CN111607817A - An alloy of iron group element and tungsten and silicon carbide composite coating and its preparation method and application - Google Patents

Abstract

The invention belongs to the technical field of surface engineering and surface treatment, and specifically discloses an alloy of iron group elements and tungsten and a silicon carbide composite coating and a preparation method and application thereof. The method is (1) preparing a composite plating solution: Fe ²⁺ /Fe ³⁺ salt, Co ²⁺ /Co ³⁺ salt, Ni ²⁺ /Ni ³⁺ salt, tungstate, complexing agent, dispersant, Silicon carbide; the solvent is water; the pH of the composite plating solution is 7 to 14; (2) the substrate is put into the composite plating solution for electroplating; the current used for electroplating is direct current, single pulse current, double pulse current or direct current/ Pulse superimposed current; and mechanical, air, jet or ultrasonic agitation during electroplating. The matrix alloy coating used in the present invention is a binary or multi-component alloy of an iron group metal element and tungsten, which is one of the alloy coatings with the highest hardness among the existing chromium-substituting coatings.

Description

A kind of iron group element and tungsten alloy and silicon carbide composite coating and preparation method thereof application

technical field

The invention belongs to the technical field of surface engineering and surface treatment, and particularly relates to an alloy of iron group elements and tungsten and a silicon carbide composite coating and a preparation method and application thereof.

Background technique

The chrome electroplating process has low cost, high efficiency, good coating finish and strong wear and corrosion resistance. It is widely used in the surface strengthening of key parts of aerospace, vehicles and ships, as well as the repair after wear and corrosion, but the electrochromic process is seriously polluted. The environment, affecting human health, has been gradually restricted from use. At present, there is no mature green surface technology system that can replace the electroplating chrome technology, which is widely used in the repair and strengthening of equipment. In view of the above problems, the development of a high-performance coating preparation technology that can replace chrome electroplating and its suitable material system is one of the major problems that need to be solved urgently in the field of equipment support.

Chromium-substituting coatings refer to alloy coatings that are close to chromium coatings in terms of appearance, hardness, wear resistance, corrosion resistance, etc., mainly including iron group (iron, cobalt, nickel) alloys, and iron group elements and phosphorus, boron , molybdenum, carbon and tungsten and other binary or multi-component alloys. At present, the widely studied chromium replacement processes mainly include electroplating Fe-W, Co-W, Co-Ni, Ni-W, Ni-B, Ni-P, Ni-Mo, Fe-Ni-W, Co-Ni- Alloys such as C and Co-Ni-B. The above alloys all have high hardness, corrosion resistance and friction and wear resistance, but they are still inferior to chrome plating. Only after heat treatment can the hardness of part of the plating reach the level of chrome plating. However, the heat treatment needs to be carried out under the protection of an inert gas. Therefore, the above-mentioned chromium-substituting coating has a long preparation period, complicated process and high cost, and none of them has been widely used so far. Composite electroplating is a composite coating method of depositing metal and solid particles (including: diamond, carbide, nitride, boride, oxide, etc.) with good bonding force on the substrate by electrolysis. The performance of the composite coating is determined by the coating metal. It is jointly determined with the second phase mixed in it, so it has better mechanical strength, friction and wear resistance and corrosion resistance than pure metal plating. In addition, under the premise that the coating metal is determined, the composition, size and content of the second phase become the key factors to determine the performance of the composite coating, so that the performance of the composite coating can be controlled. (Surface and Coatings Technology, 2017, 309:337-343.) Ni-W/diamond composite coating prepared by composite plating technology reached the hardness level of chromium coating without any post-treatment, breaking through It solves the technical bottleneck that traditional chrome-alloy plating requires heat treatment. However, this method is also limited by the high cost of diamond, making it difficult to popularize.

In summary, the composite coating composed of binary or multi-component alloys of iron group elements (iron, cobalt, nickel) and tungsten and low-cost reinforcing phase particles is expected to be the best choice for high-performance and practical chromium-replacement coatings. Silicon carbide, as a reinforcing phase particle, although its cost is low, the mechanical strength of the composite coating prepared at the micron scale is not as good as that of the diamond-based composite coating, so nano-scale silicon carbide needs to be selected, and because the nano-scale particles are very easy to agglomerate, conventional stirring It can only inhibit its sedimentation, but not its agglomeration. Therefore, how to inhibit the agglomeration of nano-silicon carbide particles in the plating solution is a difficulty that needs to be overcome in combination with the matrix coating.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for preparing an alloy of an iron group element and tungsten and a silicon carbide composite coating.

Another object of the present invention is to provide an alloy of iron group elements and tungsten and a silicon carbide composite coating prepared by the above method.

Another object of the present invention is to provide the application of the above-mentioned alloy of iron group elements and tungsten and silicon carbide composite coating in equipment additive repair and remanufacturing.

The object of the present invention is realized through the following scheme:

A preparation method of an alloy of iron group elements and tungsten and a silicon carbide composite coating, comprising the following steps:

(1) Preparation of composite plating solution: Fe ²⁺ /Fe ³⁺ salt 10～100g/L, Co ²⁺ /Co ³⁺ salt 0～100g/L, Ni ²⁺ /Ni ³⁺ salt 0～100g/L, Tungstate 20-200g/L, complexing agent 30-300g/L, dispersant 0.1-10g/L, silicon carbide 1-20g/L; the solvent is water; the pH of the composite plating solution is 7-14;

(2) The substrate is put into the composite electroplating solution for electroplating; the electric current used in electroplating is direct current, single pulse current, double pulse current or direct current/pulse superimposed current; and mechanical, air, jet or ultrasonic stirring is performed during electroplating.

The complexing agent described in step (1) is tartaric acid, pyrophosphoric acid, hypophosphorous acid, citric acid, nitrilotriacetic acid, oxalic acid, lactic acid, nicotinic acid, sulfamic acid, fluoroboric acid, hydroxyethylidene diphosphoric acid, 5,5' -At least one of dimethylhydantoin, ammonia and their salts.

The dispersant described in step (1) is at least one of cetyltrimethylammonium bromide, sodium lauryl sulfate, polyoxyethylene ethers, sodium polyacrylate and polyvinylpyrrolidone.

In step (2), the substrate is any conductor insoluble in plating solution and metallized insulator, preferably silver, copper, iron, aluminum and ceramics, wood, glass, plastic, etc. which are chemically plated with copper or nickel.

Preferably, in step (2), according to the difference in the material of the substrate to be plated and the state of the oil on the surface, it can be pre-treated first, and specifically, sodium hydroxide aqueous solution, detergent, decontamination powder, acetone, alcohol, gasoline, etc. can be used. Degrease the substrate with organic solvent for 5-10min, and then rinse with water; then use dilute nitric acid and dilute hydrochloric acid to remove rust from the substrate. rinse.

The specific parameters of the single-pulse current in step (2) are: on-time T _on =0.1-1ms, off-time _Toff =0.4-1ms, frequency f=500-2000Hz, current density Jm =0.5-10A/ _dm ² ; the specific parameters of the double-pulse current are: T _on =0.1～1ms, T _off =0.4～1ms, pulse on-off period T=0.5～2ms, f=500～2000Hz, forward current density J _m ⁺ =0.5 ～10A/dm ² , reverse current density J _m ⁻ =0.025～1A/dm ² ; the specific parameters of the DC/pulse superimposed current are: f=500～2000Hz, J=0.5～10A/dm ² , J _m = 0.5～10A/dm ² (DC/single pulse superposition) or f=500～2000Hz, J=0.5～10A/dm ² , J _m ＝0.5～10A/dm ² , J _m ^- =0.025～1A/dm ² ( DC/Double Pulse Superposition).

The speed of the mechanical stirring in step (2) is 600～3000r/min, the flow rate of air stirring is 10～200m ³ /h, the flow rate of jet flow stirring is 10～200m ³ /h, and the frequency of ultrasonic stirring is 1～100kHz . The stirring rate can affect the dispersion properties of silicon carbide particles and eliminate concentration polarization, which in turn affects the morphology, composition and structure of the composite coating; strong stirring can also improve the upper limit of cathode current density and current efficiency.

In step (2), the electroplating temperature is 5-95° C., and the electroplating time is 0.1-10 h.

An alloy of an iron group element and tungsten and a silicon carbide composite coating are prepared by the above method.

Preferably, the matrix alloy in the composite coating layer is Fe-W, Fe-Co-W, Fe-Ni-W or Fe-Co-Ni-W.

Preferably, the reinforcing phase in the composite coating layer is micro-scale (0.1-10 μm), nano-scale (1-100 nm) or micro-nano mixed SiC particles.

Preferably, the thickness of the composite plating layer is 1-3000 μm, the grain size of the matrix alloy is 0.01-10 μm, the silicon carbide content is 5-50 at.%, and the distribution is uniform.

The anode of the composite coating layer includes iron, cobalt, nickel, tungsten and any inert anode that is insoluble in the plating solution, such as stainless steel, platinum, graphite, tantalum-iridium-titanium, ruthenium-titanium-iridium and the like.

Application of the alloy of iron group elements and tungsten and silicon carbide composite coating in equipment additive repair and remanufacturing.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. The matrix alloy coating used in the present invention is a binary or multi-element alloy (Fe-W, Fe-Co-W, Fe-Ni-W or Fe-Co-Ni-W) of an iron group metal element and tungsten, which is It is one of the alloy coatings with the highest hardness among the existing chromium-based coatings.

2. The silicon carbide particles used in the present invention are one of the lowest-cost ceramic particles in the existing composite coating reinforcement phase.

3. The Fe, Co, Ni-W-SiC composite coating prepared on the steel surface by the present invention does not fall off after the 90° bending test; it meets the national standard GB5270-200X. Require.

4. The Fe, Co, Ni-W-SiC composite coating prepared by the present invention has good corrosion resistance, and meets the 5% salt water neutrality of the national standard GB5938-86 "Corrosion Resistance Test Method for Metal Coatings and Chemically Treated Layers of Light Industrial Products" Salt spray test indicators.

5. The Fe, Co, Ni-W-SiC composite coating prepared by the present invention can reach the hardness level of the chromium coating without heat treatment.

6. In the present invention, polyvinyl pyrrolidone plays the dual role of suppressing nano-silicon carbide agglomeration and improving the grain size of the coating (this is because after the polyvinyl pyrrolidone is added, the grain size of the iron-tungsten alloy in the composite coating is compared to before adding Reduced). Physical and mechanical stirring is helpful for the dispersion of silicon carbide, but has little effect on inhibiting the agglomeration of nano-silicon carbide.

Description of drawings

FIG. 1 is a SEM photograph of the Fe-W-SiC micro-composite coating (micro-SiC) in Example 1.

FIG. 2 is a SEM photograph of the Fe-W matrix coating in Example 1. FIG.

FIG. 3 is the EDS spectrum of the Fe-W matrix coating in Example 1. FIG.

4 is a SEM photograph of the Fe-W-SiC nanocomposite coating (nano-SiC) in Example 2.

Fig. 5 is the SEM photograph of Fe-W-SiC nanocomposite coating prepared by the plating solution described in Example 2 without adding dispersant

6 is the nanoindentation curve of the Fe-W-SiC nanocomposite coating in Example 7.

Detailed ways

The present invention will be described in further detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

The reagents used in the examples can be routinely purchased from the market unless otherwise specified.

Example 1: Preparation of Fe-W-SiC micro-composite coating

A preparation method of Fe-W-SiC micron composite coating, wherein the particle size of SiC is in the range of micron scale (0.1-10 μm), and specifically comprises the following steps:

1. The steel substrate was ultrasonically cleaned in acetone solution for 8 minutes, and then rinsed with deionized water;

2. Use dilute nitric acid and dilute hydrochloric acid to remove rust on the substrate, treat at room temperature for 20s, and then rinse with deionized water;

3. According to the main salt (iron sulfate FeSO ₄ ·7H ₂ O 55g/L, sodium tungstate Na ₂ WO ₄ 132g/L) 187g/L, complexing agent (sodium citrate Na ₃ C ₆ H ₅ O ₇ ) 147g /L, dispersant [polyvinylpyrrolidone (C ₆ H ₉ NO) _n ] 1g/L, SiC 2g/L to prepare electroplating solution, and the solvent is deionized water;

In the plating solution, ferric sulfate and sodium tungstate are used as main salts to provide the metal ions required for the matrix Fe-W alloy coating; sodium citrate is used as a complexing agent to coordinate metal ions and regulate the proportion of Fe-W alloy. As a dispersant, polyvinylpyrrolidone can significantly improve the uniformity of SiC dispersion in the composite plating solution and coating; SiC is used as the reinforcing phase ceramic particles of the composite coating, and its content directly affects the grain size of the Fe-W alloy, and the composite coating High mechanical strength, friction and wear resistance, corrosion resistance and corrosion wear ability; the plating solution has the characteristics of strong dispersing ability, good covering ability, moderate conductivity, simple composition and easy maintenance. Contains toxic substances, green and environmental protection;

4. Add the substrate processed in steps 1 and 2 into the composite plating solution obtained in step 3 for electroplating. The specific process parameters are: the temperature is 70°C, the power supply mode is constant current, the average current density is 3A/dm ² , and the electroplating The time is 60min, magnetic stirring is used, and the stirring rate is 2000r/min to inhibit the agglomeration of SiC in the plating solution. The anode of the composite coating is ruthenium titanium iridium.

The obtained Fe-W-SiC micro-composite coating has a thickness of about 10 μm, wherein the grain size of the Fe-W matrix alloy is about 0.5 to 1 μm, and the particle size of SiC is about 1 to 2 μm and the distribution is uniform, as shown in Figure 1; Comparing the pure Fe-W alloy coatings (as shown in Figure 2) prepared from the baths with the same contents of ferric sulfate, sodium tungstate and sodium citrate under the same process conditions, it can be seen that polyvinylpyrrolidone and SiC The addition of Fe-W has the effect of refining Fe-W grains. The grain size of Fe-W is about 2-4 μm, and the atomic percentage of Fe and W is about 1:1 (as shown in Figure 3). The matrix is firmly bonded, and there is no obvious fall off after the 90° bending test and the cross-cut test.

Example 2: Preparation of Fe-W-SiC nanocomposite coating

The difference between this example and Example 1 is that the particle size of SiC used in step 3 is in the nanoscale range (about 40 nm), the content of the dispersant polyvinylpyrrolidone is 2 g/L, and the others are the same as in Example 1.

The thickness and composition of the Fe-W-SiC nanocomposite coating prepared in Example 2 are similar to those of the composite coating prepared in Example 1, but it is finer, and the grain size of the coating is in the nanoscale range, as shown in Figure 4. In addition, compared with the Fe-W-SiC composite coating prepared without adding dispersant (as shown in Figure 5, it can be seen that the SiC agglomeration in the composite coating is serious), it can be seen that the addition of polyvinylpyrrolidone effectively inhibits the nano-SiC reunion.

Example 3: Preparation of Fe-W-SiC micro-nano composite coating

The difference between this example and Example 1 is that the particle size of the SiC used in the third step is in the range of micro-nano scale (40 nm-2 μm), and the others are the same as Example 1.

The thickness, composition and morphology of the Fe-W-SiC micro-nano composite coating prepared in Example 3 are similar to those of the composite coatings prepared in Examples 1 and 2.

Example 4: Preparation of Fe-Ni-W-SiC composite coating

The difference between this embodiment and Embodiments 1-3 is that nickel sulfate (NiSO ₄ ·6H ₂ O) 27 g/L is added to the composite plating solution used in step 3, and the others are the same as those in Embodiments 1-3.

The thickness and morphology of the Fe-Ni-W-SiC micro-, nano- or micro-nano composite coatings prepared in Example 4 are similar to those of the micro, nano or micro-nano composite coatings prepared in Examples 1-3.

Example 5: Preparation of Fe-Co-W-SiC composite coating

The difference between this embodiment and Embodiments 1-3 is that 28 g/L of cobalt sulfate (CoSO ₄ ·7H ₂ O) is added to the composite plating solution used in step 3, and others are the same as those in Embodiments 1-3.

The thickness and morphology of the Fe-Co-W-SiC micro-, nano- or micro-nano composite coatings prepared in Example 5 are similar to those of the micro, nano or micro-nano composite coatings prepared in Examples 1-3.

Example 6: Preparation of Fe-Co-Ni-W-SiC composite coating

The difference between this embodiment and Embodiments 1-3 is that 27 g/L of nickel sulfate and 28 g/L of cobalt sulfate are added to the composite plating solution used in step 3, and the others are the same as those of Embodiments 1-3.

The thickness and morphology of the Fe-Co-Ni-W-SiC micro-, nano- or micro-nano composite coatings prepared in Example 6 are similar to those of the micro, nano or micro-nano composite coatings prepared in Examples 1-3.

Example 7: Application example of Fe-W-SiC nanocomposite coating

Using the preparation method of the composite coating in Example 2, repair electroplating Fe-W-SiC nanocomposite coating was carried out on the steel-based piston, piston rod, crankshaft, roller and inner wall of the engine whose surfaces were rubbed and worn, and the structure repaired by composite plating was carried out. The surface nano-indentation test was carried out on the parts, and the test results were compared with the performance of the above-mentioned structural parts after chrome plating repair. The thickness, composition and morphology of the prepared nanocomposite coating are consistent with those of the composite coating prepared in Example 2. The nanoindentation curve is shown in Figure 6. The calculated nanohardness value is about 11.37GPa, which is better than that reported in the literature. The hardness of chromium plating is 10GPa (Powder Metallurgy and Metal Ceramics, 2009, 48(7-8): 419; Surface Engineering and Applied Electrochemistry, 2012, 48(6): 491-520).

Example 8: Application example of Fe-Ni-W-SiC nanocomposite coating

Using the composite coating preparation method of Example 4, repair electroplating Fe-Ni-W-SiC nanocomposite coating was carried out on the steel-based piston, piston rod, crankshaft, roller and inner wall of the engine whose surfaces were rubbed and worn, and the composite coating was repaired. The surface nano-indentation test of the structural parts was carried out, and the test results were compared with the performance of the above-mentioned structural parts after chrome plating repair. Similarly, the thickness, composition and morphology of the prepared nanocomposite coating are consistent with those of the composite coating prepared in Example 4, and the hardness is better than that of the chromium coating.

Example 9: Application example of Fe-Co-W-SiC nanocomposite coating

Using the composite coating preparation method of Example 5, repair electroplating Fe-Co-W-SiC nanocomposite coating was carried out on the steel-based piston, piston rod, crankshaft, roller and inner wall of the engine whose surfaces were rubbed and worn, and the composite coating was repaired. The surface nano-indentation test of the structural parts was carried out, and the test results were compared with the performance of the above-mentioned structural parts after chrome plating repair. Likewise, the thickness, composition and morphology of the prepared nanocomposite coating are consistent with those of the composite coating prepared in Example 5, and the hardness is better than that of the chromium coating.

Example 10: Application example of Fe-Co-Ni-W-SiC nanocomposite coating

Using the preparation method of the composite coating in Example 6, repair electroplating Fe-Co-Ni-W-SiC nanocomposite coating was carried out on the steel-based piston, piston rod, crankshaft, roller and inner wall of the engine whose surfaces were rubbed and worn, and the composite coating was The repaired structural parts were subjected to surface nanoindentation test, and the test results were compared with the performance of the above-mentioned structural parts repaired by chrome plating. Similarly, the thickness, composition and morphology of the prepared nanocomposite coating are consistent with those of the composite coating prepared in Example 6, and the hardness is better than that of the chromium coating.

Example 11: Application example of Fe, Co, Ni-W-SiC nanocomposite coating

The Fe, Co, Ni-W-SiC composite coatings prepared on the steel surface in Examples 1 to 6 did not fall off after the 90° bending test; the test method for the adhesion strength of the coating on the metal substrate meets the national standard GB5270-200X. requirements.

Example 12: Application example of Fe, Co, Ni-W-SiC nanocomposite coating

The Fe, Co, Ni-W-SiC composite coatings prepared in Examples 7-10 have good corrosion resistance, and meet the requirements of the national standard GB5938-86 "Corrosion Resistance Test Method for Metal Coatings and Chemically Treated Layers of Light Industrial Products" in 5% salt water Sexual salt spray test indicators.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, The simplification should be equivalent replacement manners, which are all included in the protection scope of the present invention.

Claims (10)

1. a kind of preparation method of the alloy of iron group element and tungsten and silicon carbide composite coating, it is characterized in that comprising the following steps: (1) Preparation of composite plating solution: Fe ²⁺ /Fe ³⁺ salt 10～100g/L, Co ²⁺ /Co ³⁺ salt 0～100g/L, Ni ²⁺ /Ni ³⁺ salt 0～100g/L, Tungstate 20-200g/L, complexing agent 30-300g/L, dispersant 0.1-10g/L, silicon carbide 1-20g/L; the solvent is water; the pH of the composite plating solution is 7-14; (2) The substrate is put into the composite electroplating solution for electroplating; the electric current used in electroplating is direct current, single pulse current, double pulse current or direct current/pulse superimposed current; and mechanical, air, jet or ultrasonic stirring is performed during electroplating. 2. preparation method according to claim 1, is characterized in that: The dispersant described in step (1) is at least one of cetyltrimethylammonium bromide, sodium lauryl sulfate, polyoxyethylene ethers, sodium polyacrylate and polyvinylpyrrolidone. 3. preparation method according to claim 1, is characterized in that: The complexing agent described in step (1) is tartaric acid, pyrophosphoric acid, hypophosphorous acid, citric acid, nitrilotriacetic acid, oxalic acid, lactic acid, nicotinic acid, sulfamic acid, fluoroboric acid, hydroxyethylidene diphosphoric acid, 5,5' -At least one of dimethylhydantoin, ammonia water and their salts; the substrate in step (2) is any conductor insoluble in the plating solution and a metallized insulator. 4. preparation method according to claim 1, is characterized in that: The specific parameters of the single-pulse current in step (2) are: on-time T _on =0.1-1ms, off-time _Toff =0.4-1ms, frequency f=500-2000Hz, current density Jm =0.5-10A/ _dm ² ; the specific parameters of the double-pulse current are: T _on =0.1～1ms, T _off =0.4～1ms, pulse on-off period T=0.5～2ms, f=500～2000Hz, forward current density J _m ⁺ =0.5 ～10A/dm ² , reverse current density J _m ⁻ =0.025～1A/dm ² ; the specific parameters of the DC/pulse superimposed current are: f=500～2000Hz, J=0.5～10A/dm ² , J _m = 0.5～10A/dm ² or f=500～2000Hz, J=0.5～10A/dm ² , J _m =0.5～10A/dm ² , J _m ⁻ =0.025～1A/dm ² . 5. preparation method according to claim 1, is characterized in that: The speed of the mechanical stirring in step (2) is 600～3000r/min, the flow rate of air stirring is 10～200m ³ /h, the flow rate of jet flow stirring is 10～200m ³ /h, and the frequency of ultrasonic stirring is 1～100kHz . 6. preparation method according to claim 1, is characterized in that: In step (2), the electroplating temperature is 5-95° C., and the electroplating time is 0.1-10 h. 7 . An alloy of an iron group element and tungsten and a silicon carbide composite coating, prepared by the method according to any one of claims 1 to 6 . 8. The alloy of iron group elements and tungsten and the silicon carbide composite coating according to claim 7, wherein the matrix alloy in the composite coating is Fe-W, Fe-Co-W, Fe-Ni-W or Fe-Co-Ni-W. 9 . The alloy of iron group elements and tungsten and the silicon carbide composite coating according to claim 7 , wherein the thickness of the composite coating is 1-3000 μm, the grain size of the matrix alloy is 0.01-10 μm, and the silicon carbide The content is 5～50at.%, and the distribution is uniform. 10 . The application of the alloy of iron group elements and tungsten and silicon carbide composite coating according to any one of claims 7 to 9 in equipment additive repair and remanufacturing.

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