A method for preparing a liquid-phase multi-component binder slurry-type chromium-nickel co-permeation coating layer

Abstract

The application discloses a preparation method of a liquid-phase multi-component composite binder slurry method chromium-nickel co-permeation coating, which comprises the following steps: electrolytic activation and preheating after cleaning a workpiece, coating a chromium-nickel metal slurry coating on the surface of the workpiece, then segmentally drying and solidifying, and finally rapidly sintering to obtain the chromium-nickel co-permeation coating, wherein the composition of the chromium-nickel metal slurry coating comprises solid-phase components and liquid-phase components. The chromium-nickel high-temperature corrosion-resistant coating prepared by the method has the advantages of simple preparation process, high preparation efficiency, small pollution, adjustable thickness, good wear resistance, excellent high-low temperature corrosion resistance and steam oxidation resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of material surface coatings, and in particular relates to a method for preparing a chromium-nickel co-penetration coating using a liquid-phase multi-component composite adhesive through a slurry method. Background Art

[0002] Currently, the most common anti-corrosion technology is the infiltration of corrosion-resistant metals on alloy surfaces, such as Cr, Si, and Al. Cr infiltration forms a Cr2O3 film on the alloy surface, and the compactness of chromium oxide hinders water vapor corrosion of the substrate. Si infiltration improves the corrosion resistance of the substrate itself, and the combination of the two improves overall corrosion resistance. The corrosion resistance of the coating is limited by surface defects in the metal powder coating film. Due to limitations in the coating preparation process, the coating's adhesion is often poor, resulting in a limited coating lifespan. Summary of the Invention

[0003] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0004] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0005] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a chromium-nickel co-penetration coating using a slurry method with a liquid-phase multi-component composite binder.

[0006] In order to solve the above technical problems, the present invention provides the following technical solution: it includes cleaning the workpiece, electrolytically activating it and then preheating it, applying a chromium-nickel metal slurry coating to the surface of the workpiece, then drying and curing it in sections, and finally rapidly sintering it, wherein the chromium-nickel metal slurry coating is composed of a solid phase component and a liquid phase component.

[0007] As a preferred embodiment of the preparation method of the present invention, the solid phase components include, by mass percentage, 50-80% chromium powder, 0-10% nickel powder, 2-20% iron, 0-5% aluminum powder and 0-45% lanthanum oxide.

[0008] As a preferred embodiment of the preparation method of the present invention, the liquid phase components include, by mass percentage, 10-30% Al(H2PO4)3, 5-15% water glass, 5-10% ammonium bromide, 10-30% acrylic resin, 10-30% epoxy resin and 10-30% curing agent.

[0009] As a preferred solution of the preparation method of the present invention, the workpiece includes but is not limited to carbon steel, austenitic stainless steel and high-temperature alloy.

[0010] As a preferred embodiment of the preparation method of the present invention, the preheating temperature is 150-220° C. and the preheating time is 30-60 minutes.

[0011] As a preferred embodiment of the preparation method of the present invention, the solid phase component and the liquid phase component are mixed at a solid-liquid (g:ml) ratio of 10:1 to 5.

[0012] As a preferred embodiment of the preparation method of the present invention, the solid phase component is ground at a speed of 350 to 400 r / min for a time of 6 to 24 hours.

[0013] As a preferred embodiment of the preparation method of the present invention, the staged drying and curing comprises pre-drying at 75-85°C for 5-30 minutes, then drying at 140-160°C for 30-60 minutes, and finally medium-temperature curing at 250-300°C for 30-60 minutes.

[0014] As a preferred embodiment of the preparation method of the present invention, the sintering temperature is 900-1150° C. and the sintering time is 5-30 minutes.

[0015] Another object of the present invention is to overcome the deficiencies in the prior art and provide a chromium-nickel co-penetration coating prepared by a slurry method of a liquid-phase multi-component composite binder.

[0016] Beneficial effects of the present invention:

[0017] (1) The metal powder raw material described in the present invention is suitable for various metal workpieces whose surfaces need to be strengthened, including carbon steel, austenitic stainless steel, and high-temperature alloy workpieces. It has a wide range of applications and is extremely practical.

[0018] (2) The metal powder-infiltrated chromium-nickel high-temperature corrosion-resistant coating and its preparation method described in the present invention do not need to be carried out under vacuum conditions, and the preparation process is simple. At the same time, the chromium-nickel infiltrated layer has high preparation efficiency, low pollution, adjustable thickness, good wear resistance, and especially excellent resistance to high and low temperature corrosion and steam oxidation.

[0019] (3) The metal powder-infiltrated chromium-nickel high-temperature corrosion-resistant coating of the present invention has a liquid phase composed of a variety of organic binders, which can comprehensively improve the adhesion of the coating and help extend the service life of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0021] Figure 1 This is a cross-sectional morphology of the chromium-rich high-temperature corrosion-resistant coating prepared on the surface of austenitic steel in Example 1 of the present invention.

[0022] Figure 2 This is a cross-sectional morphology of the chromium-rich high-temperature corrosion-resistant coating prepared on the surface of austenitic steel in Example 5 of the present invention. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0026] Unless otherwise specified, the raw materials used in the examples of the present invention are commercially available.

[0027] Example 1

[0028] 1) Pipeline surface cleaning

[0029] Use alcohol / acetone to clean the oil stains, dust, etc. on the surface of the pipe, and use a steel brush to remove the surface oxide scale. Place the treated workpiece in the electrolytic cell with the workpiece to be treated as the anode and graphite as the cathode. 2 Electrolysis was carried out for 100 s. The electrolyte consisted of NiCl2·6H2O, HCl and NaCl.

[0030] 2) Slurry coating on pipeline surface

[0031] After preheating the pipe at 220℃ for 30 minutes, apply the slurry to the appropriate thickness in one go by spraying (or brushing, etc.). Do not apply the slurry in multiple layers; the thickness of the coating slurry layer is 0.5mm.

[0032] The preparation method of the metal powder coating raw material is as follows: according to the mass percentage of the solid phase components, 50% chromium powder, 10% nickel powder, 10% iron, 5% aluminum powder and 25% lanthanum oxide are weighed respectively, and the mixed metal mixed powder is ball milled at a ball milling speed of 350 r / min and a ball milling time of 8 hours to obtain the final solid phase component.

[0033] The liquid phase component is composed of 30% Al(H2PO4)3, 15% water glass, 10% ammonium bromide, 15% acrylic resin, 10% epoxy resin, and 20% curing agent, measured by mass percentage, and stirred to obtain a liquid phase component. The solid phase component and the liquid phase component are then mixed at a solid-liquid (g:ml) ratio of 10:2 to obtain the final metal powder coating raw material.

[0034] 3) Drying and curing

[0035] The metal pipe coated with the chromizing material was pre-dried at 60°C for 5 minutes, then dried at 100°C for 55 minutes, and finally cured at 250°C for 30 minutes.

[0036] 4) Rapid sintering

[0037] The pipe was rapidly sintered and diffused chromized by a rapid heating method, and then air-cooled to room temperature; the heating rate was set to 1000℃ / min, the holding temperature was 950℃, and the holding time was 30min.

[0038] Example 2

[0039] 1) Pipeline surface cleaning

[0040] Use alcohol / acetone to clean the oil stains, dust, etc. on the surface of the pipe, and use a steel brush to remove the surface oxide scale. Place the treated workpiece in the electrolytic cell with the workpiece to be treated as the anode and graphite as the cathode. 2 Electrolysis was carried out for 100 s. The electrolyte consisted of NiCl2·6H2O, HCl and NaCl.

[0041] 2) Slurry coating on pipeline surface

[0042] After preheating the pipe at 220℃ for 20 minutes, apply the slurry to the appropriate thickness in one go by spraying (or brushing, etc.). Do not apply the slurry in multiple layers; the thickness of the coating slurry layer is 0.5mm.

[0043] The preparation method of the metal powder coating raw material is as follows: according to the mass percentage of the solid phase components, 65% of chromium powder, 5% of nickel powder, 5% of iron, 5% of aluminum powder and 20% of lanthanum oxide are weighed respectively, and the mixed metal mixed powder is ball milled at a ball milling speed of 400 r / min and a ball milling time of 8 hours to obtain the final solid phase component.

[0044] The liquid phase component is composed of 20% Al(H2PO4)3, 10% water glass, 7% ammonium bromide, 20% acrylic resin, 18% epoxy resin, and 25% curing agent, measured by mass percentage, and stirred to obtain a liquid phase component. The solid phase component and the liquid phase component are then mixed at a solid-liquid (g:ml) ratio of 10:3 to obtain the final metal powder coating raw material.

[0045] 3) Drying and curing

[0046] The metal pipe coated with the chromizing material was pre-dried at 70°C for 5 minutes, then dried at 120°C for 55 minutes, and finally cured at 300°C for 30 minutes.

[0047] 4) Rapid sintering

[0048] The pipe was rapidly sintered and diffused chromized by a rapid heating method, and then air-cooled to room temperature; the heating rate was set to 1000°C / min, the holding temperature was 1000°C, and the holding time was 30min.

[0049] Example 3

[0050] 1) Pipeline surface cleaning

[0051] Use alcohol / acetone to clean the oil stains, dust, etc. on the surface of the pipe, and use a steel brush to remove the surface oxide scale. Place the treated workpiece in the electrolytic cell with the workpiece to be treated as the anode and graphite as the cathode. 2 Electrolysis was carried out for 100 s. The electrolyte consisted of NiCl2·6H2O, HCl and NaCl.

[0052] 2) Slurry coating on pipeline surface

[0053] After preheating the pipeline at 200℃ for 50 minutes, apply the slurry to the appropriate thickness in one go by spraying (or brushing, etc.). Do not apply the slurry in multiple layers; the thickness of the coating slurry layer is 1.0mm.

[0054] The preparation method of the metal powder coating raw material is as follows: according to the mass percentage of the solid phase components, 80% of chromium powder, 5% of nickel powder, 2% of iron, 3% of aluminum powder and 10% of lanthanum oxide are weighed respectively, and the mixed metal mixed powder is ball milled at a ball milling speed of 400 r / min and a ball milling time of 24 hours to obtain the final solid phase component.

[0055] The liquid phase component is obtained by mixing and stirring 20% ​​Al(H2PO4)3, 10% water glass, 5% ammonium bromide, 30% acrylic resin, 30% epoxy resin, and 15% curing agent, calculated by weight. The solid phase component and the liquid phase component are then mixed at a solid-liquid (g:ml) ratio of 10:1 to 5 to obtain a final metal powder coating raw material.

[0056] 3) Drying and curing

[0057] The metal pipe coated with the chromizing material was pre-dried at 80°C for 10 minutes, then dried at 150°C for 30 minutes, and finally cured at 300°C for 20 minutes.

[0058] 4) Rapid sintering

[0059] The pipe was rapidly sintered and diffused chromized by a rapid heating method, and then air-cooled to room temperature; the heating rate was set to 1000℃ / min, the holding temperature was 1150℃, and the holding time was 20min.

[0060] Example 4

[0061] 1) Pipeline surface cleaning

[0062] Use alcohol / acetone to clean the oil stains, dust, etc. on the surface of the pipe, and use a steel brush to remove the surface oxide scale. Place the treated workpiece in the electrolytic cell with the workpiece to be treated as the anode and graphite as the cathode. 2 Electrolysis was carried out for 100 s. The electrolyte consisted of NiCl2·6H2O, HCl and NaCl.

[0063] 2) Slurry coating on pipeline surface

[0064] After preheating the pipe at 220℃ for 30 minutes, apply the slurry to the appropriate thickness in one go by spraying (or brushing, etc.). Do not apply the slurry in multiple layers; the thickness of the coating slurry layer is 0.8mm.

[0065] The preparation method of the metal powder coating raw material is as follows: according to the mass percentage of the solid phase components, 70% of chromium powder, 5% of nickel powder, 3% of iron, 2% of aluminum powder and 20% of lanthanum oxide are weighed respectively, and the mixed metal mixed powder is ball milled at a ball milling speed of 350 to 400 r / min and a ball milling time of 6 to 24 hours to obtain the final solid phase component.

[0066] The liquid phase component is prepared by mixing and stirring 10% Al(H2PO4), 5% water glass, 5% ammonium bromide, 20% acrylic resin, 30% epoxy resin, and 30% curing agent, based on mass percentage. The solid phase component is then mixed with the liquid phase component at a solid-to-liquid (g:ml) ratio of 10:1 to 5 to obtain a final metal powder coating raw material.

[0067] 3) Drying and curing

[0068] The metal pipe coated with the chromizing material was pre-dried at 60°C for 5 minutes, then dried at 100°C for 55 minutes, and finally cured at 250°C for 30 minutes.

[0069] 4) Rapid sintering

[0070] The pipe was rapidly sintered and diffused chromized by a rapid heating method, and then air-cooled to room temperature; the heating rate was set to 1000°C / min, the holding temperature was 1100°C, and the holding time was 30min.

[0071] Example 5

[0072] The difference from Example 4 is that the liquid phase components are measured in mass percentage, including 25% Al(H2PO4), 10% water glass, 7% ammonium bromide, 20% acrylic resin, 18% epoxy resin and 20% curing agent.

[0073] The prepared coal ash is fully ground and an appropriate amount of acetone is added to form a suspension, which is then evenly coated on the surface of the chromium-nickel cladding coating sample prepared in Examples 1 to 5, with a coating amount of about 50 mg / cm2. The sample is placed in a constant temperature tubular heating furnace and heated to 750°C. Mixed flue gas is continuously introduced into the tubular furnace with a flue gas flow rate of 100 mL / min. A honeycomb Pt mesh is used as a catalyst to convert SO2 into SO3. A saturated NaOH solution is used to neutralize the remaining SO2 in the tail gas at the outlet of the tubular furnace. When the corrosion test is carried out for 50h, 200h, 300h and 500h, the sample is taken out, the coal ash remaining on the surface is removed, and the sample is weighed after cleaning and drying. The mass change (mg / cm2) of the chromium-nickel cladding coating prepared in Examples 1 to 5 in coal ash / flue gas at 750°C is shown in Table 1. 2 ) as shown in Table 1.

[0074] Table 1 Mass change of the chromium-nickel co-penetrated coating prepared in Examples 1 to 5 in 750°C coal ash / flue gas (mg / cm 2 )

[0075]

[0076] Figure 1 This is a cross-sectional morphology of the chromium-rich high-temperature corrosion-resistant coating prepared on the surface of austenitic steel in Example 1 of the present invention. Figure 2 This is a cross-sectional morphology of the chromium-rich high-temperature corrosion-resistant coating prepared on the surface of austenitic steel in Example 5 of the present invention. The chromium-nickel cladding coating prepared in Example 1 deteriorated in stability after corrosion for more than 300 hours in a 750°C coal ash / flue gas environment, began to lose weight, and the oxide film peeled off in large quantities; the chromized coatings prepared in Examples 2 and 3 gradually accelerated in corrosion rate after corrosion for more than 200 hours, with corrosion rates of 0.0119 mg / (cm 2 h) and 0.0139 mg / (cm 2 ·h), the corrosion resistance of the coating is poor; the weight gain trend of the chromium-nickel corrosion-resistant coating prepared in Example 4 within 500h conforms to the linear law, and the corrosion rate of the coating in a 750℃ coal ash / flue gas environment is basically stable; the weight gain trend of the coating prepared in Example 5 conforms to the parabolic law, and the coating has good corrosion resistance in a 650℃ coal ash / flue gas environment.

[0077] The hardness of the base material and the coatings prepared in Examples 1 to 5 was measured using a HV-1000A microhardness tester. The test load was 200 g, the holding time was 10 s, and 6 points at different horizontal positions were selected for testing, and the average value was taken. The hardness of the austenitic steel base material is 250 HV 0.2 The microhardness of the coatings prepared in Examples 1 to 5 is 269 HV 0.2 、281HV 0.2 、303HV 0.2 、328HV 0.2 and 403HV 0.2 , indicating that the chromium-nickel co-penetration coating prepared in the present invention can strengthen the matrix structure and improve the hardness and wear resistance of the pipe wall surface.

[0078] Comparative Example 1

[0079] The difference between this comparative example and Example 5 is that the liquid phase components are replaced by: 25% Al(H2PO4)3, 10% water glass, 7% ammonium bromide, 38% acrylic resin, and 20% curing agent.

[0080] Comparative Example 2

[0081] The difference between this comparative example and Example 5 is that the liquid phase components are replaced by: 25% Al(H2PO4)3, 10% water glass, 7% ammonium bromide, 38% epoxy resin, and 20% curing agent.

[0082] Comparative Example 3

[0083] The difference between this comparative example and Example 5 is that the liquid phase components are replaced by: 25% Al(H2PO4)3, 10% water glass, 7% ammonium bromide, 38% vinyl ester, and 20% curing agent.

[0084] Comparative Example 4

[0085] The difference between this comparative example and Example 5 is that the solid phase components are replaced by: 70% chromium powder, 5% nickel powder and 25% lanthanum oxide.

[0086] Comparative Example 5

[0087] The difference between this comparative example and Example 5 is that the solid phase components are replaced by: 80% chromium powder, 15% nickel powder, 3% iron and 2% aluminum powder.

[0088] Comparative Example 6

[0089] The difference between this comparative example and Example 5 is that the pretreatment process of the workpiece in step (1) is changed to using alcohol / acetone to clean oil stains, dust, etc. on the surface of the pipeline, and after removing the surface oxide scale with a steel brush, the pipeline is directly preheated at 220°C for 30 minutes without activation.

[0090] The corrosion resistance of the chromium-nickel cladding coating samples prepared in Example 5 and Comparative Examples 1 to 6 was tested in coal ash / smoke at 750°C. The mass change (mg / cm 2 ) as shown in Table 2.

[0091] Table 2 Mass changes of the chromium-nickel co-penetrated coatings prepared in Example 5 and Comparative Examples 1 to 6 in 750°C coal ash / flue gas (mg / cm 2 )

[0092]

[0093] The bond strength of the adhesive samples prepared in Example 5 and Comparative Examples 1-3 was tested in accordance with the requirements of GB / T 31541-2015, "Test Method for Interfacial Tensile and Shear Bond Strength of Fine Ceramics - Cross-Section Method." The bond strength between the adhesive sample prepared in Example 5 and the metal substrate was greater than 10 MPa, while the bond strengths of the adhesive samples prepared in Comparative Examples 1 and 2 were greater than 8 MPa but less than 10 MPa, and the bond strength of the adhesive sample prepared in Comparative Example 3 was less than 6 MPa. Acrylic resin can improve the bond strength of aluminum dihydrogen phosphate adhesives, and its enhanced bond strength is even greater when used in conjunction with epoxy resin for modification. In a 750°C coal ash / flue gas environment, the coating prepared in Comparative Example 3 showed deteriorating oxide film stability after corrosion time exceeded 300 hours, began to lose weight, and the oxide film peeled off in large quantities. The corrosion rate of the chromium-nickel cladding coatings prepared in Comparative Examples 1 and 2 gradually accelerated after corrosion time exceeded 200 hours. In summary, the multi-component composite binder used in the present invention can increase the concentration of chromium and nickel atoms on the outside of the tube wall by increasing the adhesion strength between the coating layer and the substrate, thereby improving the high and low temperature corrosion resistance and steam oxidation resistance of the carburized layer and extending the service life of the carburized layer.

[0094] After the corrosion time of the chromium-nickel cladding coating prepared in Comparative Example 6 exceeds 200 hours, the corrosion rate gradually accelerates and the corrosion resistance of the coating is poor, indicating that the electrolytic activation process can make the metal surface to be infiltrated in an "activated" state, increase the speed at which chromium and nickel atoms penetrate into the matrix, and thus improve the corrosion resistance of the coating.

[0095] The metal powder infiltrated chromium-nickel high-temperature corrosion-resistant coating and its preparation method described in the present invention do not need to be carried out under vacuum conditions, and the preparation process is simple. At the same time, the chromium-nickel infiltrated layer has high preparation efficiency, low pollution, adjustable thickness, good wear resistance, and especially excellent resistance to high and low temperature corrosion and steam oxidation.

[0096] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, and all of these should be included in the scope of the present invention.

Claims

1. A method for preparing a chromium-nickel co-penetration coating by a slurry method using a liquid-phase multi-component composite binder, characterized in that: The method comprises the following steps: cleaning the workpiece, electrolytically activating the workpiece, and then preheating the workpiece; applying a chromium-nickel metal slurry coating to the surface of the workpiece; drying and curing the workpiece in sections; and finally rapidly sintering the workpiece, wherein the chromium-nickel metal slurry coating comprises a solid phase component and a liquid phase component; The solid phase components include, by mass percentage, 50-80% chromium powder, 5-10% nickel powder, 2-20% iron, 2-5% aluminum powder, and 10-45% lanthanum oxide; The liquid phase components include, by mass percentage, 10-30% Al(H2PO4)3, 5-15% water glass, 5-10% ammonium bromide, 10-30% acrylic resin, 10-30% epoxy resin, and 10-30% curing agent; The solid phase component and the liquid phase component are mixed according to a solid-liquid (g:ml) ratio of 10:1-5.

2. The preparation method according to claim 1, wherein: The workpieces include, but are not limited to, carbon steel, austenitic stainless steel, and high temperature alloys.

3. The preparation method according to claim 1, wherein: The preheating temperature is 150-220° C., and the preheating time is 30-60 minutes.

4. The preparation method according to claim 1, wherein: The solid phase component is ground at a speed of 350-400 r / min for 6-24 hours.

5. The preparation method according to claim 1, wherein: The staged drying and curing comprises pre-drying at 75-85° C. for 5-30 minutes, drying at 140-160° C. for 30-60 minutes, and finally curing at a medium temperature of 250-300° C. for 30-60 minutes.

6. The preparation method according to claim 1, wherein: The sintering temperature is 900-1150° C., and the sintering time is 5-30 minutes.

7. The chromium-nickel co-penetration coating obtained by the preparation method according to claims 1 to 6.

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