A nuclear reactor coating material

Abstract

The application discloses a kind of nuclear reactor coating materials.For improving the surface performance of zirconium alloy in nuclear reactor, Cr base layer, CrN binding layer, CrNiN top layer are prepared on its surface.Research shows, with the increase of Ni element content in CrNiN top layer, the corrosion resistance of coating presents first promotion and then reduces the trend, the binding strength of coating presents first promotion and then tends to be stable trend.Considering production cost and material performance, the optimal test sample in self-corrosion current density is 1.62x10 ‑9 A·cm ‑2 , binding strength is 35.9MPa.In addition, although the binding strength of coating material is hardly affected by liquid nitrogen treatment, but can further improve its corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coating, in particular to a nuclear reactor coating material. BACKGROUND

[0002] The physical process that an atomic nucleus is transformed into another atomic nucleus after being hit by other particles or atomic nuclei with certain energy is called nuclear reaction. The nuclear reactor is irradiated by the high-flux neutron stream generated by the fission of U or Pu as nuclear fuel, and the target nucleus after absorbing the neutron changes to produce unstable radionuclides. During the reaction process, the nuclear fuel cladding is subjected to high temperature, high pressure, and high chemical activity environment for years, and is also subjected to strong irradiation. Due to the advantages of low neutron absorption cross section, strong corrosion resistance, low linear expansion coefficient, and good thermal conductivity, Zr alloy is widely used in nuclear fuel cladding. However, if a nuclear leakage accident occurs, the cooling water will quickly turn into water vapor and react with the Zr alloy to produce hydrogen, which will explode when the hydrogen concentration reaches a certain level. In order to reduce such risks, surface coating modification of Zr alloy is an effective method. SUMMARY

[0003] The purpose of the present application is to provide a nuclear reactor coating material, which has excellent corrosion resistance and bonding strength.

[0004] The technical scheme of the present application is as follows:

[0005] The preparation of a nuclear reactor coating material includes the following steps:

[0006] Pre-treatment: Zr-4 alloy is selected as the substrate, and sandpaper with mesh sizes of 100, 400, 1200, and 2000 is used for polishing treatment in sequence, 18-20wt% hydrochloric acid solution is used for acid pickling treatment, 22-25wt% sodium carbonate solution is used for oil removal treatment, anhydrous ethanol is used to remove the surface residual liquid, and the substrate is dried for use;

[0007] Preparation of Cr primer layer: in a magnetron sputtering coating machine, Cr is used as the target material and argon gas is used as the working gas to prepare the Cr primer layer on the surface of the substrate. The working pressure during sputtering is 0.8-1.0Pa, the sputtering time is 60-75min, the sputtering power is 100-120W, the target-substrate distance is 8-10cm, and the argon gas flow is 20-25sccm;

[0008] Preparation of CrN bonding layer: In a magnetron sputtering coating machine, Cr is used as the target material, and argon and nitrogen are used as the working gas to prepare the CrN bonding layer. During the sputtering process, the working pressure is 0.5-0.8 Pa, the sputtering time is 90-120 min, the sputtering power is 120-150 W, the target-substrate distance is 8-10 cm, the argon flow rate is 20-25 sccm, and the nitrogen flow rate is 20-25 sccm.

[0009] Preparation of CrNiN top layer: In a magnetron sputtering coating machine, Cr-Ni composite material is used as the target material, and the mass percentage of Ni in the target material is 13%-36%. Argon and nitrogen are used as the working gas to prepare the CrNiN top layer. During the sputtering process, the working pressure is 0.5-0.8 Pa, the sputtering time is 180-210 min, the sputtering power is 180-200 W, the target-substrate distance is 8-10 cm, the argon flow rate is 20-25 sccm, and the nitrogen flow rate is 30-40 sccm.

[0010] Vacuum annealing treatment: The Zr-4 alloy containing the coating material is placed in a vacuum annealing furnace for vacuum annealing treatment. The annealing time is 3-5 h, and the annealing temperature is 400-420℃.

[0011] Preferably, the concentration of the hydrochloric acid solution is 18wt%.

[0012] Preferably, the concentration of the sodium carbonate solution is 22wt%.

[0013] Preferably, the annealing time is 3h.

[0014] Preferably, the annealing temperature is 420℃.

[0015] Preferably, the mass percentage of Ni in the target material is 26%.

[0016] In order to improve the surface performance of zirconium alloy in a nuclear reactor, the Cr base layer, the CrN bonding layer, and the CrNiN top layer are prepared on the surface of the zirconium alloy. Research shows that, with the increase of the content of Ni element in the CrNiN top layer, the corrosion resistance of the coating first increases and then decreases, and the bonding strength of the coating first increases and then tends to be stable. Considering the production cost and material performance, the self-corrosion current density of the optimal test sample is 1.62x10 -9 A·cm -2 , and the bonding strength is 35.9MPa. In addition, although the liquid nitrogen treatment of the coating material has little effect on the bonding strength, it can further improve the corrosion resistance of the coating material. DETAILED DESCRIPTION

[0017] The technical effects of the present application are verified by specific examples below, but the embodiments of the present application are not limited thereto.

[0018] Example 1

[0019] Pre-treatment: Zr-4 alloy was selected as the substrate, and was polished with sandpaper of 100, 400, 1200 and 2000 grits in sequence, and was subjected to acid washing treatment with 18wt% hydrochloric acid solution, oil removal treatment with 25wt% sodium carbonate solution, and surface liquid removal with anhydrous ethanol, and was dried for use;

[0020] Preparation of Cr underlayer: Cr was used as the target material, and argon was used as the working gas in a magnetron sputtering coating machine to prepare the Cr underlayer on the surface of the substrate. The working pressure during sputtering was 0.8 Pa, the sputtering time was 60 min, the sputtering power was 120 W, the target-substrate distance was 8 cm, and the argon flow rate was 20 sccm;

[0021] Preparation of CrN binding layer: Cr was used as the target material, and argon and nitrogen were used as the working gases in a magnetron sputtering coating machine to prepare the CrN binding layer. The working pressure during sputtering was 0.5 Pa, the sputtering time was 90 min, the sputtering power was 150 W, the target-substrate distance was 8 cm, the argon flow rate was 20 sccm, and the nitrogen flow rate was 20 sccm;

[0022] Preparation of CrNiN top layer: Cr-Ni composite material (the mass fraction of Ni in the target material was 13%) was used as the target material, and argon and nitrogen were used as the working gases in a magnetron sputtering coating machine to prepare the CrNiN top layer. The working pressure during sputtering was 0.5 Pa, the sputtering time was 180 min, the sputtering power was 180 W, the target-substrate distance was 8 cm, the argon flow rate was 20 sccm, and the nitrogen flow rate was 30 sccm;

[0023] Vacuum annealing treatment: the Zr-4 alloy containing the coating material was placed in a vacuum annealing furnace for vacuum annealing treatment. The annealing time was 3 h, and the annealing temperature was 420℃.

[0024] Example 2

[0025] Pre-treatment: Zr-4 alloy was selected as the substrate, and was polished with sandpaper of 100, 400, 1200 and 2000 grits in sequence, and was subjected to acid washing treatment with 18wt% hydrochloric acid solution, oil removal treatment with 25wt% sodium carbonate solution, and surface liquid removal with anhydrous ethanol, and was dried for use;

[0026] Preparation of Cr underlayer: Cr was used as the target material, and argon was used as the working gas in a magnetron sputtering coating machine to prepare the Cr underlayer on the surface of the substrate. The working pressure during sputtering was 0.8 Pa, the sputtering time was 60 min, the sputtering power was 120 W, the target-substrate distance was 8 cm, and the argon flow rate was 20 sccm;

[0027] Preparation of CrN bonding layer: In the magnetron sputtering coating machine, Cr is used as the target material, and argon and nitrogen are used as the working gas to prepare the CrN bonding layer. The working pressure during sputtering is 0.5 Pa, the sputtering time is 90 min, the sputtering power is 150 W, the target-substrate distance is 8 cm, the argon flow rate is 20 sccm, and the nitrogen flow rate is 20 sccm.

[0028] Preparation of CrNiN top layer: In the magnetron sputtering coating machine, Cr-Ni composite material is used as the target material (the mass fraction of Ni in the target material is 20%), and argon and nitrogen are used as the working gas to prepare the CrNiN top layer. The working pressure during sputtering is 0.5 Pa, the sputtering time is 180 min, the sputtering power is 180 W, the target-substrate distance is 8 cm, the argon flow rate is 20 sccm, and the nitrogen flow rate is 30 sccm.

[0029] Vacuum annealing treatment: The Zr-4 alloy containing the coating material is placed in a vacuum annealing furnace for vacuum annealing treatment. The annealing time is 3 h, and the annealing temperature is 420℃.

[0030] Example 3

[0031] Pre-treatment: Zr-4 alloy is selected as the substrate, and sandpaper with grits of 100, 400, 1200, and 2000 is used for polishing treatment in sequence. An 18wt% hydrochloric acid solution is used for acid pickling treatment, a 25wt% sodium carbonate solution is used for oil removal treatment, anhydrous ethanol is used to remove residual liquid on the surface, and the substrate is dried for use.

[0032] Preparation of Cr primer layer: In the magnetron sputtering coating machine, Cr is used as the target material, and argon is used as the working gas to prepare the Cr primer layer on the surface of the substrate. The working pressure during sputtering is 0.8 Pa, the sputtering time is 60 min, the sputtering power is 120 W, the target-substrate distance is 8 cm, and the argon flow rate is 20 sccm.

[0033] Preparation of CrN bonding layer: In the magnetron sputtering coating machine, Cr is used as the target material, and argon and nitrogen are used as the working gas to prepare the CrN bonding layer. The working pressure during sputtering is 0.5 Pa, the sputtering time is 90 min, the sputtering power is 150 W, the target-substrate distance is 8 cm, the argon flow rate is 20 sccm, and the nitrogen flow rate is 20 sccm.

[0034] Preparation of CrNiN top layer: In the magnetron sputtering coating machine, Cr-Ni composite material is used as the target material (the mass fraction of Ni in the target material is 26%), and argon and nitrogen are used as the working gas to prepare the CrNiN top layer. The working pressure during sputtering is 0.5 Pa, the sputtering time is 180 min, the sputtering power is 180 W, the target-substrate distance is 8 cm, the argon flow rate is 20 sccm, and the nitrogen flow rate is 30 sccm.

[0035] Vacuum annealing treatment: the Zr-4 alloy containing coating material was placed in a vacuum annealing furnace for vacuum annealing treatment, the annealing time was 3h, and the annealing temperature was 420℃.

[0036] Example 4

[0037] Pre-treatment: Zr-4 alloy was selected as the substrate, and sandpaper with mesh sizes of 100, 400, 1200 and 2000 was used for polishing treatment in sequence, 18wt% hydrochloric acid solution was used for acid pickling treatment, 25wt% sodium carbonate solution was used for oil removal treatment, anhydrous ethanol was used to remove the residual liquid on the surface, and the substrate was dried for use;

[0038] Preparation of Cr underlayer: in a magnetron sputtering coating machine, Cr was used as the target material, and argon was used as the working gas to prepare the Cr underlayer on the surface of the substrate. During the sputtering process, the working pressure was 0.8Pa, the sputtering time was 60min, the sputtering power was 120W, the target-substrate distance was 8cm, and the argon flow rate was 20sccm;

[0039] Preparation of CrN bonding layer: in a magnetron sputtering coating machine, Cr was used as the target material, and argon and nitrogen were used as the working gases to prepare the CrN bonding layer. During the sputtering process, the working pressure was 0.5Pa, the sputtering time was 90min, the sputtering power was 150W, the target-substrate distance was 8cm, the argon flow rate was 20sccm, and the nitrogen flow rate was 20sccm;

[0040] Preparation of CrNiN top layer: in a magnetron sputtering coating machine, Cr-Ni composite material was used as the target material (the mass fraction of Ni in the target material was 30%), argon and nitrogen were used as the working gases to prepare the CrNiN top layer. During the sputtering process, the working pressure was 0.5Pa, the sputtering time was 180min, the sputtering power was 180W, the target-substrate distance was 8cm, the argon flow rate was 20sccm, and the nitrogen flow rate was 30sccm;

[0041] Vacuum annealing treatment: the Zr-4 alloy containing coating material was placed in a vacuum annealing furnace for vacuum annealing treatment, the annealing time was 3h, and the annealing temperature was 420℃.

[0042] Example 5

[0043] Pre-treatment: Zr-4 alloy was selected as the substrate, and sandpaper with mesh sizes of 100, 400, 1200 and 2000 was used for polishing treatment in sequence, 18wt% hydrochloric acid solution was used for acid pickling treatment, 25wt% sodium carbonate solution was used for oil removal treatment, anhydrous ethanol was used to remove the residual liquid on the surface, and the substrate was dried for use;

[0044] Preparation of Cr undercoat layer: In a magnetron sputtering coating machine, Cr was used as the target material, and argon was used as the working gas to prepare the Cr undercoat layer on the surface of the substrate. During the sputtering process, the working pressure was 0.8 Pa, the sputtering time was 60 min, the sputtering power was 120 W, the target-substrate distance was 8 cm, and the argon flow rate was 20 sccm.

[0045] Preparation of CrN binding layer: In a magnetron sputtering coating machine, Cr was used as the target material, and argon and nitrogen were used as the working gases to prepare the CrN binding layer. During the sputtering process, the working pressure was 0.5 Pa, the sputtering time was 90 min, the sputtering power was 150 W, the target-substrate distance was 8 cm, the argon flow rate was 20 sccm, and the nitrogen flow rate was 20 sccm.

[0046] Preparation of CrNiN top layer: In a magnetron sputtering coating machine, Cr-Ni composite material was used as the target material (the mass fraction of Ni in the target material was 36%), and argon and nitrogen were used as the working gases to prepare the CrNiN top layer. During the sputtering process, the working pressure was 0.5 Pa, the sputtering time was 180 min, the sputtering power was 180 W, the target-substrate distance was 8 cm, the argon flow rate was 20 sccm, and the nitrogen flow rate was 30 sccm.

[0047] Vacuum annealing treatment: The Zr-4 alloy containing the coating material was placed in a vacuum annealing furnace for vacuum annealing treatment. The annealing time was 3 h, and the annealing temperature was 420℃.

[0048] Example 6

[0049] Pre-treatment: Zr-4 alloy was selected as the substrate, and sandpaper with mesh sizes of 100, 400, 1200, and 2000 was used for polishing treatment in sequence. An 18wt% hydrochloric acid solution was used for acid washing treatment, a 25wt% sodium carbonate solution was used for oil removal treatment, anhydrous ethanol was used to remove residual liquid on the surface, and the substrate was dried for use;

[0050] Preparation of Cr undercoat layer: In a magnetron sputtering coating machine, Cr was used as the target material, and argon was used as the working gas to prepare the Cr undercoat layer on the surface of the substrate. During the sputtering process, the working pressure was 0.8 Pa, the sputtering time was 60 min, the sputtering power was 120 W, the target-substrate distance was 8 cm, and the argon flow rate was 20 sccm.

[0051] Preparation of CrN binding layer: In a magnetron sputtering coating machine, Cr was used as the target material, and argon and nitrogen were used as the working gases to prepare the CrN binding layer. During the sputtering process, the working pressure was 0.5 Pa, the sputtering time was 90 min, the sputtering power was 150 W, the target-substrate distance was 8 cm, the argon flow rate was 20 sccm, and the nitrogen flow rate was 20 sccm.

[0052] Preparation of CrNiN top layer: In a magnetron sputtering coating machine, Cr-Ni composite material was used as the target material (the mass ratio of Ni in the target material was 26%), argon and nitrogen were used as the working gas, and the CrNiN top layer was prepared. The working pressure during sputtering was 0.5 Pa, the sputtering time was 180 min, the sputtering power was 180 W, the target-substrate distance was 8 cm, the argon flow rate was 20 sccm, and the nitrogen flow rate was 30 sccm;

[0053] Vacuum annealing treatment: The Zr-4 alloy containing the coating material was placed in a vacuum annealing furnace for vacuum annealing treatment, the annealing time was 3 h, and the annealing temperature was 420℃.

[0054] Liquid nitrogen treatment: The cooled Zr-4 alloy containing the coating material was placed in liquid nitrogen at -196℃ for 2.5 h.

[0055] Comparative Example 1

[0056] Pre-treatment: Zr-4 alloy was selected as the substrate, and sandpaper with mesh sizes of 100, 400, 1200 and 2000 were used for polishing treatment in sequence. The substrate was subjected to acid pickling treatment with 18wt% hydrochloric acid solution, oil removal treatment with 25wt% sodium carbonate solution, and surface liquid removal with anhydrous ethanol, and then dried for use;

[0057] Preparation of Cr base layer: In a magnetron sputtering coating machine, Cr was used as the target material, and argon was used as the working gas to prepare the Cr base layer on the surface of the substrate. The working pressure during sputtering was 0.8 Pa, the sputtering time was 60 min, the sputtering power was 120 W, the target-substrate distance was 8 cm, and the argon flow rate was 20 sccm.

[0058] Preparation of CrN binding layer: In a magnetron sputtering coating machine, Cr was used as the target material, and argon and nitrogen were used as the working gas to prepare the CrN binding layer. The working pressure during sputtering was 0.5 Pa, the sputtering time was 90 min, the sputtering power was 150 W, the target-substrate distance was 8 cm, the argon flow rate was 20 sccm, and the nitrogen flow rate was 20 sccm.

[0059] Preparation of CrN top layer: In a magnetron sputtering coating machine, Cr was used as the target material, and argon and nitrogen were used as the working gas to prepare the CrN top layer. The working pressure during sputtering was 0.5 Pa, the sputtering time was 180 min, the sputtering power was 180 W, the target-substrate distance was 8 cm, the argon flow rate was 20 sccm, and the nitrogen flow rate was 30 sccm.

[0060] Vacuum annealing treatment: The Zr-4 alloy containing the coating material was placed in a vacuum annealing furnace for vacuum annealing treatment, the annealing time was 3 h, and the annealing temperature was 420℃.

[0061] Comparative Example 2

[0062] Pre-treatment: Zr-4 alloy was selected as the substrate, and was polished with sandpaper of 100, 400, 1200 and 2000 grits in turn, and was subjected to acid pickling treatment with 18wt% hydrochloric acid solution, oil removal treatment with 25wt% sodium carbonate solution, and surface residual liquid removal with anhydrous ethanol, and was dried for use;

[0063] Preparation of Cr undercoat layer: a Cr undercoat layer was prepared on the surface of the substrate in a magnetron sputtering coating machine with Cr as the target material and argon as the working gas, the working pressure during sputtering was 0.8 Pa, the sputtering time was 60 min, the sputtering power was 120 W, the target-substrate distance was 8 cm, and the argon flow rate was 20 sccm;

[0064] Preparation of CrN binding layer: a CrN binding layer was prepared in a magnetron sputtering coating machine with Cr as the target material and argon and nitrogen as the working gases, the working pressure during sputtering was 0.5 Pa, the sputtering time was 90 min, the sputtering power was 150 W, the target-substrate distance was 8 cm, the argon flow rate was 20 sccm, and the nitrogen flow rate was 20 sccm;

[0065] Preparation of CrNiN top layer: a CrNiN top layer was prepared in a magnetron sputtering coating machine with a Cr-Ni composite material as the target material (the mass ratio of Ni in the target material was 50%) and argon and nitrogen as the working gases, the working pressure during sputtering was 0.5 Pa, the sputtering time was 180 min, the sputtering power was 180 W, the target-substrate distance was 8 cm, the argon flow rate was 20 sccm, and the nitrogen flow rate was 30 sccm;

[0066] Vacuum annealing treatment: the Zr-4 alloy containing the coating material was placed into a vacuum annealing furnace for vacuum annealing treatment, the annealing time was 3 h, and the annealing temperature was 420℃.

[0067] Next, the corrosion resistance and the binding strength of the samples in Examples 1-6 and Comparative Examples 1-2 were evaluated, the corrosion resistance was selected by using a CHI660E electrochemical workstation, a three-electrode system was used, the sample was sealed with paraffin wax before testing, only the surface of the sample to be tested was exposed, the shape of the surface to be tested was ensured to be square, the sample to be tested was placed into a 5wt% NaCl solution for 30 min, and then the test was started, and the Tafel extrapolation method was used to calculate the self-corrosion current density of the sample. The coating binding strength was tested by the indentation method.

[0068] The test results are shown in Table 1:

[0069] Table 1: Corrosion resistance and binding strength of each sample

[0070] No. Self-corrosion current density / A-cm -2 ]] Bonding strength / MPa Example 1 4.17 x 10 -8 ]]> 25.7 Example 2 6.38 x 10 -9 ]] 28.1 Example 3 1.62 x 10 -9 ]] 35.9 Example 4 5.30 x 10 -8 ]]> 36.2 Example 5 8.44 x 10 -7 ]] 36.5 Example 6 8.52 x 10 -10 ]] 35.7 Comparative Example 1 9.72 x 10 -8 ]]> 18.3 Comparative Example 2 3.11 x 10 -6 ]]> 37.1

[0071] As can be seen from Table 1, with the increase of the content of Ni element in the CrNiN top layer, the corrosion resistance of the coating presents a trend of first increasing and then decreasing, and the bonding strength of the coating presents a trend of first increasing and then tending to be stable. Considering the production cost and material performance, the self-corrosion current density of the optimal test sample is 1.62×10 -9 A·cm -2 , and the bonding strength is 35.9 MPa. In addition, the liquid nitrogen treatment on the coating material can further improve the corrosion resistance of the coating material, although it has little effect on the bonding strength.

[0072] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A nuclear reactor coating material, characterized by, The preparation of the coating material comprises the following steps: Pre-treatment: Zr-4 alloy is selected as the substrate, and is polished with sandpaper with mesh sizes of 100, 400, 1200 and 2000 in sequence, is subjected to acid pickling treatment with an 18-20wt% hydrochloric acid solution, is subjected to oil removal treatment with a 22-25wt% sodium carbonate solution, is subjected to surface liquid removal with anhydrous ethanol, and is dried for use; Preparation of a Cr base layer: a Cr base layer is prepared on the surface of the substrate in a magnetron sputtering coating machine with Cr as the target material and argon as the working gas, the working pressure during sputtering is 0.8-1.0Pa, the sputtering time is 60-75min, the sputtering power is 100-120W, the target-substrate distance is 8-10cm, and the argon flow rate is 20-25sccm; Preparation of a CrN binding layer: a CrN binding layer is prepared in a magnetron sputtering coating machine with Cr as the target material and argon and nitrogen as the working gases, the working pressure during sputtering is 0.5-0.8Pa, the sputtering time is 90-120min, the sputtering power is 120-150W, the target-substrate distance is 8-10cm, the argon flow rate is 20-25sccm, and the nitrogen flow rate is 20-25sccm; Preparation of a CrNiN top layer: a CrNiN top layer is prepared in a magnetron sputtering coating machine with a Cr-Ni composite material as the target material, the mass ratio of Ni in the target material being 20%-36%, argon and nitrogen as the working gases, the working pressure during sputtering being 0.5-0.8Pa, the sputtering time being 180-210min, the sputtering power being 180-200W, the target-substrate distance being 8-10cm, the argon flow rate being 20-25sccm, and the nitrogen flow rate being 30-40sccm; Vacuum annealing treatment: the Zr-4 alloy containing the coating material is placed in a vacuum annealing furnace for vacuum annealing treatment, the annealing time being 3-5h and the annealing temperature being 400-420℃.

2. A nuclear reactor coating material as claimed in claim 1, characterized in that The concentration of the hydrochloric acid solution is 18wt%.

3. The nuclear reactor coating material of claim 1, wherein, The concentration of the sodium carbonate solution is 22wt%.

4. The nuclear reactor coating material of claim 1, wherein, The annealing time is 3h.

5. The nuclear reactor coating material of claim 1, wherein, The annealing temperature is 420℃.

6. A nuclear reactor coating material as defined in claim 1, wherein, The mass ratio of Ni in the target material is 26%.