hydrogen gas was pre-purged for 20 min, while the chamber pressure was maintained at 35 Pa. Then, the temperature was increased. When the temperature reached 300℃, the ion source was turned on, and the bias voltage was set to 500 V, the duty cycle to 20%, and the current to 19 mA. After 30 min of plasma hydrogen permeation, the ion source was turned off, and the atmosphere was converted to high-purity argon gas, while the chamber pressure was maintained at 20-30 Pa. The sample was then cooled to room temperature and removed from the furnace.

[0043] The hydrogen content of the sample was tested to be 0.022 wt%.

[0044] Example 2

[0045] The target hydrogen content was 0.025 wt%. The sample was a CZ2 alloy, weighing 4 g. The CZ alloy sample was placed in the sample chamber of the hydrogen permeation apparatus, and the vacuum degree in the sample chamber was controlled to be ≤1.0×10-3 Pa. Then, hydrogen gas was pre-purged for 20 min, while the chamber pressure was maintained at 35 Pa. Then, the temperature was increased, and when the temperature reached 300℃, the ion source was turned on, with the bias voltage set to 600 V, the duty cycle to 20%, and the current to 35 mA. After plasma hydrogen permeation for 30 min, the ion source was turned off, and the atmosphere was converted to high-purity argon gas, while the chamber pressure was maintained at 20-30 Pa. The sample was then cooled to room temperature and removed from the furnace.

[0046] The hydrogen content of the sample was tested to be 0.025 wt%.

[0047] Example 3

[0048] The target hydrogen content was 0.028 wt%. The sample was a CZ2 alloy, weighing 4 g. The CZ alloy sample was placed in the sample chamber of the hydrogen permeation apparatus, and the vacuum degree in the sample chamber was controlled to be ≤1.0×10-3 Pa. Then, hydrogen gas was pre-purged for 20 min, while the chamber pressure was maintained at 35 Pa. Then, the temperature was increased, and when the temperature reached 300℃, the ion source was turned on, with the bias voltage set to 700 V, the duty cycle to 20%, and the current to 40 mA. After 30 min of plasma hydrogen permeation, the ion source was turned off, and the atmosphere was converted to high-purity argon gas, while the chamber pressure was maintained at 20-30 Pa. The sample was then cooled to room temperature and removed from the furnace.

[0049] The hydrogen content of the sample was tested to be 0.028 wt%.

[0050] Example 4

[0051] The target hydrogen content was 0.031 wt%. The sample was a CZ2 alloy, weighing 4 g. The CZ alloy sample was placed in the sample chamber of the hydrogen permeation apparatus, and the vacuum degree in the sample chamber was controlled to be ≤1.0×10-3 Pa. Then, hydrogen gas was pre-purged for 20 min, while the chamber pressure was maintained at 35 Pa. Then, the temperature was increased. When the temperature reached 300℃, the ion source was turned on, and the bias voltage was set to 800 V, the duty cycle to 20%, and the current to 45 mA. After plasma hydrogen permeation for 30 min, the ion source was turned off, and the atmosphere was converted to high-purity argon gas, while the chamber pressure was maintained at 20-30 Pa. The sample was then cooled to room temperature and removed from the furnace.

[0052] The hydrogen content of the sample was tested to be 0.030 wt%.

[0053] Example 5

[0054] The target hydrogen content was 0.037 wt%. The sample was a CZ2 alloy, weighing 4 g. The CZ alloy sample was placed in the sample chamber of the hydrogen permeation apparatus, and the vacuum degree in the sample chamber was controlled to be ≤1.0×10-3 Pa. Then, hydrogen gas was pre-purged for 20 min, while the chamber pressure was maintained at 35 Pa. Then, the temperature was increased, and when the temperature reached 300℃, the ion source was turned on, the bias voltage was set to 800 V, the duty cycle was 20%, and the current was 45 mA. After 90 min of plasma hydrogen permeation, the ion source was turned off, and the atmosphere was converted to high-purity argon gas, while the chamber pressure was maintained at 20-30 Pa. The sample was then cooled to room temperature and removed from the furnace.

[0055] The hydrogen content of the sample was tested to be 0.037 wt%.

[0056] Example 6

[0057] The target hydrogen content was 0.070 wt%. The sample was a CZ2 alloy, weighing 4 g. The CZ alloy sample was placed in the sample chamber of the hydrogen permeation apparatus, and the vacuum degree in the sample chamber was controlled to be ≤1.0×10-3 Pa. Then, hydrogen gas was pre-purged for 20 min, while the chamber pressure was maintained at 35 Pa. Then, the temperature was increased. When the temperature reached 300℃, the ion source was turned on, and the bias voltage was set to 800 V, the duty cycle to 20%, and the current to 45 mA. After plasma hydrogen permeation for 150 min, the ion source was turned off, and the atmosphere was converted to high-purity argon gas, while the chamber pressure was maintained at 20-30 Pa. The sample was then cooled to room temperature and removed from the furnace.

[0058] The hydrogen content of the sample was tested to be 0.070 wt%.

[0059] The above description is intended to be illustrative and not restrictive. For example, the above examples (or one or more of them) can be used in combination with each other, and these embodiments can be combined with each other in various combinations or arrangements. The scope of this application should be determined by reference to the appended claims and the full scope of their equivalents.

[0060] In summary, this invention achieves precise control of hydrogen content through the synergistic regulation of various factors during plasma hydrogen permeation treatment. The invention is simple, fast, efficient, and highly safe.

[0061] It should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for controllable plasma hydrogen permeation on the surface of a zirconium alloy, characterized in that, Includes the following steps: a. After placing zirconium or zirconium alloy in a vacuum chamber, introduce a hydrogen-argon mixture and adjust it to the target hydrogen partial pressure before heating. b. Apply an adjustable negative bias voltage to the surface of the zirconium or zirconium alloy matrix to generate plasma in a pulse mode; c. By adjusting the bias voltage, temperature, and plasma hydrogen permeation time, combined with real-time monitoring signals, the hydrogen content and hydride morphology can be controlled; where hydrogen content is ∝ hydrogen gas integral number × chamber pressure × negative bias voltage. d. After hydrogen permeation is complete, turn off the plasma source, convert the chamber atmosphere to high-purity argon, and cool it down using a pressure-controlled method.

2. The method for controllable plasma hydrogen permeation of zirconium alloy surface according to claim 1, characterized in that, In step a, the vacuum condition inside the vacuum chamber is: 1.0 × 10⁻⁶ -4 ~1.0×10 -3 Pa.

3. The method for controllable plasma hydrogen permeation of zirconium alloy surface according to claim 1, characterized in that, In step a, the volume ratio of hydrogen to argon in the hydrogen-argon mixture is 10 to 8:

1.

4. The controllable plasma hydrogen permeation method for zirconium alloy surface according to claim 1, characterized in that, In step a, the target hydrogen partial pressure is 20–45 Pa.

5. The method for controllable plasma hydrogen permeation of zirconium alloy surface according to claim 1, characterized in that, In step a, the temperature range for heating is 200–400°C.

6. The method for controllable plasma hydrogen permeation of zirconium alloy surface according to claim 1, characterized in that, In step b, the negative bias voltage range is 500–1000V.

7. The method for controllable plasma hydrogen permeation of zirconium alloy surface according to claim 1, characterized in that, In step b, the duty cycle of the pulse mode is 18-22%.

8. The method for controllable plasma hydrogen permeation of zirconium alloy surface according to claim 1, characterized in that, In step c, the real-time monitoring signal is a current signal.

9. The method for controllable plasma hydrogen permeation of zirconium alloy surface according to claim 1, characterized in that, In step d, the air pressure in the chamber is 20 Pa when the pressure is controlled to cool down.

10. A zirconium alloy surface controllable plasma hydrogen permeation component, characterized in that, The plasma hydrogen-permeated part is prepared by the controllable plasma hydrogen permeation method on the zirconium alloy surface as described in any one of claims 1 to 9.

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