An ordered layered structure Cr / Cr x N / M x O y Composite tritium barrier coating and preparation method thereof

Abstract

The present invention provides a novel ordered layered structure Cr / Cr x N / M x O y composite tritium barrier coating and a preparation method thereof. The coating is composed of a metal Cr layer, a metal nitride Cr x N layer, and a hydrogen-resistant hydroxide M x O y formed by three-layer ordering. In M x O y , M represents different metal elements, including common metal elements in the field of tritium barrier coatings such as Al, Zr, Er, Y, Cr, etc., and the M x O y coating can represent a unit metal oxide or a binary, ternary or other multi-metal oxide and their mixture coatings. On the one hand, the composite tritium barrier coating increases the diffusion path of tritium in the coating, increases the coating diffusion interface, and effectively improves the tritium barrier performance of the coating. On the other hand, the introduction of the metal Cr layer and Cr x N can form a metallurgical structure with the substrate, avoid film cracking and peeling, significantly improve the film-substrate adhesion, and chromium nitride can effectively alleviate the thermal mismatch problem between the metal oxide and the substrate, improving the thermal shock resistance of the coating.

Description

Technical Field

[0001] The invention relates to a method for constructing a novel ordered layered structure to improve the tritium barrier performance of a tritium barrier coating, the bonding force with a substrate and the thermal cycle stability of the tritium barrier coating, and belongs to the technical field of surface engineering. Background Art

[0002] Using tritium permeation barrier coating (TPB) to reduce tritium loss in structural materials is one of the key scientific and technological issues in fusion reactor research. Ceramics have the characteristics of low tritium permeability, high corrosion resistance, high hardness and high thermal stability, and are currently the preferred material for tritium barrier coatings in fusion reactors.

[0003] In the study of tritium barrier coatings, oxide coatings (such as Cr 2 O 3 、Al 2 O 3 , Er 2 O 3 , Y 2 O 3 、ZrO 2 etc.) have excellent hydrogen permeability, chemical stability, wear resistance, and corrosion resistance, and have received extensive attention in recent years. However, due to the large difference in thermal expansion coefficient between the oxide coating and the substrate, such as α-Al 2 O 3 The thermal expansion coefficients of the stainless steel substrate are 7.5×10 -6 K -1 and 18.5×10 -6 K -1 The oxide coating directly deposited on the stainless steel substrate is prone to cracking and falling off, and is far from reaching its theoretical tritium barrier factor. Therefore, there is a technical demand in this field for further improvement of the tritium barrier coating structure and preparation process. The thermal expansion coefficient of CrN is 9.4×10 -6 K -1 , and has good thermal compatibility with the substrate. Therefore, constructing a new type of metal nitride / oxygen barrier composite coating with an ordered layered combination can greatly improve the tritium barrier performance and at the same time enhance the bonding strength and thermal shock resistance of the coating to the substrate. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the present invention provides a new ordered layered structure Cr / Cr x N / M x O y The composite tritium-barrier coating and its preparation method can effectively improve the tritium-barrier performance of the coating by studying and improving the coating composition, structure and preparation technology. The coating has the advantages of simple coating preparation process, low cost and the ability to cover complex parts of different shapes.

[0005] In order to achieve the above purpose, this paper adopts the following technical solutions:

[0006] A new ordered layered structure Cr / Cr x N / M x O y The composite tritium barrier coating comprises a metal Cr layer, a metal nitride Cr x N layer, hydrogen-blocking compound M x O y composed of layers.

[0007] Furthermore, the composite coating is an ordered multilayer structure, including a metal Cr layer at the bottom, a metal nitride Cr layer in the middle, and a x N layer and the outermost hydrogen-inhibiting compound M x O y layer.

[0008] Furthermore, the thickness of the metal Cr layer in the composite coating is 1-7 μm; the metal nitride Cr in the composite coating is x The thickness of the N layer is 0.1-3 μm, and the Cr x In N, x is 1 or 2; the composite coating contains a hydrogen-blocking compound M x O y The layer thickness is 20 nm-5 μm.

[0009] Furthermore, the thickness of the metal Cr layer in the composite coating is 1-7 μm; the metal nitride Cr in the composite coating is x The thickness of the N layer is 0.1-3 μm, and the Cr x In N, x is 1 or 2; the composite coating contains a hydrogen-blocking compound M x O y The layer thickness is 20 nm-5 μm.

[0010] A new ordered layered structure Cr / Cr x N / M x The preparation method of Oy composite tritium barrier coating comprises the following steps:

[0011] (1) Preparation of Cr-containing plating solution: including CrO 3 As a hexavalent chromium source and CrCl 3 The invention discloses a method for preparing a plating solution of a trivalent chromium source; cutting, grinding and ultrasonically cleaning a stainless steel substrate for use;

[0012] (2) Formation of metal Cr layer: The substrate obtained in (1) is used as the cathode, the platinum electrode is used as the anode, the water bath temperature of the electroplating solution is 30~90℃, and the electroplating current density is 0.1~3A / cm 2, the electroplating time is 10~120 min, and a uniform and complete metal Cr layer is prepared;

[0013] (3) Nitriding heat treatment of the metal Cr layer: The metal Cr layer obtained in (2) is dried and then subjected to heat treatment in a nitrogen-containing atmosphere to form a Cr x N / Cr coating, heat treatment temperature is 600~800 ℃, heat treatment time is 1~4 h, heating rate is 2~10℃ / min;

[0014] (4) Hydroxide inhibitor M x O y Preparation of sol: using anhydrous ethanol, acetone, glacial acetic acid and triethanolamine as raw materials, fully stirring and dissolving to form a metal oxide mixed sol;

[0015] (5) The metal oxide mixed sol obtained in step (4) is uniformly coated on the Cr obtained in step (3) by an immersion pulling method. x N coating surface, Cr x N and the substrate are immersed in the mixed sol, and the substrate rising speed is controlled to be 50-500 um / s, until the substrate completely floats out of the liquid surface and dries and solidifies to obtain the precursor, the drying temperature is 40-90 °C, and the drying time is 0.5-3 h;

[0016] (6) placing the precursor coating obtained in step (5) in a muffle furnace at 200°C to 500°C for 20 to 60 minutes to remove organic matter inside the coating;

[0017] (7) Repeat the above steps (5) to (6) 1 to 20 times, and finally perform heat treatment in an atmospheric atmosphere at 500 to 800 °C in a muffle furnace for 0.5 to 5 h at a heating rate of 2 to 5 °C min to form the composite tritium barrier coating.

[0018] Furthermore, the metal salt is one or a mixture of aluminum salt, zirconium salt, chromium salt, yttrium salt and uranium salt.

[0019] Furthermore, the metal salt includes metal nitrates, metal acetates, metal alkoxides that are soluble in ethanol, and metal alkoxides that can form a unit, binary or ternary system or a mixture thereof.

[0020] Furthermore, the composite coating is an ordered multilayer structure, including a metal Cr layer at the bottom, a metal nitride Cr layer in the middle, and a x N layer and the outermost hydrogen-inhibiting compound M x O y layer.

[0021] Furthermore, the thickness of the metal Cr layer in the composite coating is 1-7 μm; the metal nitride Cr in the composite coatingx The thickness of the N layer is 0.1-3 μm, and the Cr x In N, x is 1 or 2; the composite coating contains a hydrogen-blocking compound M x O y The layer thickness is 20 nm-5 μm.

[0022] The present invention has the following beneficial effects:

[0023] 1. The novel ordered layered structure designed by the present invention integrates Cr x N coating and M x O y The coating has excellent tritium penetration resistance, increases the diffusion path of tritium in the coating, and improves the diffusion interface of the coating, thereby greatly improving the tritium resistance of the composite coating;

[0024] 2. The present invention uses metal Cr and Cr x The structural design of N as the intermediate layer of the composite coating can form a metallurgical structure with the substrate, improve the bonding strength with the substrate, and relieve the stress of the metal oxide film and the metal substrate to prevent the film from cracking and peeling;

[0025] 3. The preparation process of the present invention is simple and mature, suitable for the inner and outer surfaces of complex pipelines, has strong repeatability, and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a spectrum point scanning analysis diagram of the cross section of the composite tritium barrier coating in Example 1;

[0027] Figure 2 This is a graph of the steady-state permeation current of deuterium ions in the high-temperature gas-phase deuterium barrier experiment of Example 2;

[0028] Figure 3 This is a graph of the steady-state permeation current of deuterium ions in the high-temperature gas phase deuterium barrier experiment of Example 3;

[0029] Figure 4 This is a graph of the steady-state permeation current of deuterium ions in the high-temperature gas phase deuterium barrier experiment of Example 4;

[0030] Figure 5 This is a SEM image of the cross section of the composite tritium barrier coating of Example 1. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0032] A new ordered layered structure Cr / Cr x N / M x O y Composite tritium barrier coating, where M x O y For Al 2 O 3 Cr 2 O 3 、ZrO 2 The composite oxide (ternary oxide) composed of three phases, the composite tritium barrier coating is prepared by the following method:

[0033] 1. CrO 3 (chromic anhydride), concentrated H 2 SO 4 Add deionized water to dissolve, stir thoroughly to form a solution for later use; cut 321 stainless steel into discs with a diameter of 12 mm and grind them flat with 800-grit sandpaper, then ultrasonicate with ethanol for 15 min and then wash with deionized water for later use;

[0034] 2. Use the platinum electrode as the anode and the substrate obtained in step 1 as the cathode to electroplate metal Cr. Set the plating solution water bath temperature to 72 °C and the current density to 0.3 A / cm 2 , the electroplating time is 80 min.

[0035] 3. After the Cr coating obtained in step 2 is dried in a drying oven for more than 2 h, it is placed in pure ammonia for high-temperature nitriding at a heating rate of 5 °C / min, a nitriding temperature of 700 °C, and a nitriding time of 2 h.

[0036] 4. Weigh 1 g of zirconium acetate, add 18 ml of anhydrous ethanol, 0.8 ml of acetone, and 50 μL of glacial acetic acid, place it on a magnetic stirrer and stir for about 10 h until it is fully dissolved and becomes clear and transparent. Let it stand for 24 h to obtain zirconium sol. Weigh 0.95 g of aluminum nitrate and 0.82 g of chromium acetate and dissolve them in the zirconium sol. Stir to obtain a clear green mixed sol.

[0037] 5. The Cr obtained in step 3 x N was immersed in the sol of step 4 together with the substrate. After standing for 1 min, it was pulled out of the liquid surface at a uniform speed of 300 μm / s. After pulling, the wet sol and the substrate were placed at 80 °C for drying for 1 h, kept at 400 °C for 30 min, and the second layer was pulled after cooling. The previous operation was repeated for six times, and finally heat treated at 600 °C for 1 h with a heating rate of 5 °C / min. Example

[0038] A new ordered layered structure Cr / Cr x N / M x O y Composite tritium barrier coating, where M x O y For Al 2 O 3 Cr 2 O 3 、ZrO 2 The composite oxide (ternary oxide) composed of three phases, the composite tritium barrier coating is prepared by the following method:

[0039] 1. CrO 3 (chromic anhydride), concentrated H 2 SO 4 Add deionized water to dissolve, stir thoroughly to form a solution for later use; cut 321 stainless steel into discs with a diameter of 12 mm and grind them flat with 800-grit sandpaper, then ultrasonicate with ethanol for 15 min and then wash with deionized water for later use;

[0040] 2. Use the platinum electrode as the anode and the substrate obtained in step 1 as the cathode to electroplate metal Cr. Set the plating solution water bath temperature to 72 °C and the current density to 0.3 A / cm 2 , the electroplating time is 80 min.

[0041] 3. After the Cr coating obtained in step 2 is dried in a drying oven for more than 2 h, it is placed in pure ammonia for high-temperature nitriding at a heating rate of 5 °C / min, a nitriding temperature of 700 °C, and a nitriding time of 2 h.

[0042] 4. Weigh 1 g of zirconium acetate, add 18 ml of anhydrous ethanol, 0.8 ml of acetone, and 50 μL of glacial acetic acid, place it on a magnetic stirrer and stir for about 10 h until it is fully dissolved and becomes clear and transparent. Let it stand for 24 h to obtain zirconium sol. Weigh 0.95 g of aluminum nitrate and 0.82 g of chromium acetate and dissolve them in the zirconium sol. Stir to obtain a clear green mixed sol.

[0043] 5. The Cr obtained in step 3 x N was immersed in the sol of step 4 together with the substrate. After standing for 1 min, it was pulled out of the liquid surface at a uniform speed of 300 μm / s. After pulling, the wet sol and the substrate were placed at 80 °C for drying for 1 h, kept at 400 °C for 30 min, and the second layer was pulled after cooling. The previous operation was repeated for three times, and finally heat treated at 600 °C for 1 h with a heating rate of 5 °C / min. Example

[0044] A new ordered layered structure Cr / Cr x N / M x Oy Composite tritium barrier coating, where M x O y For Er 2 O 3 Unit oxide, the composite tritium barrier coating is prepared by the following method:

[0045] 1. CrO 3 (chromic anhydride), concentrated H 2 SO 4 Add deionized water to dissolve, stir thoroughly to form a solution for later use; cut 321 stainless steel into discs with a diameter of 12 mm and grind them with 800-grit sandpaper until they are flat, then ultrasonicate with ethanol for 15 min and then wash with deionized water for later use;

[0046] 2. Use the platinum electrode as the anode and the substrate obtained in step 1 as the cathode to electroplate metal Cr. Set the plating solution water bath temperature to 72 °C and the current density to 0.3 A / cm 2 , the electroplating time is 80 min.

[0047] 3. After the Cr coating obtained in step 2 is dried in a drying oven for more than 2 h, it is placed in pure ammonia for high-temperature nitriding at a heating rate of 5 °C / min, a nitriding temperature of 700 °C, and a nitriding time of 2 h.

[0048] 4. Weigh 0.5 g of erbium acetate, add 30 ml of anhydrous ethanol and 20 μL of triethanolamine, place on a magnetic stirrer and stir for 30 minutes to form a clear and transparent solution.

[0049] 5. The Cr obtained in step 3 x N is immersed in the sol of step 4 together with the substrate. After standing for 1 minute, it is pulled out of the liquid surface at a uniform speed of 300 μm / s. After pulling, the wet sol and the substrate are placed at 80 °C for drying for 1 hour, and kept at 400 °C for 30 minutes. After cooling, the second layer is pulled. The previous operation is repeated for three times. Finally, it is heat treated at 500 °C for 1 hour with a heating rate of 5 °C / min. Example

[0050] A new ordered layered structure Cr / Cr x N / M x O y Composite tritium barrier coating, where M x O y Cr 2 O 3 、ZrO 2 The composite oxide (binary oxide) composed of two phases is prepared by the following method:

[0051] 1. CrO 3(chromic anhydride), concentrated H 2 SO 4 Add deionized water to dissolve, stir thoroughly to form a solution for later use; cut 321 stainless steel into discs with a diameter of 12 mm and grind them with 800-grit sandpaper until they are flat, then ultrasonicate with ethanol for 15 min and then wash with deionized water for later use;

[0052] 2. Use the platinum electrode as the anode and the substrate obtained in step 1 as the cathode to electroplate metal Cr. Set the plating solution water bath temperature to 72 °C and the current density to 0.3 A / cm 2 , the electroplating time is 80 min.

[0053] 3. After the Cr coating obtained in step 2 is dried in a drying oven for more than 2 h, it is placed in pure ammonia for high-temperature nitriding at a heating rate of 5 °C / min, a nitriding temperature of 700 °C, and a nitriding time of 2 h.

[0054] 4. Weigh 1 g of zirconium acetate, add 18 ml of anhydrous ethanol, 0.8 ml of acetone, and 50 μL of glacial acetic acid, place it on a magnetic stirrer and stir for about 10 h until it is fully dissolved and becomes clear and transparent. Let it stand for 24 h to obtain zirconium sol, weigh 0.82 g of chromium acetate and dissolve it in the zirconium sol, and stir to obtain a clear green mixed sol.

[0055] 5. The Cr obtained in step 3 x N is immersed in the sol of step 4 together with the substrate. After standing for 1 minute, it is pulled out of the liquid surface at a uniform speed of 300 μm / s. After pulling, the wet sol and the substrate are placed at 80 °C for drying for 1 hour, kept at 400 °C for 30 minutes, and the second layer is pulled after cooling. The previous operation is repeated for three times, and finally heat treated at 600 °C for 1 hour with a heating rate of 5 °C / min.

[0056] Reference Figure 1 From the cross-sectional SEM scan results, we know that the composite coating is divided into three layers. The outermost layer is a metal oxide layer of three metals: Al, Cr, and Zr. According to the atomic ratio, the middle layer is Cr. 2 N, and the existence of O element content proves that the metal oxide diffuses inward to a certain extent; the bottom layer is the metal Cr layer obtained by electroplating, and the Fe element atomic ratio is 1.44%, which proves that Cr and the substrate diffuse with each other to form a metallurgical structure, which greatly improves the bonding strength between the composite coating and the substrate.

[0057] Reference Figure 2 , know in Cr x The Cr / Cr formed by pulling Al, Cr, and Zr sol three times on the N coating surface x N / M x O y(M is Al, Cr, Zr) composite coating relative to pure Al 2 O 3 / Cr 2 O 3 / ZrO 2 The high temperature deuterium ion steady-state current value of the coating decreased by 6 times at 500 ℃. x N / M x O y The deuterium penetration reduction factor (PRF) of the composite coating (M is Al, Cr, Zr) at 500 ℃ is 1700, and the pure Cr x The PRF value of N coating at 500℃ is 50, and that of pure Al 2 O 3 / Cr 2 O 3 / ZrO 2 The PRF value of the coating prepared at 650 °C at 500 °C is 269, indicating that the Cr / Cr x N / M x O y (M is Al, Cr, Zr) composite coating has better deuterium penetration resistance.

[0058] Reference Figure 3 , know in Cr x The Cr / Cr formed by pulling the Er-containing sol three times on the N coating surface x N / Er 2 O 3 Compared with pure Er 2 O 3 The high temperature deuterium ion steady-state current value of the coating decreased by 3.6 times at 500 ℃. x N / Er 2 O 3 The deuterium penetration reduction factor (PRF) of the composite coating at 500 ℃ is 286, while that of pure Cr x The PRF value of N coating at 500 ℃ is 50, and that of pure Er is 2 O 3 The PRF value of the coating at 500 °C is 80, indicating that the Cr / Cr x N / Er 2 O 3 The composite coating has better deuterium penetration resistance.

[0059] Reference Figure 4 , know in Cr x The Cr / Cr formed by pulling the sol containing binary Cr and Zr three times on the surface of N coating x N / M x O y (M is Cr, Zr) composite coating is relative to pure Cr2 O 3 / ZrO 2 The high temperature deuterium ion steady-state current value of the coating decreased by 6 times at 500 ℃. x N / M x O y The deuterium penetration reduction factor (PRF) of the composite coating (M is Cr, Zr) at 500 ℃ is 1521, while that of pure Cr x The PRF value of N coating at 500 ℃ is 50, and that of pure Cr 2 O 3 / ZrO 2 The PRF value of the coating at 500 °C is 253, indicating that the Cr / Cr x N / M x O y (M is Cr, Zr) composite coating has better deuterium penetration resistance.

[0060] Figure 5 Cr x Cr / Cr prepared by pulling Al, Cr, and Zr sols six times on the surface of N coating x N / M x O y The cross-sectional view of the (M is Al, Cr, Zr) composite tritium barrier coating. As can be seen from the figure, the cross-section can be divided into a metal oxide layer, a chromium nitride layer, a metal Cr layer and the bottom substrate layer. The layers are dense and free of defects, holes and cracks, indicating that the new type of layered ordered structure composite coating prepared by electroplating nitridation combined with immersion pulling method has the characteristics of good interface bonding.

[0061] In summary, the unit oxide (Er 2 O 3 ), binary oxide (Cr 2 O 3 / ZrO 2 ), ternary oxide (Al 2 O 3 / Cr 2 O 3 / ZrO 2 ) combined with Cr x New ordered layered structure Cr / Cr prepared by N coating x N / M x The Oy composite tritium barrier coating has better tritium penetration resistance and more prominent interface bonding characteristics.

[0062] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An ordered layered structure Cr / Cr x N / M x Preparation method of Oy composite tritium barrier coating, It is characterized in that The steps include: (1) Preparation of Cr-containing plating solution: including CrO 3 As a hexavalent chromium source and CrCl 3 The invention discloses a method for preparing a plating solution of a trivalent chromium source; cutting, grinding and ultrasonically cleaning a stainless steel substrate for use; (2) Formation of metal Cr layer: The substrate obtained in (1) is used as the cathode, the platinum electrode is used as the anode, the water bath temperature of the electroplating solution is 30~90℃, and the electroplating current density is 0.1~3A / cm 2 , the electroplating time is 10~120 min, and a uniform and complete metal Cr layer is prepared; (3) Nitriding heat treatment of the metal Cr layer: The metal Cr layer obtained in (2) is dried and then subjected to heat treatment in a nitrogen-containing atmosphere to form a Cr x N / Cr coating, heat treatment temperature is 600~800 ℃, heat treatment time is 1~4 h, heating rate is 2~10℃ / min; (4) Hydroxide inhibitor M x O y Preparation of sol: using anhydrous ethanol, acetone, glacial acetic acid and triethanolamine as raw materials, fully stirring and dissolving to form a metal oxide mixed sol; (5) The metal oxide mixed sol obtained in step (4) is uniformly coated on the Cr obtained in step (3) by an immersion pulling method. x N coating surface, Cr x N and the substrate are immersed in the mixed sol, and the substrate rising speed is controlled to be 50-500 um / s, until the substrate completely floats out of the liquid surface and dries and solidifies to obtain the precursor, the drying temperature is 40-90 °C, and the drying time is 0.5-3 h; (6) placing the precursor coating obtained in step (5) in a muffle furnace at 200°C to 500°C for 20 to 60 minutes to remove organic matter inside the coating; (7) Repeat the above steps (5) to (6) 1 to 20 times, and finally perform heat treatment in an atmospheric atmosphere at 500 to 800 °C in a muffle furnace for 0.5 to 5 h at a heating rate of 2 to 5 °C min to form the composite tritium barrier coating.

2. The ordered layered structure Cr / Cr according to claim 1 x N / M x Preparation method of Oy composite tritium barrier coating, It is characterized in that The metal M salt is one or a mixture of aluminum salt, zirconium salt, chromium salt, yttrium salt and uranium salt.

3. The ordered layered structure Cr / Cr according to claim 1 x N / M x Preparation method of Oy composite tritium barrier coating, It is characterized in that The metal M salt includes metal nitrates, metal acetates, metal alkoxides soluble in ethanol, and metal alkoxides or mixtures thereof that can form a unit, binary or ternary system.

4. The ordered layered structure Cr / Cr according to claim 1 x N / M x Preparation method of Oy composite tritium barrier coating, It is characterized in that The composite tritium-resistant coating is an ordered multi-layer structure, including a metal Cr layer at the bottom, a metal nitride Cr x N layer in the middle layer, and a hydrogen-resistant hydroxide M x O y layer at the outermost layer.

5. The ordered layered structure Cr / Cr according to claim 1 x N / M x Preparation method of Oy composite tritium barrier coating, It is characterized in that The thickness of the metal Cr layer in the composite tritium barrier coating is 1-7 μm; the metal nitride Cr in the composite tritium barrier coating x The thickness of the N layer is 0.1-3 μm, and the Cr x In N, x is 1 or 2; the composite tritium-blocking coating contains a hydrogen-blocking compound M x O y The layer thickness is 20 nm-5 μm.

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