An anti-abrasion composite layer and its preparation method

Abstract

The present invention provides an anti-abrasion and corrosion composite layer and a preparation method thereof. The anti-abrasion and corrosion composite layer includes a passivation layer, a first zinc-iron composite layer, and a second zinc-iron composite layer from the surface to the interior; wherein, the iron content in the first zinc-iron composite layer is lower than that in the second zinc-iron composite layer, so as to form a gradient coating with the corrosion potential and hardness increasing from low to high. Wear-resistant particles are included in both the first zinc-iron composite layer and the second zinc-iron composite layer, and the wear-resistant particles form a wedge-shaped structure between the first zinc-iron composite layer and the second zinc-iron composite layer. The anti-abrasion and corrosion composite layer has good wear resistance and corrosion resistance, and can significantly improve the service ability of metal components such as electric power fittings under abrasion and corrosion conditions.

Description

Technical Field

[0001] The invention relates to the technical field of surface treatment, and in particular to an anti-abrasion composite layer and a preparation method thereof. Background Art

[0002] As the most important basic material, carbon steel is widely used in industries such as electricity, communications, chemicals, and automobiles. For example, U-shaped rings, ball head hanging rings and other power fittings are exposed to various meteorological conditions all year round, and corrosion occurs all the time. Breeze vibration, dancing, icing, sub-span vibration, wire de-icing and jumping, etc., cause wear of line fittings to varying degrees, which makes power fittings have both corrosion and wear conditions. The commonly used hot-dip galvanized layer is neither corrosion-resistant nor wear-resistant in the coastal environment of high temperature, high humidity, high chlorine, and strong winds, resulting in frequent cases of abrasion failure of power fittings. On the other hand, people have put forward higher requirements on the environmental protection and cost of anti-abrasion materials. Therefore, the development of environmentally friendly and low-cost anti-abrasion layers with good performance has significant practical significance.

[0003] In order to improve the corrosion resistance of carbon steel components, researchers have studied zinc alloy coatings such as Zn-Ni, Zn-Co, and Zn-Fe. Among them, the Zn-Fe alloy layer has the lowest cost and is more environmentally friendly. Therefore, there are many studies on the deposition of Zn-Fe alloys with low and high iron contents. For example, CN104120466A, CN105442000A, CN109137016A, and CN1162571C prepared Zn-Fe alloy coatings with low iron content in acidic or alkaline baths, and CN117535744A and CN101545125A prepared Zn-Fe alloy coatings with iron contents of 12% to 18% and 17% to 20%, respectively. However, the composition of the Zn-Fe alloy has an important influence on its structure, which makes the performance of the alloy layer significantly different. A single Zn-Fe alloy coating is obviously difficult to meet the requirements of metal components such as power fittings in abrasive working conditions.

[0004] Researchers used a composite deposition technique to improve the wear resistance of the Zn-Fe coating to a certain extent. Fan Yunying et al. added 20-60 g / L of SiO2 particles with a particle size of 0.76 μm to an acidic Zn-Fe system to prepare a ZnFe-SiO2 composite coating with a Fe content of about 10 wt.% and a maximum SiO2 content of 0.51 wt.% (Fan Yunying et al., Influence of plating solution composition on the composition of Zn-Fe-SiO2 alloy composite coating, Surface Technology, 2003, 32(5): 53-55). This team also disclosed the preparation method of Zn-Fe-SiO2 composite coating in an acidic system through CN1854351A, CN1854350A, CN1289717C, etc. CN109137016A and CN111636080A disclosed the electroplating process for preparing Zn-Fe-graphene composite coating in an alkaline system. However, in the prior art, due to the failure to take targeted measures to increase the content of micro-nano particles in the composite layer, the particle content in the composite layer is extremely limited, so the improvement of wear resistance is restricted. Summary of the Invention

[0005] In order to solve the above problems in the prior art, the purpose of the present invention is to provide an anti-abrasive composite layer and its preparation method. The anti-abrasive composite layer has good wear resistance and corrosion resistance.

[0006] In order to achieve the above purpose, according to the first aspect of the present invention, an anti-abrasive composite layer is provided. The anti-abrasive composite layer includes a passivation layer, a first Zn-Fe composite layer, and a second Zn-Fe composite layer from the surface to the inside; wherein, the iron content in the first Zn-Fe composite layer is lower than the iron content in the second Zn-Fe composite layer;

[0007] In the first Zn-Fe layer, Zn-Fe is in the η phase, and in the second Zn-Fe layer, Zn-Fe is in the γ phase;

[0008] Both the first Zn-Fe composite layer and the second Zn-Fe composite layer contain wear-resistant particles. The particle size of the wear-resistant particles in the first Zn-Fe composite layer is 10 nanometers to 10 micrometers, and the particle size of the wear-resistant particles in the second Zn-Fe composite layer is 10 nanometers to 30 micrometers;

[0009] The thicknesses of the first Zn-Fe composite layer and the second Zn-Fe composite layer are each independently 8-18 micrometers;

[0010] The composite amount of the wear-resistant particles in the anti-abrasive composite layer is 5-8 wt%.

[0011] Among them, the composite amount is measured according to the following method:

[0012] Peel off part of the composite coating and weigh the mass of the composite coating ( ), heat in an HNO3 aqueous solution with a volume ratio of concentrated nitric acid to water of 1:1 (where the concentrated nitric acid is a concentrated nitric acid aqueous solution with a mass concentration of 67%) until the metal in the coating is completely dissolved. After the wear-resistant particles are completely precipitated, separate and dry them, and weigh the mass of the particles in the coating ( ), and calculate the composite amount from this .

[0013] The anti-corrosion and wear-resistant composite layer of the present invention ensures the corrosion resistance of the coating to the substrate in many aspects. First, the passivation property of the outer layer with a low Fe content coating is used to form a passivation film, ensuring that the three-layer structure has good corrosion resistance. Second, the potential difference between the coating and the steel substrate gradually decreases through the gradient of increasing Fe content from the surface to the inside, so that it still has a certain corrosion resistance after the outer layer is gradually consumed. Third, the Zn-Fe layer acts as a sacrificial anode to provide cathodic protection for the substrate.

[0014] At the same time, the anti-corrosion and wear-resistant composite layer of the present invention ensures the wear resistance of the coating to the substrate in many aspects. First, by using the Fe content gradient in the coating from the surface to the inside, the component forms a structural gradient of a passivation layer, η phase to γ phase, and then forms a hardness gradient of the three-layer structure. Second, the hardness of the anti-corrosion and wear-resistant composite layer is further improved through the dispersion strengthening effect of the wear-resistant particles. Finally, the friction coefficient of the anti-corrosion and wear-resistant composite layer is greatly reduced by using the wear-resistant particles, and the effect is strengthened by the mutual matching of the large-particle-size wear-resistant particles in the inner layer and the small-particle-size wear-resistant particles in the outer layer. In addition, the anti-corrosion and wear-resistant composite layer of the present invention contains more wear-resistant particles, which can also better provide wear and corrosion resistance.

[0015] In some preferred embodiments of the present invention, the iron content in the first zinc-iron layer is 0.03 to 1.0 wt%.

[0016] In some preferred embodiments of the present invention, the iron content in the second zinc-iron layer is 5 to 30 wt%.

[0017] In some preferred embodiments of the present invention, the particle size of the wear-resistant particles in the first zinc-iron composite layer is 100 nanometers to 8 micrometers.

[0018] In some preferred embodiments of the present invention, the particle size of the wear-resistant particles in the second zinc-iron composite layer includes two types: 45 nanometers to 10 micrometers and 15 micrometers to 30 micrometers. The present invention preferably uses the mutual matching of wear-resistant particles with different particle sizes, which is more beneficial to improving the anti-corrosion and wear-resistant effect of the multi-layer structure. In addition to providing the same dispersion strengthening and self-lubricating effects as the small-particle-size wear-resistant particles, the large-particle-size wear-resistant particles also significantly improve the bonding strength between the first zinc-iron composite layer and the second zinc-iron composite layer through the wedge structure.

[0019] In some preferred embodiments of the present invention, the wear-resistant particles include one or a combination of two or more of diamond wear-resistant particles, silicon carbide wear-resistant particles, silicon dioxide wear-resistant particles, boron nitride wear-resistant particles, aluminum oxide wear-resistant particles, molybdenum disulfide wear-resistant particles, zirconium dioxide wear-resistant particles, titanium dioxide wear-resistant particles, silicon nitride wear-resistant particles, tungsten carbide wear-resistant particles, polytetrafluoroethylene wear-resistant particles, carbon fiber wear-resistant particles, carbon nanotube wear-resistant particles, graphite wear-resistant particles, and graphene wear-resistant particles.

[0020] Preferably, the wear-resistant particles include self-lubricating wear-resistant particles. More preferably, the self-lubricating wear-resistant particles include one or a combination of two or more of boron nitride wear-resistant particles, aluminum oxide wear-resistant particles, polytetrafluoroethylene wear-resistant particles, molybdenum disulfide wear-resistant particles, graphite wear-resistant particles, carbon nanotube wear-resistant particles, and graphene wear-resistant particles. The self-lubricating property of the above-mentioned preferred wear-resistant particles is beneficial to reducing the friction coefficient of the anti-abrasion composite layer and enhancing the wear resistance of the anti-abrasion composite layer.

[0021] In some preferred embodiments of the present invention, a substrate with an anti-wear composite layer is provided. The anti-abrasion composite layer is the above-mentioned anti-abrasion composite layer, and the material of the substrate includes one or a combination of two or more of carbon steel, stainless steel, copper, and aluminum. In some preferred embodiments of the present invention, the first zinc-iron composite layer is prepared from a first solution. Based on the total volume of the first solution, the first solution includes: 8-15 g / L of zinc oxide, 60-140 g / L of sodium hydroxide, 1.5-15 g / L of ammonium ferrous sulfate hexahydrate, 3-150 g / L (preferably 50-100 g / L) of the wear-resistant particles, 100-150 ml / L of a first multi-component complexing system, 80-120 ml / L of a combined brightening agent, 100-140 ml / L of a leveling agent, 80-120 ml / L of a stabilizer, and 80-120 ml / L of an additive; wherein, the first multi-component complexing system includes a first main complexing agent and a first auxiliary complexing agent. Among them, the first main complexing agent includes one or a combination of two or more of sodium citrate, ammonium citrate, sodium salicylate, and pyridine; the first auxiliary complexing agent includes sodium gluconate and / or triethanolamine.

[0022] In some preferred embodiments of the present invention, the second zinc-iron composite layer is prepared from a second solution. Based on the total volume of the second solution, the second solution comprises: zinc oxide 8 - 15 g / L, sodium hydroxide 60 - 140 g / L, ammonium ferrous sulfate hexahydrate 10 - 40 g / L, the wear-resistant particles 3 - 150 g / L, a second multi-component complexing system 100 - 150 ml / L, a combined brightening agent 80 - 120 ml / L, a leveling agent 80 - 120 ml / L, a stabilizer 80 - 120 ml / L, and an additive 80 - 120 ml / L; wherein, the second multi-component complexing system comprises a second main complexing agent and a second auxiliary complexing agent, and the second main complexing agent comprises one or a combination of two or more of tetraethylenepentamine, triethylenetetramine, and ethylenediamine, and the second auxiliary complexing agent comprises sodium gluconate and / or triethanolamine.

[0023] In some preferred embodiments of the present invention, the wear-resistant particles in the second solution include two types with particle sizes of 45 nm to 10 μm and 15 μm to 30 μm. Moreover, the concentration of the wear-resistant particles with a particle size of 45 nm to 10 μm is 5 - 50 g / L, and the concentration of the wear-resistant particles with a particle size of 15 μm to 30 μm is 60 - 120 g / L. Selecting two sizes of wear-resistant particles compounded according to the above concentrations is more conducive to improving the bonding strength between the first zinc-iron composite layer and the second zinc-iron composite layer by using the wedge-shaped structure.

[0024] The present invention adjusts the iron content in the deposited layer by using the difference in the complexing ability of different multi-component complexing systems and the difference in the concentration of Fe 2+ in the solution. When preparing the first zinc-iron composite layer with a low Fe content, a complexing system with strong complexing ability with Fe 2+ and weak complexing ability with Zn 2+ such as sodium citrate, ammonium citrate, etc.) is selected, and at the same time, a low Fe 2+ concentration is adopted; when preparing the second zinc-iron composite layer with a high Fe content, a complexing system with weak complexing ability with Fe 2+ and strong complexing ability with Zn 2+ such as tetraethylenepentamine, etc.) is selected, and at the same time, a high Fe 2+ concentration is adopted.

[0025] The electrolyte solution of the present invention utilizes the antioxidant effect of the stabilizer and the complexing effect of the complexing system on Fe 2+ to inhibit the oxidation of Fe 2+ in the solution.

[0026] In some preferred embodiments of the present invention, the solvent for preparing the solution is water.

[0027] In some preferred embodiments of the present invention, based on the total volume of the first multi-component complexing system, in the first multi-component complexing system, the concentration of sodium citrate and / or ammonium citrate is 100 - 300 g / L (preferably 120 - 250 g / L), the concentration of sodium salicylate is 18 - 180 g / L (preferably 24 - 120 g / L), the concentration of pyridine is 0 - 180 g / L (preferably 0 - 120 g / L), the concentration of sodium gluconate is 150 - 200 g / L (preferably 150 - 200 g / L), and the concentration of triethanolamine is 100 - 300 mL / L (preferably 150 - 250 mL / L).

[0028] In the present invention, when the expression of the concentration of a certain component A "and / or" a certain component B is within a certain range is used, it means that the certain component A and the certain component B are regarded as a group, and within this "group", optionally, there is component A and / or component B, and the total concentration of this "group" is within the stated range.

[0029] In some preferred embodiments of the present invention, based on the total volume of the second multi-component complexing system, in the second multi-component complexing system, the concentration of tetraethylenepentamine is 100 - 300 mL / L (preferably 150 - 250 mL / L), the concentration of triethylenetetramine is 0 - 200 mL / L (preferably 0 - 150 mL / L), the concentration of ethylenediamine is 0 - 200 mL / L (preferably 0 - 150 mL / L), the concentration of sodium gluconate is 100 - 300 g / L (preferably 150 - 200 g / L), and the concentration of triethanolamine is 50 - 200 mL / L (preferably 100 - 150 mL / L).

[0030] In some preferred embodiments of the present invention, the combination brightener includes one or a combination of two or more of benzylpyridinium carboxylate, vanillin, piperonal, heliotropin, polyethylene glycol, and butynediol.

[0031] In some preferred embodiments of the present invention, the leveling agent includes one or a combination of two or more of Mirapol WT, sodium vinylsulfonate, sodium allylsulfonate, and sodium tellurate.

[0032] In some preferred embodiments of the present invention, the stabilizer includes one or a combination of two or more of potassium sodium tartrate, sodium sulfite, manganese dichloride, and sodium ascorbate.

[0033] In some preferred embodiments of the present invention, the additive includes one or a combination of two of a surfactant and a rare earth salt; preferably, in the second solution, the additive includes tetrahydrothiazolethione. Preferably, the additive includes tetrahydrothiazolethione only when the substrate is an aluminum substrate.

[0034] Preferably, the surfactant includes a cationic surfactant. Adding the cationic surfactant is beneficial to its adsorption on the surface of the wear-resistant particles, improving the Zeta potential of the wear-resistant particles, and thus increasing the composite amount of the wear-resistant particles.

[0035] Preferably, the surfactant includes one or a combination of more than two of quaternary ammonium salt surfactants and pyridine surfactants. Preferably, the surfactant includes bromogeramine.

[0036] In some preferred embodiments of the present invention, other additives are further included in the first multi-component complexing system and / or the second multi-component complexing system; preferably, the other additives include a combination of one or two of glass balls and plastic balls.

[0037] Preferably, the plastic balls have a particle size of 1-4 mm, and the plastic material is preferably PVC or PA. The collision of the glass balls and plastic balls on the surface of the coating is also beneficial to improving the compactness of the coating.

[0038] In some preferred embodiments of the present invention, the rare earth salt includes a combination of one or more of nitrates, acetates, sulfates, and chlorides of rare earth elements. Rare earth salt ions are easily adsorbed on the surface of the electrode and the wear-resistant particles, thereby increasing the polarization resistance of the deposition system, promoting grain refinement, and further improving the hardness of the anti-abrasion composite layer. Moreover, the cathodic polarization effect of the rare earth salt and the wear-resistant particles makes the deposition layer more compact, which is beneficial to increasing the composite amount and also beneficial to enhancing the corrosion resistance of the anti-abrasion composite layer.

[0039] In some preferred embodiments of the present invention, the concentration of the benzylpyridinium carboxylate is 0.5-2 ml / L (preferably 0.6-1.2 mL / L), the concentration of one or a combination of more than two of vanillin, piperonal, and heliotropin is 0.5-1.5 g / L (preferably 0.6-1 g / L), and the concentration of polyethylene glycol and / or butynediol is 0.4-1.2 g / L (preferably 0.5-0.8 g / L).

[0040] In some preferred embodiments of the present invention, the concentration of Mirapol WT in the leveling agent is 10-20 g / L, the concentration of sodium vinyl sulfonate and / or sodium allyl sulfonate is 0.06-0.2 g / L (preferably 0.08-0.14 g / L), and the concentration of sodium tellurite is 0-0.16 g / L (preferably 0-0.1 g / L).

[0041] In some preferred embodiments of the present invention, the concentration of potassium sodium tartrate is 80-200 g / L (preferably 100-150 g / L), the concentration of sodium sulfite in the first solution is 0.25-1 g / L (preferably 0.4-0.8 g / L), the concentration of sodium sulfite in the second solution is 0.5-2 g / L (preferably 0.6-1.2 g / L), and the concentration of manganese dichloride and / or ascorbic acid is 0-50 g / L (preferably 0-30 g / L).

[0042] In some preferred embodiments of the present invention, the concentration of the surfactant is 0.4-8 g / L, the concentration of the rare earth salt is 0-0.25 mol / L, the concentration of tetrahydrothiazolethione is 0-0.2 g / L, and the concentration of glass balls and / or plastic balls is 40-250 particles / L.

[0043] Preferably, the concentration of tetrahydrothiazolethione is 10-20 mg / L.

[0044] In some preferred embodiments of the present invention, the solution for preparing the passivation layer is denoted as the third solution. Based on the total volume of the third solution, the third solution includes chromium nitrate nonahydrate 40-80 g / L, sodium nitrate 5-20 g / L, sodium oxalate 10-20 g / L, sodium malonate 10-20 g / L, maleic anhydride 1-2 g / L, cobalt nitrate hexahydrate 5-8 g / L, and amino silicone 3-5 mL / L; the pH of the third solution is 2-2.5.

[0045] According to another aspect of the present invention, there is provided a method for preparing the above anti-abrasion composite layer, which includes:

[0046] After pretreating the substrate, it is used as the cathode;

[0047] The second zinc-iron composite layer is electroplated and deposited on the cathode in sequence, and the first zinc-iron composite layer is electroplated and deposited on the second zinc-iron layer to obtain an intermediate product; the electroplating and deposition are carried out under intermittent stirring;

[0048] The intermediate product is passivated to obtain the anti-abrasion composite layer;

[0049] Wherein, the anode includes one or a combination of two or more of stainless steel, nickel-plated steel sheet, and nickel plate.

[0050] Through intermittent stirring, wear-resistant particles can be transported to the cathode, and the wear-resistant particles retained on the cathode surface can also be flushed. Obviously, the flushing effect of stirring is weakened during the intermittent period. Moreover, the inventors have found through research that the interfacial force existing between the newly formed metal and the wear-resistant particles during composite deposition is conducive to the retention of the wear-resistant particles on the cathode surface. The intermittent period can make full use of the retention effect of the interfacial force, thereby significantly increasing the content of wear-resistant particles in the composite layer. At the same time, rare earth ions are added in the present invention, which can enable the wear-resistant particles to adsorb more positive charges, promote the movement of the wear-resistant particles towards the cathode and their retention on the cathode surface, thereby increasing the composite amount. In addition, in some embodiments of the present invention, a cationic surfactant is added, which is beneficial to adsorb on the surface of the wear-resistant particles, increase the Zeta potential of the wear-resistant particles, and thus promote the transport and retention of the wear-resistant particles towards the cathode.

[0051] The intermittent stirring method can be mechanical stirring and should not be air stirring. Preferably, the stirring intensity is such that the wear-resistant particles are not likely to settle during the preparation of the second zinc-iron composite layer, and during the preparation of the first zinc-iron composite layer, it is appropriate for glass balls and / or plastic balls (if any) to collide with the cathode surface. Specifically, it is adjusted according to the size of the tank, the particle size and density of the wear-resistant particles, etc.

[0052] In some preferred embodiments of the present invention, the conditions for the intermittent stirring include: stirring for 10 s to 20 s, intermittent for 5 s to 20 s, and the stirring intensity is 0 to 3000 rpm; in the preferred embodiments, the intermittent time during the deposition of the first zinc-iron composite layer is 10 s to 20 s, the stirring intensity is 0 to 1500 rpm, the intermittent time during the deposition of the second zinc-iron composite layer is 5 s to 12 s, and the stirring intensity is 0 to 3000 rpm. When tribological properties are not required, stirring may not be needed, or only mild stirring is required to remove the bubbles on the electrode surface.

[0053] In some preferred embodiments of the present invention, the conditions for electroplating and depositing the second zinc-iron composite layer and depositing the first zinc-iron composite layer each include: the cathode current density is 0.5 to 6 A / dm 2 , the temperature is 10 to 40 °C, and the time is 20 to 60 minutes; the deposition is carried out under the conditions of intermittent stirring.

[0054] In some preferred embodiments of the present invention, the conditions for the passivation treatment include: the pH value is 2 to 2.5, the temperature is 20 to 45 °C, and the time is 30 to 60 s.

[0055] Compared with hot-dip galvanizing, the present invention replaces the existing hot-dip galvanizing process at about 450 °C with a normal-temperature Zn-Fe deposition process, and has obvious low-carbon advantages; compared with Zn-Ni deposition, the present invention uses Fe 2+ to replace Ni in Zn-Ni deposition 2+ , and has good environmental protection properties. The present invention also has the advantage of low cost, Zn 2+With Fe 2+ It is widely sourced and inexpensive.

[0056] In some preferred embodiments of the present invention, the pre-treatment method includes degreasing - water washing - rust removal - water washing - activation. For the purpose of obtaining a fresh substrate surface, conventional treatment processes can be used. Brightening can be carried out using a 0.2 - 0.5% dilute nitric acid solution.

[0057] Compared with the prior art, the beneficial technical effects of the present invention include:

[0058] Provided is an environmentally friendly and low-cost anti-abrasion composite layer, which simultaneously has excellent wear resistance and corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 Shows a schematic structural diagram of the anti-abrasion composite layer of Example 4 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0060] In order to have a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the technical solutions of the present invention will now be described in detail below, but it should not be construed as a limitation on the scope of implementation of the present invention.

[0061] Example 1

[0062] A 10×20×2 mm copper sheet was polished with #2000 sandpaper, washed with deionized water, and then subjected to pre-treatment of degreasing - water washing - rust removal - water washing - activation. After washing with water, it was used as the cathode and put into the second solution under charge. The anode was a nickel plate.

[0063] The composition of the second solution is as follows: zinc oxide 10 g / L, sodium hydroxide 100 g / L, ammonium ferrous sulfate hexahydrate 30 g / L; for the wear-resistant particles, 90 g / L of hexagonal boron nitride with a particle size of 30 μm and 30 g / L of hexagonal boron nitride with a particle size of 3 μm are taken; for the multi-component complexing system, tetraethylenepentamine 20 mL / L, triethylenetetramine 5 mL / L, sodium gluconate 20 g / L, and triethanolamine 10 mL / L are taken; for the combined brightening agent, benzylpyridinium carboxylate 0.1 mL / L, vanillin 80 mg / L, and polyethylene glycol 60 mg / L are taken; for the leveling agent, Mirapol WT 1.5 g / L, sodium vinylsulfonate 10 mg / L, and sodium tellurite 8 mg / L are taken; for the stabilizer, sodium potassium tartrate 15 g / L, sodium sulfite 50 g / L, and manganese dichloride 3 g / L are taken; for the additive, cerium sulfate 1 g / L and benzalkonium bromide 0.04 g / L are taken; the balance is water.

[0064] During the electroplating process, the cathode current density is 3 A / dm 2, the water bath temperature is 25 °C, intermittent stirring is adopted, stirring for 10 s and then intermittent for 10 s, and the stirring speed is 450 rpm; after 30 minutes, a uniform second zinc-iron composite layer is obtained on the surface of the copper sheet, with a thickness of about 17 microns.

[0065] EDS semi-quantitative analysis was carried out on the part of the second zinc-iron composite layer without wear-resistant particles. The results showed that the zinc content in the obtained second zinc-iron composite layer was 70.2 wt.%, the iron content was 21.4 wt.%, and the balance was other elements such as Cu. The hardness value measured by a microhardness tester was 662 HV.

[0066] The measured composite amount was 7.8 wt.%. The composite amount was measured according to the following method:

[0067] Peel off part of the composite coating, weigh the mass of the composite coating ( ), heat it in an HNO3 aqueous solution with a volume ratio of nitric acid to water of 1:1 to completely dissolve the metal in the coating. After the wear-resistant particles are completely precipitated, separate and dry them, and weigh the mass of the wear-resistant particles in the coating ( ), and calculate the composite amount from this . The weighing was carried out on an electronic balance BS210S of Sartorius Company, Germany, with an error of ±0.2 mg.

[0068] Example 2

[0069] A copper sheet of 10×20×2 mm was polished with #2000 sandpaper, washed with deionized water, and then subjected to pre-treatment of degreasing - water washing - rust removal - water washing - activation. After washing with water, it was used as the cathode and put into the first solution while being charged, and the anode was a nickel plate.

[0070] The composition of the first solution is: zinc oxide 10 g / L, sodium hydroxide 100 g / L, ammonium ferrous sulfate hexahydrate 4 g / L; the wear-resistant particles are hexagonal boron nitride with a particle size of 3 μm, 90 g / L; the first multi-component complex system takes sodium citrate 25 g / L, sodium salicylate 5 g / L, sodium gluconate 15 g / L, triethanolamine 10 mL / L; the combined brightener takes benzylpyridinium carboxylate 0.1 mL / L, piperonal 70 mg / L, butynediol 60 mg / L; the leveling agent takes Mirapol WT 1.5 g / L, sodium vinylsulfonate 10 mg / L, sodium tellurate 8 mg / L; the stabilizer takes sodium potassium tartrate 12 g / L, sodium sulfite 8 mg / L, manganese dichloride 1 g / L; the rare earth salt in the additive takes cerium sulfate 2 g / L, benzalkonium bromide 0.04 g / L; the balance is water.

[0071] During the electroplating process, the cathode current density is 3 A / dm 2; The stirring speed was 380 rpm. Intermittent stirring was adopted, with 10 s of stirring and 10 s of interruption; the water bath temperature was 25 °C; after 30 minutes, a bright and smooth composite coating with a thickness of 16 microns was obtained on the surface of the copper sheet.

[0072] EDS semi - quantitative analysis was carried out on the part of the coating without wear - resistant particles. The results showed that the zinc content in the obtained coating was 91.6 wt.%, the iron content was 0.6 wt.%, and the balance was other elements such as Cu.

[0073] The hardness value measured by a micro - hardness tester was 168 HV.

[0074] The measured composite amount was 5.2 wt.%.

[0075] Example 3

[0076] A copper sheet of 10×20×2 mm was polished with #2000 sandpaper, washed with deionized water, and then subjected to pre - treatment of degreasing - water washing - rust removal - water washing - activation. After water washing, it was used as the cathode and put into the first solution with electricity, and the anode was a nickel plate.

[0077] Based on the composition of the first solution in Example 2, 200 plastic balls with a diameter of 2 mm made of PVC material were added per liter, and the stirring intensity was increased to 520 rpm. The other parameters were the same as those in Example 2. The thickness of the obtained coating was 15 microns.

[0078] EDS semi - quantitative analysis was carried out on the part of the obtained coating without wear - resistant particles. The results showed that the zinc content in the obtained coating was 90.8 wt.%, the iron content was 0.9 wt.%, and the balance was other elements such as Cu.

[0079] The measured composite amount was 5.0 wt.%.

[0080] The hardness value measured by a micro - hardness tester was 192 HV, showing a significant increase compared with the hardness value in Example 2. It can be seen that the collision of plastic balls has a positive effect on the improvement of the coating hardness.

[0081] The coating obtained after deposition in the first solution was washed with water and then subjected to post - treatment processes such as brightening - water washing - passivation - water washing - sealing - drying to obtain the required passivation layer. The solution used for passivation treatment was: chromium nitrate nonahydrate 60 g / L, sodium nitrate 15 g / L, sodium oxalate 10 g / L, sodium malonate 10 g / L, maleic anhydride 2 g / L, cobalt nitrate hexahydrate 6 g / L, and amino - silicon 4 mL / L. The pH value of the solution was adjusted to 2, the temperature was 30 °C, and the passivation treatment time was 40 s.

[0082] A 1000 - hour neutral salt spray test was carried out on the non - passivated sample of Example 2 and the passivated sample of Example 3. Red rust was visible on the former, while no red rust was visible on the latter.

[0083] Example 4

[0084] In this example, a U-shaped ring of type U-7 made of Q235 is used as the base material, and an anti-abrasion composite layer is deposited.

[0085] First, perform degreasing - water washing - rust removal - water washing - activation pretreatment. After water washing, it is used as the cathode and put into the second solution while being charged. The anode is a nickel plate, and the deposition process is as in Example 1.

[0086] Subsequently, it is directly used as the cathode and put into the first solution while being charged. The anode is also a nickel plate, and the deposition process is as in Example 3, and passivation treatment is carried out according to the method in Example 3.

[0087] The total thickness of the anti-abrasion composite layer is 33 microns. Among them, the thickness of the first zinc-iron composite layer is 16 microns, and the thickness of the second zinc-iron composite layer is 17 microns.

[0088] EDS semi-quantitative analysis is carried out on the part of the obtained coating without wear-resistant particles. The results show that in the obtained first zinc-iron composite layer, the zinc content is 96.1 wt.%, the iron content is 1.0 wt.%, and the balance is other elements such as C; in the obtained second zinc-iron composite layer, the zinc content is 68.5 wt.%, the iron content is 26.6 wt.%, and the balance is other elements such as C.

[0089] The measured composite amount is 6.9 wt.%.

[0090] The hardness value of the first zinc-iron composite layer measured by a microhardness tester is 207 HV, and the hardness value of the second zinc-iron composite layer is 649 HV. No red rust is seen after the sample undergoes a 1200-hour neutral salt spray test.

[0091] Figure 1 It is a schematic diagram of the structure of the anti-abrasion composite layer prepared in Example 4 of the present invention. As the iron content increases from the surface to the inside, the potential difference between the anti-abrasion composite layer and the carbon steel base material gradually decreases, so as to maintain good corrosion resistance under the combined action with the passivation film. At the same time, the evolution of the outer η phase to the inner γ phase causes a significant increase in the hardness value, and the synergistic effect of self-lubricating wear-resistant particles with different particle sizes together endows the anti-abrasion layer with excellent tribological properties.

[0092] Example 5

[0093] A 5052 aluminum test piece of 10×20×2 mm is polished with #2000 sandpaper, washed with deionized water, and then undergoes degreasing - water washing - rust removal - water washing - activation pretreatment. After water washing, it is used as the cathode and put into the second solution while being charged. The anode is a nickel plate.

[0094] The composition of the second solution is as follows: zinc oxide 10 g / L, sodium hydroxide 100 g / L, ammonium ferrous sulfate hexahydrate 30 g / L; for the wear-resistant particles, hexagonal boron nitride with a particle size of 30 μm is 90 g / L and hexagonal boron nitride with a particle size of 3 μm is 30 g / L; for the multi-component complexing system, tetraethylenepentamine is 20 mL / L, triethylenetetramine is 5 mL / L, sodium gluconate is 20 g / L, and triethanolamine is 10 mL / L; for the combined brightener, benzylpyridinium carboxylate is 0.1 mL / L, vanillin is 80 mg / L, and polyethylene glycol is 60 mg / L; for the leveling agent, Mirapol WT is 1 g / L, sodium vinylsulfonate is 10 mg / L, and sodium tellurate is 8 mg / L; for the stabilizer, sodium potassium tartrate is 15 g / L, sodium sulfite is 50 mg / L, and manganese dichloride is 3 g / L; for the rare earth salt in the additive, ceric sulfate is 1 g / L, benzalkonium bromide is 0.04 g / L, and tetrahydrothiazolethione is 20 mg / L.

[0095] The cathode current density is 3 A / dm 2 , the water bath temperature is 25 °C, the stirring speed is 450 rpm, stirring for 10 s and intermittent for 10 s. After 20 minutes, a composite coating with good bonding is obtained on the surface of the 5052 aluminum test piece, and the thickness is 10 microns.

[0096] EDS semi-quantitative analysis is carried out on the part of the obtained coating without wear-resistant particles. The results show that the zinc content in the obtained coating is 80.4 wt.%, the iron content is 14 wt.%, and the balance is other elements such as Al. The measured hardness of the coating is 424 HV. Due to the thin coating, the hardness value is on the low side affected by the aluminum substrate, and the composite amount is 4.6 wt.%.

[0097] This example shows that the composite coating of the present invention can be well applied on the aluminum substrate.

[0098] Comparative Example 1

[0099] A 10×20×2 mm copper sheet is polished with #2000 sandpaper, washed with deionized water, and then subjected to pretreatment of degreasing - water washing - rust removal - water washing - activation. After washing with water, it is used as the cathode and put into the second solution under charged conditions, and the anode is a nickel plate.

[0100] The composition of the second solution is as follows: zinc oxide 10 g / L, sodium hydroxide 100 g / L, ammonium ferrous sulfate hexahydrate 30 g / L. For the multi-component complex system, tetraethylenepentamine 20 mL / L, triethylenetetramine 5 mL / L, sodium gluconate 20 g / L, and triethanolamine 10 mL / L are taken. For the combined brightener, benzylpyridinium carboxylate 0.1 mL / L, vanillin 80 mg / L, and polyethylene glycol 60 mg / L are taken. For the leveling agent, Mirapol WT 1.5 g / L, sodium vinylsulfonate 10 mg / L, and sodium tellurite 8 mg / L are taken. For the stabilizer, potassium sodium tartrate 15 g / L, sodium sulfite 50 mg / L, and manganese dichloride 3 g / L are taken. For the rare earth salt in the additive, cerium sulfate 0.004 mol / L is taken, and benzalkonium bromide 0.04 g / L. The cathode current density is 3 A / dm 2 , and after 30 minutes, a bright and smooth coating is obtained on the surface of the copper sheet at a water bath temperature of 25 °C.

[0101] The results of EDS semi-quantitative analysis show that the zinc content in the obtained coating is 75.2 wt.%, the iron content is 23.1 wt.%, and the balance is others. The hardness value measured by a microhardness tester is 458 HV.

[0102] Comparative Example 2

[0103] A 10×20×2 mm copper sheet is polished with #2000 sandpaper, washed with deionized water, and then undergoes pre-treatment of degreasing - water washing - rust removal - water washing - activation. After water washing, it is used as the cathode and put into the second solution while being charged, and the anode is a nickel plate.

[0104] The composition of the second solution is as follows: zinc oxide 10 g / L, sodium hydroxide 100 g / L, ammonium ferrous sulfate hexahydrate 30 g / L. For the wear-resistant particles, hexagonal boron nitride with a particle size of 30 μm, 90 g / L, and hexagonal boron nitride with a particle size of 3 μm, 30 g / L are taken. For the multi-component complex system, tetraethylenepentamine 20 mL / L, triethylenetetramine 5 mL / L, sodium gluconate 20 g / L, and triethanolamine 10 mL / L are taken. For the combined brightener, benzylpyridinium carboxylate 0.1 mL / L, vanillin 80 mg / L, and polyethylene glycol 60 mg / L are taken. For the leveling agent, Mirapol WT 1.5 g / L, sodium vinylsulfonate 10 mg / L, and sodium tellurite 8 mg / L are taken. For the stabilizer, potassium sodium tartrate 15 g / L, sodium sulfite 50 mg / L, and manganese dichloride 3 g / L are taken. For the rare earth salt in the additive, cerium sulfate 1 g / L and benzalkonium bromide 0.04 g / L are taken. The cathode current density is 3 A / dm 2 , and at a water bath temperature of 25 °C, continuous stirring is carried out at a stirring speed of 450 rpm. After 30 minutes, a bright and uniform composite coating is obtained on the surface of the copper sheet, and the coating thickness is 16 microns.

[0105] The hardness value measured by a microhardness tester is 544 HV.

[0106] The composite content in the composite coating is 5.2 wt.%.

[0107] By comparing Comparative Example 1 with Example 1, it can be found that in the present invention, the dispersion strengthening effect of the wear-resistant particles improves the microhardness of the composite coating, and the self-lubricating property of the hexagonal boron nitride wear-resistant particles also significantly improves the tribological properties of the material. By comparing Comparative Example 2 with Example 1, it can be found that the appropriate intermittent stirring method promotes the increase of the composite content, and there is also a significant improvement compared with the prior art, further enhancing the tribological properties of the material surface.

Claims

1. An anti-abrasion composite layer, characterized in that, The anti-abrasion composite layer sequentially includes a passivation layer, a first Zn-Fe composite layer, and a second Zn-Fe composite layer from the surface to the interior; wherein, the iron content in the first Zn-Fe composite layer is lower than that in the second Zn-Fe composite layer; In the first Zn-Fe composite layer, Zn-Fe presents an η phase, and in the second Zn-Fe composite layer, Zn-Fe presents a γ phase; the iron content in the first Zn-Fe composite layer is 0.03-1.0 wt%; the iron content in the second Zn-Fe composite layer is 5-30 wt%; Both the first Zn-Fe composite layer and the second Zn-Fe composite layer contain hexagonal boron nitride. The particle size of hexagonal boron nitride in the first Zn-Fe composite layer is 10 nanometers to 10 micrometers, and the particle size of hexagonal boron nitride in the second Zn-Fe composite layer includes 45 nanometers to 10 micrometers and 15-30 micrometers; The thicknesses of the first Zn-Fe composite layer and the second Zn-Fe composite layer are each independently 8-18 micrometers; The composite amount of the hexagonal boron nitride in the anti-abrasion composite layer is 5-15 wt%; The first Zn-Fe composite layer is prepared from a first solution. Based on the total volume of the first solution, the first solution includes: zinc oxide 10 g / L, sodium hydroxide 100 g / L, ammonium ferrous sulfate hexahydrate 4 g / L, the hexagonal boron nitride 3-150 g / L, a first multi-component complexing system 100-150 ml / L, a combined brightening agent 80-120 ml / L, a leveling agent 100-140 ml / L, a stabilizer 80-120 ml / L, and an additive 80-120 ml / L; The second Zn-Fe composite layer is prepared from a second solution. Based on the total volume of the second solution, the second solution includes: zinc oxide 10 g / L, sodium hydroxide 100 g / L, ammonium ferrous sulfate hexahydrate 30 g / L, the hexagonal boron nitride 3-150 g / L, a second multi-component complexing system 100-150 ml / L, a combined brightening agent 80-120 ml / L, a leveling agent 80-120 ml / L, a stabilizer 80-120 ml / L, and an additive 80-120 ml / L; The first Zn-Fe composite layer and the second Zn-Fe composite layer are prepared by electroplating deposition; The conditions for electroplating and depositing the second zinc-iron composite layer and depositing the first zinc-iron composite layer respectively include: a cathode current density of 0.5 to 6 A / dm 2 , a temperature of 10 to 40 °C, and a time of 20 to 60 minutes; During the electroplating process, intermittent stirring is adopted, stirring for 10-20 s, with an interval of 5-20 s, and the stirring intensity is 0-3000 rpm.

2. A substrate with an anti-abrasion composite layer, characterized in that, The anti-abrasion composite layer is the anti-abrasion composite layer described in claim 1, and the material of the substrate includes one or a combination of two or more of carbon steel, stainless steel, copper, and aluminum.

3. A method for preparing the anti-abrasion composite layer according to claim 1, characterized in that Including: After the substrate is pretreated, it is used as the cathode; The second Zn-Fe composite layer is electroplated and deposited on the cathode in sequence, and the first Zn-Fe composite layer is electroplated and deposited on the second Zn-Fe composite layer to obtain an intermediate product; the electroplating deposition is carried out under the condition of intermittent stirring; The intermediate product is passivated to obtain the anti-abrasion composite layer; Wherein, the anode includes one or a combination of two or more of stainless steel, nickel-plated steel sheet, and nickel plate; Among them, the first zinc-iron composite layer is prepared from a first solution. Based on the total volume of the first solution, the first solution includes: zinc oxide 10 g / L, sodium hydroxide 100 g / L, ammonium ferrous sulfate hexahydrate 4 g / L, the hexagonal boron nitride 3 - 150 g / L, a first multi-component complexing system 100 - 150 ml / L, a combined brightening agent 80 - 120 ml / L, a leveling agent 100 - 140 ml / L, a stabilizer 80 - 120 ml / L, and an additive 80 - 120 ml / L; The second zinc-iron composite layer is prepared from a second solution. Based on the total volume of the second solution, the second solution includes: zinc oxide 10 g / L, sodium hydroxide 100 g / L, ammonium ferrous sulfate hexahydrate 30 g / L, the hexagonal boron nitride 3 - 150 g / L, a second multi-component complexing system 100 - 150 ml / L, a combined brightening agent 80 - 120 ml / L, a leveling agent 80 - 120 ml / L, a stabilizer 80 - 120 ml / L, and an additive 80 - 120 ml / L; The second zinc-iron composite layer includes hexagonal boron nitride with particle sizes of 45 nanometers to 10 micrometers and 15 - 30 micrometers; Among them, the conditions for electroplating and depositing the second zinc-iron composite layer and depositing the first zinc-iron composite layer respectively include: the cathode current density is 0.5 to 6 A / dm 2 , the temperature is 10 to 40 °C, and the time is 20 to 60 minutes; During the electroplating process, intermittent stirring is adopted, with stirring for 10 - 20 s and an interval of 5 - 20 s, and the stirring intensity is 0 - 3000 rpm.

4. The preparation method according to claim 3, wherein, The conditions for the passivation treatment include: pH value of 2 - 2.5, temperature of 20 - 45 °C, and time of 30 - 60 s.

5. The preparation method according to claim 3, characterized in that, The first multi-component complexing system includes a first main complexing agent and a first auxiliary complexing agent. Among them, the first main complexing agent includes one or a combination of two or more of sodium citrate, ammonium citrate, sodium salicylate, and pyridine; the first auxiliary complexing agent includes sodium gluconate and / or triethanolamine; and / or, The second multi-component complexing system includes a second main complexing agent and a second auxiliary complexing agent. Among them, the second main complexing agent includes one or a combination of two or more of tetraethylenepentamine, triethylenetetramine, and ethylenediamine, and the second auxiliary complexing agent includes sodium gluconate and / or triethanolamine; and / or, Based on the total volume of the first multi-component complexing system, in the first multi-component complexing system, the concentration of sodium citrate and / or ammonium citrate is 100 - 300 g / L, the concentration of sodium salicylate is 18 - 180 g / L, the concentration of pyridine is 0 - 180 g / L, the concentration of sodium gluconate is 150 - 200 g / L, and the concentration of triethanolamine is 100 - 300 mL / L; and / or, Based on the total volume of the second multi-component complexing system, in the second multi-component complexing system, the concentration of tetraethylenepentamine is 100 - 300 mL / L, the concentration of triethylenetetramine is 0 - 200 mL / L, the concentration of ethylenediamine is 0 - 200 mL / L, the concentration of sodium gluconate is 100 - 300 g / L, and the concentration of triethanolamine is 50 - 200 mL / L.

6. The preparation method according to claim 3, wherein The combined brightening agent includes one or a combination of two or more of benzylpyridinium carboxylate, vanillin, piperonal, heliotropin, polyethylene glycol, and butynediol; and / or, The displacement agent includes one or a combination of two or more of Mirapol WT, sodium vinyl sulfonate, sodium allyl sulfonate, and sodium tellurate; and / or, The stabilizer includes one or a combination of two or more of potassium sodium tartrate, sodium sulfite, manganese dichloride, and sodium ascorbate; and / or, The additive includes one or a combination of two or more of a surfactant and a rare earth salt; in the second solution, the additive includes tetrahydrothiazolidinethione; and / or, The first multi-component complex system and / or the second multi-component complex system further include other additives; the other additives include glass balls, plastic balls or a combination of the two.

7. The preparation method according to claim 6, characterized in that, The concentration of the benzylpyridinium carboxylate is 0.5-2 ml / L, the concentration of one or a combination of two or more of vanillin, piperonal and heliotropin is 0.5-1.5 g / L, and the concentration of the polyethylene glycol and / or butynediol is 0.4-1.2 g / L; and / or, The concentration of Mirapol WT is 10-20 g / L, the concentration of sodium vinyl sulfonate and / or sodium allyl sulfonate is 0.06-0.2 g / L, and the concentration of sodium tellurate is 0-0.16 g / L; and / or, The concentration of potassium sodium tartrate is 80-200 g / L, the concentration of sodium sulfite in the first solution is 0.25-1 g / L, the concentration of sodium sulfite in the second solution is 0.5-2 g / L, and the concentration of manganese dichloride and / or ascorbic acid is 0-50 g / L; The concentration of the surfactant is 0.4-8 g / L, the concentration of the rare earth salt is 0-0.25 mol / L, and the concentration of the tetrahydrothiazolidinethione is 0-0.2 g / L; The concentration of the glass balls and / or the plastic balls is 40-250 particles / L.

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