Multi-element multi-layer composite chemical plating method for high-wear-resistance metal card clothing of carding machine

Abstract

The invention relates to the technical field of chemical plating, in particular to a multi-element multi-layer composite chemical plating method for high-wear-resistance carding machine metal card clothing, which comprises the following steps: substrate pretreatment: a carding machine metal card clothing substrate is 65 Mn steel or 20 CrMnTi steel, and is sequentially subjected to oil removal, rust removal and activation treatment to obtain a pretreated substrate with a clean surface; the bottom layer is a nickel-phosphorus alloy plating layer, the middle layer is a nickel-cobalt-tungsten-phosphorus-nano hard particle composite plating layer, and the top layer is a nickel-boron-antifriction particle composite plating layer; the plating intermediate is sequentially subjected to heat treatment and precise polishing, and the high-wear-resistance metal card clothing is obtained. The bottom nickel-phosphorus alloy ensures strong binding force with a substrate; nano hard particles are embedded into nickel, cobalt, tungsten and phosphorus in the middle layer, so that the overall hardness and plastic deformation resistance of the plating layer are remarkably improved; and the surface friction coefficient is effectively reduced by the nickel-boron composite antifriction particles on the top layer.

Description

Technical Field

[0001] This invention relates to the field of chemical plating technology, and in particular to a multi-element, multi-layer composite chemical plating method for metal carding cloth of a high abrasion-resistant carding machine. Background Technology

[0002] As a core consumable component in the carding process of textile textiles, the wear resistance of metal carding cloth in carding machines directly affects yarn quality, production efficiency, and production costs. Traditional surface strengthening of carding cloth often employs electroplating chromium or a single chemical nickel-phosphorus plating process. Electroplating chromium poses environmental pollution problems, and the plating layer has high internal stress, making it prone to micro-cracks; while conventional chemical nickel-phosphorus plating, although uniform and corrosion-resistant, offers limited improvement in hardness and wear resistance, making it difficult to meet the stringent requirements of modern high-speed, high-yield carding machines for the ultra-long lifespan of carding cloth. Furthermore, existing technologies mostly use single-component plating, which cannot simultaneously achieve comprehensive properties such as high hardness, high toughness, and low coefficient of friction.

[0003] The coating process parameters are often fixed and cannot be adaptively optimized according to batch differences in the needle cloth substrate, resulting in fluctuations in product quality.

[0004] Therefore, developing an environmentally friendly, high-performance composite coating technology that enables intelligent process optimization has become crucial for improving the service life of metal needle cloths and promoting the upgrading of textile equipment. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems and proposes a multi-element, multi-layer composite chemical plating method for high abrasion-resistant metal carding machine needle cloth.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a multi-element, multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth, comprising the following steps:

[0007] S1. Substrate pretreatment: The metal carding cloth substrate of the carding machine is 65Mn steel or 20CrMnTi steel. The substrate is subjected to degreasing, derusting and activation treatment in sequence to obtain a clean pretreated substrate.

[0008] S2. Multi-layer composite chemical plating: chemical plating of the bottom layer, the middle layer, and the top layer are performed sequentially on the surface of the pretreated substrate to obtain a plating intermediate; the bottom layer is a nickel-phosphorus alloy plating layer, the middle layer is a nickel-cobalt-tungsten-phosphorus-nano hard particle composite plating layer, and the top layer is a nickel-boron-friction-reducing particle composite plating layer.

[0009] S3. Post-processing: The plating intermediate is subjected to heat treatment and precision polishing in sequence to obtain high wear-resistant metal needle cloth.

[0010] The heat treatment is carried out under an inert atmosphere, which is nitrogen or argon with a purity ≥99.99%, and no separate medium-temperature insulation platform at 200-250℃ is provided.

[0011] Preferably, in step S1:

[0012] The degreasing process uses an alkaline degreasing agent, with the degreasing temperature set at a constant temperature water bath of 50-60°C, and a treatment time of 10-15 minutes. The alkaline degreasing agent, by mass concentration, comprises: 20-30 g / L sodium hydroxide, 15-25 g / L sodium carbonate, 10-20 g / L sodium phosphate, and a surfactant, wherein the surfactant is sodium dodecylbenzene sulfonate with a mass concentration of 1-3 g / L.

[0013] The rust removal process uses a 10%-15% hydrochloric acid solution at a room temperature of 20-25℃ for 5-8 minutes. After rust removal, the solution is rinsed with deionized water until the pH reaches 6.5-7.5.

[0014] The activation process uses a 5%–8% sulfuric acid solution at a temperature of 40–50°C for 3–5 minutes. After activation, the surface roughness Ra of the substrate is controlled at 0.2–0.5 μm and is measured using a laser roughness meter. The measurement area is within 5 mm on both sides of the working edge of the needle cloth.

[0015] Preferably, the process parameters for the bottom layer electroless plating in step S2 include:

[0016] The plating solution contains, by mass concentration: nickel sulfate (NiSO4·6H2O) 20-30 g / L, sodium hypophosphite (NaH2PO2·H2O) 15-25 g / L, sodium acetate (CH3CO0Na·3H2O) 5-10 g / L, and sodium citrate (Na3C5H5O7·2H2O) 3-8 g / L;

[0017] The plating temperature is based on the plating solution temperature and is measured using a platinum resistance thermometer; the temperature is 85-90℃; the pH value is 4.5-5.5, which is monitored in real time using a pH meter and adjusted using dilute sulfuric acid or dilute sodium hydroxide solution; the treatment time is 15-20 minutes.

[0018] The thickness of the bottom coating is 5-10 μm. Metallographic samples were prepared by cutting the cross-section of the needle cloth and using a metallographic microscope. The phosphorus content is 8%-12%. X-ray fluorescence spectrometry was used to detect the phosphorus content, and the detection spot diameter was 50 μm.

[0019] Preferably, the process parameters for the intermediate layer electroless plating in step S2 include:

[0020] The plating solution, by mass concentration, contains: nickel sulfate (NiSO4·6H2O) 15-20 g / L, cobalt chloride (CoCl2·6H2O) 5-10 g / L, sodium tungstate (Na2WO4·2H2O) 3-8 g / L, sodium hypophosphite (NaH2PO2·H2O) 20-30 g / L, and nano-hard particles 2-5 g / L;

[0021] The nano-hard particles are one or more of SiC, diamond or WC, with a particle size of 50-100nm. They are detected by dynamic light scattering (DLS) at a detection temperature of 25℃, and the dispersion medium is deionized water.

[0022] The plating temperature is 88-92℃, based on the plating solution temperature and measured with a platinum resistance thermometer; the pH value is 5.0-6.0, adjusted in real time with a pH meter; the stirring rate is 200-300 r / min, using a paddle stirrer with a paddle diameter of 1 / 3 of the inner diameter of the plating tank; the processing time is 30-45 min.

[0023] The thickness of the intermediate coating is 20-40μm, and it is inspected using a metallographic microscope. The inspection method is the same as above.

[0024] Preferably, the process parameters for the top-layer electroless plating in step S2 include:

[0025] The plating solution contains, by mass concentration: nickel sulfate NiSO4·6H2O 10-15 g / L, sodium borohydride NaBH4 2-5 g / L, sodium citrate Na3C5H5O7·2H2O 10-15 g / L, and friction-reducing particles 1-3 g / L.

[0026] The friction-reducing particles are PTFE or MoS2 with a particle size of 100-200 nm. The average particle size is calculated by analyzing the images of 50 randomly selected particles using scanning electron microscopy (SEM).

[0027] The plating temperature is 60-70℃, based on the temperature of the plating solution and measured with a platinum resistance thermometer; the pH value is 8.0-9.0, adjusted with dilute hydrochloric acid or dilute sodium hydroxide solution; the treatment time is 10-15 minutes.

[0028] The thickness of the top coating is 3-8μm, and it is inspected using a metallographic microscope. The inspection method is the same as above.

[0029] Preferably, in step S2, the thickness ratio of the bottom layer, the middle layer, and the top layer is (1-2):(4-8):(0.6-1.6), and the total thickness of the multilayer coating is 30-50 μm;

[0030] Thickness is measured at the working edge area of ​​the metal needle cloth, 0.5-1 mm from the tip of the edge. Three measurement points are randomly selected for each sample, and the arithmetic mean is taken as the final thickness value.

[0031] Preferably, in step S3:

[0032] The heat treatment procedure is as follows: based on the substrate surface temperature, heat to 300-400℃ at a rate of 2-5℃ / min, hold for 60-90min, and cool to room temperature with the furnace, with room temperature ≤30℃.

[0033] The precision polishing uses diamond polishing paste with a particle size of 1-3μm, and polishes at a rate of 150-200r / min for 5-10min on a metallographic polishing machine;

[0034] After polishing, the surface roughness Ra of the top layer is ≤0.2μm, which is detected by a laser roughness meter in the same area as above.

[0035] Preferably, before performing step S2, a plating parameter optimization step S0 is also included:

[0036] S01. Obtain the surface hardness (HV0) and expected wear life (T) of the current batch of substrates:

[0037] The surface hardness HV0 was tested using a Vickers hardness tester with a load of 500g and a holding time of 10s. Five points were randomly tested on each substrate and the average value was taken.

[0038] The expected abrasion resistance life T is the design service life of the metal carding cloth of the carding machine, in hours, with a range of 500-2000 hours.

[0039] The plating factor (PFO) is calculated using the formula PFO = k × (HV0 / ρb) × (T / 1000), where:

[0040] ρb is the base density; the density of 65Mn steel is taken as 7.85 g / cm³. 3 The density of 20CrMnTi steel is taken as 7.83 g / cm³. 3 ;

[0041] k is the equipment calibration constant, determined through calibration experiments: using a standard hardness block (HV500±20) and a standard density sample, with the standard density sample ρb=7.85g / cm³. 3 Three parallel experiments were conducted on the same plating equipment, and the average value of k was calculated. The range of k values ​​was 0.8-1.2.

[0042] S02. Based on the PFO value and a pre-established mapping relationship, determine the content of intermediate layer nanoparticles and the heat treatment holding time.

[0043] The mapping relationship is obtained by training a gradient boosting regression tree model. The training dataset contains more than 100 sets of corresponding data on PFO value, nanoparticle content, heat preservation time, and actual wear resistance life.

[0044] Preferably, the method is performed by an intelligent plating system, which includes:

[0045] Substrate parameter measurement module: integrates Vickers hardness tester, laser roughness tester and three-dimensional profilometer. The Vickers hardness tester has a load range of 200-1000g, the laser roughness tester has a detection range of 0.01-10μm, and the three-dimensional profilometer has a measurement accuracy of ±1μm. It is used to obtain the surface characteristic parameters of the substrate, and the data acquisition frequency is ≥1 time / 5min.

[0046] Plating solution control module: Includes an online refractometer, pH meter, and platinum resistance thermometer. The online refractometer has a concentration detection accuracy of ±0.1 g / L, the pH meter has a detection accuracy of ±0.01 pH, and the platinum resistance thermometer has a temperature detection accuracy of ±0.1℃. It can adjust the concentration of plating solution components, pH value, and temperature in real time. The concentration adjustment accuracy is ±0.5 g / L with a response time ≤30s, the pH adjustment accuracy is ±0.1 pH, and the temperature adjustment accuracy is ±1℃.

[0047] Data processing module: Embedded plating factor calculation model and multi-layer process parameter mapping relationship, the mapping relationship is the same as the GBRT model above, can output the optimal process command in real time according to the substrate parameters, and the command transmission delay is ≤1s.

[0048] Preferably, the nano-hard particles of the intermediate layer mentioned in step S2 undergo surface modification treatment before being added to the plating solution. The specific modification process includes:

[0049] Step 1: Dispersion: Disperse the nano-hard particles in an ethanol-deionized water solution with a volume ratio of 3:1, and use an ultrasonic cleaner to ultrasonically disperse for 15-20 minutes. The ultrasonic cleaner power is 300-500W and the ultrasonic frequency is 25-40kHz. After ultrasonication, there is no obvious agglomeration of particles.

[0050] The second step of the modification reaction: add silane coupling agent KH-550 to the dispersed mixture. The mass concentration of silane coupling agent KH-550 in the mixture is 1%-3%. Place the mixture in a constant temperature water bath for 2-4 hours. The temperature of the constant temperature water bath is 60-70℃. Stir the mixture during the reaction.

[0051] The third step is separation and drying: After the reaction is completed, the mixture is centrifuged for 10-15 minutes at a speed of 8000-10000 r / min. The precipitate is collected after centrifugation. The collected precipitate is placed in a vacuum drying oven and dried for 1-2 hours at a temperature of 80-100℃ and a vacuum degree of ≤-0.09MPa. After drying, modified nano-hard particles are obtained.

[0052] The surface hydroxyl content of the modified hard nanoparticles was reduced by 15%–25% compared to the unmodified ones. The wavenumber was detected by Fourier transform infrared spectroscopy and was around 3400 cm⁻¹. After the modified hard nanoparticles were added to the intermediate layer plating solution and left to stand for 24 hours, the settling rate was ≤0.5 mm / h. The settling rate was observed using a graduated measuring cylinder with an accuracy of 1 mm.

[0053] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0054] The bottom layer of nickel-phosphorus alloy ensures strong adhesion to the substrate; the middle layer of nickel-cobalt-tungsten-phosphorus alloy incorporates nano-hard particles, which significantly improves the overall hardness and resistance to plastic deformation of the coating; and the top layer of nickel-boron composite anti-friction particles effectively reduces the surface friction coefficient.

[0055] A smart optimization step based on plating factor (PFO) was introduced. By detecting the hardness of the substrate in real time and combining it with the expected lifespan, the key parameters of the intermediate layer (such as nanoparticle content) and the post-processing process were dynamically optimized, which enabled the plating process to have personalized adaptability and ensured the stability and optimal performance of different batches of needle cloth.

[0056] Finally, the entire process is environmentally friendly (chemical plating) and controllable, and can be precisely executed through an intelligent plating system. The final card cloth coating has a controllable total thickness, strong adhesion, and smooth surface. Its wear resistance life is expected to be several times higher than that of traditional card cloth, which has significant economic and technical value. Attached Figure Description

[0057] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0059] In the description of this invention, it should be understood that the terms length, width, up, down, front, back, left, right, vertical, horizontal, top, bottom, inside, outside, etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "multiple" means two or more, unless otherwise explicitly specified.

[0060] according to Figure 1The present invention proposes a multi-element, multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth, comprising the following steps:

[0061] S1. Substrate pretreatment: The metal carding cloth substrate of the carding machine is 65Mn steel or 20CrMnTi steel. The substrate is subjected to degreasing, derusting and activation treatment in sequence to obtain a clean pretreated substrate.

[0062] S2. Multi-layer composite chemical plating: chemical plating of the bottom layer, the middle layer, and the top layer are performed sequentially on the surface of the pretreated substrate to obtain a plating intermediate; the bottom layer is a nickel-phosphorus alloy plating layer, the middle layer is a nickel-cobalt-tungsten-phosphorus-nano hard particle composite plating layer, and the top layer is a nickel-boron-friction-reducing particle composite plating layer.

[0063] S3. Post-processing: The plating intermediate is subjected to heat treatment and precision polishing in sequence to obtain high wear-resistant metal needle cloth.

[0064] The heat treatment is carried out under an inert atmosphere, which is nitrogen or argon with a purity ≥99.99%, and no separate medium-temperature insulation platform at 200-250℃ is provided.

[0065] As an optional embodiment, in step S1:

[0066] The degreasing process uses an alkaline degreasing agent, with the degreasing temperature set at a constant temperature water bath of 50-60°C, and a treatment time of 10-15 minutes. The alkaline degreasing agent, by mass concentration, comprises: 20-30 g / L sodium hydroxide, 15-25 g / L sodium carbonate, 10-20 g / L sodium phosphate, and a surfactant, wherein the surfactant is sodium dodecylbenzene sulfonate with a mass concentration of 1-3 g / L.

[0067] The rust removal process uses a 10%-15% hydrochloric acid solution at a room temperature of 20-25℃ for 5-8 minutes. After rust removal, the solution is rinsed with deionized water until the pH reaches 6.5-7.5.

[0068] The activation process uses a 5%–8% sulfuric acid solution at a temperature of 40–50°C for 3–5 minutes. After activation, the surface roughness Ra of the substrate is controlled at 0.2–0.5 μm and is measured using a laser roughness meter. The measurement area is within 5 mm on both sides of the working edge of the needle cloth.

[0069] As an optional embodiment, the process parameters for the bottom chemical plating in step S2 include:

[0070] The plating solution contains, by mass concentration: nickel sulfate (NiSO4·6H2O) 20-30 g / L, sodium hypophosphite (NaH2PO2·H2O) 15-25 g / L, sodium acetate (CH3CO0Na·3H2O) 5-10 g / L, and sodium citrate (Na3C5H5O7·2H2O) 3-8 g / L.

[0071] The plating temperature is based on the plating solution temperature and is measured using a platinum resistance thermometer; the temperature is 85-90℃; the pH value is 4.5-5.5, which is monitored in real time using a pH meter and adjusted using dilute sulfuric acid or dilute sodium hydroxide solution; the treatment time is 15-20 minutes.

[0072] The thickness of the bottom coating is 5-10 μm. Metallographic samples were prepared by cutting the cross-section of the needle cloth and using a metallographic microscope. The phosphorus content is 8%-12%. X-ray fluorescence spectrometry was used to detect the phosphorus content, and the detection spot diameter was 50 μm.

[0073] As an optional embodiment, the process parameters for the intermediate layer electroless plating in step S2 include:

[0074] The plating solution, by mass concentration, contains: nickel sulfate (NiSO4·6H2O) 15-20 g / L, cobalt chloride (CoCl2·6H2O) 5-10 g / L, sodium tungstate (Na2WO4·2H2O) 3-8 g / L, sodium hypophosphite (NaH2PO2·H2O) 20-30 g / L, and nano-hard particles 2-5 g / L;

[0075] The nano-hard particles are one or more of SiC, diamond or WC, with a particle size of 50-100nm. They are detected by dynamic light scattering (DLS) at a detection temperature of 25℃, and the dispersion medium is deionized water.

[0076] The plating temperature is 88-92℃, based on the plating solution temperature and measured with a platinum resistance thermometer; the pH value is 5.0-6.0, adjusted in real time with a pH meter; the stirring rate is 200-300 r / min, using a paddle stirrer with a paddle diameter of 1 / 3 of the inner diameter of the plating tank; the processing time is 30-45 min.

[0077] The thickness of the intermediate coating is 20-40μm, and it is inspected using a metallographic microscope. The inspection method is the same as above.

[0078] As an optional embodiment, the process parameters for the top layer electroless plating in step S2 include:

[0079] The plating solution contains, by mass concentration: nickel sulfate NiSO4·6H2O 10-15 g / L, sodium borohydride NaBH4 2-5 g / L, sodium citrate Na3C5H5O7·2H2O 10-15 g / L, and friction-reducing particles 1-3 g / L.

[0080] The friction-reducing particles are PTFE or MoS2 with a particle size of 100-200 nm. The average particle size is calculated by analyzing the images of 50 randomly selected particles using scanning electron microscopy (SEM).

[0081] The plating temperature is 60-70℃, based on the temperature of the plating solution and measured with a platinum resistance thermometer; the pH value is 8.0-9.0, adjusted with dilute hydrochloric acid or dilute sodium hydroxide solution; the treatment time is 10-15 minutes.

[0082] The thickness of the top coating is 3-8μm, and it is inspected using a metallographic microscope. The inspection method is the same as above.

[0083] As an optional embodiment, the thickness ratio of the bottom layer, intermediate layer and top layer in step S2 is (1-2):(4-8):(0.6-1.6), and the total thickness of the multilayer coating is 30-50μm;

[0084] Thickness is measured at the working edge area of ​​the metal needle cloth, 0.5-1 mm from the tip of the edge. Three measurement points are randomly selected for each sample, and the arithmetic mean is taken as the final thickness value.

[0085] As an optional embodiment, in step S3:

[0086] The heat treatment procedure is as follows: based on the substrate surface temperature, heat to 300-400℃ at a rate of 2-5℃ / min, hold for 60-90min, and cool to room temperature with the furnace, with room temperature ≤30℃.

[0087] The precision polishing uses diamond polishing paste with a particle size of 1-3μm, and polishes at a rate of 150-200r / min for 5-10min on a metallographic polishing machine;

[0088] After polishing, the surface roughness Ra of the top layer is ≤0.2μm, which is detected by a laser roughness meter in the same area as above.

[0089] As an optional embodiment, a plating parameter optimization step S0 is further included before performing step S2:

[0090] S01. Obtain the surface hardness (HV0) and expected wear life (T) of the current batch of substrates:

[0091] The surface hardness HV0 was tested using a Vickers hardness tester with a load of 500g and a holding time of 10s. Five points were randomly tested on each substrate and the average value was taken.

[0092] The expected abrasion resistance life T is the design service life of the metal carding cloth of the carding machine, in hours, with a range of 500-2000 hours.

[0093] The plating factor (PFO) is calculated using the formula PFO = k × (HV0 / ρb) × (T / 1000), where:

[0094] ρb is the base density; the density of 65Mn steel is taken as 7.85 g / cm³. 3 The density of 20CrMnTi steel is taken as 7.83 g / cm³. 3 ;

[0095] k is the equipment calibration constant, determined through calibration experiments: using a standard hardness block (HV500±20) and a standard density sample, with the standard density sample ρb=7.85g / cm³. 3 Three parallel experiments were conducted on the same plating equipment, and the average value of k was calculated. The range of k values ​​was 0.8-1.2.

[0096] S02. Based on the PFO value and a pre-established mapping relationship, determine the content of intermediate layer nanoparticles and the heat treatment holding time.

[0097] The mapping relationship is obtained by training a gradient boosting regression tree model. The training dataset contains more than 100 sets of corresponding data on PFO value, nanoparticle content, heat preservation time, and actual wear resistance life.

[0098] As an optional embodiment, the method is performed by an intelligent plating system, which includes:

[0099] Substrate parameter measurement module: integrates Vickers hardness tester, laser roughness tester and three-dimensional profilometer. The Vickers hardness tester has a load range of 200-1000g, the laser roughness tester has a detection range of 0.01-10μm, and the three-dimensional profilometer has a measurement accuracy of ±1μm. It is used to obtain the surface characteristic parameters of the substrate, and the data acquisition frequency is ≥1 time / 5min.

[0100] Plating solution control module: Includes an online refractometer, pH meter, and platinum resistance thermometer. The online refractometer has a concentration detection accuracy of ±0.1 g / L, the pH meter has a detection accuracy of ±0.01 pH, and the platinum resistance thermometer has a temperature detection accuracy of ±0.1℃. It can adjust the concentration of plating solution components, pH value, and temperature in real time. The concentration adjustment accuracy is ±0.5 g / L with a response time ≤30s, the pH adjustment accuracy is ±0.1 pH, and the temperature adjustment accuracy is ±1℃.

[0101] Data processing module: Embedded plating factor calculation model and multi-layer process parameter mapping relationship, the mapping relationship is the same as the GBRT model above, can output the optimal process command in real time according to the substrate parameters, and the command transmission delay is ≤1s.

[0102] As an optional embodiment, the nano-hard particles of the intermediate layer in step S2 undergo surface modification treatment before being added to the plating solution. The specific modification process includes:

[0103] Step 1: Dispersion: Disperse the nano-hard particles in an ethanol-deionized water solution with a volume ratio of 3:1, and use an ultrasonic cleaner to ultrasonically disperse for 15-20 minutes. The ultrasonic cleaner power is 300-500W and the ultrasonic frequency is 25-40kHz. After ultrasonication, there is no obvious agglomeration of particles.

[0104] The second step of the modification reaction: add silane coupling agent KH-550 to the dispersed mixture. The mass concentration of silane coupling agent KH-550 in the mixture is 1%-3%. Place the mixture in a constant temperature water bath for 2-4 hours. The temperature of the constant temperature water bath is 60-70℃. Stir the mixture during the reaction.

[0105] The third step is separation and drying: After the reaction is completed, the mixture is centrifuged for 10-15 minutes at a speed of 8000-10000 r / min. The precipitate is collected after centrifugation. The collected precipitate is placed in a vacuum drying oven and dried for 1-2 hours at a temperature of 80-100℃ and a vacuum degree of ≤-0.09MPa. After drying, modified nano-hard particles are obtained.

[0106] The surface hydroxyl content of the modified hard nanoparticles was reduced by 15%–25% compared to the unmodified ones. The wavenumber was detected by Fourier transform infrared spectroscopy and was around 3400 cm⁻¹. After the modified hard nanoparticles were added to the intermediate layer plating solution and left to stand for 24 hours, the settling rate was ≤0.5 mm / h. The settling rate was observed using a graduated measuring cylinder with an accuracy of 1 mm.

[0107] Example 1: Surface modification treatment of SiC nanoparticles in the intermediate layer

[0108] 1. Experimental materials and equipment;

[0109] 1.1 Experimental materials;

[0110] Intermediate layer hard nanoparticles: SiC nanoparticles (average particle size 80nm, purity ≥99.5%, purchased from Aladdin Reagent Co., Ltd.);

[0111] Dispersion media: anhydrous ethanol (analytical grade, purity ≥99.7%, purchased from Sinopharm Chemical Reagent Co., Ltd.), deionized water (conductivity ≤10μS / cm, prepared in the laboratory);

[0112] Modifier: Silane coupling agent KH-550 (industrial grade, purity ≥98%, purchased from Nanjing Shuguang Chemical Group Co., Ltd.);

[0113] Intermediate layer plating solution (for dispersion stability testing): contains 18 g / L nickel sulfate (NiSO4·6H2O), 8 g / L cobalt chloride (CoCl2·6H2O), 5 g / L sodium tungstate (Na2WO4·2H2O), and 25 g / L sodium hypophosphite (NaH2PO2·H2O) by mass concentration, prepared in the laboratory.

[0114] 1.2 Experimental equipment;

[0115] Ultrasonic cleaning machine: KQ-500DE model, Kunshan Ultrasonic Instrument Co., Ltd., power adjustment range 0-500W, ultrasonic frequency 25-40kHz;

[0116] Thermostatic water bath: HH-S4 model, manufactured by Xicheng Xinrui Instrument Factory, Jintan District; temperature control accuracy ±0.5℃.

[0117] Magnetic stirrer: Model 85-2, Shanghai Sile Instrument Co., Ltd., stirring speed adjustment range 0-1000r / min;

[0118] High-speed centrifuge: TGL-16M model, Hunan Xiangyi Laboratory Instrument Development Co., Ltd., maximum speed 16000r / min;

[0119] Vacuum drying oven: DZF-6050 model, Shanghai Jinghong Experimental Equipment Co., Ltd., temperature control range RT+10℃-250℃, vacuum degree ≤-0.098MPa;

[0120] Fourier Transform Infrared Spectrometer (FTIR): Nicoleti S50, Thermo Fisher Scientific, wavenumber range 400–4000 cm⁻¹ -1 ;

[0121] Scale measuring cylinder: 100mL specification, 1mm accuracy, purchased from Shanghai Glass Instrument Factory;

[0122] Electronic analytical balance: FA2004, Shanghai Precision Scientific Instruments Co., Ltd., accuracy 0.1mg.

[0123] 2. Specific modification process steps;

[0124] 2.1 First step: Nanoparticle dispersion;

[0125] Measure 75 mL of anhydrous ethanol and 25 mL of deionized water using a graduated cylinder, mix them to prepare an ethanol-deionized water solution with a volume ratio of 3:1, and pour it into a 250 mL beaker.

[0126] Weigh 5g of SiC nanoparticles using an electronic analytical balance, slowly add them to the above mixed solution, and stir with a glass rod in the same direction for 1 minute until the particles are completely wetted.

[0127] Place the beaker in the water bath of the ultrasonic cleaner, add deionized water to cover the bottom of the beaker by 3cm, set the ultrasonic power to 400W and the ultrasonic frequency to 30kHz, and start ultrasonic dispersion for 18min. During the ultrasonic process, pause the equipment every 6min to observe the particle aggregation state in the solution. Continue ultrasonication after ensuring that there are no visible agglomerates.

[0128] 2.2 Second step: Modification reaction;

[0129] After the ultrasound is completed, transfer the beaker to the water bath of the constant temperature water bath, add deionized water to half the height of the side wall of the beaker, set the water bath temperature to 65℃, and turn on the heating; after the thermometer shows that the solution temperature is stable at 65℃±0.5℃, place the beaker on the magnetic stirrer, put in the stir bar, and set the stirring speed to 180r / min.

[0130] Use a 10mL pipette to draw 3mL of silane coupling agent KH-550, place the pipette outlet close to the surface of the solution, and slowly add it dropwise into the stirred mixture at a rate of 1mL / min. After the addition is complete, keep the water bath temperature and stirring rate constant, and continue stirring for 3 hours to complete the modification reaction.

[0131] 2.3 Third step: Separation and drying;

[0132] After the reaction is complete, first turn off the heating switch of the constant temperature water bath. After the solution temperature drops below 40℃, turn off the magnetic stirrer and remove the stir bar. Slowly transfer the mixture along the glass rod into 50mL centrifuge tubes, and fill each centrifuge tube with 40mL of the mixture.

[0133] Place the centrifuge tubes into the rotor of the high-speed centrifuge, symmetrically to balance the speed, set the centrifuge speed to 9000 r / min and the centrifugation time to 12 min, and start the centrifugation program; after centrifugation, open the centrifuge lid, remove the centrifuge tubes, use a pipette to remove the supernatant, and retain the SiC precipitate at the bottom of the tube;

[0134] Use a small spoon to transfer the collected SiC precipitate into a pre-weighed ceramic boat. Place the ceramic boat into a vacuum drying oven, close the oven door, set the drying temperature to 90℃ and the vacuum degree to -0.095MPa, and start the drying program. After drying for 1.5 hours, close the vacuum drying oven and wait for the temperature inside the oven to drop to room temperature before taking out the ceramic boat to obtain modified SiC nanoparticles.

[0135] 3. Results of modification effect testing;

[0136] 3.1 Detection of surface hydroxyl content;

[0137] Weigh 2 mg of SiC nanoparticles before and after modification using an electronic analytical balance, place them in an agate mortar, add 200 mg of potassium bromide powder (analytical grade, dried at 120℃ for 2 h) to each, and grind for 10 min until they are mixed evenly.

[0138] The ground mixed powder was transferred to a tableting mold, and a pressure of 15 MPa was applied on the tableting machine and held for 30 seconds to prepare a transparent tablet with a diameter of 13 mm and a thickness of 1 mm, which was used as an FTIR detection sample.

[0139] Place the sample into the FTIR sample holder and set the scanning range to 400–4000 cm⁻¹. -1 32 scans, 4cm resolution -1 Start the scan; using the FTIR spectral analysis software, select a wavenumber of 3400 cm⁻¹. -1 The characteristic area of ​​the hydroxyl characteristic peaks in the vicinity is calculated: the area of ​​the hydroxyl characteristic peak of unmodified SiC is 1256 (arbitrary units), and the area of ​​the modified SiC is 982 (arbitrary units).

[0140] The calculated reduction rate of hydroxyl content is approximately 21.8% (1256-982) / 1256×100%, which meets the technical requirement of "reducing by 15%-25% compared to the unmodified state".

[0141] 3.2 Dispersion stability test;

[0142] Measure 50 mL of the laboratory-prepared intermediate layer plating solution using a graduated cylinder and slowly pour it into a 100 mL graduated cylinder to avoid plating solution adhering to the walls; weigh 0.25 g of modified SiC nanoparticles using an electronic analytical balance and slowly add them to the plating solution in the graduated cylinder.

[0143] Tightly close the graduated cylinder lid, gently invert the graduated cylinder 5 times (keeping it upright for 30 seconds after each inversion) to ensure that the nanoparticles are evenly dispersed in the plating solution; place the graduated cylinder on a horizontal test platform and record the initial time (0h) as 50.0 mL of the particle liquid level.

[0144] After standing for 24 hours, observe the particle settling interface in the graduated cylinder under natural light and read the settling interface height as 48.8 mL. According to the volume-height correspondence of the graduated cylinder (100 mL graduated cylinder height is 25 cm, that is, 1 mL corresponds to 0.25 cm = 2.5 mm), calculate the height difference: (50.0-48.8) mL × 2.5 mm / mL = 12 mm.

[0145] The calculated settlement rate is 12mm ÷ 24h = 0.5mm / h, which meets the technical requirement of "settlement rate ≤ 0.5mm / h after standing for 24 hours".

[0146] Performance reference of unmodified SiC nanoparticles in Comparative Example 1

[0147] SiC nanoparticles (without surface modification) of the same batch and specifications as in Example 1 were used, and the dispersion stability was tested according to the method described in 3.2 of Example 1:

[0148] Take 50 mL of the same intermediate layer plating solution, add 0.25 g of unmodified SiC nanoparticles, and disperse by inverting the graduated cylinder 5 times. The initial liquid level is 50.0 mL.

[0149] After standing for 24 hours, obvious white agglomerated particles were observed in the plating solution, with a settling section height of 35.2 mL; the calculated height difference was (50.0-35.2) mL × 2.5 mm / mL = 14.8 mm.

[0150] The calculated settling rate is 14.8mm ÷ 24h ≈ 0.617mm / h, which exceeds the technical requirement of "settling rate ≤ 0.5mm / h after standing for 24 hours". Furthermore, the agglomerated particles will cause defects such as porosity and uneven hardness in the subsequent coating, which cannot meet the performance requirements of the intermediate composite coating.

[0151] The SiC nanoparticles treated with the surface modification process described in this embodiment (ethanol-deionized water mixing and dispersion, silane coupling agent KH-550 modification, centrifugal separation and vacuum drying) have significantly reduced surface hydroxyl content and greatly improved dispersion stability in the intermediate layer plating solution. Compared with unmodified particles, the modified particles can effectively avoid agglomeration and sedimentation in the plating solution, ensuring that the subsequent intermediate layer composite coating has uniform composition and dense structure, providing reliable process support for the abrasion resistance of high abrasion-resistant carding machine metal needle cloth.

[0152] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A multi-element, multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth, characterized in that, Includes the following steps: S1. Substrate pretreatment: The metal carding cloth substrate of the carding machine is 65Mn steel or 20CrMnTi steel. The substrate is subjected to degreasing, derusting and activation treatment in sequence to obtain a clean pretreated substrate. S2. Multi-layer composite chemical plating: chemical plating of the bottom layer, the middle layer, and the top layer are performed sequentially on the surface of the pretreated substrate to obtain a plating intermediate; the bottom layer is a nickel-phosphorus alloy plating layer, the middle layer is a nickel-cobalt-tungsten-phosphorus-nano hard particle composite plating layer, and the top layer is a nickel-boron-friction-reducing particle composite plating layer. S3. Post-processing: The plating intermediate is subjected to heat treatment and precision polishing in sequence to obtain high wear-resistant metal needle cloth.

2. The multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth according to claim 1, characterized in that, In step S1: The degreasing process uses an alkaline degreasing agent, with the degreasing temperature set at a constant temperature water bath of 50-60°C, and a treatment time of 10-15 minutes. The alkaline degreasing agent, by mass concentration, comprises: 20-30 g / L sodium hydroxide, 15-25 g / L sodium carbonate, 10-20 g / L sodium phosphate, and a surfactant, wherein the surfactant is sodium dodecylbenzene sulfonate with a mass concentration of 1-3 g / L. The rust removal process uses a 10%-15% hydrochloric acid solution at a room temperature of 20-25℃ for 5-8 minutes. After rust removal, the solution is rinsed with deionized water until the pH reaches 6.5-7.

5. The activation process uses a 5%–8% sulfuric acid solution at a temperature of 40–50°C for 3–5 minutes. After activation, the surface roughness Ra of the substrate is controlled at 0.2–0.5 μm and is measured using a laser roughness meter. The measurement area is within 5 mm on both sides of the working edge of the needle cloth.

3. The multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth according to claim 1, characterized in that, The process parameters for the bottom layer electroless plating mentioned in step S2 include: The plating solution contains, by mass concentration: nickel sulfate (NiSO4·6H2O) 20-30 g / L, sodium hypophosphite (NaH2PO2·H2O) 15-25 g / L, sodium acetate (CH3CO0Na·3H2O) 5-10 g / L, and sodium citrate (Na3C5H5O7·2H2O) 3-8 g / L. The plating temperature is based on the plating solution temperature and is measured using a platinum resistance thermometer; the temperature is 85-90℃; the pH value is 4.5-5.5, which is monitored in real time using a pH meter and adjusted using dilute sulfuric acid or dilute sodium hydroxide solution; the treatment time is 15-20 minutes. The thickness of the bottom coating is 5-10 μm. Metallographic samples were prepared by cutting the cross-section of the needle cloth and using a metallographic microscope. The phosphorus content is 8%-12%. X-ray fluorescence spectrometry was used to detect the phosphorus content, and the detection spot diameter was 50 μm.

4. The multi-element, multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth according to claim 1, characterized in that, The process parameters for the intermediate layer electroless plating in step S2 include: The plating solution, by mass concentration, contains: nickel sulfate (NiSO4·6H2O) 15-20 g / L, cobalt chloride (CoCl2·6H2O) 5-10 g / L, sodium tungstate (Na2WO4·2H2O) 3-8 g / L, sodium hypophosphite (NaH2PO2·H2O) 20-30 g / L, and nano-hard particles 2-5 g / L; The nano-hard particles are one or more of SiC, diamond or WC, with a particle size of 50-100nm. They are detected by a dynamic light scattering instrument at a detection temperature of 25℃, and the dispersion medium is deionized water. The plating temperature is 88-92℃, based on the plating solution temperature and measured with a platinum resistance thermometer; the pH value is 5.0-6.0, adjusted in real time with a pH meter; the stirring rate is 200-300 r / min, using a paddle stirrer with a paddle diameter of 1 / 3 of the inner diameter of the plating tank; the processing time is 30-45 min. The thickness of the intermediate coating is 20-40μm, and it is inspected using a metallographic microscope. The inspection method is the same as above.

5. The multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth according to claim 1, characterized in that, The process parameters for the top-layer electroless plating in step S2 include: The plating solution contains, by mass concentration: nickel sulfate NiSO4·6H2O 10-15 g / L, sodium borohydride NaBH4 2-5 g / L, sodium citrate Na3C5H5O7·2H2O 10-15 g / L, and friction-reducing particles 1-3 g / L. The friction-reducing particles are PTFE or MoS2 with a particle size of 100-200 nm. The average particle size is calculated by randomly selecting 50 particles using scanning electron microscopy image analysis. The plating temperature is 60-70℃, based on the temperature of the plating solution and measured with a platinum resistance thermometer; the pH value is 8.0-9.0, adjusted with dilute hydrochloric acid or dilute sodium hydroxide solution; the treatment time is 10-15 minutes. The thickness of the top coating is 3-8μm, and it is inspected using a metallographic microscope. The inspection method is the same as above.

6. The multi-element, multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth according to claim 1, characterized in that, In step S2, the thickness ratio of the bottom layer, the middle layer, and the top layer is (1-2):(4-8):(0.6-1.6), and the total thickness of the multilayer coating is 30-50μm. Thickness is measured at the working edge area of ​​the metal needle cloth, 0.5-1 mm from the tip of the edge. Three measurement points are randomly selected for each sample, and the arithmetic mean is taken as the final thickness value.

7. The multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth according to claim 1, characterized in that, In step S3: The heat treatment procedure is as follows: based on the substrate surface temperature, heat to 300-400℃ at a rate of 2-5℃ / min, hold for 60-90min, and cool to room temperature with the furnace, with room temperature ≤30℃. The precision polishing uses diamond polishing paste with a particle size of 1-3μm, and polishes at a rate of 150-200r / min for 5-10min on a metallographic polishing machine; After polishing, the surface roughness Ra of the top layer is ≤0.2μm, which is detected by a laser roughness meter in the same area as above.

8. The multi-element, multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth according to claim 1, characterized in that, Before performing step S2, a plating parameter optimization step S0 is also included: S01. Obtain the surface hardness and expected wear resistance life of the current batch of substrates: The surface hardness HV0 was tested using a Vickers hardness tester with a load of 500g and a holding time of 10s. Five points were randomly tested on each substrate and the average value was taken. The expected abrasion resistance life T is the design service life of the metal carding cloth of the carding machine, in hours, with a range of 500-2000 hours. The plating factor (PFO) is calculated using the formula PFO = k × (HV0 / ρb) × (T / 1000), where: ρb is the base density; the density of 65Mn steel is taken as 7.85 g / cm³. 3 The density of 20CrMnTi steel is taken as 7.83 g / cm³. 3 ; k is the equipment calibration constant, determined through calibration experiments: using a standard hardness block (HV500±20) and a standard density sample, with the standard density sample ρb=7.85g / cm³. 3 Three parallel experiments were conducted on the same plating equipment, and the average value of k was calculated. The range of k values ​​was 0.8-1.

2. S02. Based on the PFO value and a pre-established mapping relationship, determine the content of intermediate layer nanoparticles and the heat treatment holding time. The mapping relationship is obtained by training a gradient boosting regression tree model. The training dataset contains more than 100 sets of corresponding data on PFO value, nanoparticle content, heat preservation time, and actual wear resistance life.

9. The multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth according to claim 1, characterized in that, The method is performed by an intelligent plating system, which includes: Substrate parameter measurement module: integrates Vickers hardness tester, laser roughness tester and three-dimensional profilometer. The Vickers hardness tester has a load range of 200-1000g, the laser roughness tester has a detection range of 0.01-10μm, and the three-dimensional profilometer has a measurement accuracy of ±1μm. It is used to obtain the surface characteristic parameters of the substrate, and the data acquisition frequency is ≥1 time / 5min. Plating solution control module: Includes an online refractometer, pH meter, and platinum resistance thermometer. The online refractometer has a concentration detection accuracy of ±0.1 g / L, the pH meter has a detection accuracy of ±0.01 pH, and the platinum resistance thermometer has a temperature detection accuracy of ±0.1℃. It can adjust the concentration of plating solution components, pH value, and temperature in real time. The concentration adjustment accuracy is ±0.5 g / L with a response time ≤30s, the pH adjustment accuracy is ±0.1 pH, and the temperature adjustment accuracy is ±1℃. Data processing module: Embedded plating factor calculation model and multi-layer process parameter mapping relationship, the mapping relationship is the same as the GBRT model above, can output the optimal process command in real time according to the substrate parameters, and the command transmission delay is ≤1s.

10. The multi-layer composite chemical plating method for high abrasion-resistant carding machine metal needle cloth according to claim 4, characterized in that, The nano-hard particles in the intermediate layer mentioned in step S2 undergo surface modification treatment before being added to the plating solution. The specific modification process includes: Step 1: Dispersion: Disperse the nano-hard particles in an ethanol-deionized water solution with a volume ratio of 3:1, and use an ultrasonic cleaner to ultrasonically disperse for 15-20 minutes. The ultrasonic cleaner power is 300-500W and the ultrasonic frequency is 25-40kHz. After ultrasonication, there is no obvious agglomeration of particles. The second step of the modification reaction: add silane coupling agent KH-550 to the dispersed mixture. The mass concentration of silane coupling agent KH-550 in the mixture is 1%-3%. Place the mixture in a constant temperature water bath for 2-4 hours. The temperature of the constant temperature water bath is 60-70℃. Stir the mixture during the reaction. The third step is separation and drying: After the reaction is completed, the mixture is centrifuged for 10-15 minutes at a speed of 8000-10000 r / min. The precipitate is collected after centrifugation. The collected precipitate is placed in a vacuum drying oven and dried for 1-2 hours at a temperature of 80-100℃. After drying, modified nano-hard particles are obtained. The surface hydroxyl content of the modified hard nanoparticles was reduced by 15%–25% compared to the unmodified particles, as detected by Fourier transform infrared spectroscopy.

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