Tungsten carbide composite coating as well as preparation method and application thereof

Abstract

The invention relates to the technical field of tungsten carbide coatings, and discloses a tungsten carbide composite coating and a preparation method and application thereof. The tungsten carbide composite coating comprises the following raw materials in parts by mass: 5-10 parts of modified tungsten carbide, 1-2 parts of nickel-cobalt alloy and 0.2-0.5 part of titanium carbide. The minimum corrosion rate of the tungsten carbide composite coating in a 3.5% NaCl corrosion medium can reach 0.009 g / m < 2 > h, the minimum corrosion rate of the tungsten carbide composite coating in a 0.1 mo l / L NaOH corrosion medium can reach 0.017 g / m < 2 > h, the minimum corrosion rate of the tungsten carbide composite coating in a 0.1 mo l / L H2SO4 corrosion medium can reach 0.025 g / m < 2 > h, and the tungsten carbide composite coating has good corrosion resistance; according to the tungsten carbide composite coating provided by the invention, the corrosion rate change rate is only 30.0% in a corrosive medium of 3.5% NaCl, the corrosion rate change rate is only 10.0% in a corrosive medium of 0.1 mo l / L NaOH, the corrosion rate change rate is only 10.0% in a corrosive medium of 0.1 mo l / L H2SO4, and the tungsten carbide composite coating has good high-temperature oxidation resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of tungsten carbide coatings, and in particular to a tungsten carbide composite coating and a preparation method and application thereof. Background Art

[0002] Tungsten carbide coating is a hard alloy surface coating containing tungsten carbide. Its preparation method is to use tungsten carbide, cobalt, etc. as raw materials, and deposit the raw materials onto the surface of the substrate by physical vapor deposition or chemical vapor deposition. Tungsten carbide coating has the characteristics of high hardness, strong wear resistance, high temperature resistance, corrosion resistance, etc. Therefore, tungsten carbide coating is widely used in aerospace, mechanical processing and other fields.

[0003] However, since tungsten carbide, the main component of tungsten carbide coating, is easily oxidized at high temperatures, especially in the temperature range of 500℃ to 800℃, tungsten carbide will be severely oxidized and decomposed into tungsten carbide and carbon, resulting in a significant decrease in the strength and hardness of the tungsten carbide coating, seriously affecting the service life and performance of the tungsten carbide coating.

[0004] In order to improve the high-temperature oxidation resistance of tungsten carbide coatings, some researchers have introduced titanium carbide into tungsten carbide coatings. Titanium carbide reacts with oxygen under high temperature conditions to form a titanium dioxide film. The titanium dioxide film has good high-temperature oxidation resistance and can effectively protect the tungsten carbide coating from oxidation. However, titanium carbide can form a (Ti, W) C solid solution with tungsten carbide. The presence of the (Ti, W) C solid solution will reduce the corrosion resistance of the tungsten carbide coating to a certain extent, which is not conducive to the application of tungsten carbide coatings in corrosive environments.

[0005] Based on this, providing a tungsten carbide composite coating with good corrosion resistance and high-temperature oxidation resistance has become a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0006] The purpose of the present invention is to provide a tungsten carbide composite coating and a preparation method and application thereof, wherein the tungsten carbide composite coating has good corrosion resistance and high temperature oxidation resistance.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] One of the technical solutions of the present invention:

[0009] A tungsten carbide composite coating comprises the following raw materials in parts by mass: 5 to 10 parts of modified tungsten carbide, 1 to 2 parts of nickel-cobalt alloy and 0.2 to 0.5 parts of titanium carbide.

[0010] Furthermore, the preparation method of the modified tungsten carbide comprises the following steps:

[0011] 1) mixing ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid, stirring and reacting to obtain silica sol;

[0012] 2) adding tungsten carbide powder to the silica sol prepared in step 1), and dispersing by ultrasonic to obtain silica sol dispersed with tungsten carbide powder;

[0013] 3) spray drying the silica sol dispersed with tungsten carbide powder prepared in step 2) to obtain the modified tungsten carbide.

[0014] Furthermore, in step 1), the hydrochloric acid is hydrochloric acid with a volume fraction of 10%.

[0015] Furthermore, in step 1), the molar ratio of tetraethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid is 1:5:10:0.1.

[0016] Furthermore, in step 1), the stirring reaction is specifically: stirring the reaction at 60° C. for 12 hours.

[0017] Furthermore, in step 2), the molar ratio of the tungsten carbide powder to tetraethyl orthosilicate is (2-5):1.

[0018] Furthermore, in step 2), the duration of the ultrasonic dispersion is 2 hours.

[0019] Furthermore, in step 3), the spray drying parameters are: inlet air temperature 150-180°C, outlet air temperature 80-90°C, atomization pressure 140-160KPa, feed volume 10mL·min -1 .

[0020] Furthermore, the method for preparing the nickel-cobalt alloy comprises the following steps:

[0021] 1) mixing nickel ingots and cobalt ingots, smelting, and obtaining a nickel-cobalt alloy precursor;

[0022] 2) quenching the nickel-cobalt alloy precursor prepared in step 1) to obtain the nickel-cobalt alloy.

[0023] Furthermore, in step 1), the mass ratio of the nickel ingot to the cobalt ingot is 1:(0.6-0.8).

[0024] Furthermore, in step 1), the smelting is specifically: preheating at 600-800°C for 30 minutes in a nitrogen atmosphere, and then smelting at 1480-1520°C for 2 hours.

[0025] Furthermore, in step 2), the quenching treatment is specifically: heating the nickel-cobalt alloy precursor to 900-1200° C. in a nitrogen atmosphere, using water as a quenching medium, and quenching the nickel-cobalt alloy precursor, and repeating it 2-3 times.

[0026] The second technical solution of the present invention:

[0027] The preparation method of the above-mentioned tungsten carbide composite coating comprises the following steps:

[0028] 1) Mixing the modified tungsten carbide, nickel-cobalt alloy and titanium carbide, and ball milling for 1 to 3 hours to obtain tungsten carbide composite coating powder;

[0029] 2) Using supersonic flame spraying technology, spray the tungsten carbide composite coating powder prepared in step 1) onto the surface of the substrate to form the tungsten carbide composite coating.

[0030] Furthermore, in step 2), the parameters of the supersonic flame spraying technology are: spraying current 500A, spraying voltage 70V, spraying distance 350mm, and spray gun moving speed 300mm / s.

[0031] The third technical solution of the present invention:

[0032] The application of the above tungsten carbide composite coating in material anti-corrosion treatment.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The tungsten carbide composite coating provided by the present invention has a corrosion rate as low as 0.009 g / m in a 3.5% NaCl corrosive medium. 2 h, in the corrosive medium of 0.1mol / L NaOH, the corrosion rate can be as low as 0.017g / m 2 h, at 0.1 mol / LH 2 SO 4 In the corrosive medium, the corrosion rate can be as low as 0.025g / m 2 h, has good corrosion resistance;

[0035] The tungsten carbide composite coating provided by the present invention has a corrosion rate change rate of only 30.0% in a corrosive medium of 3.5% NaCl, a corrosion rate change rate of only 10.0% in a corrosive medium of 0.1 mol / L NaOH, and a corrosion rate change rate of only 10.0% in a corrosive medium of 0.1 mol / L NaOH. 2 SO 4 In the corrosive medium, the corrosion rate change rate is only 10.0%, and it has good resistance to high temperature oxidation. DETAILED DESCRIPTION

[0036] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0037] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0038] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0039] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0040] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0041] In the following embodiment, a method for preparing a tungsten carbide composite coating comprises the following steps:

[0042] 1. Preparation of modified tungsten carbide:

[0043] 1) According to the molar ratio of ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid being 1:5:10:0.1, ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid with a volume fraction of 10% are mixed, and stirred at 60° C. for 12 hours to obtain a silica sol;

[0044] 2) adding tungsten carbide powder to the silica sol prepared in step 1) at a molar ratio of tungsten carbide powder to tetraethyl orthosilicate of (2-5):1, and ultrasonically dispersing for 2 hours to obtain silica sol dispersed with tungsten carbide powder;

[0045] 3) Control the inlet air temperature to 150-180℃, the outlet air temperature to 80-90℃, the atomization pressure to 140-160KPa, and the feed rate to 10mL·min -1 , spray drying the silica sol dispersed with tungsten carbide powder prepared in step 2) to obtain modified tungsten carbide;

[0046] 2. Preparation of nickel-cobalt alloy:

[0047] 1) According to the mass ratio of nickel ingot to cobalt ingot being 1:(0.6-0.8), the nickel ingot and the cobalt ingot are mixed, preheated at 600-800° C. for 30 min in a nitrogen atmosphere, and then smelted at 1480-1520° C. for 2 h to obtain a nickel-cobalt alloy precursor;

[0048] 2) heating the nickel-cobalt alloy precursor prepared in step 1) to 900-1200° C. in a nitrogen atmosphere, using water as a quenching medium to quench the nickel-cobalt alloy precursor, repeating this process 2-3 times to obtain a nickel-cobalt alloy;

[0049] 3. Preparation of tungsten carbide composite coating:

[0050] 1) According to the mass ratio of modified tungsten carbide, nickel-cobalt alloy and titanium carbide being (5-10):(1-2):(0.2-0.5), the modified tungsten carbide prepared in step 1, the nickel-cobalt alloy prepared in step 2 and titanium carbide are mixed, and ball milled for 1-3 hours to obtain tungsten carbide composite coating powder;

[0051] 2) using supersonic flame spraying technology to spray the tungsten carbide composite coating powder prepared in step 1) onto the surface of the substrate to form the tungsten carbide composite coating;

[0052] Among them, the parameters of supersonic flame spraying technology are: spraying current 500A, spraying voltage 70V, spraying distance 350mm, and spray gun moving speed 300mm / s.

[0053] Example 1

[0054] A tungsten carbide composite coating

[0055] 1. Preparation of modified tungsten carbide:

[0056] 1) According to the molar ratio of ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid being 1:5:10:0.1, ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid with a volume fraction of 10% are mixed, and stirred at 60° C. for 12 hours to obtain a silica sol;

[0057] 2) adding tungsten carbide powder to the silica sol prepared in step 1) at a molar ratio of tungsten carbide powder to tetraethyl orthosilicate of 2:1, and ultrasonically dispersing for 2 hours to obtain silica sol dispersed with tungsten carbide powder;

[0058] 3) Control the inlet air temperature to 150℃, the outlet air temperature to 80℃, the atomization pressure to 140KPa, and the feed rate to 10mL·min -1 , spray drying the silica sol dispersed with tungsten carbide powder prepared in step 2) to obtain modified tungsten carbide;

[0059] 2. Preparation of nickel-cobalt alloy:

[0060] 1) mixing the nickel ingot and the cobalt ingot in a mass ratio of 1:0.6, preheating at 600° C. for 30 min in a nitrogen atmosphere, and then smelting at 1480° C. for 2 h to obtain a nickel-cobalt alloy precursor;

[0061] 2) heating the nickel-cobalt alloy precursor prepared in step 1) to 900° C. in a nitrogen atmosphere, using water as a quenching medium to quench the nickel-cobalt alloy precursor, repeating the process twice to obtain a nickel-cobalt alloy;

[0062] 3. Preparation of tungsten carbide composite coating:

[0063] 1) According to the mass ratio of modified tungsten carbide, nickel-cobalt alloy and titanium carbide being 5:1:0.2, the modified tungsten carbide prepared in step 1, the nickel-cobalt alloy prepared in step 2 and titanium carbide are mixed, and ball milled for 1 hour to obtain tungsten carbide composite coating powder;

[0064] 2) using supersonic flame spraying technology to spray the tungsten carbide composite coating powder prepared in step 1) onto the surface of the substrate to form the tungsten carbide composite coating;

[0065] Among them, the parameters of supersonic flame spraying technology are: spraying current 500A, spraying voltage 70V, spraying distance 350mm, and spray gun moving speed 300mm / s.

[0066] Example 2

[0067] A tungsten carbide composite coating

[0068] 1. Preparation of modified tungsten carbide:

[0069] 1) According to the molar ratio of ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid being 1:5:10:0.1, ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid with a volume fraction of 10% are mixed, and stirred at 60° C. for 12 hours to obtain a silica sol;

[0070] 2) adding tungsten carbide powder to the silica sol prepared in step 1) at a molar ratio of tungsten carbide powder to tetraethyl orthosilicate of 4:1, and ultrasonically dispersing for 2 hours to obtain silica sol dispersed with tungsten carbide powder;

[0071] 3) Control the air inlet temperature to 170℃, the air outlet temperature to 85℃, the atomization pressure to 150KPa, and the feed rate to 10mL·min -1 , spray drying the silica sol dispersed with tungsten carbide powder prepared in step 2) to obtain modified tungsten carbide;

[0072] 2. Preparation of nickel-cobalt alloy:

[0073] 1) mixing the nickel ingot and the cobalt ingot in a mass ratio of 1:0.7, preheating at 700° C. for 30 min in a nitrogen atmosphere, and then smelting at 1500° C. for 2 h to obtain a nickel-cobalt alloy precursor;

[0074] 2) heating the nickel-cobalt alloy precursor prepared in step 1) to 1000° C. in a nitrogen atmosphere, using water as a quenching medium to quench the nickel-cobalt alloy precursor, repeating the process twice to obtain a nickel-cobalt alloy;

[0075] 3. Preparation of tungsten carbide composite coating:

[0076] 1) According to the mass ratio of modified tungsten carbide, nickel-cobalt alloy and titanium carbide being 8:1.5:0.3, the modified tungsten carbide prepared in step 1, the nickel-cobalt alloy prepared in step 2 and titanium carbide are mixed, and ball milled for 2 hours to obtain tungsten carbide composite coating powder;

[0077] 2) using supersonic flame spraying technology to spray the tungsten carbide composite coating powder prepared in step 1) onto the surface of the substrate to form the tungsten carbide composite coating;

[0078] Among them, the parameters of supersonic flame spraying technology are: spraying current 500A, spraying voltage 70V, spraying distance 350mm, and spray gun moving speed 300mm / s.

[0079] Example 3

[0080] A tungsten carbide composite coating

[0081] 1. Preparation of modified tungsten carbide:

[0082] 1) According to the molar ratio of ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid being 1:5:10:0.1, ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid with a volume fraction of 10% are mixed, and stirred at 60° C. for 12 hours to obtain a silica sol;

[0083] 2) adding tungsten carbide powder to the silica sol prepared in step 1) at a molar ratio of tungsten carbide powder to tetraethyl orthosilicate of 5:1, and ultrasonically dispersing for 2 hours to obtain silica sol dispersed with tungsten carbide powder;

[0084] 3) Control the air inlet temperature to 180℃, the air outlet temperature to 90℃, the atomization pressure to 160KPa, and the feed rate to 10mL·min -1 , spray drying the silica sol dispersed with tungsten carbide powder prepared in step 2) to obtain modified tungsten carbide;

[0085] 2. Preparation of nickel-cobalt alloy:

[0086] 1) mixing the nickel ingot and the cobalt ingot in a mass ratio of 1:0.8, preheating at 800° C. for 30 min in a nitrogen atmosphere, and then smelting at 1520° C. for 2 h to obtain a nickel-cobalt alloy precursor;

[0087] 2) heating the nickel-cobalt alloy precursor prepared in step 1) to 1200° C. in a nitrogen atmosphere, using water as a quenching medium to quench the nickel-cobalt alloy precursor, and repeating this process three times to obtain a nickel-cobalt alloy;

[0088] 3. Preparation of tungsten carbide composite coating:

[0089] 1) According to the mass ratio of modified tungsten carbide, nickel-cobalt alloy and titanium carbide being 10:2:0.5, the modified tungsten carbide prepared in step 1, the nickel-cobalt alloy prepared in step 2 and titanium carbide are mixed, and ball milled for 3 hours to obtain tungsten carbide composite coating powder;

[0090] 2) using supersonic flame spraying technology to spray the tungsten carbide composite coating powder prepared in step 1) onto the surface of the substrate to form the tungsten carbide composite coating;

[0091] Among them, the parameters of supersonic flame spraying technology are: spraying current 500A, spraying voltage 70V, spraying distance 350mm, and spray gun moving speed 300mm / s.

[0092] Comparative Example 1

[0093] A tungsten carbide composite coating

[0094] 1. Preparation of nickel-cobalt alloy:

[0095] 1) mixing the nickel ingot and the cobalt ingot in a mass ratio of 1:0.7, preheating at 700° C. for 30 min in a nitrogen atmosphere, and then smelting at 1500° C. for 2 h to obtain a nickel-cobalt alloy precursor;

[0096] 2) heating the nickel-cobalt alloy precursor prepared in step 1) to 1000° C. in a nitrogen atmosphere, using water as a quenching medium to quench the nickel-cobalt alloy precursor, repeating the process twice to obtain a nickel-cobalt alloy;

[0097] 2. Preparation of tungsten carbide composite coating:

[0098] 1) According to the mass ratio of tungsten carbide, nickel-cobalt alloy and titanium carbide being 8:1.5:0.3, tungsten carbide, the nickel-cobalt alloy prepared in step 1 and titanium carbide are mixed, and ball milled for 2 hours to obtain tungsten carbide composite coating powder;

[0099] 2) using supersonic flame spraying technology to spray the tungsten carbide composite coating powder prepared in step 1) onto the surface of the substrate to form the tungsten carbide composite coating;

[0100] Among them, the parameters of supersonic flame spraying technology are: spraying current 500A, spraying voltage 70V, spraying distance 350mm, and spray gun moving speed 300mm / s.

[0101] Comparative Example 2

[0102] A tungsten carbide composite coating

[0103] 1. Preparation of modified tungsten carbide:

[0104] 1) According to the molar ratio of ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid being 1:5:10:0.1, ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid with a volume fraction of 10% are mixed, and stirred at 60° C. for 12 hours to obtain a silica sol;

[0105] 2) adding tungsten carbide powder to the silica sol prepared in step 1) at a molar ratio of tungsten carbide powder to tetraethyl orthosilicate of 4:1, and ultrasonically dispersing for 2 hours to obtain silica sol dispersed with tungsten carbide powder;

[0106] 3) Control the air inlet temperature to 170℃, the air outlet temperature to 85℃, the atomization pressure to 150KPa, and the feed rate to 10mL·min -1 , spray drying the silica sol dispersed with tungsten carbide powder prepared in step 2) to obtain modified tungsten carbide;

[0107] 2. Preparation of nickel-cobalt alloy:

[0108] The nickel ingot and the cobalt ingot are mixed in a mass ratio of 1:0.7, preheated at 700°C for 30 minutes in a nitrogen atmosphere, and then smelted at 1500°C for 2 hours to obtain a nickel-cobalt alloy;

[0109] 3. Preparation of tungsten carbide composite coating:

[0110] 1) According to the mass ratio of modified tungsten carbide, nickel-cobalt alloy and titanium carbide being 8:1.5:0.3, the modified tungsten carbide prepared in step 1, the nickel-cobalt alloy prepared in step 2 and titanium carbide are mixed, and ball milled for 2 hours to obtain tungsten carbide composite coating powder;

[0111] 2) using supersonic flame spraying technology to spray the tungsten carbide composite coating powder prepared in step 1) onto the surface of the substrate to form the tungsten carbide composite coating;

[0112] Among them, the parameters of supersonic flame spraying technology are: spraying current 500A, spraying voltage 70V, spraying distance 350mm, and spray gun moving speed 300mm / s.

[0113] Comparative Example 3

[0114] A tungsten carbide composite coating

[0115] 1. Preparation of modified tungsten carbide:

[0116] 1) According to the molar ratio of ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid being 1:5:10:0.1, ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid with a volume fraction of 10% are mixed, and stirred at 60° C. for 12 hours to obtain a silica sol;

[0117] 2) adding tungsten carbide powder to the silica sol prepared in step 1) at a molar ratio of tungsten carbide powder to tetraethyl orthosilicate of 4:1, and ultrasonically dispersing for 2 hours to obtain silica sol dispersed with tungsten carbide powder;

[0118] 3) Control the air inlet temperature to 170℃, the air outlet temperature to 85℃, the atomization pressure to 150KPa, and the feed rate to 10mL·min -1 , spray drying the silica sol dispersed with tungsten carbide powder prepared in step 2) to obtain modified tungsten carbide;

[0119] 2. Preparation of tungsten carbide composite coating:

[0120] 1) According to the mass ratio of modified tungsten carbide, nickel ingot, cobalt ingot and titanium carbide being 8:0.88:0.62:0.3, the modified tungsten carbide, nickel ingot, cobalt ingot and titanium carbide prepared in step 1 are mixed, and ball milled for 2 hours to obtain tungsten carbide composite coating powder;

[0121] 2) using supersonic flame spraying technology to spray the tungsten carbide composite coating powder prepared in step 1) onto the surface of the substrate to form the tungsten carbide composite coating;

[0122] Among them, the parameters of supersonic flame spraying technology are: spraying current 500A, spraying voltage 70V, spraying distance 350mm, and spray gun moving speed 300mm / s.

[0123] Comparative Example 4

[0124] A tungsten carbide composite coating

[0125] 1. Preparation of modified tungsten carbide:

[0126] 1) According to the molar ratio of ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid being 1:5:10:0.1, ethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid with a volume fraction of 10% are mixed, and stirred at 60° C. for 12 hours to obtain a silica sol;

[0127] 2) adding tungsten carbide powder to the silica sol prepared in step 1) at a molar ratio of tungsten carbide powder to tetraethyl orthosilicate of 4:1, and ultrasonically dispersing for 2 hours to obtain silica sol dispersed with tungsten carbide powder;

[0128] 3) Control the air inlet temperature to 170℃, the air outlet temperature to 85℃, the atomization pressure to 150KPa, and the feed rate to 10mL·min -1 , spray drying the silica sol dispersed with tungsten carbide powder prepared in step 2) to obtain modified tungsten carbide; 2.

[0130] 1) According to the mass ratio of modified tungsten carbide to titanium carbide of 8:0.3, the modified tungsten carbide prepared in step 1 and titanium carbide are mixed, and ball milled for 2 hours to obtain tungsten carbide composite coating powder;

[0131] 2) using supersonic flame spraying technology to spray the tungsten carbide composite coating powder prepared in step 1) onto the surface of the substrate to form the tungsten carbide composite coating;

[0132] Among them, the parameters of supersonic flame spraying technology are: spraying current 500A, spraying voltage 70V, spraying distance 350mm, and spray gun moving speed 300mm / s.

[0133] The tungsten carbide composite coatings prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were subjected to corrosion resistance tests and high temperature oxidation resistance tests. The corrosion resistance test results are shown in Table 1; the high temperature oxidation resistance test results are shown in Table 2;

[0134] Table 1 Corrosion resistance test results

[0135]

[0136] From the data in Table 1, it can be seen that the corrosion rate of the tungsten carbide composite coating provided by the present invention in the corrosive medium of 3.5% NaCl can be as low as 0.009 g / m 2 h, in the corrosive medium of 0.1mol / L NaOH, the corrosion rate can be as low as 0.017g / m 2 h, at 0.1 mol / LH 2 SO 4 In the corrosive medium, the corrosion rate can be as low as 0.025g / m 2h, has good corrosion resistance;

[0137] Table 2 Test results of high temperature oxidation resistance

[0138]

[0139]

[0140] Note: The method for testing the high temperature oxidation resistance is as follows: the tungsten carbide composite coating is placed in a heating furnace and heated at 1000°C for 2 hours, and then the corrosion resistance of the tungsten carbide composite coating is tested;

[0141] From the data in Table 2, it can be seen that the corrosion rate change rate of the tungsten carbide composite coating provided by the present invention in the corrosive medium of 3.5% NaCl is only 30.0%, in the corrosive medium of 0.1 mol / L NaOH, the corrosion rate change rate is only 10.0%, and in the corrosive medium of 0.1 mol / L NaOH, the corrosion rate change rate is only 10.0%. 2 SO 4 In the corrosive medium, the corrosion rate change rate is only 10.0%, and it has good resistance to high temperature oxidation.

[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A tungsten carbide composite coating, characterized in that: The invention comprises the following raw materials in parts by weight: 5 to 10 parts of modified tungsten carbide, 1 to 2 parts of nickel-cobalt alloy and 0.2 to 0.5 parts of titanium carbide.

2. A tungsten carbide composite coating according to claim 1, characterized in that: The preparation method of the modified tungsten carbide comprises the following steps: 1) mixing tetraethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid, stirring and reacting to obtain silica sol; 2) adding tungsten carbide powder to the silica sol prepared in step 1), and dispersing by ultrasonic to obtain silica sol dispersed with tungsten carbide powder; 3) spray drying the silica sol dispersed with tungsten carbide powder prepared in step 2) to obtain the modified tungsten carbide.

3. A tungsten carbide composite coating according to claim 2, characterized in that: In step 1), the hydrochloric acid is 10% by volume; the molar ratio of the tetraethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid is 1:5:10:0.1; and the stirring reaction is specifically: stirring the reaction at 60°C for 12 hours.

4. A tungsten carbide composite coating according to claim 2, characterized in that: In step 2), the molar ratio of the tungsten carbide powder to tetraethyl orthosilicate is (2-5):1; and the duration of the ultrasonic dispersion is 2 hours.

5. The tungsten carbide composite coating according to claim 2, characterized in that: In step 3), the spray drying parameters are: inlet air temperature 150-180°C, outlet air temperature 80-90°C, atomization pressure 140-160KPa, feed rate 10mL·min -1 .

6. The tungsten carbide composite coating according to claim 1, characterized in that: The method for preparing the nickel-cobalt alloy comprises the following steps: 1) mixing nickel ingots and cobalt ingots, smelting, and obtaining a nickel-cobalt alloy precursor; 2) quenching the nickel-cobalt alloy precursor prepared in step 1) to obtain the nickel-cobalt alloy.

7. The tungsten carbide composite coating according to claim 6, characterized in that: In step 1), the mass ratio of the nickel ingot to the cobalt ingot is 1:(0.6-0.8). The smelting is specifically: preheating at 600-800°C for 30 minutes in a nitrogen atmosphere, and then smelting at 1480-1520°C for 2 hours.

8. The tungsten carbide composite coating according to claim 6, characterized in that: In step 2), the quenching treatment is specifically: heating the nickel-cobalt alloy precursor to 900-1200° C. in a nitrogen atmosphere, using water as a quenching medium, and quenching the nickel-cobalt alloy precursor, and repeating it 2-3 times.

9. A method for preparing a tungsten carbide composite coating according to any one of claims 1 to 9, characterized in that: The following steps are involved: 1) Mixing the modified tungsten carbide, nickel-cobalt alloy and titanium carbide, and ball milling for 1 to 3 hours to obtain tungsten carbide composite coating powder; 2) Using supersonic flame spraying technology, spray the tungsten carbide composite coating powder prepared in step 1) onto the surface of the substrate to form the tungsten carbide composite coating.

10. Use of the tungsten carbide composite coating according to any one of claims 1 to 9 in material anti-corrosion treatment.

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