Biomineralization liquid for laser cladding layer as well as preparation method and application of biomineralization liquid

Abstract

The invention belongs to the technical field of laser cladding surface modification, and provides a biomineralization liquid for a laser cladding layer as well as a preparation method and application of the biomineralization liquid. The biological mineralization liquid is prepared from the following components in parts by mass: 15 to 25 parts of bacterial liquid, 8 to 12 parts of mineralization precursor, 0.5 to 1.5 parts of dispersing agent, 0.3 to 0.8 part of stabilizing agent and 60 to 76 parts of sterile seawater. By optimizing the component proportion and the preparation process of the biomineralization liquid, a calcium magnesium carbonate mineralization film with a compact calcite structure is formed on the surface of a 30CrNi2MoV steel laser cladding layer, and multiple outstanding beneficial effects are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser cladding surface modification, and particularly relates to a biomimetic mineralization solution for a laser cladding layer and a preparation method and application thereof. BACKGROUND

[0002] As an advanced surface modification method, laser cladding technology can form a high-performance cladding layer on the surface of a metal substrate, significantly improving the wear resistance, corrosion resistance and other properties of the material. However, the traditional laser cladding layer has defects such as high porosity and micro-cracks at the bonding interface with the substrate, and still faces the risk of corrosion failure in harsh environments such as the ocean and chemical industry.

[0003] Biomimetic mineralization technology uses microbial metabolic activity to induce inorganic mineral deposition, forming a dense organic-inorganic composite film layer with self-repairing and environmental friendliness. Pseudoalteromonas, as a typical marine microorganism, can secrete extracellular polysaccharides to induce calcium magnesium carbonate mineralization and form a composite film layer with calcite structure. However, in the prior art, a single Pseudoalteromonas mineralization solution has the problems of low mineralization integrity, easy production of corrosion product layer cracks, and inability to effectively adapt to the surface characteristics of the laser cladding layer, limiting its application in the field of laser cladding modification.

[0004] Therefore, Ren Weibin et al. in their research "Composite preparation of cladding layer and mineralization film integration on the surface of 30CrNi2MoV steel via laser additive manufacturing and bio-induced mineralization" used Pseudoalteromonas bacteria to induce deposition of mineralization film. However, the prepared cladding layer still performs poorly in terms of hardness, wear resistance, corrosion resistance and impact resistance.

[0005] Therefore, it is of great significance to develop a biomimetic mineralization solution that is suitable for laser cladding layer, has high mineralization density and excellent corrosion resistance, and its preparation method and application, to improve the service life of laser cladding parts. SUMMARY

[0006] The present application relates to the technical field of laser cladding surface modification, and particularly relates to a biomimetic mineralization solution for a laser cladding layer and a preparation method and application thereof.

[0007] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions: The application provides a biomimetic liquid for a laser cladding layer, characterized by comprising the following components in mass fractions: 15-25 parts of bacterial liquid, 8-12 parts of mineralization precursor, 0.5-1.5 parts of dispersing agent, 0.3-0.8 parts of stabilizer and 60-76 parts of sterile seawater.

[0008] Preferably, the bacterial liquid is a bacterial liquid of Pseudoalteromonas bacteria, and the concentration of the bacterial liquid is 5×10 7 ~1×10 8 CFU / mL.

[0009] Preferably, the mineralization precursor comprises calcium chloride and magnesium chloride, and the mass ratio of the calcium chloride to the magnesium chloride is 2.5-3.5:1.

[0010] Preferably, the dispersing agent is polyethylene glycol, and the stabilizer is sodium molybdate.

[0011] The application further provides a preparation method of the biomimetic liquid for the laser cladding layer, comprising the following steps: After the sterile seawater, the mineralization precursor, the dispersing agent and the stabilizer are mixed, the bacterial liquid is added for dispersion, and the biomimetic liquid is obtained.

[0012] Preferably, the rotating speed of the mixing is 400-600 rpm, and the mixing time is 20-30 min.

[0013] Preferably, the dispersion comprises stirring and ultrasonic dispersion. The rotating speed of the stirring is 400-600 rpm, and the stirring time is 10-15 min. The power of the ultrasonic dispersion is 150-200 W, and the ultrasonic dispersion time is 5-10 min.

[0014] The application further provides an application of the biomimetic liquid for the laser cladding layer in preparing a mineralized film on a surface of a base material.

[0015] Preferably, the base material is 30CrNi2MoV steel.

[0016] Compared with the prior art, the application has the following beneficial effects: The application forms a dense calcite structure calcium magnesium carbonate mineralized film on the surface of the 30CrNi2MoV steel laser cladding layer by optimizing the component ratio and the preparation process of the biomimetic liquid, and multiple prominent beneficial effects are achieved: (1) The hardness and high-temperature stability are significantly improved, and the defects of insufficient hardness and easy softening at high temperature of the surface of the traditional laser cladding layer are effectively solved. (2) The corrosion resistance is greatly improved, the corrosion sensitivity problem caused by the pores and micro-cracks of the cladding layer is solved through the synergistic effect of the mineralization film physical barrier and the sodium molybdate passivation film, and the protection effect has excellent stability; (3) The wear resistance is significantly optimized, and the service life of the material is prolonged; (4) The preparation process is simple and controllable, the components have strong synergistic effect, the mineralization liquid has good stability and convenient application operation, and is suitable for surface modification of the laser cladding layer of the 30CrNi2MoV steel, and has a wide application prospect in harsh service environments such as marine engineering and chemical equipment. DETAILED DESCRIPTION

[0017] The application provides a biomimetic mineralization liquid for a laser cladding layer, characterized by comprising the following components in mass fractions: 15-25 parts of a bacterial liquid, 8-12 parts of a mineralization precursor, 0.5-1.5 parts of a dispersing agent, 0.3-0.8 parts of a stabilizer and 60-76 parts of sterile seawater.

[0018] In the application, the mass fraction of the bacterial liquid is preferably 16-24 parts, further preferably 18-23 parts, and more preferably 20-22 parts; the mass fraction of the mineralization precursor is preferably 9-11 parts, and further preferably 10 parts; the mass fraction of the dispersing agent is preferably 0.7-1.4 parts, further preferably 0.8-1.2 parts, and more preferably 1-1.1 parts; the mass fraction of the stabilizer is preferably 0.4-0.7 parts, further preferably 0.5-0.6 parts; and the mass fraction of the sterile seawater is preferably 62-74 parts, further preferably 64-72 parts, and more preferably 68-70 parts.

[0019] In the application, the bacterial liquid is preferably a bacterial liquid of Pseudoalteromonas bacteria, and the concentration of the bacterial liquid is preferably 5x10 7 ~1x10 8 CFU / mL, further preferably 6x10 7 ~9x10 7 CFU / mL, and more preferably 7x10 7 ~8x10 7 CFU / mL.

[0020] In the application, the Pseudoalteromonas bacteria are Pseudoalteromonas luteola, and the bacterial liquid is prepared by using 2216E culture medium (peptone 5g / L, yeast extract 1g / L, FePO4 0.01g / L, artificial seawater to constant volume), 28℃, 180r / min oscillation culture for 36h to prepare the bacterial liquid.

[0021] In the present application, the mineralization precursor preferably comprises calcium chloride and magnesium chloride, and the mass ratio of calcium chloride to magnesium chloride is preferably 2.5-3.5:1, further preferably 2.6-3.2:1, and more preferably 2.8-3:1.

[0022] In the present application, the mineralization precursor provides Ca 2+ and Mg 2+ required for mineralization, induces the formation of a calcite structure mineralization layer, improves the hardness of the film layer, and improves the toughness of the film layer.

[0023] In the present application, the dispersant is preferably polyethylene glycol, and the stabilizer is preferably sodium molybdate.

[0024] In the present application, the polyethylene glycol can prevent the coarsening of crystals caused by the local supersaturation of Ca 2+ and Mg 2+ , and can improve the dispersion uniformity of the bacterial cells on the surface of the cladding layer, avoiding the aggregation of the biofilm.

[0025] In the present application, the sodium molybdate can form a passivation film on the metal surface, thereby inhibiting the corrosion of the cladding layer substrate; and can buffer pH fluctuations, chelate free metal ions, promote the deposition of minerals and the combination of bioactive substances.

[0026] In the present application, the sterile seawater provides a natural ionic environment for bacteria, simulating marine mineralization conditions; wherein HCO3 - serves as a carbon source and participates in bacterial metabolism to generate CO3 2- , driving carbonate deposition.

[0027] The present application also provides a preparation method of a biological mineralization liquid for a laser cladding layer, comprising the following steps: After mixing the sterile seawater, the mineralization precursor, the dispersant, and the stabilizer, the bacterial liquid is added for dispersion, and the biological mineralization liquid is obtained.

[0028] In the present application, the mixing speed is preferably 400-600 rpm, further preferably 450-550 rpm, and more preferably 480-500 rpm, and the mixing time is preferably 20-30 min, further preferably 22-28 min, and more preferably 25-26 min.

[0029] In the present application, the dispersion preferably comprises stirring and ultrasonic dispersion; The stirring speed is preferably 400-600 rpm, further preferably 450-550 rpm, and more preferably 480-500 rpm, and the stirring time is preferably 10-15 min, further preferably 11-14 min, and more preferably 12-13 min. The power of ultrasonic dispersion is preferably 150-200 W, further preferably 160-190 W, and more preferably 170-180 W, and the time of ultrasonic dispersion is preferably 5-10 min, further preferably 6-9 min, and more preferably 7-8 min.

[0030] The application also provides a use of the biomimetic solution for laser cladding layer in preparing a mineralized film on a surface of a base material.

[0031] In the application, the base material is preferably 30CrNi2MoV steel.

[0032] In the application, the use of the biomimetic solution in preparing a mineralized film on a surface of a base material comprises the following steps: The soaking time is preferably 24-48 h, further preferably 28-42 h, and more preferably 32-36 h, and the soaking temperature is preferably 20-30℃, further preferably 22-28℃, and more preferably 24-26℃.

[0033] The technical solutions provided by the application will be described in detail below in combination with the embodiments, but they should not be understood as limiting the scope of the application.

[0034] In the embodiments of the application, the parts are all parts by mass.

[0035] Embodiment 1

[0036] In this embodiment, the components of the biomimetic solution are as follows: 15 parts of Pseudoalteromonas bacterial solution with a concentration of 10 8 CFU / mL, 10 parts of mineralized precursor (calcium chloride and magnesium chloride with a mass ratio of 3:1), 1.2 parts of polyethylene glycol, 0.5 parts of sodium molybdate, and 73.3 parts of sterile seawater; Preparation steps: The sterile seawater, the mineralized precursor, the polyethylene glycol, and the sodium molybdate are mixed at a speed of 500 rpm for 30 min to obtain a mixed solution; The bacterial solution is poured into the mixed solution, stirred at a speed of 500 rpm for 10 min, and then ultrasonically dispersed at a power of 200 W for 8 min to obtain the biomimetic solution.

[0037] Embodiment 2

[0038] In this embodiment, the components of the biomimetic solution are as follows: 20 parts of Pseudoalteromonas bacterial solution with a concentration of 10 8The mixture consisted of CFU / mL Pseudoalteromonas bacterial culture, 12 parts of mineralization precursor (calcium chloride to magnesium chloride in a mass ratio of 3.5:1), 1 part polyethylene glycol, 0.8 parts sodium molybdate, and 66.2 parts sterile seawater. Preparation steps: Sterile seawater, mineralized precursor, polyethylene glycol and sodium molybdate were mixed at 480 rpm for 25 min to obtain a mixture. Pour the bacterial solution into the mixture, stir at 480 rpm for 12 minutes, and then ultrasonically disperse at 200 W for 5 minutes to obtain the biomineralized solution.

[0039] Example 3

[0040] The components of the biomineralization solution in this embodiment are: 25 samples with a concentration of 6×10 7 The mixture consisted of CFU / mL Pseudoalteromonas bacterial culture, 8 parts mineralization precursor (calcium chloride to magnesium chloride mass ratio of 2.5:1), 0.5 parts polyethylene glycol, 0.4 parts sodium molybdate, and 66.1 parts sterile seawater. Preparation steps: Sterile seawater, mineralization precursor, polyethylene glycol and sodium molybdate were mixed at 600 rpm for 20 min to obtain a mixture. Pour the bacterial solution into the mixture, stir at 600 rpm for 15 minutes, and then ultrasonically disperse at 200 W for 10 minutes to obtain the biomineralized solution.

[0041] Example 4

[0042] The components of the biomineralization solution in this embodiment are: The concentration of 22 samples was 8.5 × 10⁻⁶. 7 The mixture consisted of CFU / mL Pseudoalteromonas bacterial culture, 12 parts of mineralization precursor (calcium chloride to magnesium chloride in a mass ratio of 3:1), 1.5 parts of polyethylene glycol, 0.8 parts of sodium molybdate, and 63.7 parts of sterile seawater. Preparation steps: Sterile seawater, mineralization precursor, polyethylene glycol and sodium molybdate were mixed at 500 rpm for 25 min to obtain a mixture. Pour the bacterial solution into the mixture, stir at 500 rpm for 10 minutes, and then ultrasonically disperse at 160 W for 7 minutes to obtain the biomineralized solution.

[0043] Example 5

[0044] The components of the biomineralization solution in this embodiment are: 20 portions with a concentration of 5×10 7Pseudoalteromonas bacteria liquid with CFU / mL, 8 parts of mineralization precursor (mass ratio of calcium chloride to magnesium chloride is 3:1), 0.5 parts of polyethylene glycol, 0.3 parts of sodium molybdate and 71.2 parts of sterile seawater; Preparation steps: The sterile seawater, the mineralization precursor, the polyethylene glycol and the sodium molybdate were mixed at a rotating speed of 500 rpm for 25 min to obtain a mixed solution; The bacteria liquid was poured into the mixed solution, and stirred at a rotating speed of 500 rpm for 10 min, and then ultrasonically dispersed at a power of 160 W for 7 min to obtain the biomimetic mineralization liquid.

[0045] Comparative Example 1

[0046] 500 mL of water, 5 x 10 7 cells of Pseudoalteromonas bacteria, 5.55 g of CaCl2, 1.68 g of sodium bicarbonate, 0.5 g of peptone and 0.5 g of urea were stirred at a rotating speed of 500 rpm for 30 min, and then the pH value was adjusted to 8.2 to obtain the biomimetic mineralization liquid.

[0047] Comparative Example 2

[0048] In Example 1, the "mass ratio of calcium chloride to magnesium chloride is 3:1" was modified to "mass ratio of calcium chloride to magnesium chloride is 2:1", and the other steps were the same as in Example 1.

[0049] Comparative Example 3

[0050] In Example 1, the "10 parts of mineralization precursor" was modified to "5 parts of mineralization precursor", and the other steps were the same as in Example 1.

[0051] The 30CrNi2MoV steel substrate was treated as follows, wherein the biomimetic mineralization liquid was the biomimetic mineralization liquid obtained in Examples 1-5 and Comparative Examples 1-3: Inconel625 alloy powder was used as raw material, IPG-YLS-4000 optical fiber laser, KR60HA type KUKA robot and GTV double powder feeder system were used to prepare cladding layer on 30CrNi2MoV steel substrate preheated to 250℃ by coaxial powder feeding process. The core parameters include: laser power 2.5 kW, spot diameter 3 mm, scanning speed 5 mm / s, powder feeding rate 13.2 g / min, carrier gas flow rate 1.5 L / min, high-purity argon gas protection was used throughout the process to prevent oxidation, and cladding layer sample was obtained; The resin material is used for embedding the cladding layer sample, only the sample to be mineralized surface is exposed, the surface to be mineralized is polished by 180#, 400#, 800# and 1200# sandpaper in turn to a surface roughness Ra≤0.8 μm, then ultrasonic cleaning with anhydrous ethanol for 15 min (power 100 W), ultrasonic cleaning with deionized water for 10 min (power 100 W), and drying in a vacuum drying oven at 60 ℃ for 2 h to obtain the pretreated substrate; The pretreated substrate is completely immersed in the biomimetic mineralization solution and placed in a 25 ℃ constant temperature incubator for static immersion for 34 h, and the container is gently shaken for 1 min every 8 h during the period; The substrate is taken out, the surface residual mineralization solution is washed with sterile seawater (washing 3 times, 10 s each time), and naturally air-dried for 2 h to obtain a 30CrNi2MoV steel sample covered with a biomimetic mineralization film.

[0052] The pretreated substrate is taken as a blank control group.

[0053] The 30CrNi2MoV steel samples treated by the biomimetic mineralization solutions obtained in Examples 1-5 and Comparative Examples 1-3 are subjected to the following performance detection: Hardness test: the hardness of the 30CrNi2MoV steel samples treated by the biomimetic mineralization solutions obtained and the blank control group at different temperatures is tested according to the national standard GB / T 4340.1-2009 “Metallic materials Vickers hardness test Part 1: Test method”, and the test results are shown in Table 1; Table 1 Hardness test results of the 30CrNi2MoV steel samples treated by the biomimetic mineralization solutions obtained in Examples 1-5 and Comparative Examples 1-3 and the blank control group

[0054] As can be seen from the table, the hardness of the 30CrNi2MoV steel sample treated by the biomimetic mineralization solution of the application at room temperature, 500 ℃ and 700 ℃ is significantly better than that of the comparative examples and the blank control group, the average hardness at room temperature reaches 470.60 HV 0.2 , which is 34.6% higher than that of the blank control group, the average attenuation rate at 500 ℃ and 700 ℃ is only 2.8% and 7.5%, which is much lower than the 6.2-15.5% of the control group, and the hardness data fluctuation among the examples is very small, and the stability is better than that of the comparative examples. This progress is due to the high hardness, high binding force aragonite structure calcium magnesium carbonate mineralization film induced by Pseudoalteromonas bacteria, which cooperates with the stable passivation film formed by sodium molybdate, not only realizes the hardness strengthening of the substrate, but also inhibits the high temperature oxidation softening and grain growth, and the good controllability of the component ratio and preparation process of the mineralization solution guarantees the consistency of the strengthening effect, which makes up for the defects of the traditional laser cladding layer, such as insufficient surface hardness and fast high temperature hardness attenuation.

[0055] Electrochemical corrosion performance test: the sample is connected with the electrochemical workstation through the lead wire, and the test surface is placed in the specified position and locked by the locking device for testing. The flat specimen (surface area of 1 cm 2 ), thin platinum foil and silver chloride electrode are used as working electrode, counter electrode and reference electrode respectively, the potentiodynamic polarization curve is tested at a scanning rate of 1 mV / s and a potential range of-1.3~0.5 V relative to open circuit potential, and the electrochemical impedance spectroscopy (EIS) test is carried out at open circuit potential, and the test results are shown in Table 2.

[0056] Table 2 Corrosion resistance test results of 30CrNi2MoV steel samples treated by the biological mineralization liquid of examples 1~5 and comparative examples 1~3 and the blank control group

[0057] It can be seen from the table that the corrosion resistance of the sample treated by the biological mineralization liquid of the application is significantly better than that of the comparative examples and the blank control group, the average value of the self-corrosion potential is-0.934 V, which is positively shifted by 17.2% compared with the blank control group, the average value of the self-corrosion current density is 2.371×10 -6 A cm -2 , which is reduced by 66.1% compared with the blank control group, and the standard deviation of the self-corrosion current density is only 7.8×10 -8 A cm -2 , which is far more stable than the comparative examples. This progress is due to the synergistic protection of the dense calcite mineralization film induced by Pseudoalteromonas bacteria and the sodium molybdate passivation film, which not only blocks the penetration of corrosive medium and inhibits the anodic reaction through a physical barrier, but also ensures the continuity of protection by chelating metal ions and buffering pH fluctuations, effectively solving the corrosion sensitivity problem caused by pores and microcracks in traditional laser cladding layers, and at the same time, the optimization of the components of the mineralization liquid ensures the stability of the protection effect.

[0058] Friction and wear performance test: the MDW-02 friction and wear tester is used to test the wear resistance of the substrate and the cladding layer, the test is carried out at room temperature without lubrication, the friction pair is selected as 6.5 mm GCr15 hard alloy ball, the loading frequency is 3 Hz, the sliding stroke is 5 mm, and the friction time is 30 min. After the experiment is completed, the sample is subjected to ultrasonic bath to remove surface contaminants, alcohol rinsing and drying with a hair dryer, and the weight before and after wear is recorded with an electronic balance with an accuracy of 0.1 mg. The test results are shown in Table 3: Table 3 Friction and wear performance test results of 30CrNi2MoV steel samples treated by the biological mineralization liquid of examples 1~5 and comparative examples 1~3 and the blank control group

[0059] As can be seen from the table, the wear resistance of the sample treated by the biological mineralization liquid of the application is significantly better than that of the comparative examples and the blank control group, the average wear loss is 4.26 mg, which is reduced by 38.3% compared with the blank control group, the wear resistance is increased by nearly 40%, and the standard deviation of the wear loss is only 0.15 mg, and the stability is better. This progress is due to the high hardness and low friction coefficient calcite structure calcium magnesium carbonate mineralization film induced by Pseudoalteromonas bacteria, which acts as a "wear-resistant protective layer" to bear the main friction load, not only reduces adhesive wear and abrasive wear, but also the obtained mineralization film is uniform in thickness and stable in structure.

[0060] The above only describes the preferred embodiments of the application, and it should be pointed out that for ordinary skilled persons in the art, some improvements and refinements can be made without departing from the principles of the application, and these improvements and refinements should also be considered as the protection scope of the application.

Claims

1. A biomimetic fluid for laser cladding layer, characterized in that, The components include the following mass fractions: 15-25 parts of bacterial solution, 8-12 parts of mineralization precursor, 0.5-1.5 parts of dispersant, 0.3-0.8 parts of stabilizer and 60-76 parts of sterile seawater.

2. The biomimetic fluid for laser cladding layer according to claim 1, characterized in that, The bacterial solution is a bacterial solution of Pseudoalteromonas bacteria, and the concentration of the bacterial solution is 5 x 10 7 ~1 x 10 8 CFU / mL.

3. The biomimetic fluid for laser cladding layer according to claim 2, characterized in that, The mineralization precursor includes calcium chloride and magnesium chloride, and the mass ratio of calcium chloride to magnesium chloride is 2.5-3.5:

1.

4. The biomimetic fluid for laser cladding layer according to claim 2 or 3, characterized in that, The dispersant is polyethylene glycol, and the stabilizer is sodium molybdate.

5. The method for preparing a biomimetic solution for laser cladding layer according to any one of claims 1 to 4, characterized in that, The method includes the following steps: After mixing the sterile seawater, the mineralization precursor, the dispersant and the stabilizer, the bacterial solution is added for dispersion, and the bio-mineralization solution is obtained.

6. The method for preparing a biomineralized solution for laser cladding layers according to claim 5, characterized in that, The rotation speed of the mixing is 400-600 rpm, and the mixing time is 20-30 min.

7. The method for preparing a biomineralized solution for laser cladding layers according to claim 6, characterized in that, The dispersion includes stirring and ultrasonic dispersion. The rotation speed of the stirring is 400-600 rpm, and the stirring time is 10-15 min. The power of the ultrasonic dispersion is 150-200 W, and the ultrasonic dispersion time is 5-10 min.

8. Application of the bio-mineralization solution for laser cladding layer in claim 1-4 in preparing a mineralization film on the surface of a substrate material.

9. Use of a biomimetic solution for laser cladding layer according to claim 8 for the preparation of a mineralized film on the surface of a substrate material, characterized in that, The substrate material is 30CrNi2MoV steel.

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