Nickel-cadmium plating method for gas turbine blade made of Cr17Ni2 and 1Cr16Ni2MoN

Abstract

The invention provides a nickel-cadmium plating method for a gas turbine blade made of Cr17Ni2 and 1Cr16Ni2MoN. The nickel-cadmium plating method comprises the following steps of inspection before plating, clamping, chemical degreasing, degreasing solution cleaning, degreasing quality inspection, anode pickling, acid pickling solution static dissolution, acid pickling solution cleaning, activation, activation solution cleaning, nickel plating, nickel plating solution static dissolution and nickel plating solution cleaning. The method comprises the following steps: checking a nickel plating layer, plating cadmium, statically dissolving a cadmium plating solution, cleaning the cadmium plating solution, carrying out chemical passivation, not cleaning a passivation solution, refining and cleaning, drying, checking the cadmium plating layer, dismounting, annealing, and carrying out acceptance inspection. The method is fine in technological process, scientific in equipment selection, simple to operate, high in production efficiency, strict in quality control and environment-friendly, and a high-quality coating with good corrosion resistance, wear resistance and bonding strength can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of metal surface treatment, and in particular relates to a nickel-cadmium plating method for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN. Background Art

[0002] In the field of gas turbines, materials Cr17Ni2 and 1Cr16Ni2MoN are often used for gas turbine compressor blades due to their excellent mechanical properties, good corrosion resistance and easy processing. However, in order to provide higher performance of the blades, it is often necessary to further surface treat the blades to improve corrosion resistance, enhance wear resistance and improve surface properties. Specifically, improve corrosion resistance: gas turbine blades will be exposed to various corrosive media during operation, such as high-temperature gas, moisture and impurities in the air. Nickel-cadmium plating can form a dense protective film on the surface of the blades, effectively preventing the erosion of the blades by the corrosive media and improving the corrosion resistance of the blades. The purpose of improving corrosion resistance is: gas turbine blades will be exposed to various corrosive media during operation, such as high-temperature gas, moisture and impurities in the air. Nickel-cadmium plating can form a dense protective film on the surface of the blades, effectively preventing the erosion of the blades by the corrosive media and improving the corrosion resistance of the blades. The purpose of enhancing wear resistance is that during high-speed rotation of gas turbine blades, they will rub against the surrounding air and other components. Nickel-cadmium plating can improve the hardness and wear resistance of the blade surface, reduce blade wear, and extend the service life of the blade. The purpose of improving surface performance is that nickel-cadmium plating can make the blade surface smoother, reduce airflow resistance, and improve the efficiency of the gas turbine. At the same time, it can also improve the antioxidant properties of the blades and prevent the blades from oxidizing and discoloring at high temperatures.

[0003] There are some obvious deficiencies in the existing methods for nickel-cadmium plating of gas turbine blades. The existing methods are relatively simple in process, which often leads to a lack of fine control of each link in the process. For example, the pre-plating treatment stage is not sufficient to effectively remove the oxide film, impurities, etc. on the surface of the blade, thereby affecting the bonding strength and quality of the subsequent coating. In the process of nickel-cadmium plating, the control of parameters such as solution composition, temperature, time, and current density is not strict enough, which can easily cause problems such as uneven coating thickness, rough surface, and defects. Moreover, the existing methods are not clear enough in terms of equipment material and structural requirements, which makes it easy for equipment to not meet process requirements, solution leakage, uneven stirring, etc. during the production process, further affecting the coating quality and production efficiency. In addition, the existing methods do not pay enough attention to intermediate links such as cleaning and activation, resulting in insufficient bonding strength between the coating and the blade substrate, and problems such as coating delamination are prone to occur, reducing the service life and reliability of the blade.

[0004] In view of the disadvantages of existing methods, it is particularly necessary to develop a new nickel-cadmium plating method for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN materials. Summary of the Invention

[0005] The object of the present invention is to provide a nickel-cadmium plating method for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN materials. This method has a fine technological process, scientific equipment selection, simple operation, high production efficiency, strict quality control and environmental protection, and can obtain high-quality coatings with good corrosion resistance, wear resistance and bonding strength.

[0006] A nickel-cadmium plating method for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN materials, comprising the following steps:

[0007] S1, pre-plating inspection: Visually inspect the surface state of the blade on the inspection table before nickel-cadmium plating. The blade surface should be free of oxide film, scale, corrosion, indentation, burr, scratch, dent, burn, pores and abrasion.

[0008] S2, clamping: Clamp the blade onto a copper fixture. After clamping, it should be ensured that the solution can enter all the holes and recesses of the blade, and no bubbles should form on the blade surface and around it.

[0009] S3, chemical degreasing: Conduct chemical degreasing treatment in a degreasing tank with a solution composition of 30 - 50 g / L of trisodium phosphate and 3 - 5 g / L of OP-7 emulsifier. The degreasing temperature is 60 - 80 °C and the time is 10 - 20 minutes.

[0010] S4, cleaning the degreasing solution: Immerse the blade in a flowing hot water tank at 60 - 90 °C and wash it 3 - 5 times, with each washing time being 1 - 2 minutes.

[0011] S5, degreasing quality inspection: Immerse the blade in a flowing cold water tank and wash it 3 - 5 times, with each washing time being 1 - 2 minutes.

[0012] S6, anodic pickling: Use a core made of lead with 6% - 8% antimony added as the anode for the blade, and place it in an anodic pickling tank with a pickling solution composition of 150 - 250 g / L of chromic anhydride and 1.5 - 2.5 g / L of sulfuric acid for pickling. The pickling temperature is 60 - 65 °C, the current density is 50 - 60 A / dm², the time is 1 - 1.5 minutes, and Sa:Sk = 1:1, where Sa is the anode surface area and Sk is the cathode surface area.

[0013] S7, static dissolution of the pickling solution: Immerse the blade in a non-flowing cold water tank and wash it 3 - 5 times, with each washing time being 1 - 2 minutes.

[0014] S8, Cleaning the pickling solution: Immerse the blade in a flowing cold water tank and wash it 3 - 5 times, with each washing time being 1 - 2 minutes;

[0015] S9, Activation: Conduct activation treatment in an activation tank with a solution composition of 100 - 150 grams per liter of hydrochloric acid, at a treatment temperature of 18 - 30 degrees Celsius for 1 - 2 minutes;

[0016] S10, Cleaning the activation solution: Immerse the blade in a flowing cold water tank and wash it 3 - 5 times, with each washing time being 1 - 2 minutes;

[0017] S11, Nickel plating: Conduct nickel plating in a nickel plating tank with an electrolyte composition of 140 - 170 grams per liter of nickel sulfate, 10 - 15 grams per liter of nickel chloride hexahydrate, 130 - 170 grams per liter of sodium sulfate, 20 - 30 grams per liter of boric acid, at a nickel plating temperature of 28 - 35 degrees Celsius, a current density of 0.4 - 0.6 amperes per square decimeter, a time of 45 - 60 minutes, a pH value of 4 - 6, and Sa:Sk = 2:1;

[0018] S12, Static dissolution of the nickel plating solution: Immerse the blade in a non - flowing cold water tank and wash it 3 - 5 times, with each washing time being 1 - 2 minutes;

[0019] S13, Cleaning the nickel plating solution: Immerse the blade in a flowing cold water tank and wash it 3 - 5 times, with each washing time being 1 - 2 minutes;

[0020] S14, Inspecting the nickel plating layer: Inspect the nickel plating layer on the inspection table. The appearance of the nickel plating layer should be smooth, without bulging, bubbles, and delamination, and non - plating is not allowed;

[0021] S15, Cadmium plating: Conduct cadmium plating in a cadmium plating tank with an electrolyte composition of 40 - 500 grams per liter of cadmium sulfate, 48 - 52 grams per liter of sodium sulfate, 100 - 120 grams per liter of sodium sulfate, 3 - 5 grams per liter of OP - 7 emulsifier, at a cadmium plating temperature of 18 - 30 degrees Celsius, a current density of 1.5 - 2.5 amperes per square decimeter, a time of 6 - 10 minutes, and Sa:Sk = 2:1;

[0022] S16, Static dissolution of the cadmium plating solution: Immerse the blade in a non - flowing cold water tank and wash it 3 - 5 times, with each washing time being 1 - 2 minutes;

[0023] S17, Cleaning the cadmium plating solution: Immerse the blade in a flowing cold water tank and wash it 3 - 5 times, with each washing time being 1 - 2 minutes;

[0024] S18, Chemical passivation: Conduct chemical passivation in a passivation tank with a solution composition of 100 - 150 grams per liter of potassium dichromate, 10 - 15 grams per liter of sulfuric acid, 10 - 15 grams per liter of hydrochloric acid, at a passivation temperature of 18 - 30 degrees Celsius for 3 - 5 times;

[0025] S19, cleaning the passivation solution: immersing the blade in a non-flowing cold water tank for cleaning 3 to 5 times, each cleaning time being 1 to 2 minutes;

[0026] S20, fine cleaning: immerse the leaves in a still distilled water tank for cleaning 3 to 5 times, each cleaning time is 0.5 to 1 minute;

[0027] S21, drying: use clean compressed air to dry the moisture on the leaf surface;

[0028] S22, check the cadmium plating layer: check the cadmium plating layer on the inspection table. The nickel plating layer should be smooth, without bulging or delamination, and in the form of fine crystals;

[0029] S23, disassembly: remove the blade from the copper tooling on the disassembly table and store it in a dry and clean environment;

[0030] S24, annealing: heating the leaves in a drying oven for annealing, the annealing temperature is 350-370 degrees Celsius, the annealing time is 60-90 minutes, and the annealing time is counted from the time when the annealing temperature is reached;

[0031] S25, Acceptance inspection: Check the appearance of the nickel-cadmium coating, its adhesion strength to the blade base metal and its microhardness on the inspection bench.

[0032] Furthermore, the inspection tables described in S1, S14, S2, S25 and the disassembly table described in S23 are covered with polyvinyl chloride plastic.

[0033] Furthermore, the S3 degreasing tank and S4 flowing hot water tank are made of stainless steel, and are structurally provided with side air extraction ports, serpentine steam pipes with a pressure rating of 0.3 MPa, and compressed air agitators with a working pressure greater than 0.2 MPa.

[0034] Furthermore, the flowing cold water tanks in S5, S8, S10, S13 and S17 are made of stainless steel, and are structurally provided with a cleaning tank made of polyvinyl chloride plastic material and a compressed air agitator with a working pressure greater than 0.2 MPa.

[0035] Furthermore, the anode pickling tank in S6 is made of titanium, and is structurally provided with a side exhaust port and a serpentine steam pipe with a pressure resistance level of 0.3 MPa.

[0036] Furthermore, the non-flowing cold water tanks in S7, S12, S16 and S19 and the non-flowing distilled water tank in S20 are made of stainless steel, and are structurally provided with a cleaning basket made of polyvinyl chloride plastic material.

[0037] Furthermore, the activation tank in S9 and the passivation tank in S18 should be made of stainless steel, with a polyvinyl chloride plastic lining, a side air suction port and a compressed air agitator with a working pressure greater than 0.2 MPa.

[0038] Further, the nickel plating tank in S11 and the cadmium plating tank in S15 are made of stainless steel, and are structurally provided with a lining of polyvinyl chloride plastic and a side air extraction port.

[0039] Further, the compressed air in S21 blows the mirror surface or filter paper for at least 3 - 4 minutes per month, and there should be no moisture and oil residue on the mirror surface or filter paper.

[0040] Further, the drying oven in S24 can automatically adjust the temperature, with a temperature difference within ±10 degrees Celsius, to ensure that the blades are evenly heated.

[0041] The beneficial effects of the present invention are as follows:

[0042] 1. Fine process: Strictly inspect the surface of the blades before nickel - cadmium plating, eliminate various defects, and lay a foundation for high - quality coatings. Adopt chemical degreasing and multiple cleaning and activation steps to remove oil and impurities, strengthen the bonding strength between the coating and the substrate, and precisely control the process parameters of nickel plating and cadmium plating to ensure that the coating quality is stable, uniform, and smooth.

[0043] 2. Scientific equipment: Select equipment made of stainless steel for different process links, and equip specific structures to meet the process requirements. The copper - made tooling can be replaced by copper wire to increase the clamping flexibility, and at the same time, clarify the clamping requirements to ensure the uniformity of nickel - cadmium plating.

[0044] 3. Strict quality control: Set up multiple inspection links, including inspection of the nickel plating layer, cadmium plating layer, and acceptance inspection to ensure the coating quality. Conduct annealing treatment to eliminate the internal stress in the coating, enhance the bonding strength and stability, and extend the service life of the blades.

[0045] 4. Environmental protection consideration: Carefully select the solution components to reduce the degree of environmental pollution. The equipment structure fully considers environmental protection factors, such as having an air extraction port to exhaust waste gas, and standardizing the equipment cleaning and maintenance to reduce adverse effects.

[0046] 5. Stable coating quality: The present invention ensures the cleanliness of the blade surface, precise control of process parameters, and stable treatment of the solution through strict pre - plating inspection and cleaning, optimization of the nickel plating and cadmium plating process parameters, and the use of appropriate tooling and equipment, so that the coating thickness is uniform, dense, the appearance is smooth, and there are no defects such as bulging, bubbling, and delamination. Compared with the prior art, the stability of the coating quality is greatly improved.

[0047] 6. Good corrosion resistance: The nickel plating layer and cadmium plating layer of the present invention are tightly combined to form a good protective barrier, which can effectively prevent the blades from being corroded in harsh environments, and better adapt to the material properties of Cr17Ni2 and 1Cr16Ni2MoN, improve the bonding force between the coating and the base metal. Coupled with the dense oxide film formed by chemical passivation treatment, the corrosion resistance is further enhanced, and it has more excellent corrosion resistance performance compared with the prior art.

[0048] 7. Easy to operate: The nickel-cadmium plating method of the present invention has a simple and clear operation process, smooth connection of steps, easy for operators to master and execute. At the same time, the equipment adopted has a reasonable structure, easy to maintain and control. The clear operation conditions and parameter regulations facilitate accurate control of the process and quality monitoring management. Compared with the prior art, it can improve production efficiency, reduce operation errors, and make the operation more simple and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] The present invention will be further described below with reference to the drawings.

[0051] As Figure 1 shown, a nickel-cadmium plating method for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN materials includes the following steps:

[0052] S1. Pre-plating inspection: Visually inspect the surface state of the blade on the inspection table before nickel-cadmium plating. The blade surface should be free of oxide film, scale, corrosion, indentation, burr, scratch, dent, burn, pores and abrasion;

[0053] The inspection table desktop is covered with polyvinyl chloride plastic;

[0054] S2. Clamping: Clamp the blade onto a copper fixture. After clamping, it should be ensured that the solution can enter all the holes and recesses of the blade, and no bubbles should be formed on the blade surface and around it;

[0055] The copper fixture can be replaced by copper wire;

[0056] S3. Chemical degreasing: Conduct chemical degreasing treatment in a degreasing tank with a solution composition of 30 - 50 grams per liter of trisodium phosphate and 3 - 5 grams per liter of OP-7 emulsifier. The degreasing temperature is 60 - 80 degrees Celsius, and the time is 10 - 20 minutes;

[0057] The degreasing tank is made of stainless steel, with a side air extraction port, a serpentine steam pipe with a pressure resistance level of 0.3 MPa, and a compressed air stirrer with a working pressure greater than 0.2 MPa in terms of structure;

[0058] S4. Cleaning the degreasing solution: Immerse the blade in a flowing hot water tank at 60 - 90 degrees Celsius and wash it 3 - 5 times, with each washing time being 1 - 2 minutes;

[0059] The flowing hot water tank is made of stainless steel, with a side air extraction port, a serpentine steam pipe with a pressure resistance level of 0.3 MPa, and a compressed air stirrer with a working pressure greater than 0.2 MPa in terms of structure

[0060] S5, Degreasing quality inspection: Immerse the blades in a flowing cold water tank and wash them 3 - 5 times, with each washing time being 1 - 2 minutes;

[0061] The flowing cold water tank is made of stainless steel, and structurally has a cleaning tank made of polyvinyl chloride plastic and a compressed air stirrer with a working pressure greater than 0.2 MPa;

[0062] S6, Anodic pickling: Use a core made of lead with 6% - 8% antimony added as the anode for the blades, and place them in an anodic pickling tank with a pickling solution composition of 150 - 250 g / L of chromic anhydride and 1.5 - 2.5 g / L of sulfuric acid for pickling. The pickling temperature is 60 - 65 °C, the current density is 50 - 60 A / dm², the time is 1 - 1.5 minutes, and Sa:Sk = 1:1, where Sa is the anode surface area and Sk is the cathode surface area;

[0063] The anodic pickling tank is made of titanium, and structurally has a side air extraction port and a serpentine steam pipe with a pressure resistance level of 0.3 MPa;

[0064] S7, Static dissolution of pickling solution: Immerse the blades in a non - flowing cold water tank and wash them 3 - 5 times, with each washing time being 1 - 2 minutes;

[0065] The non - flowing cold water tank is made of stainless steel, and structurally has a cleaning basket made of polyvinyl chloride plastic;

[0066] S8, Cleaning pickling solution: Immerse the blades in a flowing cold water tank and wash them 3 - 5 times, with each washing time being 1 - 2 minutes;

[0067] The flowing cold water tank is made of stainless steel, and structurally has a cleaning tank made of polyvinyl chloride plastic and a compressed air stirrer with a working pressure greater than 0.2 MPa;

[0068] S9, Activation: Conduct activation treatment in an activation tank with a solution composition of 100 - 150 g / L of hydrochloric acid, at a treatment temperature of 18 - 30 °C, and a time of 1 - 2 minutes;

[0069] The activation tank is made of stainless steel, and structurally has a lining made of polyvinyl chloride plastic, a side air extraction port, and a compressed air stirrer with a working pressure greater than 0.2 MPa;

[0070] S10, Cleaning activation solution: Immerse the blades in a flowing cold water tank and wash them 3 - 5 times, with each washing time being 1 - 2 minutes;

[0071] The flowing cold water tank is made of stainless steel, and structurally has a cleaning tank made of polyvinyl chloride plastic and a compressed air stirrer with a working pressure greater than 0.2 MPa

[0072] S11, Nickel plating: Nickel plating is carried out in a nickel plating bath with an electrolyte composition of 140 - 170 g / L nickel sulfate, 10 - 15 g / L nickel chloride hexahydrate, 130 - 170 g / L sodium sulfate, and 20 - 30 g / L boric acid. The nickel plating temperature is 28 - 35 °C, the current density is 0.4 - 0.6 A / dm², the time is 45 - 60 minutes, the pH value is 4 - 6, and Sa:Sk = 2:1;

[0073] The nickel plating bath is made of stainless steel and is structurally equipped with a polyvinyl chloride plastic lining and a side air extraction port;

[0074] S12, Static dissolution of nickel plating solution: The blades are immersed in a non-flowing cold water bath and cleaned 3 - 5 times, with each cleaning time being 1 - 2 minutes;

[0075] The non-flowing cold water bath is made of stainless steel and is structurally equipped with a cleaning basket made of polyvinyl chloride plastic;

[0076] S13, Cleaning of nickel plating solution: The blades are immersed in a flowing cold water bath and cleaned 3 - 5 times, with each cleaning time being 1 - 2 minutes;

[0077] The flowing cold water bath is made of stainless steel and is structurally equipped with a cleaning tank made of polyvinyl chloride plastic and a compressed air stirrer with a working pressure greater than 0.2 MPa;

[0078] S14, Inspection of nickel plating layer: The nickel plating layer is inspected on an inspection table. The appearance of the nickel plating layer should be smooth, without bulging, bubbles, and delamination, and no missing plating is allowed;

[0079] The desktop of the inspection table should be covered with polyvinyl chloride plastic;

[0080] S15, Cadmium plating: Cadmium plating is carried out in a cadmium plating bath with an electrolyte composition of 40 - 500 g / L cadmium sulfate, 48 - 52 g / L sodium sulfate, 100 - 120 g / L sodium sulfate, and 3 - 5 g / L OP-7 emulsifier. The cadmium plating temperature is 18 - 30 °C, the current density is 1.5 - 2.5 A / dm², the time is 6 - 10 minutes, and Sa:Sk = 2:1;

[0081] The cadmium plating bath is made of stainless steel and is structurally equipped with a polyvinyl chloride plastic lining and a side air extraction port;

[0082] S16, Static dissolution of cadmium plating solution: The blades are immersed in a non-flowing cold water bath and cleaned 3 - 5 times, with each cleaning time being 1 - 2 minutes;

[0083] The non-flowing cold water bath is made of stainless steel and is structurally equipped with a cleaning basket made of polyvinyl chloride plastic;

[0084] S17, Cleaning of cadmium plating solution: The blades are immersed in a flowing cold water bath and cleaned 3 - 5 times, with each cleaning time being 1 - 2 minutes;

[0085] The flowing cold water tank is made of stainless steel, and is structurally equipped with a cleaning tank made of polyvinyl chloride plastic and a compressed air stirrer with a working pressure greater than 0.2 MPa;

[0086] S18, Chemical passivation: Conduct chemical passivation in a passivation tank with a solution composition of 100 - 150 g / L of potassium dichromate, 10 - 15 g / L of sulfuric acid, and 10 - 15 g / L of hydrochloric acid. The passivation temperature is 18 - 30 °C, and the passivation is carried out 3 - 5 times;

[0087] The passivation tank is made of stainless steel, and is structurally equipped with a lining made of polyvinyl chloride plastic, a side air extraction port, and a compressed air stirrer with a working pressure greater than 0.2 MPa;

[0088] S19, Clean the passivation solution: Immerse the blade in a non - flowing cold water tank and clean it 3 - 5 times, with each cleaning time being 1 - 2 minutes;

[0089] The non - flowing cold water tank is made of stainless steel, and is structurally equipped with a cleaning basket made of polyvinyl chloride plastic;

[0090] S20, Refined cleaning: Immerse the blade in a non - flowing distilled water tank and clean it 3 - 5 times, with each cleaning time being 0.5 - 1 minute;

[0091] After multiple previous cold water washes (including non - flowing cold water wash and flowing cold water wash) and chemical passivation and other steps, there may still be a very small amount of impurities remaining on the blade surface, such as some ionic components, etc. Using a non - flowing distilled water tank for cleaning can utilize the high purity of distilled water to further remove these remaining impurities, improve the cleanliness of the blade surface, and thus provide better conditions for the subsequent drying step to ensure the quality of the blade surface after drying;

[0092] The flowing distilled water tank is made of stainless steel, and is structurally equipped with a cleaning basket made of polyvinyl chloride plastic;

[0093] S21, Drying: Blow dry the moisture on the blade surface with clean compressed air;

[0094] The compressed air should blow the mirror surface or filter paper for at least 3 - 4 minutes every month, and there should be no moisture and oil stain residues on the mirror surface or filter paper;

[0095] S22, Inspect the cadmium plating layer: Inspect the cadmium plating layer on the inspection table. The appearance of the nickel plating layer should be smooth, without bulging, delamination, and should be in a fine crystal state;

[0096] The desktop of the inspection table should be covered with polyvinyl chloride plastic;

[0097] S23, Disassembly: Remove the blade from the copper fixture on the disassembly table and store it in a dry and clean environment;

[0098] The disassembly table desktop should be covered with polyvinyl chloride plastic;

[0099] S24, Annealing: Heat the blade in a drying oven for annealing. The annealing temperature is 350 - 370 °C, and the annealing time is 60 - 90 minutes. The annealing time starts from the moment when the annealing temperature is reached;

[0100] The drying oven can automatically adjust the temperature, with a temperature difference within ±10 °C, to ensure that the blade is evenly heated;

[0101] S25, Acceptance Inspection: Comprehensively inspect the appearance of the nickel - cadmium coating on the inspection table. It is required that there should be no bulging and delamination of the coating on the blade surface, and the coating should be smooth without rough surfaces; Comprehensively inspect the adhesion strength with the base metal of the blade, and there should be no delamination, bulging, peeling of the coating and uncoated areas; Ensure the micro - hardness of the nickel - cadmium coating by checking whether the annealing system meets the requirements of S24.

[0102] The nickel - cadmium plating method of the present invention has the remarkable advantages of complete processes and clear requirements. Starting from the pre - plating inspection, strictly control the surface state of the blade to ensure that the blades entering the subsequent processes meet the quality requirements. In the clamping link, the clamping requirements are clarified to ensure that the solution can fully enter all parts of the blade and avoid the generation of bubbles. Each step, such as chemical degreasing, hot water cleaning, cold water cleaning, anodic pickling, activation, nickel plating, cadmium plating, passivation, etc., has detailed parameter requirements for solution composition, temperature, time, current density, etc., to ensure that each link can be precisely controlled, thus obtaining a high - quality coating. At the same time, the material and structure of each device are also clearly specified, such as the material and structure requirements of the degreasing tank, hot water tank, cold water tank, anodic pickling tank, activation tank, nickel plating tank, cadmium plating tank, passivation tank, etc., to ensure that the equipment can meet the process requirements, improve production efficiency and coating quality. In addition, the setting of multiple cleaning and activation steps enhances the bonding strength between the coating and the blade substrate and reduces the risk of coating delamination. Through the method of the present invention, more reliable and high - quality nickel - cadmium treatment can be provided for gas turbine blades, extending the service life of the blades and improving the performance and reliability of gas turbines.

[0103] The outstanding advantages and improvements of the present invention compared with the prior art are as follows:

[0104] Improve the pickling step: Add steps such as chemical degreasing, isolation, and de - isolation, making the pickling process more perfect and better meeting the pickling requirements of titanium alloy blades for gas turbines.

[0105] Optimize the solution formula: Optimize the composition of the pickling solution and the degreasing solution, improving the pickling and degreasing effects.

[0106] Strictly control parameters: The parameters such as temperature and time in each step are strictly controlled to ensure the stability and reliability of the pickling process.

[0107] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for plating nickel-cadmium on gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN, characterized in that: The following steps are involved: S1, inspection before plating: before nickel-cadmium plating, visually inspect the surface condition of the blade on the inspection table. The blade surface should be free of oxide film, oxide scale, corrosion, indentation, burr, scratch, dent, burn, pore and abrasion; S2, clamping: clamp the blade to the copper fixture. After clamping, ensure that the solution can enter all holes and recesses of the blade, and no bubbles should be formed on the surface and around the blade; S3, chemical degreasing: chemical degreasing treatment is carried out in a degreasing tank with a solution composition of 30-50 g / L trisodium phosphate and 3-5 g / L OP-7 emulsifier, the degreasing temperature is 60-80 degrees Celsius, and the time is 10-20 minutes; S4, cleaning degreasing solution: immersing the leaves in a flowing hot water tank at 60 to 90 degrees Celsius for 3 to 5 times, each cleaning time is 1 to 2 minutes; S5, degreasing quality inspection: immerse the leaves in a flowing cold water tank for 3 to 5 times, each washing time is 1 to 2 minutes; S6, anode pickling: the blade is pickled in an anode pickling tank with a core made of lead and filled with 6% to 8% antimony as the anode, and the pickling solution composition is 150 to 250 grams per liter of chromic acid and 1.5 to 2.5 grams per liter of sulfuric acid, the pickling temperature is 60 to 65 degrees Celsius, the current density is 50 to 60 amperes per square decimeter, the time is 1 to 1.5 minutes, and Sa:Sk=1:1, wherein Sa is the anode surface area, Sk: is the cathode surface area; S7, static dissolution pickling solution: immerse the blades in a non-flowing cold water tank for 3 to 5 times, each washing time is 1 to 2 minutes; S8, cleaning the pickling solution: immersing the blade in a flowing cold water tank for 3 to 5 times, each washing time is 1 to 2 minutes; S9, activation: activation treatment is performed in an activation tank containing 100 to 150 g / L of hydrochloric acid at a temperature of 18 to 30 degrees Celsius for 1 to 2 minutes; S10, cleaning the activation solution: immersing the leaves in a flowing cold water tank for 3 to 5 times, each washing time is 1 to 2 minutes; S11, nickel plating: nickel plating is performed in a nickel plating bath having an electrolyte composition of 140-170 g / L nickel sulfate, 10-15 g / L nickel chloride hexahydrate, 130-170 g / L sodium sulfate, and 20-30 g / L boric acid, with a nickel plating temperature of 28-35 degrees Celsius, a current density of 0.4-0.6 amperes per square decimeter, a time of 45-60 minutes, a pH value of 4-6, and Sa:Sk=2:1; S12, static dissolution of nickel plating solution: immersing the blade in a non-flowing cold water tank for cleaning 3 to 5 times, each cleaning time is 1 to 2 minutes; S13, cleaning the nickel plating solution: immersing the blade in a flowing cold water tank for 3 to 5 times, each washing time is 1 to 2 minutes; S14, check the nickel plating: Check the nickel plating on the inspection table. The nickel plating should be smooth, without bulging, bubbles and delamination. No leakage is allowed. S15, cadmium plating: cadmium plating is carried out in a cadmium plating tank with an electrolyte composition of 40-500 g / L cadmium sulfate, 48-52 g / L sodium sulfate, 100-120 g / L sodium sulfate, and 3-5 g / L OP-7 emulsifier, the cadmium plating temperature is 18-30 degrees Celsius, the current density is 1.5-2.5 amperes per square decimeter, the time is 6-10 minutes, and Sa:Sk=2:1; S16, static dissolution of cadmium plating solution: immerse the leaves in a non-flowing cold water tank for 3 to 5 times, each washing time is 1 to 2 minutes; S17, cleaning the cadmium plating solution: immersing the leaves in a flowing cold water tank for 3 to 5 times, each washing time is 1 to 2 minutes; S18, chemical passivation: chemical passivation is performed in a passivation tank containing 100-150 g / L potassium dichromate, 10-15 g / L sulfuric acid, and 10-15 g / L hydrochloric acid at a passivation temperature of 18-30 degrees Celsius for 3-5 times; S19, cleaning the passivation solution: immersing the blade in a non-flowing cold water tank for cleaning 3 to 5 times, each cleaning time being 1 to 2 minutes; S20, fine cleaning: immerse the leaves in a still distilled water tank for cleaning 3 to 5 times, each cleaning time is 0.5 to 1 minute; S21, drying: use clean compressed air to dry the moisture on the leaf surface; S22, check the cadmium plating layer: check the cadmium plating layer on the inspection table. The nickel plating layer should be smooth, without bulging or delamination, and in the form of fine crystals; S23, disassembly: remove the blade from the copper tooling on the disassembly table and store it in a dry and clean environment; S24, annealing: heating the leaves in a drying oven for annealing, the annealing temperature is 350-370 degrees Celsius, the annealing time is 60-90 minutes, and the annealing time is counted from the time when the annealing temperature is reached; S25, Acceptance inspection: Check the appearance of the nickel-cadmium coating, its adhesion strength to the blade base metal and its microhardness on the inspection bench.

2. A method for plating nickel-cadmium for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN according to claim 1, characterized in that: The inspection tables described in S1, S14, S2, S25 and the disassembly table described in S23 are covered with polyvinyl chloride plastic.

3. A method for plating nickel-cadmium for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN according to claim 1, characterized in that: The S3 degreasing tank and S4 flowing hot water tank are made of stainless steel, and are structurally provided with side air extraction ports, serpentine steam pipes with a pressure rating of 0.3 MPa, and compressed air agitators with a working pressure greater than 0.2 MPa.

4. A method for plating nickel-cadmium for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN according to claim 1, characterized in that: The flowing cold water tanks in S5, S8, S10, S13 and S17 are made of stainless steel, and are structurally provided with a cleaning tank made of polyvinyl chloride plastic material and a compressed air agitator with a working pressure greater than 0.2 MPa.

5. A method for plating nickel-cadmium for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN according to claim 1, characterized in that: The anode pickling tank in S6 is made of titanium and has a side exhaust port and a serpentine steam pipe with a pressure rating of 0.3 MPa.

6. A method for plating nickel-cadmium for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN according to claim 1, characterized in that: The non-flowing cold water tanks in S7, S12, S16 and S19 and the non-flowing distilled water tank in S20 are made of stainless steel and are structurally provided with a cleaning basket made of polyvinyl chloride plastic material.

7. A method for plating nickel-cadmium for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN according to claim 1, characterized in that: The activation tank in S9 and the passivation tank in S18 should be made of stainless steel, with a polyvinyl chloride plastic lining, a side exhaust port and a compressed air agitator with a working pressure greater than 0.2 MPa.

8. A method for plating nickel-cadmium for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN according to claim 1, characterized in that: The nickel plating tank in S11 and the cadmium plating tank in S15 are made of stainless steel, and are structurally provided with a polyvinyl chloride plastic lining and a side exhaust port.

9. A method for plating nickel-cadmium for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN according to claim 1, characterized in that: The compressed air in S21 blows the mirror surface or filter paper for at least 3 to 4 minutes every month, and there should be no moisture or oil residue on the mirror surface or filter paper.

10. A method for plating nickel-cadmium for gas turbine blades made of Cr17Ni2 and 1Cr16Ni2MoN according to claim 1, characterized in that: The drying box in S24 can automatically adjust the temperature within a temperature difference of ±10 degrees Celsius to ensure that the blades are evenly heated.

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