Radiation-resistant infrared radiation coating, preparation method and product

Abstract

Provided is a radiation-resistant infrared radiation coating for a space nuclear reactor, the chemical composition of the coating includes, by mass percentage: Cr 2 O 3 54‑60wt%, NiO 24‑29wt%, SiO 2 2‑3wt%, TiO 2 4‑5wt%, La 2 O 3 5‑6wt% and SiC 1‑3wt%, the sum of the mass percentages of each component being 100%. A method for preparing a radiation-resistant infrared radiation coating for a space nuclear reactor is also provided, comprising the following steps: mixing raw material powders in proportion and then calcining them, and then preparing the coating by a plasma spraying process, wherein the raw material powders include powders prepared according to the following mass percentages: Cr 2 O 3 54‑60wt%, NiO 24‑29wt%, SiO 2 2‑3wt%, TiO 2 4‑5wt%, La 2 O 3 5-6wt% SiC and 1-3wt% SiC, the sum of the mass percentages of each component is 100%. Also provided is a product including a coating, comprising: a substrate; the above-mentioned radiation-resistant infrared radiation coating; and a bonding bottom layer, wherein the bonding bottom layer is arranged between the substrate and the coating. The radiation-resistant infrared radiation coating of the present invention has good radiation resistance in a strong gamma and neutron environment.

Description

Technical Field

[0001] The present disclosure relates to the field of nuclear reactions, and in particular to a radiation-resistant infrared radiation coating, a preparation method and a product. Background Art

[0002] High emissivity coating is a coating with high emissivity in all normal directions. This coating can absorb thermal radiation and emit a large amount of infrared rays, so it is also called infrared radiation coating. In space nuclear reactors, infrared radiation coatings have two main functions: the first is to use its good thermal radiation characteristics to discharge the waste heat of the nuclear reactor into the space environment; the second is to simulate the space environment when conducting ground tests. However, due to the large amount of strong gamma rays and neutron radiation in space nuclear reactors, infrared radiation coatings are required to have good radiation resistance and still have high emissivity in strong gamma and neutron environments. Summary of the invention

[0003] In one aspect, a radiation-resistant infrared radiation coating for a space nuclear reactor is provided, wherein the chemical composition of the coating comprises, by mass percentage, 54-60wt% of Cr2O3, 24-29wt% of NiO, 2-3wt% of SiO2, 4-5wt% of TiO2, 5-6wt% of La2O3 and 1-3wt% of SiC, and the sum of the mass percentages of the components is 100%.

[0004] On the other hand, a method for preparing a radiation-resistant infrared radiation coating for a space nuclear reactor is provided, comprising the following steps: mixing raw material powders in proportion and then calcining them, and then preparing the coating by a plasma spraying process, wherein the raw material powders include powders prepared according to the following mass percentages: Cr2O3 54-60wt%, NiO 24-29wt%, SiO2 2-3wt%, TiO2 4-5wt%, La2O3 5-6wt% and SiC 1-3wt%, and the sum of the mass percentages of each component is 100%.

[0005] In another aspect, a product including a coating is provided, the product including: a substrate; the irradiation-resistant infrared radiation coating as described above; and a bonding primer, wherein the bonding primer is disposed between the substrate and the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Other objects and advantages of the present disclosure will be apparent from the following description of the present disclosure with reference to the accompanying drawings, and will help to have a comprehensive understanding of the present disclosure.

[0007] Figure 1 is a schematic diagram of the working principle of the radiation-resistant infrared radiation coating according to an embodiment of the present disclosure;

[0008] Figure 2is a flow chart of preparation and testing of a radiation-resistant infrared radiation coating for a space nuclear reactor according to an embodiment of the present disclosure;

[0009] Figure 3 is a schematic diagram of a testing device according to an embodiment of the present disclosure;

[0010] Figure 4 (a) is an appearance diagram of the radiation-resistant infrared radiation coating according to Example 1 of the present disclosure before irradiation; and

[0011] Figure 4 (b) is an appearance diagram of the radiation-resistant infrared radiation coating after irradiation according to Example 1 of the present disclosure. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0013] Unless otherwise defined, the technical terms or scientific terms used in this disclosure should be understood by ordinary technicians in the field. "First", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprising" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0014] In this document, unless otherwise specified, directional terms such as "upper", "lower", "left", "right", "inner", "outer", etc. are used to indicate the orientation or positional relationship based on the drawings, and are only for the convenience of describing the present disclosure, and do not indicate or imply that the device, element or component referred to must have a specific orientation, be constructed or operate in a specific orientation. It should be understood that when the absolute position of the described object changes, the relative positional relationship they represent may also change accordingly. Therefore, these directional terms should not be understood as limiting the present disclosure.

[0015] The radiation characteristics of infrared radiation materials depend on the temperature and emissivity of the material, among which emissivity is an important characteristic value of infrared radiation materials. Commonly used infrared radiation materials with high emissivity include carbon, carbide, oxide, silicide and nickel-chromium spinel. There are two main uses of infrared radiation coatings in space nuclear reactors: the first is to use its good thermal radiation characteristics to discharge the waste heat of nuclear reactors into the space environment; the second is to simulate the space environment when conducting ground tests.

[0016] An embodiment of the present disclosure provides a radiation-resistant infrared radiation coating for a space nuclear reactor, wherein the chemical composition of the coating comprises, by mass percentage, Cr2O3 54-60wt%, NiO 24-29wt%, SiO2 2-3wt%, TiO2 4-5wt%, La2O3 5-6wt% and SiC 1-3wt%, and the sum of the mass percentages of the various components is 100%.

[0017] In an embodiment of the present disclosure, the thickness of the coating is 60-100 μm, and this coating thickness can balance the radiation resistance of the coating and the bonding strength between the coating and the substrate, so as to maximize the performance of the coating in the reactor.

[0018] In the embodiments of the present disclosure, the thermal radiation coefficient of the coating is 0.87-0.92, which can meet the actual demand for high emissivity of special space nuclear reactors.

[0019] In an embodiment of the present disclosure, the density of the coating is ≥90% TD.

[0020] In an embodiment of the present disclosure, the irradiation includes gamma irradiation and neutron irradiation.

[0021] It should be noted that there are a large number of rays in space nuclear reactors, among which gamma irradiation and neutron irradiation are two types of rays that have a greater impact on infrared radiation coatings. Therefore, the irradiation in the embodiments of the present disclosure mainly includes gamma irradiation and neutron irradiation.

[0022] The embodiment of the present disclosure also provides a method for preparing a radiation-resistant infrared radiation coating for a space nuclear reactor, comprising the following steps: mixing raw material powders in proportion and then calcining them, and then using a plasma spraying process to prepare the coating, wherein the raw material powders include powders prepared according to the following mass percentages: Cr2O3 54-60wt%, NiO 24-29wt%, SiO2 2-3wt%, TiO2 4-5wt%, La2O3 5-6wt% and SiC 1-3wt%, and the sum of the mass percentages of each component is 100%. Plasma spraying is a method for preparing a coating that heats and accelerates the spraying material so that the material reaches a molten or highly plastic state and has a certain speed when it hits the surface of the substrate, and its heat source is a plasma flame flow. The spraying material hits the surface of the substrate at high speed, and due to its certain kinetic energy and plasticity, it will spread out under the action of the impact, and countless particles will hit the surface of the substrate one after another and spread out, forming a layered structure. Plasma flame flow has the characteristics of high flame flow speed and good stability. In addition, plasma spraying uses electricity as the fundamental source of heat, and the voltage and current are both controllable, so it also has the characteristics of good adjustability. Due to the above characteristics, the plasma spraying process is particularly suitable for the spraying of high melting point materials such as ceramics.

[0023] It should be noted that plasma spraying requires sandblasting and preheating of the substrate surface before use. Sandblasting helps to increase the surface roughness of the substrate and plays a cleaning role, which can improve the bonding strength between the substrate and the coating. Preheating can effectively reduce cracking and shedding of the coating. The specific parameters of sandblasting and preheating can be selected according to actual conditions, and are not limited to the embodiments of the present disclosure.

[0024] In the embodiments of the present disclosure, the calcination temperature is 1000-1300° C., the heating rate is 3° C. / min, and the holding time is 10-30 minutes.

[0025] The embodiment of the present disclosure also provides a product including a coating, the product including: a substrate; the above-mentioned radiation-resistant infrared radiation coating; and a bonding bottom layer, wherein the bonding bottom layer is arranged between the substrate and the coating. The substrate can be selected according to the actual situation and when the coating is sprayed at different positions in the reactor according to actual needs. The embodiment of the present disclosure does not limit this.

[0026] In an embodiment of the present disclosure, the bonding strength between the radiation-resistant infrared radiation coating and the substrate is ≥8MPa.

[0027] In the disclosed embodiment, the thickness of the bonding bottom layer of the coating is 10-15 μm.

[0028] It should be noted that, since the substrate and the infrared radiation resistant coating have great differences in chemical bonds, crystal structures, and thermophysical properties, in order to improve the bonding strength between the substrate and the coating and alleviate the difference in physical properties between the two, it is necessary to spray a layer of bonding primer on the substrate. The composition of the bonding primer can be selected according to the composition of the substrate and the coating. The disclosed embodiments do not limit the type of bonding primer.

[0029] Figure 1 It is a schematic diagram of the working principle of the radiation-resistant infrared radiation coating according to an embodiment of the present disclosure.

[0030] like Figure 1 As shown, a space nuclear reactor 4 generates a large amount of waste heat during operation, and the radiation-resistant infrared radiation coating 1 uses its good thermal radiation characteristics to discharge the waste heat of the nuclear reactor into the space environment. At the same time, in order to improve the bonding strength between the radiation-resistant infrared radiation coating 1 and the substrate 3, a bonding bottom layer 2 is prepared between the two as a transition.

[0031] Figure 2 The flowchart of the preparation and testing of the radiation-resistant infrared radiation coating for the space nuclear reactor according to the embodiment of the present disclosure is schematically shown.

[0032] like Figure 2 As shown, in the disclosed embodiment, the preparation and testing of the radiation-resistant infrared radiation coating requires first determining the composition of the coating, selecting the process for preparing the coating, and then preparing the coating sample that needs to be irradiated in the pile. Then, it is necessary to determine the irradiation plan according to the actual needs of the space nuclear reactor, and design the corresponding irradiation device to facilitate the delivery of the sample into the pile for irradiation. After the irradiation is completed, the irradiated sample needs to be tested and analyzed to determine the changes in its performance before and after irradiation. Since the induced radioactivity of the sample after irradiation is strong, a special testing device needs to be established.

[0033] Figure 3 is a schematic diagram of a testing device according to an embodiment of the present disclosure.

[0034] like Figure 3 As shown, when the coating sample needs to be sent into the reactor for irradiation experiment, it is necessary to first align the centering device 10 of the test device with the process hole of the reactor, turn the rotary shielding plug 9, and open the opening. Connect the push rod 5 and the manipulator 6, put the coating sample into the sample box 7, and push the sample box forward to enter the reactor. Use the manipulator 6 to put the coating sample into the specified position to perform gamma irradiation and neutron irradiation on the coating sample. After irradiation, use the manipulator 6 to put the coating sample back into the sample box 7, retract the push rod 5, return the sample box 7 to the lead tank 8, close the rotary shielding plug 9, and then put the sample into the isolation chamber for testing.

[0035] The radiation resistance performance of the radiation-resistant infrared radiation coating of the present application will be described in detail below in combination with embodiments and related experiments.

[0036] Example 1

[0037] In this embodiment, the plasma spray coating has a thickness of 60 μm, a thermal radiation coefficient before irradiation of 0.9102, and a bonding strength of 12.6 MPa.

[0038] Irradiation test parameters: fast neutron (>0.1Mev) injection 6.87E+18n / cm 2 , γ dose 1.57E+8Gy, irradiation time 72h.

[0039] The tests after irradiation are as follows:

[0040] (1) Appearance inspection: There is no obvious change in appearance before and after irradiation.

[0041] Figure 4 (a) is an appearance diagram of the radiation-resistant infrared radiation coating according to Example 1 of the present disclosure before irradiation. Figure 4 (b) is an appearance diagram of the radiation-resistant infrared radiation coating after irradiation according to Example 1 of the present disclosure.

[0042] like Figure 4 As shown in (a) and (b), it can be seen that there is no obvious change in the appearance of the coating before and after irradiation, indicating that the prepared infrared radiation coating has good radiation resistance and the irradiation does not cause obvious damage to the coating surface.

[0043] (2) Thermal radiation coefficient inspection: The thermal radiation coefficient of the irradiated samples was inspected using a Fourier transform infrared spectrometer. The thermal radiation coefficient of the coating after irradiation was in the range of 0.87-0.92, and the test results met the design requirements.

[0044] (3) Adhesion strength: The coating adhesion of the irradiated samples was checked using Posi Test AT-A, a special adhesion measurement device. The adhesion strength between the coating and the substrate after irradiation was ≥8 MPa, which met the design requirements.

[0045] Example 2

[0046] In this embodiment, the plasma spray coating has a thickness of 100 μm, a thermal radiation coefficient before irradiation of 0.8905, and a bonding strength of 18.6 MPa.

[0047] Irradiation test parameters: fast neutron (>0.1Mev) injection 1.14E+19n / cm 2 , γ dose 5.2E+8Gy, irradiation time 240h.

[0048] The tests after irradiation are as follows:

[0049] (1) Appearance inspection: There is no obvious change in appearance before and after irradiation.

[0050] (2) Thermal radiation coefficient inspection: The thermal radiation coefficient of the irradiated samples was inspected using a Fourier transform infrared spectrometer. The thermal radiation coefficient of the coating after irradiation was in the range of 0.87-0.92, and the test results met the design requirements.

[0051] (3) Adhesion strength: The coating adhesion of the irradiated samples was checked using Posi Test AT-A, a special adhesion measurement device. The adhesion strength between the coating and the substrate after irradiation was ≥8 MPa, which met the design requirements.

[0052] According to the above description, the radiation-resistant coating of the embodiment of the present disclosure has good radiation resistance and still has high emissivity in strong gamma and neutron environments.

[0053] Although some embodiments according to the overall technical concept of the present disclosure have been shown and described, those skilled in the art will appreciate that changes may be made to these embodiments without departing from the principles and spirit of the overall technical concept of the present disclosure, and the scope of the present disclosure is defined by the claims and their equivalents.

Claims

1. A radiation-resistant infrared radiation coating for a space nuclear reactor, characterized in that: The chemical composition of the coating includes, by mass percentage, Cr2O3 54-60wt%, NiO 24-29wt%, SiO2 2-3wt%, TiO2 4-5wt%, La2O35-6wt% and SiC 1-3wt%, and the sum of the mass percentages of the above components is 100%; The thickness of the coating is 60-100 μm, and the thickness of the coating can balance the radiation resistance of the coating and the bonding strength between the coating and the substrate; The thermal radiation coefficient of the coating is 0.87-0.92, which can meet the actual demand for high emissivity of special space nuclear reactors.

2. The radiation-resistant infrared radiation coating according to claim 1, characterized in that: The irradiation includes gamma irradiation and neutron irradiation.

3. A method for preparing a radiation-resistant infrared radiation coating for a space nuclear reactor according to claim 1, characterized in that: The following steps are involved: The raw material powders are mixed in proportion and then calcined, and then the coating is prepared using a plasma spraying process. The raw material powder includes powders prepared according to the following mass percentages: Cr2O3 54-60wt%, NiO 24-29wt%, SiO2 2-3wt%, TiO2 4-5wt%, La2O3 5-6wt% and SiC 1-3wt%, and the sum of the mass percentages of the above components is 100%.

4. The preparation method according to claim 3, characterized in that: The calcination temperature is 1000-1300° C., the heating rate is 3° C. / min, and the heat preservation time is 10-30 minutes.

5. An article comprising a coating, characterized in that The product comprises: matrix; The irradiation-resistant infrared radiation coating according to claim 1 or 2; and Bonding the bottom layer, Wherein, the bonding bottom layer is arranged between the substrate and the coating.

6. The product according to claim 5, characterized in that The bonding strength between the radiation-resistant infrared radiation coating and the substrate is ≥8MPa.

7. The product according to claim 5, characterized in that The thickness of the bonding bottom layer is 10-15 μm.

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