A device and method for in-situ XRD characterization in oxygen-controlled lead-bismuth corrosion environment

Abstract

The application discloses a device and a method for in-situ XRD characterization in an oxygen-controlled lead-bismuth corrosion environment, which comprises a sample cabin, an oxygen concentration control system, a low-temperature water bath device and an oxygen concentration detection system; the flow control system comprises an Ar gas cylinder and an Ar / 5% H2 mixed gas cylinder, the output ends of the two are respectively connected with the input ends of first and second mass flow controllers; the low-temperature water bath device comprises a low-temperature constant-temperature water bath box and a water bath bottle, the output ends of the two mass flow controllers are mixed and divided into two branches, the first branch is connected with the gas inlet of the sample cabin, the second branch is connected with the gas inlet of the water bath bottle, and the gas outlet of the water bath bottle is connected with the gas inlet of the sample cabin; the oxygen concentration detection system comprises an oxygen concentration detection cabin and a liquid metal container provided with lead and bismuth, a Bi / Bi2O3 reference electrode and a Mo working electrode are inserted into the top of the oxygen concentration detection cabin, the gas inlet of the oxygen concentration detection cabin is connected with the gas outlet of the sample cabin, and the gas outlet of the oxygen concentration detection cabin is connected with a back pressure valve.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of lead-bismuth reactors, and relates to a device and a method for in-situ XRD characterization in an oxygen-controlled lead-bismuth corrosion environment. BACKGROUND

[0002] As one of the fourth generation advanced nuclear power reactor systems, the lead-bismuth reactor uses molten lead-bismuth eutectic alloy (LBE) as a coolant, and its low melting point, high evaporation point, good thermal conductivity, low reactivity and good neutron yield make it a safe and high-performance coolant in a radiation environment. However, one of the major challenges it faces is the inherent corrosion of liquid heavy metals. In its working temperature range of about 450-550 DEG C, surface reactions occur between traditional structural materials and atoms and impurity atoms in the liquid metal, and some of the main alloying elements in the direct contact lead-bismuth environment have a large solubility, thereby causing serious intergranular corrosion. Due to factors such as thermal expansion coefficient, the oxide scale formed often cracks or peels off after a long service life, causing the infiltration of liquid lead-bismuth metal, which is crucial to the safety and service life of the reactor. Therefore, the corrosion mechanism of the structural material in the lead-bismuth eutectic alloy environment is one of the key technical problems of the research.

[0003] Considering the possibility of anion-vacancy transport growth of the oxide in the "Pb-Bi / oxide / matrix" system, which is related to volume change, the growth of the oxide generates local strain, local stress and local deformation, which change the vacancy concentration at the boundary of the oxide layer by affecting the formation free energy of defects at the interface (vacancies), in addition, the existence of stress gradient across the oxide layer will deviate the random migration of defects. Traditional XRD stress meter is difficult to accurately measure the distribution information of stress in the oxide film along the thickness direction. The wave band focusing of the hard X-ray micro-focusing beam line can focus the spot size to about 3 μm, and the beam is scanned along the thickness direction of the sample surface to obtain the information along the thickness direction. At the same time, due to the high working temperature and strong corrosion of liquid lead-bismuth eutectic alloy, the traditional work is to use non-in situ characterization after corrosion to study the structural materials under various corrosion conditions. It is very important to expand the related experimental and characterization methods to obtain the corrosion data and behavior of the material more objectively and intuitively. The use of synchrotron XRD in situ characterization of the influence of different factors on the structure and phase composition changes of the oxide film at different depths of the material, relying on its high resolution to discover and analyze the influence of organizational feature changes on the corrosion mechanism, and can distinguish Fe3O4 and FeCr2O4 phases which cannot be distinguished by traditional XRD. The in situ characterization technology of synchrotron XRD is of great significance to exclude the strain of the oxide film caused by the change of the environment in the off-site observation, to non-destructively characterize the sample without damaging the sample, and to make the characterization results more accurate. The third generation of synchrotron radiation source has the advantages of high flux, high coherence and high pulse repetition rate, and the X-ray diffraction characterization method based on it has the advantages of high temporal and spatial resolution and strong penetration of several microns to sub-microns, which can obtain non-destructive information of the spatial distribution, concentration and morphology of trace elements related to morphology and crystal orientation, and can systematically study the damage mechanism of materials under various environments. In situ characterization technology can apply various physical and chemical fields to a large extent to avoid errors that may be introduced by the experimental process, and can study the microstructure, micro-mechanics, phase transition behavior and other physical and chemical phenomena of materials in the working environment, which has incomparable advantages in the characterization of multi-dimensional spatial structure and electronic energy state structure of materials.

[0004] However, as an electromagnetic wave, X-rays will interact with matter (mainly photoelectric effect, Compton effect and pair effect) and lose a lot of energy when passing through matter. When X-rays pass through LBE, the energy attenuation is very large. Due to the presence of a large amount of LBE in the general immersion corrosion test environment, it is difficult for X-rays to penetrate the corrosion medium and express the information on the surface of the sample. Therefore, a very thin LBE film needs to be prepared on the surface of the sample to meet the simulation of the LBE corrosion environment and the characterization of the corrosion information on the surface of the sample by in-situ XRD at the same time. The general thin film preparation method is evaporation. The adhesion of the thin film obtained by this method to the substrate (sample) is poor, and the corrosion test temperature needs to be higher than the melting point of LBE, which makes the LBE thin film prepared by evaporation more likely to fall off the sample, resulting in the corrosion environment changing from LBE to gas phase direct corrosion, and thus the experimental results are invalid.

[0005] It is generally believed that temperature, oxygen concentration, type of steel, LBE flow rate and temperature difference between high and low temperature parts in the loop experiment have a great influence on the corrosion behavior in LBE liquid. Among them, the high and low oxygen concentration directly determines whether the oxidation corrosion and dissolution corrosion occur or not. Therefore, accurate control of the oxygen concentration in the corrosion test environment is a necessary step to study the influence of oxygen concentration on the corrosion behavior of materials in LBE. However, the existing in-situ characterization equipment of synchrotron radiation XRD cannot control the oxygen concentration in the atmosphere in the sample chamber. Since the oxygen solubility in LBE is very low, it is difficult to directly control the oxygen concentration. At present, the main oxygen control method is to control the partial pressure of oxygen in the gas phase by controlling the partial pressure of H2 and H2O in the gas phase according to the reaction equilibrium of H2, O2 and H2O. The current oxygen control device usually needs to measure the vapor pressure of H2O in the gas phase by using a dew point instrument. However, the cost of the dew point instrument is very high, which often accounts for more than 50% of the cost of the complete oxygen control device. The measurement of the actual oxygen solubility in LBE is generally realized by using an oxygen probe. The existing oxygen probe for LBE is usually a Bi / Bi2O3 type oxygen probe. Its basic structure includes a reference electrode composed of a solid electrolyte container wrapped with Bi and Bi2O3 and a working electrode composed of an inert metal rod (usually Mo). Its working principle is that when the reference electrode and the working electrode are immersed in liquid LBE together, the potential difference between the two electrodes can be expressed as a function of the dissolved oxygen concentration in LBE, and the oxygen concentration can be calculated by measuring the voltage between the electrodes. However, for in-situ XRD experiments, due to the very low transmittance of LBE, the sample cannot be directly immersed in LBE, and the oxygen probe cannot be immersed in the experimental environment (liquid LBE) to measure the oxygen concentration. Therefore, the general oxygen concentration measurement method cannot be directly applied to this type of experiment. SUMMARY

[0006] The device and method for in-situ XRD characterization in oxygen-controlled lead-bismuth corrosion environment can realize accurate control of target oxygen concentration in an extremely low oxygen concentration environment and oxygen control experiment in the extremely low oxygen concentration environment.

[0007] To achieve the above-mentioned purpose, the following technical solutions are adopted in the present application:

[0008] The device for in-situ XRD characterization in oxygen-controlled lead-bismuth corrosion environment comprises a sample cabin, an oxygen concentration control system, a low-temperature water bath device and an oxygen concentration detection system.

[0009] The sample cabin is hollow and provided with a sample cabin gas inlet and a sample cabin gas outlet at two sides, and is internally provided with a sample stage.

[0010] The flow control system comprises an Ar gas cylinder and an Ar / 5% H2 mixed gas cylinder, and the output ends of the Ar gas cylinder and the Ar / 5% H2 mixed gas cylinder are respectively connected with the input ends of first and second mass flow controllers.

[0011] The low-temperature water bath device comprises a low-temperature constant-temperature water bath box and a water bath bottle, the water bath bottle is internally provided with ultrapure water, the water bath bottle is arranged in the low-temperature constant-temperature water bath box, the water bath bottle is provided with a water bath bottle gas inlet and a water bath bottle gas outlet, the output ends of the first and second mass flow controllers are mixed and divided into two branches, the first branch is connected with the sample cabin gas inlet, the second branch is connected with the water bath bottle gas inlet, and the water bath bottle gas outlet is connected with the sample cabin gas inlet.

[0012] The oxygen concentration detection system comprises an oxygen concentration detection cabin and a liquid metal container internally provided with lead and bismuth, the oxygen concentration detection cabin is sealingly arranged, is internally provided with a heating device, and the liquid metal container is located in the oxygen concentration detection cabin, the oxygen concentration detection cabin is provided at the top with an oxygen concentration detection cabin gas inlet, an oxygen concentration detection cabin gas outlet, a Bi / Bi2O3 reference electrode and a Mo working electrode, the oxygen concentration detection cabin gas inlet is connected with the sample cabin gas outlet, and the oxygen concentration detection cabin gas outlet is connected with a back pressure valve.

[0013] Preferably, a flame arrester is arranged between the Ar / 5% H2 mixed gas cylinder and the second mass flow controller, and the flame arrester is connected with an alarm.

[0014] Preferably, a pressure reducing valve and a filter are arranged between the Ar gas cylinder and the first mass flow controller, and between the Ar / 5% H2 mixed gas cylinder and the second mass flow controller.

[0015] Preferably, the output ends of the first and second mass flow controllers are respectively connected with first and second ball valves.

[0016] Preferably, the first mass flow controller and the second mass flow controller are connected with a first one-way valve at the output end, and the water bath bottle is connected with a second one-way valve at the gas inlet.

[0017] Preferably, the oxygen concentration detection chamber is provided with a thermocouple and an oxygen concentration detection chamber heating wire, and the oxygen concentration detection chamber heating wire is located between the oxygen concentration detection chamber and the liquid metal container, and the thermocouple is inserted into the lead bismuth.

[0018] Preferably, the sample chamber comprises a perforated shell, the perforated shell is a four-way structure, a top window is arranged at the top, side windows are arranged on both sides of the perforated shell, the two side windows are coaxial, and the axis is in a horizontal position, a first bottom perforated shell is arranged at the bottom, and a sample stage is arranged at the top of the first bottom perforated shell, and a sample chamber heating wire and a temperature measuring tube are arranged at the bottom of the first bottom perforated shell.

[0019] An in-situ XRD characterization experiment method in an oxygen-controlled lead bismuth corrosion environment based on the device of any one of the above, comprising a non-oxygen control mode and an oxygen control mode;

[0020] The sample after coating is placed on the sample stage, and the sample stage is processed to have a 0°-15° slope;

[0021] When in the non-oxygen control mode, the Ar gas cylinder and the Ar / 5% H2 mixed gas cylinder are closed, the sample chamber is heated to the target temperature, and then the in-situ XRD characterization experiment is started;

[0022] When in the oxygen control mode, the oxygen concentration detection chamber is heated to the working target temperature, the temperature of the ultrapure water in the water bath bottle is controlled to the target H2O vapor pressure corresponding temperature through the low-temperature constant-temperature water bath box, the Bi / Bi2O3 type reference electrode and the Mo working electrode are immersed in the liquid lead bismuth, the Ar / 5% H2 mixed gas cylinder is slowly opened, the first branch is closed, and the second branch is opened, the first mass flow controller and the second mass flow controller are respectively set to the corresponding control flow according to the target H2 concentration, the control flow of the first mass flow controller and the second mass flow controller is fine-tuned according to the voltage value of the Bi / Bi2O3 type reference electrode and the Mo working electrode to obtain the corresponding dissolved oxygen concentration, until the oxygen solubility in the lead bismuth is stabilized at the target oxygen concentration, the sample chamber is heated to the target temperature, and then the in-situ XRD characterization experiment is started;

[0023] The in-situ XRD characterization experiment process is as follows: the light spot of the light beam is converged to 3-5 μm in size, the light beam is horizontally injected into the sample chamber, the X-ray is incident on the sample surface at an angle of 0°-15°, the X-ray can penetrate the coating of the target thickness at this incident angle, diffraction occurs on the sample surface, and the XRD characterization of the corrosion surface is realized to obtain a diffraction image.

[0024] Preferably, the sample plating process is as follows: taking lead bismuth or lead as the target material, a certain thickness of lead bismuth or lead plating layer is prepared on the surface of the sample to be in-situ measured by metal coating technology; the thickness of the plating layer needs to be determined according to the temperature, the energy intensity of the experimental light source and the maximum X-ray attenuation rate.

[0025] Preferably, before the non-oxygen control mode or the oxygen control mode, the gas circuit is cleaned, and the cleaning process is as follows: keeping the Ar gas cylinder and the Ar / 5% H2 mixed gas cylinder in the closed state; opening the first branch, making the Bi / Bi2O3 reference electrode and the Mo working electrode separate from the liquid metal container, adjusting the opening pressure of the back pressure valve to make the gas circuit in a slightly positive pressure state when the gas is flowing, and setting the first mass flow controller to the fully open state; slowly opening the Ar gas cylinder, keeping the Ar gas flowing state for 10 minutes, until the air in the gas circuit is exhausted and only contains Ar gas protection atmosphere.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] The oxygen concentration detection system of the present application passes the tail gas through the sample chamber into the liquid lead bismuth to detect the oxygen concentration dissolved in the liquid lead bismuth or lead, which is similar to the oxygen concentration in the lead bismuth or lead film layer on the surface of the sample, realizing the detection of the oxygen concentration in the lead bismuth film layer on the surface of the sample, and adjusting the flow of each mixed gas in the gas circuit according to the detection result of the oxygen concentration to control the oxygen concentration in the simulated corrosion environment to the target oxygen concentration, which can ensure accurate control of the oxygen concentration while omitting the dew point instrument in the system to reduce the system manufacturing cost. The accurate control of the target oxygen concentration in the extremely low oxygen concentration environment can be realized, and the oxygen control experiment in the extremely low oxygen concentration environment can be carried out.

[0028] Further, the flame arrester can ensure the safety of the gas circuit and prevent H2 explosion; the flame arrester is connected with the alarm, which can timely detect whether the H2 concentration is abnormal.

[0029] Further, the pressure in the gas circuit is reduced to the target pressure by the pressure reducing valve, and the impurities in the gas circuit are filtered by the filter to protect the mass flow controller.

[0030] Further, the first mass flow controller and the second mass flow controller are connected with the first ball valve and the second ball valve respectively, realizing the separate control of the on-off of the two gas circuits.

[0031] Further, the check valve can avoid the backflow of water into the flow control system. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic diagram of the overall structure of the present application.

[0033] Figure 2 is a schematic diagram of the sample chamber structure for in-situ synchrotron XRD characterization experiment of the present application.

[0034] Figure 3 is the schematic diagram of the optical path of in-situ XRD of the present application.

[0035] Wherein: 1-holed shell, 2-top window flange, 3-top window, 4-water cooling interface, 5-sample chamber air inlet, 6-sample chamber air outlet, 7-side window flange, 8-side window, 9-sample stage, 10-first bottom holed shell, 11-temperature measuring tube, 12-second bottom holed shell, 13-sample chamber heating wire, 14-Ar gas cylinder, 15-pressure reducing valve, 16-filter, 17-alarm, 18-fire arrestor, 19-Ar / 5% H2 mixed gas cylinder, 20-first one-way valve, 21-third ball valve, 22-second one-way valve, 23-low temperature constant temperature water bath box, 24-water bath bottle, 25-water bath bottle air inlet, 26-water bath bottle air outlet, 27-fourth ball valve, 28-oxygen concentration detection chamber air inlet, 29-oxygen concentration detection chamber air outlet, 30-oxygen concentration detection chamber, 31-liquid metal container, 32-oxygen concentration detection chamber heating wire, 33-rubber sealing ring, 34-Bi / Bi2O3 reference electrode, 35-Mo working electrode, 36-back pressure valve, 37-voltage recording display terminal, 38-fifth ball valve, 39-second needle valve, 40-water cooling component, 41-first needle valve, 42-gauge, 43-second ball valve, 44-first ball valve, 45-second mass flow controller, 46-flow control terminal, 47-first mass flow controller, 48-thermocouple. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0037] It should be noted that the words "front", "back", "left", "right", "up" and "down" used in the following description refer to the directions in the drawings, and the words "in" and "out" refer to the directions towards or away from the geometric center of a particular component.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this description, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0039] As Figure 1The device shown is for in-situ XRD characterization in an oxygen-controlled lead-bismuth corrosion environment according to the present invention, including a sample chamber, an oxygen concentration control system, an oxygen concentration detection system, and a water-cooling component 40.

[0040] like Figure 2 As shown, the sample chamber includes a perforated shell 1, a top viewing flange 2, a top viewing window 3, a water-cooling interface 4, a sample chamber air inlet 5, a sample chamber air outlet 6, a side viewing flange 7, a side viewing window 8, a sample stage 9, a first bottom perforated shell 10, a temperature measuring tube 11, a second bottom perforated shell 12, and a sample chamber heating wire 13. The perforated shell 1 has a four-way structure, with a top viewing window 3 at the top, side viewing windows 8 on both sides, and a first bottom perforated shell 10 at the bottom. The side viewing windows 8 and the top viewing window 3 are made of Kapton film and are fixed to the side and top of the perforated shell 1 respectively by the side viewing flange 7 and the top viewing flange 2. The two side viewing windows 8 are coaxial and the axis is in a horizontal position, through which X-rays enter and exit. The top viewing window 3 is in a vertical position and can be used for backscatter fluorescence detection. The sample stage 9 is located in the top groove of the first bottom perforated shell 10. By changing different horizontal angles... The sample stage 9 has an angle between its surface and the horizontal plane that can be changed between 0° and 15°. Four water-cooling interfaces 4 are located at the top and bottom of the perforated housing 1 on both sides, connected to the water-cooling component 40, and protect each viewing window through water-cooling circulation. The sample chamber heating wire 13 is located directly below the sample stage 9, separated from it by the first bottom perforated housing 10. The temperature measuring tube 11 is embedded in the second bottom perforated housing 12, close to the sample chamber heating wire 13. The second bottom perforated housing 12 is welded into the bottom hole of the first bottom perforated housing 10, fixing the sample chamber heating wire 13 and the temperature measuring tube 11 within the cavity formed by the second bottom perforated housing 12 and the bottom hole of the first bottom perforated housing 10. The sample chamber air inlet 5 and sample chamber air outlet 6 are located near the perforated housing 1 on both sides, and are connected to the oxygen concentration control system and the oxygen concentration detection system, respectively, to introduce an oxygen-controlled atmosphere and simulate the oxygen-controlled lead-bismuth corrosion environment.

[0041] The oxygen concentration control system includes a flow control system and a low-temperature water bath device.

[0042] The flow control system comprises an Ar gas cylinder 14, an Ar / 5% H2 mixed gas cylinder 19, a pressure reducing valve 15, a filter 16, an alarm 17, a flame arrester 18, a first ball valve 44, a second ball valve 43, a first mass flow controller 47, a second mass flow controller 45, and a flow control terminal 46; the Ar / 5% H2 mixed gas cylinder 19 is directly connected to the flame arrester 18 to ensure the safety of the gas path and prevent H2 explosion; the flame arrester 18 is further connected to the alarm 17 to timely detect whether the H2 concentration is abnormal; the Ar gas cylinder 14 and the flame arrester 18 are respectively connected to a pressure reducing valve 15 and a filter 16, and then connected to the first mass flow controller 47 and the second mass flow controller 45, respectively, to reduce the gas pressure in the gas path to the target pressure through the pressure reducing valve 15 and to filter the impurities in the gas path through the filter 16 to protect the mass flow controller; the gas flow in the Ar gas path and the Ar / 5% H2 mixed gas path is controlled through the first mass flow controller 47 and the second mass flow controller 45, respectively, and the H2 concentration in the gas path after the mixing of the two gases can be determined according to the flow of each gas path; the first mass flow controller 47 and the second mass flow controller 45 are respectively connected to the first ball valve 44 and the second ball valve 43 to realize the independent control of the on-off of the two gases; the first ball valve 44 and the second ball valve 43 are jointly connected to the first one-way valve 20 to mix the two gases and then connected to the low-temperature water bath device through the first one-way valve 20 to avoid the backflow of water into the flow control system.

[0043] The low-temperature water bath device comprises a third ball valve 21, a second one-way valve 22, a low-temperature constant-temperature water bath box 23, a water bath bottle 24, a water bath bottle gas inlet 25, a water bath bottle gas outlet 26, a fourth ball valve 27, a gas pressure gauge 42 and a first needle valve 41. The low-temperature water bath device has two gas paths. One path does not pass through the water bath bottle, passes through the third ball valve 21, controls the on-off of the path, and is mainly used for gas path cleaning and protection gas delivery when oxygen control is not performed. The other path passes through the water bath bottle 24, is connected with the water bath bottle gas inlet 25, is connected with the second one-way valve 22 to prevent water backflow, is connected with the water bath bottle gas outlet 26 through the fourth ball valve 27 to control the on-off of the path, the water bath bottle gas inlet 25 is inserted into the ultrapure water in the water bath bottle 24, so that the Ar / H2 mixed gas entering the water bath bottle 24 can be mixed with water vapor, the lowest part of the water bath bottle gas outlet 26 is higher than the horizontal surface in the water bath bottle 24, so as to avoid being inserted into the ultrapure water and prevent liquid water from directly flowing into the sample chamber, the third ball valve 21 and the fourth ball valve 27 are connected with the sample chamber gas inlet 5 through the first needle valve 41, and a gas pressure gauge 42 is connected in front of the first needle valve 41 to display the mixed gas pressure entering the sample chamber, so as to avoid high gas pressure from damaging the side window 8 and the top window 3 in the sample chamber, the water bath bottle 24 is placed in the low-temperature constant-temperature water bath box 23, the ultrapure water temperature in the water bath bottle 24 is controlled through the constant-temperature water bath, the water vapor pressure in the water bath bottle 24 is controlled, the H2 concentration output by the flow control system is combined, and the control of the H2 and H2O vapor partial pressure ratio in the gas atmosphere output by the oxygen concentration control system is realized.

[0044] The oxygen concentration detection system comprises a Bi / Bi2O3 reference electrode 34, a Mo working electrode 35, an oxygen concentration detection cabin 30, a liquid metal container 31, a thermocouple 48, a rubber sealing ring 33, an oxygen concentration detection cabin air inlet 28, an oxygen concentration detection cabin air outlet 29, an oxygen concentration detection cabin heating wire 32 and a voltage recording terminal 37; the oxygen concentration detection cabin air inlet 28 is connected with the sample cabin air outlet 6 through a second needle valve 39, and the oxygen control atmosphere is introduced into the oxygen concentration detection cabin 30; the liquid metal container 31 is arranged in the oxygen concentration detection cabin 30 and used for containing lead bismuth; the oxygen concentration detection cabin air inlet 28 should be immersed in the molten liquid lead bismuth, the oxygen control atmosphere is introduced into the liquid lead bismuth, and the oxygen dissolution reaction rapidly reaches equilibrium; the thermocouple 48 arranged on the top of the oxygen concentration detection cabin 30 should also be immersed in the molten liquid lead bismuth, the temperature of the liquid lead bismuth is measured, and the thermocouple 48 passes through the top of the oxygen concentration detection cabin 30 through the rubber sealing ring 33 to ensure the air tightness; the oxygen concentration detection cabin heating wire 32 is wound on the side wall of the oxygen concentration detection cabin 30, cooperates with the thermocouple 48 inserted into the liquid metal to control the temperature of the liquid lead bismuth to be consistent with the temperature in the sample cabin; the oxygen concentration detection cabin air outlet 29 is connected with a back pressure valve 36 through a fifth ball valve 38, so that the gas in the gas circuit is in a micro-positive pressure state and the gas in the gas circuit is not polluted by air; the Bi / Bi2O3 reference electrode 34 and the Mo working electrode 35 are arranged on the top of the oxygen concentration detection cabin 30 and pass through the top of the oxygen concentration detection cabin 30 through the rubber sealing ring 33, so as to ensure the air tightness and meet the lifting property of the electrodes; when the lead bismuth is completely melted, the Bi / Bi2O3 reference electrode 34 and the Mo working electrode 35 are lowered and inserted into the liquid lead bismuth; the voltage recording terminal 37 is connected with the Bi / Bi2O3 reference electrode 34 and the Mo working electrode 35 and used for recording and displaying the voltage value.

[0045] The working process of the application is as follows:

[0046] The device for in-situ XRD characterization in the oxygen-controlled lead bismuth corrosion environment has two working modes, namely an oxygen-controlled working mode and a non-oxygen-controlled working mode.

[0047] Regardless of the working mode, first need to be prepared by magnetron sputtering technology with lead bismuth plating sample placed on the sample stage 9, and the sample stage 9 is placed in the groove on the top of the first bottom hole shell 10, through the bolt hole, the first bottom hole shell 10 is fixed with the hole shell 1, so that the sample cabin is sealed; keep Ar gas cylinder 14, Ar / 5% H2 mixed gas cylinder 19, second ball valve 43, fourth ball valve 27 in the closed state; open the first ball valve 44, the third ball valve 21, the first needle valve 41, the second needle valve 39, the fifth ball valve 38; keep Bi / Bi2O3 type reference electrode 34 and Mo working electrode 35 in the raised state; adjust the output pressure of the pressure reducing valve 15 and the opening pressure of the back pressure valve 36 so that the gas circuit is in a slightly positive pressure state when the air is ventilated; the first mass flow controller 47 is set to fully open state through the flow control terminal 46; slowly open the Ar gas cylinder 14, and observe the air pressure gauge 42 to avoid excessive pressure in the gas circuit; keep Ar gas ventilation state for 10 minutes to ensure that the air in the gas circuit is exhausted and only contains Ar gas protective atmosphere.

[0048] When in non-oxygen control working mode, sequentially close the Ar gas cylinder 14, the first ball valve 44, the third ball valve 21, the first needle valve 41 and the second needle valve 39, and only through the sample cabin heating wire 13 and the temperature measuring tube 11 to heat the sample cabin to the target temperature, then the in-situ XRD characterization experiment can be started.

[0049] When in oxygen control working mode, first heat the oxygen concentration detection cabin 30 to the working target temperature through the oxygen concentration detection cabin heating wire 32 and the thermocouple 48, and control the temperature of the ultrapure water in the water bath bottle 24 to the target H2O vapor pressure corresponding temperature through the low-temperature constant temperature water bath box 23; lower the Bi / Bi2O3 type reference electrode 34 and the Mo working electrode 35 and immerse them in the liquid lead bismuth; after slowly opening the Ar / 5% H2 mixed gas cylinder 19, close the third ball valve 21 and open the fourth ball valve 27; set the first mass flow controller 47 and the second mass flow controller 45 to the corresponding control flow according to the target H2 concentration through the flow control terminal 46, and slowly open the second ball valve 43; obtain the corresponding dissolved oxygen concentration according to the voltage value displayed by the voltage recording display terminal 37, and finely adjust the control flow of the first mass flow controller 47 and the second mass flow controller 45 through the flow control terminal 46 until the oxygen solubility in lead bismuth stabilizes at the target oxygen concentration; after heating the sample cabin to the target temperature through the sample cabin heating wire 13 and the temperature measuring tube 11, the in-situ XRD characterization experiment can be started.

[0050] The working process of the device is as follows:

[0051] The in-situ XRD characterization device in the oxygen control lead bismuth corrosion environment has two working modes, namely oxygen control working mode and non-oxygen control working mode.

[0052] Regardless of the working mode, first need to be prepared by magnetron sputtering technology with lead bismuth plating sample placed on the sample stage 9, and the sample stage 9 is placed in the groove on the top of the first bottom hole shell 10, through the bolt hole, the first bottom hole shell 10 is fixed with the hole shell 1, so that the sample cabin is sealed; keep Ar cylinder 14, Ar / 5% H2 mixed gas cylinder 19, second ball valve 43, fourth ball valve 27 in the closed state; open the first ball valve 44, the third ball valve 21, the first needle valve 41, the second needle valve 39, the fifth ball valve 38; keep Bi / Bi2O3 type reference electrode 34 and Mo working electrode 35 in the raised state; adjust the output pressure of the pressure reducing valve 15 and the opening pressure of the back pressure valve 36 so that the gas circuit is in a slightly positive pressure state when the air is ventilated; the first mass flow controller 47 is set to fully open state through the flow control terminal 46; slowly open the Ar cylinder 14, and observe the air pressure gauge 42 to avoid excessive pressure in the gas circuit; keep Ar gas ventilation state for 10 minutes to ensure that the air in the gas circuit is exhausted and only contains Ar gas protective atmosphere.

[0053] When in non-oxygen control mode, sequentially close the Ar cylinder 14, the first ball valve 44, the third ball valve 21, the first needle valve 41 and the second needle valve 39, and only through the sample cabin heating wire 13 and the temperature measuring tube 11 to heat the sample cabin to the target temperature, then the in-situ XRD characterization experiment can be started.

[0054] When in oxygen control mode, first heat the oxygen concentration detection cabin 30 to the working target temperature through the oxygen concentration detection cabin heating wire 32 and the thermocouple 48, and control the temperature of the ultrapure water in the water bath bottle 24 to the target H2O vapor pressure corresponding temperature through the low temperature constant temperature water bath box 23; lower the Bi / Bi2O3 type reference electrode 34 and the Mo working electrode 35 and immerse them in the liquid lead bismuth; after slowly opening the Ar / 5% H2 mixed gas cylinder 19, close the third ball valve 21 and open the fourth ball valve 27; set the first mass flow controller 47 and the second mass flow controller 45 to the corresponding control flow according to the target H2 concentration through the flow control terminal 46, and slowly open the second ball valve 43; obtain the corresponding dissolved oxygen concentration according to the voltage value displayed by the voltage recording display terminal 37, and fine tune the control flow of the first mass flow controller 47 and the second mass flow controller 45 through the flow control terminal 46 until the oxygen solubility in lead bismuth stabilizes at the target oxygen concentration; after heating the sample cabin to the target temperature through the sample cabin heating wire 13 and the temperature measuring tube 11, the in-situ XRD characterization experiment can be started.

[0055] The in-situ XRD characterization experiment method includes the following steps:

[0056] (1) Simulation of lead bismuth or lead corrosion environment when in-situ characterization (preparation of lead bismuth or lead film layer on sample surface): a certain thickness of lead bismuth or lead plating layer is prepared on the surface of the sample to be in-situ measured by metal coating technology with lead bismuth or lead as the target material; the thickness of the plating layer needs to be determined according to the temperature, the energy intensity of the experimental light source and the maximum X-ray attenuation rate, and is generally in the range of 2 to 5 μm; the metal coating technology can include magnetron sputtering method, evaporation method, etc.

[0057] (2) First, place the sample after plating on the sample table 9, process the sample table 9 to a 0°-15° slope, converge the light spot of the light beam to 3-5 μm size, and horizontally incident the light beam so that the X-ray has a 0°-15° incident angle with the sample surface; under this incident angle, the X-ray can penetrate the target thickness of the plating layer and diffract on the sample surface to realize XRD characterization of the corrosion surface and obtain a diffraction image, as shown in the specific process of Figure 3

[0058] At the same time, the oxygen control system adjusts the oxygen partial pressure of the atmosphere environment introduced into the sample chamber, and tests and monitors the lead bismuth dissolved oxygen concentration in the similar atmosphere environment after the sample chamber, so as to control the oxygen concentration in the sample corrosion environment during the characterization process and achieve the purpose of in-situ XRD characterization experiment in the precise oxygen concentration lead / lead bismuth environment.

[0059] In the process of step (2), the above device is in oxygen control mode or non-oxygen control mode.

[0060] The present application realizes the preparation of lead bismuth or lead film layer on the surface of the sample by metal coating technology, so that the X-ray can still obtain the corrosion behavior information that may occur on the corrosion surface under the high temperature film after penetrating the film, and the film prepared by the method has better adhesion and is not easy to fall off the sample surface to change the simulated corrosion environment.

[0061] The micro-focusing XRD used in the present application has the advantage of small light spot (3 μm), which can scan the micro area of the sample surface and obtain the XRD diffraction signals of each position on the sample surface with high resolution.

[0062] The present application realizes the acquisition of surface layer information by small angle grazing of X-ray in combination with the lead bismuth or lead micro-film coating technology on the surface of the sample, and realizes the acquisition of information of different surface layer depths on the sample surface by adjusting the incident angle of the light beam.

[0063] ​It is to be understood that the phrases such as "first" and "second", and the like, can merely be used for the purposes of differentiation, and do not require or imply an actual relationship or order between or among the entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0064] It is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and many applications other than the examples provided herein will be apparent to those of skill in the art upon reading the above description. The scope of the application should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for the purpose of the present disclosure. Any incorporation by reference of any article or reference which has not been available to the general public through no fault of its own is expressly disclaimed. Any incorporation by reference of patent applications or publications of the applicant which has not been available to the general public through no fault of its own is expressly disclaimed.

Claims

1. A device for in-situ XRD characterization of oxygen-controlled lead-bismuth corrosion environment, characterized by, The oxygen concentration control system comprises a flow control system and a low-temperature water bath device. The sample chamber is hollow and provided with a sample chamber air inlet (5) and a sample chamber air outlet (6) on two sides, and is internally provided with a sample table (9). The sample chamber comprises a shell (1) with holes, which is a four-way structure, is provided with a top window (3) at the top, and the axis of the top window (3) is in a vertical position for back scattered fluorescence detection. The shell (1) with holes is provided with side windows (8) on two sides, and the two side windows (8) are coaxial and the axis is in a horizontal position, X-rays are shot in and out from here, and the bottom is provided with a first bottom shell (10) with holes. The sample table (9) is located at the top of the first bottom shell (10) with holes. The bottom of the first bottom shell (10) with holes is provided with a sample chamber heating wire (13) and a temperature measuring tube (11). The water cooling interface (4) is four in number and is located at the top and bottom near the two sides of the shell (1) with holes. The sample chamber air inlet (5) and the sample chamber air outlet (6) are connected with the oxygen concentration control system and the oxygen concentration detection system respectively, and oxygen control atmosphere is introduced to realize the simulation of the oxygen control lead bismuth corrosion environment. The flow control system comprises an Ar gas cylinder (14) and an Ar / 5% H2 mixed gas cylinder (19). The output ends of the Ar gas cylinder (14) and the Ar / 5% H2 mixed gas cylinder (19) are respectively connected with the input ends of a first mass flow controller (47) and a second mass flow controller (45). The low-temperature water bath device comprises a low-temperature constant temperature water bath box (23) and a water bath bottle (24). The water bath bottle (24) is provided with ultrapure water, and is arranged in the low-temperature constant temperature water bath box (23). The water bath bottle (24) is provided with a water bath bottle air inlet (25) and a water bath bottle air outlet (26). The output ends of the first mass flow controller (47) and the second mass flow controller (45) are mixed and divided into two branches. The first branch is connected with the sample chamber air inlet (5), and the second branch is connected with the water bath bottle air inlet (25). The water bath bottle air outlet (26) is connected with the sample chamber air inlet (5). The oxygen concentration detection system comprises an oxygen concentration detection cabin (30) and a liquid metal container (31) internally provided with lead bismuth, the oxygen concentration detection cabin (30) is sealingly arranged, internally provided with a heating device, the liquid metal container (31) is located in the oxygen concentration detection cabin (30), an oxygen concentration detection cabin air inlet (28), an oxygen concentration detection cabin air outlet (29), a Bi / Bi2O3 reference electrode (34) and a Mo working electrode (35) are inserted into the top of the oxygen concentration detection cabin (30), the oxygen concentration detection cabin air inlet (28) is connected with the sample cabin air outlet (6), the oxygen concentration detection cabin air inlet (28) is immersed in the molten liquid lead bismuth, the oxygen concentration detection cabin (30) is provided with a thermocouple (48) and an oxygen concentration detection cabin heating wire (32), the oxygen concentration detection cabin heating wire (32) is located between the oxygen concentration detection cabin (30) and the liquid metal container (31), the thermocouple (48) is inserted into the lead bismuth, the thermocouple (48) installed at the top of the oxygen concentration detection cabin (30) is immersed in the molten liquid lead bismuth, the oxygen concentration detection cabin heating wire (32) cooperates with the thermocouple (48) inserted into the liquid metal to control the temperature of the liquid lead bismuth to be consistent with the temperature in the sample cabin, the oxygen concentration detection cabin air outlet (29) is connected with a back pressure valve (36), a voltage recording terminal (37) is connected with the Bi / Bi2O3 reference electrode (34) and the Mo working electrode (35) for recording and displaying the voltage value, and the corresponding dissolved oxygen concentration is obtained according to the voltage value.

2. The device for in-situ XRD characterization of oxygen-controlled lead-bismuth corrosion environment according to claim 1, characterized in that, A flame arrester (18) is arranged between the Ar / 5% H2 mixed gas cylinder (19) and the second mass flow controller (45), and the flame arrester (18) is connected with an alarm (17).

3. The apparatus for in-situ XRD characterization of lead bismuth corrosion environment under oxygen control according to claim 1, characterized in that, A pressure reducing valve (15) and a filter (16) are arranged between the Ar gas cylinder (14) and the first mass flow controller (47) and between the Ar / 5% H2 mixed gas cylinder (19) and the second mass flow controller (45).

4. The apparatus for in-situ XRD characterization of lead bismuth corrosion environment under oxygen control according to claim 1, characterized in that, The output ends of the first mass flow controller (47) and the second mass flow controller (45) are respectively connected with a first ball valve (44) and a second ball valve (43).

5. The apparatus for in-situ XRD characterization of lead bismuth corrosion environment under oxygen control according to claim 1, characterized in that, The output mixed path of the first mass flow controller (47) and the second mass flow controller (45) is connected with a first check valve (20), and a water bath bottle air inlet (25) is connected with a second check valve (22).

6. An in-situ XRD characterization method of lead bismuth corrosion environment based on the device of any one of claims 1-5, characterized in that, The working mode comprises a non-oxygen control working mode and an oxygen control working mode; The coated sample is placed on a sample table (9), and the sample table (9) is processed to have a 0°-15° slope; When in the non-oxygen control working mode, the Ar gas cylinder (14) and the Ar / 5% H2 mixed gas cylinder (19) are closed, the sample cabin is heated to the target temperature, and then the in-situ XRD characterization experiment is started. When in oxygen control mode, the oxygen concentration detection chamber (30) is heated to the target working temperature, and the temperature of the ultrapure water in the water bath bottle (24) is controlled to the temperature corresponding to the target H2O vapor pressure by the low-temperature constant-temperature water bath box (23); the Bi / Bi2O3 reference electrode (34) and the Mo working electrode (35) are immersed in liquid lead bismuth; after slowly opening the Ar / 5% H2 mixed gas cylinder (19), the first branch is closed and the second branch is opened; the first mass flow controller (47) and the second mass flow controller (45) are set to the corresponding control flow according to the target H2 concentration; the corresponding dissolved oxygen concentration is obtained according to the voltage value of the Bi / Bi2O3 reference electrode (34) and the Mo working electrode (35), and the control flow of the first mass flow controller (47) and the second mass flow controller (45) is fine-tuned until the oxygen solubility in lead bismuth stabilizes at the target oxygen concentration; after heating the sample chamber to the target temperature, in-situ XRD characterization experiment is started; The in-situ XRD characterization experiment process is: converging the light spot of the light beam to 3-5 μm size, horizontally shooting the light beam into the sample chamber, so that the X-ray has an incident angle of 0°-15° with the sample surface, the X-ray can penetrate the target thickness of the plated layer under this incident angle, and diffraction occurs on the sample surface to realize XRD characterization of the corrosion surface and obtain a diffraction image.

7. The method according to claim 6, wherein the method is characterized in that, The sample plating process is: taking lead bismuth or lead as the target material, preparing a certain thickness of lead bismuth or lead plating layer on the surface of the sample to be in-situ measured by metal coating technology; the thickness of the plating layer needs to be determined according to the temperature, the energy intensity of the experimental light source and the maximum X-ray attenuation rate.

8. The method for in-situ XRD characterization of the oxygen-controlled Pb-Bi corrosion environment according to claim 6, characterized in that, Before the non-oxygen control mode or the oxygen control mode, the gas circuit is cleaned, and the cleaning process is: keeping the Ar cylinder (14) and the Ar / 5% H2 mixed gas cylinder (19) closed; opening the first branch to separate the Bi / Bi2O3 reference electrode (34) and the Mo working electrode (35) from the liquid metal container (31), adjusting the opening pressure of the back pressure valve (36) to make the gas circuit in a slightly positive pressure state when ventilating, and setting the first mass flow controller (47) to a completely open state; slowly opening the Ar cylinder (14) and keeping the Ar gas ventilating state for 10 minutes until the air in the gas circuit is exhausted and only Ar gas protective atmosphere is left.

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