High-temperature corrosion-resistant coating for oxygen-enriched smelting top-blown lance and preparation method thereof

Abstract

The present invention discloses a high temperature resistant and corrosion resistant coating for an oxygen-enriched smelting top-blowing spray gun and a preparation method thereof. The coating substrate is a stainless steel spray gun, the bonding layer material is NiCoCrAlY, and the high temperature resistant and corrosion resistant coating material is TaC and doped modified rare earth tantalate (Y 0.6 Gd 0.4 )TaO4, the sealing agent is a polysilazane resin and an inorganic filler boron carbide, silicon nitride and a colloid of boron nitride, and the preparation method of the coating includes pretreatment, bonding layer preparation, high temperature resistant and corrosion resistant coating preparation, sealing treatment, and drying steps. The present invention uses TaC and doped modified (Y 0.6 Gd 0.4 )TaO4, as a high-temperature resistant and corrosion-resistant coating material, utilizes both the high-temperature resistance and corrosion resistance of TaC and the excellent thermal insulation and corrosion resistance of rare earth tantalate. The sealing agent penetrates into the coating at high temperature, filling the gaps and holes inside the coating, reducing gas permeability and increasing the service life of the oxygen-enriched smelting top-blowing lance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high-temperature-resistant and corrosion-resistant coating, and particularly relates to a high-temperature-resistant and corrosion-resistant coating for an oxygen-rich smelting top-blowing lance and a preparation method thereof. BACKGROUND

[0002] At present, the Isa smelting method is a modern non-ferrous metal bath smelting process, which can be used for primary and secondary smelting of copper and lead, copper-nickel smelting and copper blowing. The operation of the lance is the most important part of the entire Isa smelting technology, and needs to be specially designed according to different furnace types and processes. The lance is vertically arranged above the top-blowing furnace, and can be lifted and replaced by a lifting and fixing device during the blowing process. The lance can adopt a multi-layer concentric sleeve, the center pipe of which is used to transport fuel such as oil or natural gas, and if pulverized coal is transported, compressed air is needed to carry the pulverized coal into the pipe. The second layer is used to transport oxygen, the third layer is used to transport combustion air, and the fourth layer is used to transport process air. Meanwhile, there is also a double-layer sleeve, the center layer of which is used to transport oil or natural gas, and the outer layer is used to transport oxygen-rich air. The head of the lance is inserted into the range of 150-300 mm of the slag layer, and can be automatically lifted and adjusted according to the air supply pressure. The most easily damaged part is the length of the lance, which is generally 800-2000 mm, and the outer sleeve is usually made of stainless steel. The outer sleeve is about 500 mm longer than the other inner pipes, and protects the inner pipes. The outer surface of the lance is wrapped with a layer of splashed slag, which plays a protective role and prevents the lance from being burned out.

[0003] The service life of the lance head is about one week, and the longest can reach 10 days. When the lance is replaced, the damaged lance is lifted out by the lifting device and the new lance is put in, and it takes 20-40 minutes to replace the lance. The replaced lance only needs to cut off the damaged head and weld a new pipe to be used again. Under normal circumstances, the top of the furnace is operated at a slight negative pressure. The lance mainly blows oxygen-rich air into the furnace, and strongly stirs the slag layer to transfer mass and heat. Compared with the lance / nozzle of the flash furnace, the Mitsubishi furnace and the Vanarkov furnace, the lance of the Isa furnace has the characteristics of long length and large inner diameter, and must be replaced outside the furnace. Since the Isa furnace cannot operate for a long time, it is necessary to stop production for maintenance, but the furnace body still needs to be insulated during the stop production, and the frequent replacement of the lance also delays the construction period, resulting in the reduction of the production efficiency of the factory.

[0004] Therefore, in view of the above technical problems and defects, it is urgent to design and develop a high-temperature-resistant and corrosion-resistant coating for an oxygen-rich smelting top-blowing lance and a preparation method thereof. SUMMARY

[0005] To overcome the deficiencies and difficulties of the prior art, the first object of the present application is to provide a high-temperature-resistant and corrosion-resistant coating for an oxygen-rich smelting top-blowing lance.

[0006] The second object of the present application is to provide a preparation method of a high-temperature-resistant and corrosion-resistant coating for an oxygen-enriched smelting top-blowing lance.

[0007] The first object of the present application is achieved in that the coating comprises a bonding layer arranged on a substrate stainless steel lance, and a high-temperature-resistant and corrosion-resistant coating and a sealing layer arranged on the bonding layer in turn from bottom to top.

[0008] The material of the bonding layer is NCoiCrAlY; the material of the high-temperature-resistant and corrosion-resistant coating is TaC and doped modified (Y 0.6 Gd 0.4 )TaO4; and the material of the sealing layer is a colloid of polysilazane resin, inorganic filler boron carbide, silicon nitride and boron nitride.

[0009] The second object of the present application is achieved in that the method comprises the following steps: pretreatment, bonding layer preparation, high-temperature-resistant and corrosion-resistant coating preparation, sealing layer preparation, and drying.

[0010] A. Pretreatment: cleaning and sandblasting treatment of the stainless steel lance substrate;

[0011] B. Bonding layer preparation: preparation of a NiCoCrAlY bonding layer on the surface of the pretreated stainless steel lance substrate by using supersonic flame spraying;

[0012] C. High-temperature-resistant and corrosion-resistant coating preparation: preparation of (Y 0.6 Gd 0.4 )TaO4 coating and TaC coating on the bonding layer in turn by using atmospheric plasma spraying process;

[0013] D. Sealing layer preparation: mixing polysilazane resin, boron carbide, silicon nitride and boron nitride in a mass ratio of 5:1:1:1, stirring for 3 hours by using a stirrer to obtain an approximately thick colloid, and brushing the colloid on the surface of the high-temperature-resistant and corrosion-resistant coating;

[0014] E. Drying: after the sealing layer preparation is completed, the sealing layer is cured in an oven at 500 DEG C for 10 hours.

[0015] The present application sprays (Y 0.6 Gd 0.4 )TaO4 coating and then TaC coating on the bonding layer, and the main principle is that the thermal expansion coefficients of (Y 0.6 Gd 0.4 )TaO4 (10.5x10 -6 K -1 ) and the stainless steel lance substrate (13x10 -6 K -1 ) are close, and the (Y 0.6 Gd 0.4)TaO4 and TaC (6.3×10 -6 K -1 ) are close to each other, but the thermal expansion coefficients of TaC coating and stainless steel spray gun substrate are quite different. In order to avoid the failure of coating peeling caused by thermal mismatch, (Y 0.6 Gd 0.4 )TaO4 coating, then spray TaC coating. In addition, (Y 0.6 Gd 0.4 )TaO4 has low thermal conductivity and oxygen ion conductivity, which effectively reduces heat transfer and oxygen penetration into the spray gun base. TaC has a high melting point (3880℃) and slag corrosion resistance. It is sprayed on (Y 0.6 Gd 0.4 )TaO4 surface, which helps to further improve the high temperature resistance and corrosion resistance of the coating system.

[0016] The present invention prepares a sealing layer with a thickness of 10-20µm on the high-temperature resistant and corrosion-resistant coating. During high-temperature service, the polysilazane resin decomposes to generate silicon carbide, which is filled in cracks and holes with high-temperature resistant inorganic fillers such as boron carbide, silicon nitride, and boron nitride, blocking the gas transmission channel and preventing the gas from penetrating into the substrate and oxidizing the stainless steel spray gun.

[0017] That is to say, the present invention adopts a double ceramic layer structure on the bonding layer, and selectively selects specific coating materials and coating processes, so that the phase composition, organization, and structure of the coating form a more targeted form, so as to solve the problems of high temperature resistance and corrosion resistance of the oxygen-enriched smelting top-blowing spray gun, and significantly improve the service life of the stainless steel spray gun. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 In Example 1 of the present invention (Y 0.6 Gd 0.4 Thermal properties of TaO4: (a) thermal expansion coefficient; (b) thermal conductivity; (c) schematic diagram of oxygen ion conductivity;

[0019] Figure 2 Schematic diagram of the XRD pattern of the top coating of the spray gun tube in Example 1 of the present invention;

[0020] Figure 3 Schematic diagram of the SEM image of the top coating of the spray gun tube in Example 1 of the present invention;

[0021] Figure 4 Schematic diagram of the SEM spectrum of the top coating of the spray gun tube in Comparative Example 1 of the present invention;

[0022] Figure 5 Schematic diagram of the SEM spectrum of the top coating of the spray gun tube in Comparative Example 2 of the present invention;

[0023] Figure 6 SEM image of the top end coating of the lance tube in Example 3 of the present application. DETAILED DESCRIPTION

[0024] The present application will be further described below with reference to the drawings, but the present application is not limited in any way by the following description, and any modification or substitution based on the teaching of the present application is within the scope of the present application.

[0025] As shown in the accompanying Figures 1-6 The present application provides a high-temperature-resistant and corrosion-resistant coating for an oxygen-enriched smelting top-blowing lance, which comprises a bonding layer arranged on a base stainless steel lance, and a high-temperature-resistant and corrosion-resistant coating and a sealing layer arranged on the bonding layer in turn from bottom to top.

[0026] The material of the bonding layer is NCoiCrAlY; the material of the high-temperature-resistant and corrosion-resistant coating is TaC and doped modified (Y 0.6 Gd 0.4 )TaO4; and the material of the sealing layer is a colloid of polysilazane resin, inorganic filler boron carbide, silicon nitride and boron nitride.

[0027] The high-temperature-resistant and corrosion-resistant coating comprises a (Y 0.6 Gd 0.4 )TaO4 coating and a TaC coating.

[0028] The thickness of (Y 0.6 Gd 0.4 )TaO4 in the high-temperature-resistant and corrosion-resistant coating is 100-150 µm, the thickness of TaC is 100-150 µm, the thickness of the bonding layer is 100-120 µm, the thickness of the sealing layer is 10-20 µm, and the total thickness is 310-460 µm.

[0029] The bonding layer is prepared by supersonic flame spraying of NiCoCrAlY, the high-temperature-resistant and corrosion-resistant coating is prepared by atmospheric plasma spraying of a (Y 0.6 Gd 0.4 )TaO4 coating on the bonding layer and then spraying of a TaC coating, and the sealing layer is prepared by brushing of a colloid of polysilazane resin and inorganic filler boron carbide, silicon nitride and boron nitride.

[0030] To achieve the object of the present application, a preparation method of a high-temperature-resistant and corrosion-resistant coating for an oxygen-enriched smelting top-blowing lance is also provided, which comprises the steps of pretreatment, bonding layer preparation, high-temperature-resistant and corrosion-resistant coating preparation, sealing layer preparation and drying.

[0031] A. Pretreatment: cleaning and sandblasting treatment of the base stainless steel lance;

[0032] B. Bonding layer preparation: an ultrasonic flame spraying process was used to prepare a NiCoCrAlY bonding layer on the surface of the pretreated stainless steel spray gun substrate;

[0033] C. High-temperature corrosion-resistant coating preparation: an atmospheric plasma spraying process was used to prepare a (Y 0.6 Gd 0.4 )TaO4 coating and a TaC coating on the bonding layer, respectively;

[0034] D. Sealing layer preparation: poly-silazane resin, boron carbide, silicon nitride, and boron nitride were mixed in a mass ratio of 5:1:1:1, stirred for 3 hours using a blender to obtain a nearly thick colloidal substance, which was then brushed on the surface of the high-temperature corrosion-resistant coating;

[0035] E. Drying: after the sealing layer preparation was completed, it was cured in a 500°C oven for 10 hours.

[0036] In the B step, an ultrasonic flame spraying process was used to prepare a NiCoCrAlY bonding layer on the surface of the metal substrate, and the parameters of the ultrasonic flame spraying process were as follows: oxygen pressure 0.6-1.3 MPa, hydrogen pressure 0.9-1.5 MPa, powder feeding gas pressure 1.1-1.4 MPa, and spraying distance 220-260 mm.

[0037] The process parameters of the ultrasonic flame spraying process were as follows: oxygen pressure 1.3 MPa, hydrogen pressure 1.5 MPa, powder feeding gas pressure 1.4 MPa, and spraying distance 260 mm.

[0038] In the C step, the particle size of (Y 0.6 Gd 0.4 )TaO4 and TaC was 45-105 µm, the sphericity was >95%, and the flowability was 30-105 s / 50 g;

[0039] The atmospheric plasma spraying process parameters of the (Y 0.6 Gd 0.4 )TaO4 coating were as follows: spraying voltage 70-78 V, current 545-630 A, argon flow rate 20-25 L / min, hydrogen flow rate 4-6 L / min, powder feeding rate 30-40 g / min, and spraying distance 80-100 mm;

[0040] The atmospheric plasma spraying process parameters of the TaC coating were as follows: spraying voltage 75-80 V, current 620-650 A, argon flow rate 20-30 L / min, hydrogen flow rate 6-8 L / min, powder feeding rate 30-40 g / min, and spraying distance 80-100 mm.

[0041] An atmospheric plasma spraying process was used to spray a layer of doped and modified rare earth tantalate (Y0.6 Gd 0.4 )TaO4 coating, wherein the atmospheric plasma spraying process parameters are: spraying voltage 70 V, current 630 A, argon flow rate 25 L / min, hydrogen flow rate 6 L / min, powder feeding rate 40 g / min, spraying distance 100 mm;

[0042] A layer of TaC coating with a thickness of about 100 µm is sprayed on the bonding layer by atmospheric plasma spraying process, and the atmospheric plasma spraying process parameters are: spraying voltage 80 V, current 650 A, argon flow rate 30 L / min, hydrogen flow rate 8 L / min, powder feeding rate 40 g / min, spraying distance 100 mm.

[0043] The E step is drying in an air atmosphere, and the drying time is > 10 h.

[0044] Specifically, in a specific embodiment of the present application, a high-temperature corrosion-resistant coating for an oxygen-enriched smelting top-blowing lance comprises a bonding layer arranged on a substrate stainless steel lance and a (Y 0.6 Gd 0.4 )TaO4 and TaC high-temperature corrosion-resistant coating and a sealing layer, the material of the bonding layer is NCoiCrAlY; the material of the high-temperature corrosion-resistant coating is TaC and doped modified (Y 0.6 Gd 0.4 )TaO4; the material of the sealing layer is polysilazane resin and inorganic filler boron carbide, silicon nitride and boron nitride colloidal. The thickness of the bonding layer is 100-120 µm, the thickness of (Y 0.6 Gd 0.4 )TaO4 in the high-temperature corrosion-resistant coating is 100-150 µm, the thickness of TaC is 100-150 µm, the thickness of the sealing layer is 10-20 µm, and the total thickness is 310-460 µm. That is, the coating comprises a bonding layer NiCoCrAlY arranged on a substrate and (Y 0.6 Gd 0.4 )TaO4 coating, TaC coating and sealing layer arranged on the bonding layer in turn from bottom to top.

[0045] The high-temperature corrosion-resistant coating is first sprayed on the bonding layer (Y 0.6 Gd 0.4 )TaO4 coating, and then TaC coating is sprayed, and the main principle is that (Y 0.6 Gd 0.4 )TaO4 (10.5×10 -6 K -1 ) is close to the thermal expansion coefficient of the stainless steel lance substrate (13×10 -6 K -1 ), and (Y0.6 Gd 0.4 )TaO4 and TaC (6.3×10 -6 K -1 ) are close to each other, but the thermal expansion coefficients of TaC coating and stainless steel spray gun substrate are quite different. In order to avoid the coating peeling failure caused by thermal mismatch, (Y 0.6 Gd 0.4 )TaO4 coating, then spray TaC coating. In addition, (Y 0.6 Gd 0.4 )TaO4 has low thermal conductivity and oxygen ion conductivity, which effectively reduces heat transfer and oxygen penetration into the spray gun base. TaC has a high melting point (3880℃) and slag corrosion resistance. It is sprayed on (Y 0.6 Gd 0.4 )TaO4 surface, which helps to further improve the high temperature resistance and corrosion resistance of the coating system.

[0046] Specifically, the bonding layer is prepared by supersonic flame spraying NiCoCrAlY, and the high temperature resistant and corrosion resistant coating is prepared by atmospheric plasma spraying (Y 0.6 Gd 0.4 )TaO4 coating and TaC coating are prepared, and the sealing layer is obtained by brushing polysilazane resin and inorganic filler boron carbide, silicon nitride and boron nitride colloid.

[0047] A method for preparing a high-temperature resistant and corrosion-resistant coating for an oxygen-enriched smelting top-blowing spray gun includes pretreatment, bonding layer preparation, high-temperature resistant and corrosion-resistant coating preparation, sealing layer preparation, and drying steps. The specific steps are:

[0048] A. Pretreatment: Clean and sandblast the stainless steel spray gun base;

[0049] B. Bonding layer preparation: A NiCoCrAlY bonding layer was prepared on the surface of a pretreated stainless steel spray gun substrate using high velocity oxygen fuel (HVOF) spraying;

[0050] C. Preparation of high temperature resistant and corrosion resistant coating: atmospheric plasma spraying process is used to prepare (Y 0.6 Gd 0.4 )TaO4 coating and TaC coating;

[0051] D. Preparation of sealing layer: polysilazane resin, boron carbide, silicon nitride and boron nitride were mixed in a mass ratio of 5:1:1:1, stirred in a blender for 3 hours to obtain a nearly viscous colloid, and then applied to the surface of the high-temperature resistant and corrosion-resistant coating by brushing;

[0052] E. Drying: After the sealing layer is prepared, it is kept in an oven at 500°C for 10 hours to solidify.

[0053] In step B, a NiCoCrAlY bonding layer is prepared on the surface of the metal substrate by a supersonic flame spraying process. The parameters of the supersonic flame spraying process are: oxygen pressure 0.6~1.3MPa, hydrogen pressure 0.9~1.5MPa, powder feeding gas pressure 1.1~1.4MPa, and spraying distance 220~260mm.

[0054] In the step C (Y 0.6 Gd 0.4 )TaO4 and TaC particle size is 45~105μm, sphericity>95%, fluidity is 30~105s / 50g; (Y 0.6 Gd 0.4 ) The atmospheric plasma spraying process parameters of the TaO4 coating are: spraying voltage 70~78V, current 545~630A, argon flow rate 20~25L / min, hydrogen flow rate 4~6L / min, powder feeding rate 30~40g / min, and spraying distance 80~100mm; the atmospheric plasma spraying process parameters of the TaC coating are: spraying voltage 75~80V, current 620~650A, argon flow rate 20~30L / min, hydrogen flow rate 6~8L / min, powder feeding rate 30~40g / min, and spraying distance 80~100mm.

[0055] In step E, drying is performed in air for >10 hours. Specifically, polysilazane resin, boron carbide, silicon nitride, and boron nitride are mixed in a mass ratio of 5:1:1:1 and stirred in a blender for 3 hours to obtain a nearly viscous colloid. The viscous colloid is then applied to the surface of the high-temperature-resistant and corrosion-resistant coating and then cured in an oven at 500°C for 10 hours.

[0056] In other words, if Figures 1 to 4 As shown, the self-healing thermal barrier coating for resisting CMAS corrosion of the present invention comprises a bonding layer arranged on a substrate and (Y 0.6 Gd 0.4 )TaO4 and TaC high temperature resistant corrosion resistant coating, sealing layer. The material of the bonding layer is NiCoCrAlY; the material of the high temperature resistant corrosion resistant coating is (Y 0.6 Gd 0.4 )TaO4 and TaC; the sealing layer is a colloid of polysilazane resin and inorganic fillers boron carbide, silicon nitride and boron nitride.

[0057] The thickness of the bonding layer is 100-120 μm, and the high temperature resistant and corrosion resistant coating (Y 0.6 Gd 0.4The thickness of TaO4 is 100-150 µm, the thickness of TaC is 100-150 µm, the thickness of the sealing layer is 10-20 µm, and the total thickness is 310-460 µm.

[0058] The high-temperature corrosion-resistant coating is prepared by first spraying a (Y 0.6 Gd 0.4 )TaO4 coating on the bonding layer and then spraying a TaC coating. 0.6 Gd 0.4 The bonding layer is prepared by supersonic flame spraying NiCoCrAlY, the high-temperature corrosion-resistant coating is prepared by atmospheric plasma spraying (Y 0.6 Gd 0.4 )TaO4 coating and a TaC coating, and the sealing layer is prepared by brushing a colloidal mixture of polysilazane resin, boron carbide, silicon nitride, and boron nitride.

[0059] The present application also provides a preparation method of the high-temperature corrosion-resistant coating.

[0060] A. Pretreatment: cleaning and sandblasting the stainless steel lance base;

[0061] B. Bonding layer preparation: preparing a NiCoCrAlY bonding layer on the surface of the pretreated stainless steel lance base by supersonic flame spraying (HVOF);

[0062] C. High-temperature corrosion-resistant coating preparation: preparing a (Y 0.6 Gd 0.4 )TaO4 coating and a TaC coating on the bonding layer by atmospheric plasma spraying;

[0063] D. Sealing layer preparation: mixing polysilazane resin, boron carbide, silicon nitride, and boron nitride at a mass ratio of 5:1:1:1, stirring for 3 hours to obtain a nearly thick colloidal mixture, and brushing the colloidal mixture on the surface of the high-temperature corrosion-resistant coating;

[0064] E. Drying: after the sealing layer preparation, drying the sealing layer in a 500℃ oven for 10 hours for solidification.

[0065] In the B step, the NiCoCrAlY bonding layer is prepared on the surface of the metal base by supersonic flame spraying, and the parameters of the supersonic flame spraying process are as follows: oxygen pressure 0.6-1.3 MPa, hydrogen pressure 0.9-1.5 MPa, powder feeding pressure 1.1-1.4 MPa, and spraying distance 220-260 mm.

[0066] In the C step, the (Y 0.6 Gd 0.4)TaO4 and TaC particle size is 45~105μm, sphericity>95%, fluidity is 30~105s / 50g; (Y 0.6 Gd 0.4 ) The atmospheric plasma spraying process parameters of the TaO4 coating are: spraying voltage 70~78V, current 545~630A, argon flow rate 20~25L / min, hydrogen flow rate 4~6L / min, powder feeding rate 30~40g / min, and spraying distance 80~100mm; the atmospheric plasma spraying process parameters of the TaC coating are: spraying voltage 75~80V, current 620~650A, argon flow rate 20~30L / min, hydrogen flow rate 6~8L / min, powder feeding rate 30~40g / min, and spraying distance 80~100mm.

[0067] The high-temperature resistant and corrosion-resistant coating for an oxygen-enriched smelting top-blowing spray gun and its preparation method, wherein the step E is drying in an air atmosphere, and the drying time is greater than 10 hours.

[0068] Example 1

[0069] S100: Use acetone to remove stains on the surface of the centrifuge working base, and then sandblast the surface with corundum sand with a particle size of 40μm.

[0070] S200: Then, a NiCoCrAlY bonding layer with a thickness of about 100µm is sprayed on the surface of the pretreated metal substrate using the supersonic velocity oxygen fuel (HVOF) process. The process parameters of the supersonic velocity oxygen fuel (HVOF) spraying are: oxygen pressure 1.3MPa, hydrogen pressure 1.5MPa, powder feed gas pressure 1.4MPa, and spraying distance 260mm.

[0071] S300: A layer of doped modified rare earth tantalate (Y) with a thickness of about 150µm is sprayed on the bonding layer using atmospheric plasma spraying technology. 0.6 Gd 0.4 ) TaO4 coating, where the atmospheric plasma spraying process parameters are: spray voltage 70V, current 630A, argon flow rate 25L / min, hydrogen flow rate 6L / min, powder feed rate 40g / min, and spray distance 100mm. Then, a TaC coating with a thickness of approximately 100µm was sprayed on the bonding layer using atmospheric plasma spraying process parameters: spray voltage 80V, current 650A, argon flow rate 30L / min, hydrogen flow rate 8L / min, powder feed rate 40g / min, and spray distance 100mm.

[0072] S400: Polysilazane resin, boron carbide, silicon nitride and boron nitride are mixed in a mass ratio of 5:1:1:1, stirred for 3 hours with a blender to obtain a nearly thick colloid, which is brushed on the surface of the high-temperature corrosion-resistant coating with a thickness of about 10 μm, and then cured in an oven at 500°C for 10 hours. The total thickness of the bonding layer, high-temperature corrosion-resistant coating and sealing layer prepared above is 360 μm.

[0073] As shown in Figure 1 (a), the doped modified rare earth tantalate (Y 0.6 Gd 0.4 )TaO4 has a thermal expansion coefficient of 10.5×10 -6 K -1 at 1200°C, which is close to the thermal expansion coefficient of the bonding layer NiCoCrAlY (13×10 -6 K -1 ) and also close to the thermal expansion coefficient of TaC (6.3×10 -6 K -1 ), so that (Y 0.6 Gd 0.4 )TaO4 coating is sprayed on the bonding layer first, and then TaC coating is sprayed, which can effectively avoid the peeling failure of the coating caused by thermal mismatch. As shown in Figure 1 (b), (Y 0.6 Gd 0.4 )TaO4 has a lower thermal conductivity (about 1.52 W·m -1 ·K -1 ) at 800°C, indicating that (Y 0.6 Gd 0.4 )TaO4 has higher thermal insulation performance. As shown in Figure 1 (c), (Y 0.6 Gd 0.4 )TaO4 has a lower oxygen ion conductivity (about 2.8×10 -5 S·cm -1 ) at 800°C, indicating that (Y 0.6 Gd 0.4 )TaO4 has excellent oxygen barrier performance, inhibits the oxidation rate of the stainless steel spray gun, and improves its service life. After the spray gun with the bonding layer, high-temperature corrosion-resistant coating and sealing layer is placed in an Isa furnace for 5 hours, the top end coating of the spray gun tube is taken for XRD characterization, as shown in Figure 2 From Figure 2 it can be seen that there is basically no oxide composition, only some Ni3Fe slag. From Figure 3It can be found that the bonding layer does not occur obvious oxidation, further through energy spectrum analysis, no slag composition is tested, indicating that the ceramic layer and the slag do not have obvious reaction diffusion behavior, and the coating system has good high-temperature resistance and slag corrosion resistance and oxidation resistance.

[0074] Comparative Example 1

[0075] The difference from Example 1 is that no sealing layer is made, and after being placed in the isar furnace for 5 hours, as shown in Figure 4 , the bonding layer is severely oxidized compared with Example 1, indicating that the sealing layer hinders the penetration of gas, and further through energy spectrum analysis, it is found that the coating contains copper composition, indicating that the slag penetrates into the coating through pores or cracks.

[0076] Comparative Example 2

[0077] The difference from Example 1 is that there is no TaC coating, and after being placed in the isar furnace for 5 hours, as shown in Figure 5 , the bonding layer is not obviously oxidized compared with Example 1. Further through energy spectrum analysis, it is found that the coating contains copper composition, indicating that the slag reacts and diffuses to the coating surface through the sealing layer.

[0078] Comparative Example 3

[0079] The difference from Example 1 is that there is no (Y 0.6 Gd 0.4 )TaO4coating, and after being placed in the isar furnace for 5 hours, as shown in Figure 6 , the bonding layer is partially oxidized compared with Example 1. Further through energy spectrum analysis, it is found that the coating contains copper composition, indicating that the slag reacts and diffuses to the coating surface through the sealing layer.

[0080] Example 2

[0081] S100: Remove stains on the surface of the centrifuge working substrate with acetone, and then perform surface sand blasting treatment with corundum sand with a particle size of 40 pm.

[0082] S200: Then, a layer of NiCoCrAlY bonding layer with a thickness of about 120 pm is sprayed on the surface of the pretreated metal substrate by using a high-velocity oxygen fuel spraying (HVOF) process, wherein the process parameters of the high-velocity oxygen fuel spraying (HVOF) process are as follows: oxygen pressure 0.6 MPa, hydrogen pressure 0.9 MPa, powder feeding gas pressure 1.1 MPa, and spraying distance 220 mm.

[0083] S300: A layer of doped modified rare earth tantalate (Y 0.6 Gd 0.4) TaO4 coating, where the atmospheric plasma spraying process parameters are: spray voltage 78V, current 545A, argon flow rate 20L / min, hydrogen flow rate 4L / min, powder feed rate 30g / min, and spray distance 80mm. Then, a TaC coating with a thickness of approximately 150µm was sprayed on the bonding layer using the atmospheric plasma spraying process parameters: spray voltage 75V, current 620A, argon flow rate 20L / min, hydrogen flow rate 6L / min, powder feed rate 30g / min, and spray distance 80mm.

[0084] S400: Polysilazane resin, boron carbide, silicon nitride, and boron nitride were mixed in a mass ratio of 5:1:1:1 and stirred in a blender for 3 hours to obtain a nearly viscous colloid. This colloid was then applied to the surface of the high-temperature and corrosion-resistant coating to a thickness of approximately 20µm. The mixture was then cured in a 500°C oven for 10 hours. The total thickness of the adhesive layer, high-temperature and corrosion-resistant coating, and sealing layer prepared in this manner was 490µm.

[0085] After the coating system prepared in Example 2 was placed in an ISA furnace for 5 hours, no copper was found in the coating, indicating that no significant reaction and diffusion occurred between the ceramic layer and the slag. At the same time, no significant oxidation was found in the bonding layer.

[0086] Comparative Example 4

[0087] The difference from Example 2 is that the thickness of the sealing layer is 5µm. After being placed in the Isa furnace for 5 hours, the bonding layer was partially oxidized compared to Example 2. Further energy spectrum analysis revealed that the coating contained trace amounts of copper, indicating that slag and gas diffused through the sealing layer to the coating surface. Therefore, the thickness of the sealing layer should be above 10µm.

Claims

1. A high temperature corrosion resistant coating for an oxygen-enriched smelting top- blown lance, characterized in that, The coating comprises a bonding layer arranged on a substrate stainless steel spray gun, and a high-temperature corrosion-resistant coating and a sealing layer arranged on the bonding layer in turn from bottom to top, with a total thickness of 310-460µm; The material of the bonding layer is NiCoCrAlY, which is prepared by supersonic flame spraying NiCoCrAlY, with a thickness of 100-120µm; The material of the high-temperature-resistant and corrosion-resistant coating is TaC and doped and modified (Y 0.6 Gd 0.4 )TaO4, and the coating is prepared by spraying (Y 0.6 Gd 0.4 )TaO4 on the bonding layer by using atmospheric plasma and then spraying a TaC coating. 0.6 Gd 0.4 The thickness of the (Y Gd )TaO4 coating is 100-150 µm, and the thickness of the TaC coating is 100-150 µm. The material of the sealing layer is polysilazane resin, inorganic filler boron carbide, silicon nitride and boron nitride, mixed in a mass ratio of 5:1:1:1, stirred for 3 hours to obtain a nearly thick colloidal, which is brushed on the surface of the high-temperature corrosion-resistant coating, with a thickness of 10-20µm.

2. A process for the production of a high temperature corrosion resistant coating for an oxygen enriched smelting top blown lance as claimed in claim 1, characterized in that, The process comprises the steps of pretreatment, bonding layer preparation, high-temperature corrosion-resistant coating preparation, sealing layer preparation and drying: A, pretreatment: cleaning and sandblasting the stainless steel spray gun substrate; B, bonding layer preparation: supersonic flame spraying is adopted to prepare a NiCoCrAlY bonding layer on the surface of the pretreated stainless steel spray gun substrate, with the spraying process parameters of oxygen pressure 0.6-1.3MPa, hydrogen pressure 0.9-1.5MPa, powder feeding gas pressure 1.1-1.4MPa, and spraying distance 220-260mm; C. High-temperature-resistant and corrosion-resistant coating preparation: (Y 0.6 Gd 0.4 )TaO4 coating and TaC coating are prepared on the adhesive layer by atmospheric plasma spraying process, respectively. The particle size of (Y 0.6 Gd 0.4 )TaO4 and TaC is 45-105 µm, the sphericity is >95%, and the fluidity is 30-105 s / 50g. The spraying process parameters of the (Y 0.6 Gd 0.4 )TaO4 coating are spraying voltage 70-78 V, current 545-630 A, argon flow rate 20-25 L / min, hydrogen flow rate 4-6 L / min, powder feeding rate 30-40 g / min, and spraying distance 80-100 mm. The spraying process parameters of the TaC coating are spraying voltage 75-80 V, current 620-650 A, argon flow rate 20-30 L / min, hydrogen flow rate 6-8 L / min, powder feeding rate 30-40 g / min, and spraying distance 80-100 mm. D, sealing layer preparation: polysilazane resin, boron carbide, silicon nitride and boron nitride are mixed in a mass ratio of 5:1:1:1, stirred for 3 hours to obtain a nearly thick colloidal, which is brushed on the surface of the high-temperature corrosion-resistant coating; E, drying: after the sealing layer preparation is completed, it is cured in an oven at 500℃ for 10 hours.

3. The preparation method according to claim 2, characterized in that The spraying process parameters in step B are oxygen pressure 1.3MPa, hydrogen pressure 1.5MPa, powder feeding gas pressure 1.4MPa, and spraying distance 260mm.

4. The preparation method according to claim 2, characterized in that (Y 0.6 Gd 0.4 )TaO4coating spraying thickness 150 pm, spraying process parameters are spraying voltage 70 V, current 630 A, argon flow rate 25 L / min, hydrogen flow rate 6 L / min, powder feeding rate 40 g / min, spraying distance 100 mm; TaC coating spraying thickness 100 pm, spraying process parameters are spraying voltage 80 V, current 650 A, argon flow rate 30 L / min, hydrogen flow rate 8 L / min, powder feeding rate 40 g / min, spraying distance 100 mm.

5. The preparation method according to claim 2, characterized in that Step E is drying in air atmosphere.

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