CN109207960B

CN109207960B - Titanium carbide nanocrystal coating compounded on surface of M42 steel as well as preparation method and application thereof

Info

Publication number: CN109207960B
Application number: CN201710539215.4A
Authority: CN
Inventors: 马付根; 江南; 王少龙; 杨科
Original assignee: Ningbo Chenxin Vac Industrial Technology Co ltd
Current assignee: Ningbo Chenxin Vac Industrial Technology Co ltd
Priority date: 2017-07-04
Filing date: 2017-07-04
Publication date: 2021-02-02
Anticipated expiration: 2037-07-04
Also published as: CN109207960A

Abstract

The invention relates to a titanium carbide nanocrystal coating compounded on the surface of M42 steel, and a preparation method and application thereof. The invention particularly discloses a preparation method of the titanium carbide nanocrystal coating, which is used for preparing the titanium carbide nanocrystal coating on the surface of M42 steel by a low-pressure chemical vapor deposition method. The invention also discloses a titanium carbide nanocrystal coating compounded on the surface of M42 steel, which is prepared by the preparation method. The preparation method has the advantages of simple process, low cost, safety, environmental protection and the like. The coating has the characteristics of moderate friction coefficient, strong bonding force with the matrix M42 steel and the like.

Description

Titanium carbide nanocrystal coating compounded on surface of M42 steel as well as preparation method and application thereof

Technical Field

The invention relates to the field of materials, in particular to the field of preparation of ceramic-based coatings, and especially relates to a titanium carbide nanocrystal coating compounded on the surface of M42 steel, and a preparation method and application thereof.

Background

M42 high speed steel is widely used in screw industry and forging industry as a wear-resistant and impact-resistant steel material, and is particularly widely used in screw manufacturing industry.

As an important industrial part, a screw has a large number of applications in industrial products such as electronic products, mechanical products, digital products, electric power equipment, electromechanical products, and the like. However, different equipment is often used in different environments, for example, marine vessels travel throughout the ocean throughout the year, and the internal environment inevitably contains a large amount of water vapor and salt substances. This requires that the screws in each type of device be adapted to its particular environment of use. It is known that the M42 steel has excellent mechanical properties, but as an iron-based material, it cannot effectively resist various kinds of chemical corrosion or water vapor corrosion.

In order to solve the problem of corrosion resistance or corrosion resistance of the M42 steel screw, many surface protection methods, including electroplating protective layers, organic coating and the like, have been tried. The protective coatings prepared by various protection methods have different advantages and disadvantages: some coatings can protect the screw against corrosion, but limit the mechanical properties of the screw thread, for example: the friction coefficient of a common steel screw is generally in the range of 0.1-0.2, and the friction coefficient of a coating is too large or too small, so that the screw cannot be normally assembled and disassembled with a nut; some coatings have weak bonding force with the surface of the screw, and cannot be adapted to the assembly and disassembly operations of the screw and the nut to easily fall off; some coating preparation methods have high economic cost, such as preparing protective coatings by adopting a physical vapor deposition method; some coating preparation methods, such as electroplating and chemical plating, can cause environmental pollution during the preparation process.

The acid-base corrosion resistance and salt corrosion resistance of the ceramic material are superior to those of a common iron-based metal material, so that the development of the M42 steel surface ceramic-based protective coating with excellent performance and the preparation method thereof have very important application value.

Disclosure of Invention

The invention aims to provide an M42 steel surface protective coating with excellent mechanical property and protective property, and a preparation method and application thereof.

In a first aspect of the invention, a method for preparing a titanium carbide nanocrystalline coating compounded on the surface of M42 steel is provided, which comprises the following steps:

1) providing M42 high-speed steel, a carbon source, a titanium source and an auxiliary gas;

2) placing the M42 high-speed steel into a CVD furnace, and heating the CVD furnace to a deposition heat preservation temperature under the auxiliary gas atmosphere;

3) introducing the carbon source and the titanium source into the heated CVD furnace, and preserving heat for a first time period;

4) cooling the CVD furnace to a second temperature at a first cooling rate, and stopping introducing the carbon source and the titanium source;

5) and after the CVD furnace is cooled to a second temperature, stopping introducing the auxiliary gas to obtain the titanium carbide nanocrystal coating compounded on the surface of the M42 steel.

In another preferred embodiment, the carbon source is selected from the group consisting of: methane, ethane, propane, ethylene, propylene, acetylene, or combinations thereof; and/or

The titanium source comprises titanium tetrachloride.

In another preferred embodiment, the carbon source is gaseous.

In another preferred embodiment, the titanium source is in a liquid state.

In another preferred embodiment, when the titanium source is in a liquid state, the titanium source is vaporized prior to being introduced into the CVD furnace.

In another preferred embodiment, the auxiliary gas is a non-oxidizing gas.

In another preferred embodiment, the auxiliary gas is selected from the group consisting of: hydrogen, argon, or a combination thereof.

In another preferred embodiment, the auxiliary gas has an effect selected from the group consisting of:

1) as a carrier, loading the vaporized titanium source into a CVD furnace;

2) as an antioxidant gas to avoid oxidation of the titanium carbide during deposition.

In another preferred embodiment, the deposition temperature is 1000-.

In another preferred example, step 3) performs the deposition process of the coating, and in step 3), the flow ratio of the auxiliary gas and the carbon source is 3-10, preferably 4-9.

In another preferred embodiment, in step 3), the flow rate of the carbon source is 300-.

In another preferred embodiment, in step 3), the flow rate of the assist gas is 2500-.

In another preferred example, in step 3), the first time period is 20-100min, preferably 30-80min, and more preferably 40-70 min.

In another preferred example, in step 4), the first temperature-decreasing rate is 4-10 ℃/min, preferably 4-9 ℃/min, and more preferably 5-9 ℃/min.

In another preferred embodiment, the second temperature is room temperature, such as 25-40 deg.C, preferably 30-35 deg.C.

In a second aspect of the present invention, there is provided a composite material comprising:

a substrate; and

the coating is compounded on the surface of the base material and is a titanium carbide nanocrystal coating;

and the composite material is prepared by the preparation method of the first aspect of the invention.

In another preferred embodiment, the base material is M42 steel.

In another preferred embodiment, the complexing is chemical bonding.

In another preferred embodiment, the titanium carbide nanocrystal coating has a coefficient of friction of 0.1 to 0.3, preferably 0.12 to 0.28, more preferably 0.15 to 0.25; and/or

The bonding strength of the titanium carbide nanocrystal coating and the base material is more than or equal to 30N, preferably more than or equal to 40N, and more preferably more than or equal to 50N.

In another preferred embodiment, the composite material has one or more characteristics selected from the group consisting of:

1) the grain size of the grains constituting the titanium carbide nanocrystalline coating is less than 200nm, preferably less than 150nm, more preferably less than 100 nm;

2) the thickness of the titanium carbide nanocrystal coating is 0.5-3 μm, preferably 0.8-2 μm, more preferably 1-1.5 μm;

3) in the titanium carbide nanocrystal coating, the content of the titanium element is 70-80 wt%, and the content of the carbon element is 20-30 wt%.

In a third aspect of the invention, there is provided an article comprising or made from a composite material according to the second aspect of the invention.

In another preferred embodiment, the article is selected from the group consisting of: anticorrosive fastener, corrosion-resistant coating material.

It is to be understood that within the scope of the present invention, the above-described features of the present invention and those specifically described below (e.g., in the examples) may be combined with each other to form new or preferred embodiments. Not to be reiterated herein, but to the extent of space.

Drawings

Fig. 1 is an SEM test image of the titanium carbide nanocrystal coating 1 compounded on the surface of M42 steel obtained in example 1.

Fig. 2 is an SEM test image of a cross-section of the titanium carbide nanocrystal coating 1 compounded on the surface of M42 steel obtained in example 1.

Fig. 3 is an XRD test pattern of the titanium carbide nanocrystal coating 1 compounded on the surface of M42 steel obtained in example 1.

Fig. 4 is an SEM test image of the titanium carbide nanocrystal coating 2 compounded on the surface of M42 steel obtained in example 2.

FIG. 5 is an SEM image of a titanium carbide crystal coating C1 compounded on the surface of M42 steel obtained in comparative example 1.

FIG. 6 is an XRD pattern of a titanium carbide crystal coating C1 compounded on the surface of M42 steel obtained in comparative example 1.

FIG. 7 is an SEM image of a titanium carbide crystal coating C2 compounded on the surface of M42 steel obtained in comparative example 2.

FIG. 8 is an SEM image of a titanium carbide crystal coating C4 compounded on the surface of M42 steel obtained in comparative example 4.

Detailed Description

Through long-term and intensive research, the titanium carbide nanocrystal coating with excellent mechanical property and protective property is prepared on the surface of M42 steel by regulating and controlling the preparation process of the coating (such as deposition heat preservation temperature, cooling rate after deposition, raw material gas flow in the deposition process and the like). The preparation method has the advantages of simple process, low cost, safety, environmental protection and the like. The coating has the characteristics of moderate friction coefficient, strong bonding force with the matrix M42 steel and the like. On this basis, the inventors have completed the present invention.

Preparation method

The invention provides a preparation method of a titanium carbide nanocrystal coating compounded on the surface of M42 steel, which comprises the following steps:

It is understood that in the present invention, the deposition incubation temperature should be maintained between 1000 ℃ and 1030 ℃. When the deposition heat preservation temperature is lower than 1000 ℃ (as in comparative example 2), flocculent titanium carbide nanometer walls exist on the surface of the obtained titanium carbide nanometer crystal coating, and the structure and the friction performance of the coating are influenced; when the deposition holding temperature is higher than 1020 ℃ (such as comparative example 1), the obtained titanium carbide crystal has overlarge crystal grains and larger friction coefficient than that of the common fastener material, and is not beneficial to being used as a mechanical fastener coating.

It is understood that in the present invention, the flow ratio of the assist gas to the carbon source is maintained between 3 and 10, and when the flow ratio is less than 3, the grains on the surface of the titanium carbide coating layer obtained by deposition are columnar and coarse in grain size.

It is to be understood that in the present invention, the first cooling rate should be maintained at 4-10 deg.C/min. When the first cooling rate is more than 10 ℃/min, the titanium carbide coating obtained by deposition often has the problem of falling off or weak bonding force with an M42 steel substrate; when the first cooling rate is less than 4 ℃/min, unnecessary waste of electric energy and auxiliary gas resources can be generated.

Typically, the preparation method comprises the following steps:

(1) providing M42 high-speed steel, a carbon source, a titanium source and an auxiliary gas, wherein the titanium source is liquid titanium tetrachloride with the purity of 99.99 percent, the carbon source is gaseous methane with the purity of 99.99 percent, and the auxiliary gas is hydrogen with the purity of 99.99 percent;

(2) placing the M42 stainless steel in the step (1) in a CVD furnace, vacuumizing until the vacuum degree is less than 1Pa, and introducing hydrogen with the hydrogen flow of 50-150 sccm;

(3) heating to 800-; heating to 1020 ℃ at the speed of 5-20 ℃/min, introducing carbon source gas and preheated vaporized titanium tetrachloride, preserving the temperature for 20-110min, wherein the flow rate of the methane is 300-. Cooling, and stopping ventilation to obtain the titanium carbide nanocrystal coating compounded on the surface of the M42 steel.

In another preferred example, the M42 high-speed steel is subjected to derusting, washing and drying treatments before being placed in a CVD furnace.

Composite material and use thereof

The present invention also provides a composite material comprising:

a substrate; and

and the composite material is prepared by the preparation method.

In the present invention, the crystal grains constituting the titanium carbide nanocrystal coating have a size range of less than 200nm, preferably less than 150nm, and more preferably less than 100 nm.

The invention also provides an article comprising or made from the composite material.

In another preferred embodiment, the article includes (but is not limited to) the group of: anticorrosive fastener, corrosion-resistant coating material.

It is understood that when the composite material is applied to the mechanical manufacturing industries such as screws, molds and the like, the composite material can effectively play a role in corrosion prevention and corrosion prevention in a plurality of complex environments.

Compared with the prior art, the invention has the following main advantages:

(1) the preparation method has the advantages of simple process, low cost, safety, environmental protection and the like.

(2) The preparation method does not mix impurity gas in the preparation process, the preparation process is easy to control, and the method is suitable for preparing the high-purity titanium carbide nanocrystal coating.

(3) The coating has the characteristics of moderate friction coefficient, strong bonding force with the matrix M42 steel and the like.

(4) The coating has high component purity, no redundant impurities and uniform size and structure.

(5) The composite material has moderate friction coefficient and is suitable for various mechanical fasteners.

(6) The composite material has excellent acid-base corrosion resistance and brine corrosion resistance, and is suitable for various ships in service in high-salinity and high-humidity marine environments.

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out according to conventional conditions or according to conditions recommended by the manufacturers. Unless otherwise indicated, percentages and parts are by weight.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present invention. The preferred embodiments and materials described herein are intended to be exemplary only.

Experimental materials

1. The 'M42 high-speed steel' is American AISI standard mark M42 steel, which corresponds to Chinese GB standard mark W2Mo9Cr4VCo8, German DIN standard mark S2-10-1-8 and Japanese JIS standard mark SKH 55. "M42 steel" is used interchangeably with "M42 high speed steel".

2. Methane refers to methane gas with a purity of 99.99%.

3. Titanium tetrachloride refers to a liquid having a purity of 99.99%.

4. The auxiliary gas is a gas having a purity of 99.99%.

EXAMPLE 1 composite 1 (titanium carbide nanocrystalline coating on M42 Steel surface 1)

The surface of M42 high-speed steel with the size of 10mm by 5mm is polished to remove rust, and the steel is washed by alcohol, dried and placed in a CVD furnace. CVD furnace evacuationHollow to 10^-1Pa, filling hydrogen, and the gas flow is 100 cssm. And starting a heating mode of the CVD furnace, wherein the heating target temperature is 990 ℃, and the heating rate is 15 ℃/min. Heating the CVD furnace to 900 ℃, starting a titanium tetrachloride pipeline for preheating, wherein the preheating temperature is 50 ℃. Heating the CVD furnace to 1010 ℃ to enter a heat preservation mode, preserving the heat for 40min, simultaneously introducing methane and titanium tetrachloride, wherein the flow rate of the methane is 500sccm, the titanium tetrachloride is loaded into the CVD furnace by taking hydrogen as carrier gas, and the flow rate of the carrier gas is 4000 sccm. After the CVD furnace finishes the heat preservation mode, the temperature is reduced at the cooling rate of 5 ℃/min, and simultaneously, the introduction of methane and titanium tetrachloride is stopped. And after cooling to room temperature, stopping introducing the hydrogen to obtain the titanium carbide nanocrystal coating 1 (namely the composite material 1) compounded on the surface of the M42 steel.

Results

The titanium carbide nanocrystalline coating 1 compounded on the surface of the M42 steel obtained in example 1 was subjected to SEM, EDS, XRD and other tests.

FIG. 1 shows: the titanium carbide nanocrystalline coating 1 compounded on the surface of the M42 steel obtained in the example 1 has a compact surface, and the crystal grains are in a nanometer level (less than 100 nm).

FIG. 2 shows: the titanium carbide nanocrystalline coating 1 compounded on the surface of the M42 steel obtained in example 1 has a dense surface and a thickness of about 1 um.

FIG. 3 shows: the titanium carbide nanocrystal coating 1 compounded on the surface of the M42 steel obtained in example 1 has a titanium carbide component.

The titanium carbide nanocrystal coating 1 compounded on the surface of the M42 steel obtained in example 1 was calculated to have titanium and carbon elements, wherein the titanium element content was about 76.32% by weight, and the carbon element content was about 23.68% by weight (as shown in table 1).

TABLE 1

Element(s)	Content by weight%	The content of elements%
			C	23.68	55.31
Ti	76.32	44.69
			Total up to	100.00

Through tests, the bonding force between the titanium carbide nanocrystal coating and the M42 steel substrate in the composite material 1 is 52N; the titanium carbide nanocrystalline coating has a coefficient of friction between 0.1 and 0.2.

EXAMPLE 2 composite 2 (titanium carbide nanocrystalline coating 2 on the surface of M42 Steel)

The surface of M42 high-speed steel with the size of 10mm by 5mm is polished to remove rust, and the steel is washed by alcohol, dried and placed in a CVD furnace. The CVD furnace is vacuumized to 10^-1Pa, filling hydrogen, and the gas flow is 100 cssm. And starting a heating mode of the CVD furnace, wherein the heating target temperature is 1010 ℃, and the heating rate is 5 ℃/min. Heating the CVD furnace to 910 ℃, starting a titanium tetrachloride pipeline for preheating, wherein the preheating temperature is 50 ℃. Heating the CVD furnace to 1020 ℃ to enter a heat preservation mode, preserving the heat for 60min, simultaneously introducing methane and titanium tetrachloride, wherein the flow rate of the methane is 750sccm, and the flow rate of the methane is fourThe titanium chloride was carried into the CVD furnace with hydrogen as a carrier gas at a flow rate of 3500 sccm. After the CVD furnace finishes the heat preservation mode, the temperature is reduced at the cooling rate of 9 ℃/min, and simultaneously, the introduction of methane and titanium tetrachloride is stopped. And after cooling to room temperature, stopping introducing the hydrogen to obtain the titanium carbide nanocrystal coating 2 (namely the composite material 2) compounded on the surface of the M42 steel.

Results

The titanium carbide nanocrystalline coating 2 compounded on the surface of the M42 steel obtained in example 2 was subjected to SEM, EDS and the like tests.

FIG. 4 shows: the titanium carbide nanocrystalline coating 2 compounded on the surface of the M42 steel obtained in the example 2 is compact in surface, and the particle size is in a nanometer level.

Through EDS measurement, the elements of the titanium carbide nanocrystal coating 2 compounded on the surface of the M42 steel obtained in example 2 are titanium element and carbon element, the content of the titanium element is about 75.72% by weight, and the content of the carbon element is about 24.28% by weight (as shown in Table 2).

TABLE 2

Through tests, the bonding force between the titanium carbide nanocrystal coating and the M42 steel substrate in the composite material 2 is 57N; the titanium carbide nanocrystalline coating has a coefficient of friction between 0.1 and 0.2.

COMPARATIVE EXAMPLE 1 COMPOSITE C1 (titanium carbide crystal coating on M42 steel surface C1)

The difference from example 1 is that: the holding temperature of the CVD furnace was 1030 ℃.

Results

The titanium carbide crystal coating C1 compounded on the surface of the M42 steel obtained in comparative example 1 is tested by SEM, EDS, XRD and the like.

As can be seen from fig. 5, the crystal grains C1 of the titanium carbide crystal coating compounded on the surface of the M42 steel obtained in comparative example 1 are tapered, the grain size is about 0.5um, and the grain size is significantly larger than that of the crystal grains of the titanium carbide nanocrystal coating 1 compounded on the surface of the M42 steel obtained in example 1.

As can be seen from fig. 6, the composition of the titanium carbide crystal coating C1 compounded on the surface of the M42 steel obtained in comparative example 1 was titanium carbide.

Through calculation, the elements of the titanium carbide crystal coating C1 compounded on the surface of the M42 steel obtained in the comparative example 1 are titanium element and carbon element, the content of the titanium element is about 66.36% by weight, and the content of the carbon element is about 33.64% by weight (as shown in Table 3).

TABLE 3

Element(s)	Content by weight%
		C	33.64
Ti	66.36
		Total up to	100.00

The titanium carbide nanocrystalline coating in composite C1 was tested to bind to the M42 steel substrate in a manner comparable to composites 1 and 2 obtained in examples 1 and 2, respectively, but the coefficient of friction of the titanium carbide crystalline coating was between 0.4 and 0.5, which is much greater than that of composites 1 and 2 and conventional fastener materials.

COMPARATIVE EXAMPLE 2 COMPOSITE C2 (titanium carbide crystal coating on M42 steel surface C2)

The difference from example 1 is that: the holding temperature of the CVD furnace is 990 ℃.

Results

The titanium carbide crystal coating C2 compounded on the surface of the M42 steel obtained in comparative example 2 is tested by SEM, EDS and the like.

As can be seen from fig. 7, flocculent impurities exist on the surface of the titanium carbide nanocrystals, and the impurities are determined to be titanium carbide nanowalls.

COMPARATIVE EXAMPLE 3 COMPOSITE C3 (titanium carbide crystal coating on M42 steel surface C3)

The difference from example 1 is that: the cooling rate after deposition is 12 ℃/min.

The titanium carbide crystal coating in the composite material C3 partially falls off, and the surface of the M42 steel matrix cannot be completely protected from acid, alkali and salt corrosion.

And, through testing, the bonding force of the titanium carbide nanocrystal coating and the M42 steel matrix is less than 10N.

COMPARATIVE EXAMPLE 4 COMPOSITE C4 (titanium carbide crystal coating on M42 steel surface C4)

The difference from example 2 is that: the methane flow rate was 1200 sccm.

SEM and EDS tests were performed on the titanium carbide crystal coating C4 obtained in comparative example 4 compounded on the surface of M42 steel.

FIG. 8 shows that the grains on the surface of the titanium carbide coating in the composite material C4 are columnar, and the grain size is 150-500 nm.

Through calculation, the elements of the titanium carbide crystal coating C4 compounded on the surface of the M42 steel obtained in the comparative example 4 are titanium element and carbon element, the content of the titanium element is about 66.36% by weight, and the content of the carbon element is about 33.64% by weight (as shown in the table 4).

TABLE 4

Element(s)	Content by weight%
		C	38.61
Ti	61.39
		Total amount:	100.00

all documents referred to herein are incorporated by reference into this application as if each were individually incorporated by reference. Furthermore, it should be understood that various changes and modifications of the present invention can be made by those skilled in the art after reading the above teachings of the present invention, and these equivalents also fall within the scope of the present invention as defined by the appended claims.

Claims

1. A preparation method of a titanium carbide nanocrystalline coating compounded on the surface of M42 steel is characterized by comprising the following steps:

2) placing the M42 high-speed steel into a CVD furnace, and heating the CVD furnace to a deposition heat preservation temperature under the auxiliary gas atmosphere; the deposition heat preservation temperature is 1000-1020 ℃;

3) introducing the carbon source and the titanium source into the heated CVD furnace, and preserving heat for a first time period; step 3) carrying out a coating deposition process, wherein in the step 3), the flow ratio of the auxiliary gas to the carbon source is 3-10; the coating is a titanium carbide nanocrystal coating;

4) cooling the CVD furnace to a second temperature at a first cooling rate, and stopping introducing the carbon source and the titanium source; the first cooling rate is 4-10 ℃/min;

2. The method of claim 1, wherein the carbon source is selected from the group consisting of: methane, ethane, propane, ethylene, propylene, acetylene, or combinations thereof; and/or

The titanium source comprises titanium tetrachloride.

3. The method of claim 1, wherein the deposition incubation temperature is 1005-1020 ℃.

4. The method of claim 1, wherein in step 3), the flow ratio of the assist gas to the carbon source is 4 to 9.

5. The method of claim 1, wherein in step 3), the first period of time is 20-100 min.

6. The method of claim 1, wherein in step 4), the first cooling rate is 5-9 ℃/min.

7. A composite material, characterized in that the composite material comprises:

a substrate; and

and the composite material is prepared by the preparation method of claim 1.

8. The composite material of claim 7, wherein the titanium carbide nanocrystalline coating has a coefficient of friction of 0.1 to 0.3; and/or

The bonding strength of the titanium carbide nanocrystal coating and the base material is more than or equal to 30N.

9. The composite material of claim 7, wherein the composite material has one or more characteristics selected from the group consisting of:

1) the grain size of the crystal grains forming the titanium carbide nanocrystal coating is less than 200 nm;

2) the thickness of the titanium carbide nanocrystal coating is 0.5-3 mu m;

10. An article selected from the group consisting of: corrosion resistant fastener, corrosion resistant coating material, characterized in that the article comprises or is made of a composite material according to claim 7.