CN106086886A - A kind of self-lubricating titanium diboride/diamond-like coating and its preparation method and application - Google Patents

Abstract

The invention discloses a self-lubricating titanium diboride (TiB ₂ )/diamond-like stone (DLC) hard coating and a preparation method thereof. The TiB ₂ /DLC hard coating is formed by periodically stacking the TiB ₂ ceramic layer and the DLC layer on the substrate by using bipolar pulse magnetron sputtering deposition technology, and the modulation period of the TiB ₂ /DLC hard coating is 15-60nm, the total thickness of the coating is 1.2-1.4μm. The TiB ₂ /DLC hard coating of the present invention combines the respective advantages of TiB ₂ and DLC, has excellent hardness and lubricating properties, and has good electrical conductivity, and the pulse magnetron sputtering deposition technology adopted at the same time is easy to operate, The process is simple, the preparation period is short, the cost is low, and it is convenient for large-scale industrial production, and can be widely used in the fields of cutting tools, moulds, microelectronics, protection and the like.

Description

A self-lubricating titanium diboride/diamond-like coating and its preparation method and application

technical field

The invention belongs to the field of surface protection technology and related coating technology, and relates to a self-lubricating multilayer coating, more specifically, to a titanium diboride (titanium diboride) with a periodic multilayer structure with high hardness and low coefficient of friction. TiB ₂ )/diamond-like carbon (DLC) coating and its preparation method and application.

Background technique

With the development of society and the advancement of industrial technology, the industrial field has put forward higher and higher requirements for the performance of materials. In many engineering applications, materials are required to have excellent comprehensive properties; not only high hardness and corrosion resistance are required , It is also required to have a low coefficient of friction, good high temperature stability, etc. In order to meet the increasingly complex and diverse engineering needs, a hard coating is applied on the surface of the material to improve the comprehensive performance of the material. A protective coating emerged as the times require. Hard coating can improve the surface properties of materials, reduce friction and wear with workpieces, effectively improve the surface hardness, toughness, wear resistance and high temperature stability of materials, and greatly increase the service life of coated products. Hard coating is an economical and practical means to improve the surface properties of materials, and currently plays an important role in machining, especially in metal cutting. Its development adapts to the high technical requirements of modern manufacturing industry for metal cutting tools, which has caused great changes in tool materials and performance, and can be widely used in machinery manufacturing, automobile industry, textile industry, geological drilling, mold industry, aerospace and other fields.

As a transition metal boride, titanium diboride (TiB ₂ ) has a series of excellent properties such as high hardness, high melting point, high wear resistance and corrosion resistance, good electrical conductivity and thermal conductivity, and excellent chemical stability. Physical and chemical properties, it is an advanced ceramic material with excellent structural properties and functional properties. Diamond-like coating (DLC) is a coating containing diamond components on the microstructure. The element that constitutes DLC is carbon, and carbon atoms are bonded in the form of sp ³ and sp ² bonds. Due to the diamond component, DLC has many excellent characteristics, such as: high hardness, low friction coefficient, excellent film Layer compactness, good chemical stability and good optical properties, etc. The special properties of DLC coatings applied to knives far exceed other hard coatings.

Due to the poor toughness of titanium diboride, it is easy to crack and fall off and fail when it is impacted, which limits its use efficiency and application field as a protective coating. At present, the commonly used hard coating toughening methods include multi-layer structure toughening and soft phase toughening. Due to the limitation of the structure and doping content, the coating performance changes periodically and becomes unstable, or the toughness increases while the hardness decreases greatly. Therefore, exploring hard and tough coatings has become an urgent technical problem in this field.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a multi-layer hard protective coating with high hardness, low stress, low friction coefficient and good toughness, which can be applied to the surface of mechanical parts, dies and other products. layer. That is to say, the combination of TiB ₂ and DLC is used, and the TiB ₂ layer and DLC layer are alternately deposited on the substrate to form a hard coating with a periodic multi-layer structure with high hardness and high friction resistance.

Another object of the present invention is to provide the preparation method of the self-lubricating titanium diboride TiB ₂ /diamond-like DLC hard coating, the preparation method has the advantages of convenient operation, simple process, short preparation period, low cost, and is convenient for large-scale industrialization production advantages.

Another object of the present invention is to provide the application of the self-lubricating titanium diboride TiB ₂ /diamond-like DLC hard coating in the fields of cutting tools, moulds, microelectronics and protection.

The above-mentioned purpose of the present invention is achieved through the following technical solutions:

A self-lubricating titanium diboride TiB ₂ /diamond-like DLC coating, the TiB ₂ /DLC coating is made of TiB ₂ ceramic target and graphite target, and is alternately sputtered on the substrate by multi-target magnetron sputtering The deposition is formed by periodic superimposition of TiB ₂ nano-ceramic layer and DLC nano-layer.

Preferably, the TiB ₂ ceramic target is a planar target, the atomic ratio of Ti and B is 1:2, and the purity is 99.99%; the graphite target is a columnar target, and the purity is 99.99%.

Preferably, the substrate is one of cemented carbide, single crystal silicon wafer, aluminum oxide wafer or glass.

Preferably, the substrate is in contact with the TiB ₂ nano-layer, the DLC nano-layer is the outermost layer, and the total thickness of the TiB ₂ /DLC hard coating is 1.2-1.4 μm.

Preferably, the thickness of the DLC layer is 5-10 nm/layer, the thickness of the TiB ₂ layer is 10-50 nm/layer, and the total number of layers of DLC and TiB ₂ in the TiB ₂ /DLC hard coating is 20-20 nm. 80 floors.

A preparation method of the above-mentioned self-lubricating TiB ₂ /DLC hard coating, comprising the following specific steps:

S1. Cleaning the substrate: Send the polished substrate into an ultrasonic cleaning machine, and then use acetone and absolute ethanol to perform ultrasonic cleaning at 15-30kHz for 10-20 minutes, then clean it with deionized water, and then clean it with a purity of ≥99.5%. Blow dry with nitrogen;

S2. Vacuumize and ion beam etch to clean the coating chamber: place the ultrasonically cleaned substrate on the workpiece support in the vacuum chamber, pump it down to a vacuum degree below 5.0×10 ^-3 Pa, then turn on the ion source, and pass through the ion source. Inject 80-100sccm argon gas, set the power of the ion source to 0.9kW, set the bias voltage of the workpiece support to -300--500V, and the etching cleaning process lasts for 20-30min;

S3. Ion beam etching substrate: place the substrate in front of the ion source, set the bias voltage to -300~-500V, and work for 15~20 minutes;

S4. Preparation of TiB ₂ /DLC hard coating: adopt bipolar pulse magnetron sputtering method, set the parameters of the substrate and the support, the distance between the target and the substrate, feed argon gas of 80-100 sccm, and control the vacuum chamber pressure to 0.5 ~0.6Pa, turn on and set the power supply parameters, in which the TiB ₂ ceramic target is A target, and the graphite target is B target, and the sample baffle is placed in front of the TiB ₂ ceramic target and graphite target, start glow, and pre-sputter for 10-15 minutes Afterwards, the sample shutter was opened, and the TiB ₂ /DLC hard coating was sputtered and deposited for 3 hours.

S5. After the deposition is completed, turn off the power, wait for the temperature of the vacuum chamber to drop to room temperature, fill the vacuum chamber with air, open the vacuum chamber to take out the sample, and form a TiB ₂ /DLC hard coating on the surface of the substrate.

Preferably, the substrate and support parameters in step S4 are: substrate bias voltage -100--300V, support rotation 3rpm/min, revolution 2-5rpm/min, deposition temperature 300°C.

Preferably, the parameters of the power supply in step S4 are: frequency 40kHz, power 3-4kW, and duty cycle of the A target pulse power supply 25-75%.

Preferably, the distance between the target and the substrate in step S4 is 6-10 cm.

The application of the self-lubricating titanium diboride/diamond-like hard coating in the field of surface protection of cutting tools, molds and microelectronics is also within the protection scope of the present invention.

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

1. The TiB ₂ /DLC hard coating of the present invention has a periodic multilayer structure, has both high hardness and good toughness, and TiB with good anti-friction, wear performance, electrical conductivity and chemical corrosion resistance ₂ /DLC hard coating. Among them, _TiB2 has a hexagonal crystal structure and (001) preferred orientation; the DLC layer contains a certain number of ^SP3 bonds. Due to the addition of the DLC layer, the TiB ₂ /DLC coating has high hardness and a low friction coefficient, and its friction coefficient with the GCr15 steel ball is lower than 0.30, thus showing excellent friction resistance, and can be used as a protective coating for With high friction resistance and high hardness engineering occasions, it can be used in the surface protection field of cutting tools, molds and microelectronics.

2. The preparation of the TiB ₂ /DLC hard coating with a nano-layer structure in the present invention has the advantages of convenient operation, simple process, short preparation period, low cost, and is convenient for large-scale industrial production.

Description of drawings

FIG. 1 is a schematic diagram of the structure of the TiB ₂ /DLC coating prepared in Example 1.

FIG. 2 is the XRD pattern of the TiB ₂ /DLC coating prepared in Example 1.

FIG. 3 is a surface SEM image of the TiB ₂ /DLC coating prepared in Example 1. FIG.

FIG. 4 is a scratch topography diagram of the TiB ₂ /DLC coating prepared in Example 1. FIG.

detailed description

The content of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but it should not be construed as a limitation of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

Example 1

1. Preparation:

S1. Cleaning the substrate: send the polished WC-Co cemented carbide substrate into an ultrasonic cleaning machine, and use acetone and absolute ethanol to perform ultrasonic cleaning at 30kHz for 10 minutes, then clean it with deionized water, and then clean it with purity ≥ 99.5% nitrogen blow dry.

S2. Vacuuming and ion beam etching to clean the cavity and substrate: the ion coating machine is equipped with a TiB ₂ planar target and a graphite columnar target, and the coating chamber is cleaned with a high-power vacuum cleaner. Place the ultrasonically cleaned substrate on the workpiece support in the vacuum chamber, pump it down to a vacuum below 5.0×10 ^-3 Pa, then turn on the ion source, feed 80 sccm argon gas into the ion source, set the ion source power to 0.9kW, and set the workpiece The stent is biased at -300V, and the etch cleaning process lasts for 20 minutes.

S3. Ion beam etching substrate: rotate the turret, place the substrate in front of the ion source, set the bias voltage to -500V, and work for 20 minutes.

S4. Introduce 80 sccm of argon gas, control the vacuum chamber pressure to 0.56Pa, adopt the method of bipolar pulse magnetron sputtering, TiB2 ceramic target is _A target, graphite target is B target, the distance between the target and the substrate is 10cm, set The substrate and support parameters are: substrate bias -100V, support rotation 3rpm/min, revolution 2rpm/min, set deposition temperature 300°C. Turn on and set the power supply parameters as follows: frequency 40kHz, power 4kW, duty cycle of A target pulse power supply is 75%. The sample baffle was transferred in front of the two sputtering targets, ignited, and after pre-sputtering for 10 minutes, the sample baffle was opened, and the formal sputtering deposition of the TiB ₂ /DLC multilayer coating was started, and the deposition time was 3 hours.

S5. After the deposition is completed, turn off the power, wait until the temperature of the vacuum chamber drops to room temperature, fill the vacuum chamber with air, open the vacuum chamber to take out the sample, and form a periodic multilayer TiB ₂ /DLC coating on the surface of the WC-Co cemented carbide substrate .

2. Performance test:

Fig. 1 is a schematic diagram of the TiB ₂ /DLC coating structure. Among them, the thickness of the DLC layer is 5-10nm/layer, the thickness of the TiB ₂ layer is 10-50nm/layer, and the total number of DLC and TiB ₂ layers in the TiB ₂ /DLC hard coating is 20-80 layers. Figure 2 is the XRD pattern of TiB ₂ /DLC coating, it can be seen that TiB ₂ is well crystallized and has a preferred orientation of 001, while DLC is amorphous. Figure 3 is the SEM image of the surface of the TiB ₂ /DLC coating, from which it can be seen that the surface of the coating is smooth without obvious particle agglomeration, and the results show that the surface of the coating grows well and is dense and uniform.

The prepared TiB ₂ /DLC coating sample was analyzed and tested, and the hardness and elastic modulus of the coating were tested with Anton Paar NHT2 nano-indenter. The results showed that the TiB ₂ /DLC coating exhibited good toughness and elastic recovery The measured coating hardness reaches 35Gpa; the friction coefficient measured by the HSR-2M coating friction and wear tester is 0.19, and no failure is seen after the sample is worn for 1 hour, which shows that the TiB ₂ /DLC coating has good Anti-friction and wear properties. The residual compressive stress of the coating is 0.5Gpa measured by the Supu thin film stress instrument; the test results of the Anton Paar MST nano-scratch instrument are shown in Figure 4, and Figure 4 is the scratch morphology of the TiB ₂ /DLC coating. It can be seen that as the load increases, the scratches gradually become wider, and the depth increases with the increase of the load. The results show that the TiB ₂ /DLC coating exhibits good toughness with little hardness loss. The combined critical load of the coating film base reaches 10GPa, and the coating has excellent adhesion performance; finally, the prepared TiB ₂ /DLC coating is tested for acid and alkali resistance at room temperature, and the results show that the TiB ₂ /DLC coating has good chemical stability.

Example 2

S1. Cleaning the substrate: Send the polished (100)-oriented single crystal silicon substrate into an ultrasonic cleaning machine, perform ultrasonic cleaning with acetone and absolute ethanol at 30kHz for 10min, then rinse with deionized water, and then rinse with deionized water. Nitrogen with a purity ≥ 99.5% is blown dry.

S2. Vacuuming and ion beam etching to clean the cavity and substrate: the ion coating machine is equipped with a TiB ₂ planar target and a graphite columnar target, and the coating chamber is cleaned with a high-power vacuum cleaner. Place the ultrasonically cleaned substrate on the workpiece support in the vacuum chamber, evacuate the vacuum chamber to a vacuum below 5.0×10 ^-3 Pa, then turn on the ion source, feed 80 sccm argon gas into the ion source, and set the ion source power to 0.9kW , set the bias voltage of the workpiece support to 300V, and the etching and cleaning process lasts for 20 minutes.

S3. Ion beam etching substrate: rotate the turret, place the substrate in front of the ion source, set the bias voltage to -500V, and work for 20 minutes.

S4. Introduce 80sccm of argon gas, control the vacuum chamber pressure to 0.56Pa, adopt the method of bipolar pulse magnetron sputtering, TiB ₂ ceramic target is A target, graphite target is B target, the distance between the target and the substrate is 6cm, set The substrate and support parameters are: substrate bias -300V, support rotation 3rpm/min, revolution 5rpm/min, set deposition temperature 300°C. Turn on and set the power supply parameters as follows: frequency 40kHz, power 4kW, duty cycle of A target pulse power supply 25%. The sample baffle was transferred in front of the two sputtering targets, ignited, and after pre-sputtering for 15 minutes, the sample baffle was opened, and the formal sputter deposition of the TiB ₂ /DLC multilayer coating was started, and the deposition time was 3 hours.

S5. After the deposition is completed, turn off the power, wait until the temperature of the vacuum chamber drops to room temperature, fill the vacuum chamber with air, open the vacuum chamber to take out the sample, and form a periodic multilayer structure of TiB ₂ /DLC on the surface of the (100)-oriented single crystal silicon substrate. layer.

The above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes in various forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (10)

1. A self-lubricating titanium diboride TiB2/diamond _- like DLC hard coating, is characterized in that, described _TiB2 /DLC coating is to be raw material with TiB2 ceramic target and graphite target, through multi _- target magnetron Alternate sputtering deposition on the substrate is formed by periodically superimposing TiB ₂ nano-ceramic layers and DLC nano-layers. 2. self-lubricating titanium diboride/diamond-like hard coating according to claim 1, is characterized in that, described TiB ₂ ceramic target is planar target, and the atomic ratio of Ti and B is 1: 2, and purity is 99.99%; the graphite target is a columnar target with a purity of 99.99%. 3. The self-lubricating titanium diboride/diamond-like hard coating according to claim 1, wherein the substrate is one of cemented carbide, single crystal silicon wafer, aluminum oxide wafer or glass. 4. according to the described self-lubricating titanium diboride/diamond-like hard coating of claim 1, it is characterized in that, described substrate is in contact with TiB ₂ nanometer layer, and described DLC nanolayer is the outermost layer, TiB ₂ /DLC The total thickness of the hard coating is 1.2-1.4 μm. 5. self-lubricating titanium diboride/diamond-like hard coating according to claim 1, is characterized in that, the thickness of described DLC layer is 5～10nm/layer, and the thickness of TiB2 layer is ₁₀ ～50nm/layer , the total number of layers of DLC and TiB ₂ in the TiB ₂ /DLC hard coating is 20-80 layers. 6. A method for preparing the self-lubricating TiB ₂ /DLC hard coating according to any one of claims 1-5, characterized in that it comprises the following specific steps: S1. Cleaning the substrate: Send the polished substrate into an ultrasonic cleaning machine, and then use acetone and absolute ethanol to perform ultrasonic cleaning at 15-30kHz for 10-20 minutes, then clean it with deionized water, and then clean it with a purity of ≥99.5%. Blow dry with nitrogen; S2. Vacuumize and ion beam etch to clean the coating chamber: place the ultrasonically cleaned substrate on the workpiece support in the vacuum chamber, pump it down to a vacuum degree below 5.0×10 ^-3 Pa, then turn on the ion source, and pass through the ion source. Inject 80-100sccm argon gas, set the power of the ion source to 0.9kW, set the bias voltage of the workpiece support to -300--500V, and the etching cleaning process lasts for 20-30min; S3. Ion beam etching substrate: place the substrate in front of the ion source, set the bias voltage to -300~-500V, and work for 15~20 minutes; S4. Preparation of TiB ₂ /DLC hard coating: adopt bipolar pulse magnetron sputtering method, set the parameters of the substrate and the support, the distance between the target and the substrate, feed argon gas of 80-100 sccm, and control the vacuum chamber pressure to 0.5 ~0.6Pa, turn on and set the power supply parameters, in which the TiB ₂ ceramic target is A target, and the graphite target is B target, and the sample baffle is placed in front of the TiB ₂ ceramic target and graphite target, start glow, and pre-sputter for 10-15 minutes Afterwards, the sample shutter was opened, and the TiB ₂ /DLC hard coating was sputtered and deposited for 3 hours. S5. After the deposition is completed, turn off the power, wait for the temperature of the vacuum chamber to drop to room temperature, fill the vacuum chamber with air, open the vacuum chamber to take out the sample, and form a TiB ₂ /DLC hard coating on the surface of the substrate. 7. The preparation method according to claim 6, wherein the parameters of the substrate and the support in step S4 are: substrate bias -100 to -300V, support rotation 3 rpm/min, revolution 2 to 5 rpm/min, setting The deposition temperature is 300°C. 8 . The preparation method according to claim 6 , wherein the power supply parameters in step S4 are: frequency 40 kHz, power 3-4 kW, duty cycle of A target pulse power supply 25-75%. 9. The preparation method according to claim 6, wherein the distance between the target and the substrate in step S4 is 6-10 cm. 10. The application of the self-lubricating titanium diboride/diamond-like coating of claims 1-6 in the field of surface protection of cutting tools, molds and microelectronics.