CN107326360A - A kind of erosion resistant coating structure of nanometer multilayer graded composite and preparation method thereof - Google Patents

Abstract

The invention discloses a nanometer multi-layer gradient composite anti-erosion coating structure. From the substrate to the coating surface, the coating structure sequentially contains a nitriding layer, an "embedded bonding layer" and a Ti metal layer, a Ti metal layer, and a Ti metal layer. →The structure composed of TiN gradient layer and TiN/Ti nanometer multi-layer cycle stacking. In addition, the invention discloses a preparation method of the above-mentioned coating structure: through surface nitriding, the material properties of the substrate surface and sub-surface are similar to those of the coating material, so as to alleviate the stress concentration phenomenon at the junction of the film base; using metal vacuum vapor ion The source implantation method is to implant ions on the surface of the substrate after nitriding to form an "embedded bonding layer"; on the bonding layer, the magnetic filter vacuum cathodic arc deposition method is used to deposit Ti by continuously controlling the input _N2 flow rate. A periodic cycle structure composed of metal layer, Ti→TiN gradient layer and TiN/Ti nanometer multilayer in sequence. The nano-gradient multilayer composite coating structure has both high hardness, high toughness and excellent film-base bonding force, so it has good erosion resistance performance.

Description

A kind of anti-erosion coating structure and preparation method of nanometer multi-layer gradient composite

technical field

The invention relates to the technical field of material surface modification, in particular to an anti-erosion composite coating which integrates a nitriding structure, an ion implantation structure, a nano-multilayer structure and a gradient structure, and has high film-base bonding force and high toughness structure; and the corresponding coating preparation method that effectively combines various surface strengthening treatment technologies such as surface nitriding, ion implantation and magnetic filtration vacuum cathode arc plasma deposition.

Background technique

Helicopters are indispensable and important equipment for my country's land aviation, sea aviation, and airborne troops to carry out diverse combat tasks such as ground attack, fire suppression, and logistics transportation in complex ground environments. The site is usually very simple, even temporary sand, earth or grass. When the helicopter takes off and lands and flies at low altitude in a dusty environment, the downwash airflow of the rotor will make the dust particles on the ground mix with the air. First, through the compressor, it will cause erosion and wear to the high-speed moving compressor rotor blades, and at the slightest, the blades will have problems such as increased surface roughness, curved leading edge, shortened chord length and reduced thickness, resulting in the pressurization of the compressor. Ratio, efficiency, and flow capacity are reduced, which in turn causes the overall parameters of the engine to attenuate, affecting its comprehensive combat performance; in severe cases, sand and dust erosion will also cause structural damage such as pits, bulges, gaps, and cracks on the blade surface, destroying the The structural integrity of the blade changes the natural frequency of the blade, reduces the fatigue strength of the blade, and seriously threatens the reliability and safety of the engine.

According to statistics, the sand and dust environment accounts for more than 50% of my country's total land area, mainly including fine sand in the northwest Taklimakan region, large areas of coarse sand in the southwest region, and beaches in the southeast coastal region. However, the northwest region has perennial problems of counter-terrorism and stability maintenance. The southwest region often has local conflicts that disrupt social stability. The southeast region needs to be always prepared to fight against secession and safeguard national sovereignty. Therefore, no matter from the perspective of national economy or national defense security, how to improve the anti-sand erosion of helicopter engine compressor blades is extremely important and urgent.

Coating is an effective measure to improve the anti-sand erosion performance of aeroengine compressor blades. In the early stage of research, the hardness of the coating was considered to be the key to improving its erosion resistance. The US military also prepared a high-hardness TiN ceramic coating on the surface of the blade in order to improve the sand and dust erosion resistance of the compressor blade. However, During the Gulf War and the Afghanistan War, it was found that the compressor blades with high hardness ceramic coatings were still severely damaged. It can be seen that a single-layer coating with simple structure and single performance cannot meet the sand and dust protection requirements of aeroengine compressor blades. Therefore, a ceramic/metal multilayer coating in which a metal material is added to a high-hardness ceramic coating and ceramic layers and metal layers are alternately arranged comes into being. Studies have shown that compared with the single-layer structure, the addition of the metal layer reduces the hardness of the coating and improves the overall toughness of the coating to a certain extent. However, there are a large number of interlayer interfaces in the traditional multi-layer structure. Due to the interface The material properties on both sides are very different, which is easy to cause stress concentration, and then initiate interlayer cracks, which eventually lead to peeling off of the coating. In order to solve the stress concentration problem caused by the different material properties on both sides of the interface between layers in the multilayer coating structure, gradient coating has become a research hotspot of scholars. This type of coating structure is based on real-time and continuous control of the input gas flow during the coating deposition process, so that a special gradient structure is formed between the metal layer and the ceramic layer, and there is no interlayer interface with sudden changes in material properties. , which can effectively eliminate the problem of stress concentration at the interface between layers. With the development of nano science and technology, due to the unique "superhard effect" and superior mechanical properties of nanostructures, nano coatings have become an important development direction of hard coating materials.

In addition to the structural characteristics of the coating itself, the bonding force between the coating and the substrate is also an important factor affecting the erosion resistance of the coating. At present, most scholars are adding a layer of transition metal Ti between the TiN ceramic layer and the substrate in order to improve the bonding force of the coating. Although this method helps to release the internal stress between the ceramic layer and the substrate, it can be used in To a certain extent, the bonding force of the film base is improved, but because there is still an obvious interlayer interface between the Ti layer and the substrate, the bonding force of the film base still cannot meet the requirements of sand and dust erosion resistance. Nitriding technology can modify the surface of the substrate, so that the material properties of the substrate surface and its subsurface are similar to those of the coating material, so as to alleviate the stress concentration at the junction of the membrane and base, and lay the foundation for the improvement of the bonding force of the membrane. In addition, ion implantation is also a surface modification technology with unique characteristics. It ionizes selected elements into charged ions in a vacuum container and makes them undergo high voltage of tens of thousands or even hundreds of thousands of volts. Accelerated and implanted into the subsurface of the substrate as energy-carrying ions to form an "embedded bonding layer". This structure can effectively connect the substrate and the coating closely together to obtain ultra-high bonding force of the film substrate.

Contents of the invention

In view of the above-mentioned technical background, one of the purposes of the present invention is to combine the advantages of nitriding structure, ion implantation structure, nano-multi-layer structure and gradient structure, and propose a kind of anti-erosion nano-multi-layer with high film-base bonding force and high toughness Gradient composite coating structure; at the same time, through the effective combination of surface nitriding, ion implantation and magnetic filtration vacuum cathode arc deposition, magnetic filtration vacuum cathode arc sputtering and other surface strengthening treatment technologies, a method for preparing the above-mentioned nano-multilayer gradient composite is proposed. Methods for Erosion Resistant Coatings. Concrete invention content is as follows:

1. The coating structure includes a nitriding structure, an "embedded bonding layer", a nano-multilayer structure and a gradient structure. From the substrate to the surface of the coating, there are nitrided layer, ion implanted layer, and a repeating structure composed of Ti metal layer, Ti→TiN gradient layer and TiN/Ti nano-multilayer structure. An anti-erosion coating structure with gradient layers; the repeating structure is stacked n times repeatedly, and the value range of n is a positive integer greater than 0.

2. The depth of the surface nitriding layer is 20-50um; the implantation depth of the embedded bonding layer is 60-200nm. The preferred range is 100 to 160 nm.

3. In one or more repeating structures of the composite coating structure, the thickness ratio of the metal Ti layer, the Ti→TiN gradient layer and the TiN/Ti nano-multilayer structure is 1: (0.5～3): (0.5～ 9);

4. In the TiN/Ti nano-multilayer structure, the thicknesses of the Ti layer and the TiN layer are both greater than 10 nm and not more than 100 nm, and the thickness ratio is 1: (0.5-9);

5. The total thickness of the composite coating structure is 18-24um;

6. In the composite coating structure, a repeating structure composed of Ti metal layer, Ti→TiN gradient layer, and TiN/Ti nanometer multi-layer sequentially stacked is stacked n times, and the value range of n is 0 <n≤10 positive integer.

7. The substrate is one or more of stainless steel, TC11 and TC4 substrates.

8. Combining surface nitriding, metal vacuum vapor ion source implantation, magnetic filtration vacuum cathode arc deposition, magnetic filtration vacuum cathode arc sputtering and compilable flow controller technologies. The surface nitriding technology can make the substrate surface and subsurface The material properties of the coating material are similar to those of the coating material, so as to alleviate the stress concentration phenomenon at the junction of the film base; the metal vacuum vapor ion source implantation method is used to perform ion implantation on the substrate surface after nitriding to form an "embedded bonding layer"; Filtration vacuum cathodic arc deposition method and compilable flow controller, by continuously controlling the input N2 flow rate, Ti metal layer, Ti→TiN gradient layer, TiN ceramic layer and TiN/Ti nano-multilayer structure can be prepared sequentially; magnetic filtration vacuum cathode The arc sputtering technology is to avoid excessive internal stress in the coating and affect its comprehensive performance.

9. The specific preparation method of each layer structure includes the following steps using glow plasma nitriding technology to carry out surface nitriding treatment on the substrate, the nitriding gas is NH ₃ , the glow voltage is 700-1000V, and the current is 12-15A. The vacuum degree in the furnace is 100-150Pa, the nitriding temperature is 300°C, and the nitriding time is 1-4h;

1) The specific preparation method of each layer structure includes the following steps using glow plasma nitriding technology to carry out surface nitriding treatment on the substrate, the nitriding gas is NH ₃ , the glow voltage is 700-1000V, and the current is 12-15A. The vacuum degree in the furnace is 100-150Pa, the nitriding temperature is 300°C, and the nitriding time is 1-4h; if the following parameters can be optimized, please give the preferred range.

2) The ion implantation bonding layer is prepared by metal vacuum vapor ion source implantation method, which is characterized in that: the degree of vacuum is 1.0×10 ^-4 ~ 1.0×10 ^-3 Pa, the implantation voltage is 8~15kV, and the beam intensity is 4~8mA , the total dose of implanted ions is 1.0×10 ¹⁵ ~1.0×10 ¹⁶ /cm ^-2 ;

3) The Ti metal layer is prepared by magnetic filtration vacuum cathodic arc deposition method, which is characterized in that: a 90° magnetic filtration elbow is used, the magnetic field current is 2 to 4A, and the vacuum degree is 1.0×10 ^-4 to 1.0×10 ^-3 Pa. The arc current is 100-110A, the negative bias voltage is 200-250V, the duty cycle is 85%-90%, and the beam current intensity is 700-800mA;

4) Combining the magnetic filtration vacuum cathodic arc deposition method and the compilable flow controller, the metal Ti _→ TiN gradient structure is prepared by continuously controlling the input N flow rate, which is characterized in that: a 90° magnetic filtration elbow is used, and the vacuum degree is 1.0 ×10 ^-4 ～5.0×10 ^-3 Pa, the arcing current is 100～110A, the negative bias voltage is 200～250V, the duty cycle is 85%～90%, the beam current intensity is 700～800mA, and the N ₂ flow rate is above Proportional function (y=kt, k>0), quadratic function (incremental part y=at ² , a>0) or sine function (incremental part y=nsin2πft, n=20～32, ) gradually increases from 0sccm to 20-32sccm, and the preferred flow rate is 26sccm;

5) Combining the magnetic filtration vacuum cathodic arc deposition method and the programmable flow controller, by controlling the N ₂ flow rate to switch between the maximum flow rate (20-32 sccm) and 0 sccm in a rapid cycle. Preparation of TiN/Ti nano multi-layer structure, characterized in that: using a 90° magnetic filter elbow, the vacuum degree is 1.0×10 ^-4 ~ 5.0×10 ^-3 Pa, the arcing current is 100 ~ 110A, and the negative bias is 200 ～250V, duty cycle 85%～90%, beam intensity 700～800mA;

6) In the preparation process, in order to avoid the formation of excessive internal stress inside the coating and affect its erosion resistance, in the preparation process except surface nitriding and ion implantation, the method of magnetic filter cathode vacuum arc sputtering is adopted , Ti sputtering is carried out every 30 to 40 minutes, the _N2 flow rate during sputtering is 0sccm, the arcing current is 110 to 120A, the negative bias voltage is -800V, -600V and -400V in turn, and the duty cycle is 85% ~90%, and keep for 30~40s under each negative bias.

10. Use 400-600, 800-1000, 1200, and 2000-mesh sandpaper in sequence to roughly grind and finely grind the TC4 substrate sample until there are no obvious horizontal and vertical grinding marks, and then use polishing flannelette and diamond polishing paste to finely grind the sample. The sample is polished until the surface roughness of the sample reaches Ra=0.02±0.005 μm.

The polished substrate must be ultrasonically cleaned twice with absolute ethanol and acetone before clamping and coating, each time for 10 minutes, and quickly dried with high-purity nitrogen.

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

1. Compared with the traditional single multilayer structure, gradient structure or nanostructure, the anti-erosion coating structure of the nano-multilayer gradient compound proposed by the present invention, the present invention analyzes the advantages of various coating structures, Combining the characteristics of various surface strengthening treatment technologies, a composite coating structure integrating nitriding structure, ion implantation structure, nano-multilayer structure and gradient structure is proposed. The coating structure not only combines high film-base bonding force and superhard properties of the nano-multilayer structure, but also solves the stress concentration caused by the difference in material properties on both sides of the interlayer interface in the multilayer structure. Therefore, the impact toughness is also very good, especially suitable for depositing on the blades of the compressor of the helicopter engine to resist the high-speed erosion of sand and dust particles, and has great application value.

2. The present invention proposes a set of preparation methods for depositing the nano-multilayer gradient composite coating. Compared with traditional PVD deposition methods such as magnetron sputtering and ion plating, the preparation method proposed in the embodiments of the present invention effectively combines Various surface strengthening treatment technologies such as surface nitriding, ion implantation, and magnetic filtration vacuum cathode arc plasma deposition, among which surface nitriding makes the material properties of the substrate surface and its subsurface similar to that of the coating material, so as to alleviate the damage at the junction of the film and substrate. The phenomenon of stress concentration lays the foundation for the improvement of the bonding force of the membrane base; in ion implantation technology, energy-carrying ions are implanted into the subsurface of the substrate, so that the subsurface of the substrate and the implanted ions form metal-substrate atoms mixed with each other, without strengthening the interface Bonding layer, this "embedded bonding layer" can effectively make the substrate and coating closely connected together to obtain super high film-base bonding force. The existence of the magnetic filter elbow can filter out almost all neutral particles, liquid droplets and large particles, which is beneficial to improve the compactness, purity and surface roughness of the film layer.

3. The present invention proposes to perform Ti sputtering every 40 minutes during the film deposition process. The addition of this process can partially release the internal stress in the deposited film on the one hand, and on the other hand, due to the sputtering process, The negative bias voltage of the substrate is set very high (-800V, -600V and -400V in turn), and the titanium ions are rapidly accelerated and hit the surface of the substrate to heat up the substrate to reduce the generation of internal stress in the subsequent deposition process, thereby improving Overall toughness and erosion resistance of composite coatings.

Description of drawings

Fig. 1 is a schematic view of the coating structure of the present invention;

Fig. 2 is a comparison of the coating provided by Example 3 of the present invention and a traditional multi-layer coating (comparative example 1) film base binding force. Wherein (a) figure is the scratch method acoustic emission signal of a certain traditional multi-layer coating, (b) figure is the scratch method acoustic emission signal of the coating proposed in embodiment 3 of the present invention, by comparing two kinds of coatings through scratching It can be known from the acoustic emission signal tested by the method that the film base binding force of the traditional coating is about 58N, while the film base binding force of the coating prepared in the embodiment of the present invention can reach 95N, which is improved compared with the film base binding force of the traditional multilayer coating. up about 70%.

Fig. 3 compares the Rockwell indentation appearance of the coating provided by the embodiment of the present invention and the traditional multilayer coating, wherein (a) figure is the Rockwell indentation appearance of the traditional coating (comparative example 1), (b ) The figure shows the Rockwell indentation appearance of the coating proposed by the present invention. After comparing the Rockwell indentation appearance of the two coatings, and counting the crack length and quantity around the indentation, it is found that under the same loading conditions, the traditional There is obvious brittle peeling phenomenon around the indentation of the multilayer coating, and the crack length and quantity around the indentation are also obviously more than the coating (embodiment 1) proposed by the present invention, thus it can be known that the coating proposed by the present invention The toughness is much better than that of traditional multi-layer coatings.

Fig. 4 is a comparison chart of nanohardness and microhardness values of various examples in the present invention. It can be seen from the figure that the coating examples proposed by the present invention (Examples 1-3) have higher nanohardness and microhardness values than the traditional multilayer coating (Comparative Example 1), which are about 60% higher.

Fig. 5 is a comparison chart of the average mass loss rate of each embodiment of the present invention under the action of sand and dust erosion. As can be seen from the figure, the mass loss rate of the coating embodiments (embodiments 1-3) proposed by the present invention has been reduced by about 90% compared with traditional multilayer coatings (comparative example 1), and has very high erosion resistance performance.

detailed description

Several embodiments (embodiments 1 to 3) of the high erosion resistance gradient multilayer composite coating structure and preparation method thereof of the present invention will be described in detail below, as well as a preparation example (comparative example) of a traditional multilayer coating 1) The specific implementation steps are as follows:

Example 1:

1) Polishing and cleaning of the substrate

Use 400-600, 800-1000, 1200 and 2000 mesh sandpaper in turn to rough and finely grind the TC4 substrate sample until there are no obvious horizontal and vertical grinding marks, and then use polishing flannelette and diamond polishing paste to polish the finely ground sample Process until the surface roughness of the sample reaches Ra=0.02±0.005 μm.

The polished substrate must be ultrasonically cleaned twice with absolute ethanol and acetone before clamping and coating, each time for 10 minutes, and quickly dried with high-purity nitrogen.

2) surface nitriding treatment

The process of nitriding the surface of the substrate is as follows: using glow plasma nitriding technology, nitriding the surface of the substrate, the nitriding gas is NH ₃ , the glow voltage is 800V, the current is 13A, and the vacuum in the furnace is 100Pa , Nitriding temperature is 400 ℃, nitriding time is 1h.

3) Preparation of "Embedded Bonding Layer"

The preparation of "embedded bonding layer" on the surface and subsurface of the substrate includes three steps:

Firstly, using metal vacuum vapor ion source (MEVVA), a certain amount of Ti element is pre-implanted on the substrate surface after nitriding treatment, the pre-implantation voltage is 8.2kV, the beam current is 5A, and the implantation dose is 5.6×10 ¹⁴ /cm ² ; then close the metal vacuum vapor ion source, utilize the magnetic filter vacuum arc deposition system (FCVA) to deposit a layer of nano-scale metal Ti on the surface of the substrate, the substrate bias of the deposited nano-Ti layer is-200V, and the duty cycle is 90 %, the arcing current is 100mA, the magnetic filter electric field current is 2.0A, the voltage is 24.2V, and the deposition time is 10s; finally, the metal vacuum vapor ion source (MEVVA) is used to increase the injection voltage, and inject A large dose of Ti element is used to finally form an "embedded bonding layer" that improves the bonding force of the membrane base. At this time, the implantation voltage of Ti ions is 12kV, the beam current is 5.8mA, and the implantation dose is 8.2×10 ¹⁴ /cm ² .

4) Metal transition Ti layer deposition

The metal Ti transition layer was deposited on the "embedded bonding layer" using a magnetic filter vacuum arc deposition (FCVA) system. The specific process parameters are as follows: magnetic filter current: 2.0A, voltage: 24.2V, vacuum degree: 8.0×10 ^{- 4} Pa, the starting current is 100A, the negative bias voltage is -200V, the duty cycle is 90%, the beam intensity is 700mA, and the deposition time is 30mins;

5) Ti→TiN gradient structure deposition

A magnetic filtered vacuum arc deposition (FCVA) system is used to continuously control the input _N2 flow through a programmable flow controller in real time, and a gradient structure gradually transforming from metallic Ti to ceramic TiN is deposited on the metal transition layer. The specific process parameters are as follows: the degree of vacuum is 8.0×10 ^-4 ~5.0×10 ^-3 Pa, the arcing current is 100A, the negative bias voltage is 200V, the duty cycle is 90%, the beam intensity is 700mA, and the _N2 flow rate is The form of the proportional function y=0.007t (t represents the deposition time) gradually increases from 0 sccm to 26 sccm, and the deposition time is 60 mins.

6) TiN/Ti nano multilayer structure deposition

Utilize the magnetic filtration vacuum arc deposition (FCVA) system, through the compilable flow controller, realize the step type cycle switch between 26sccm and 0sccm _two kinds of flows to the input N flow, the specific process parameters are as follows: the vacuum degree is 1.0 ×10 ^-4 ～5.0×10 ^-3 Pa, the arcing current is 100A, the negative bias voltage is 200V, the duty cycle is 90%, the beam current intensity is 700～800mA, and the deposition time of each nano-Ti layer is 12s, The deposition time of each nano-TiN layer is 48s, and the total deposition time of the TiN/Ti nano-multilayer structure is 90min.

In addition, Ti ion sputtering was carried out every 40 minutes during deposition of other film layers except surface nitriding and ion implantation. On the one hand, this process can release the internal stress in the deposited film. On the other hand, Ti ions hit the substrate at high speed, which can increase the temperature of the substrate to reduce the generation of subsequent internal stress, thereby improving the overall toughness and other mechanical properties of the film. The specific process parameters are as follows: arcing current: 110mA, magnetic filter current: 2.0A, voltage: 24.2V, the substrate bias voltage was adjusted to -800V, -600V and -400V in turn, and sputtering was performed under each bias voltage for 30s.

Example 2:

1) Polishing and cleaning of the substrate

Use 400-600, 800-1000, 1200 and 2000 mesh sandpaper in sequence to rough and finely grind the TC4 matrix sample, and then use polishing flannelette and diamond polishing paste to polish the finely ground sample until the surface of the sample is rough The degree reaches Ra=0.02±0.005μm.

After polishing, the substrate must be ultrasonically cleaned with absolute ethanol and acetone for 10 minutes before clamping and coating, and then quickly dried with high-purity nitrogen.

2) surface nitriding treatment

The process of nitriding the surface of the substrate is as follows: using glow plasma nitriding technology, nitriding the surface of the substrate, the nitriding gas is NH ₃ , the glow voltage is 800V, the current is 13A, and the vacuum in the furnace is 100Pa , Nitriding temperature is 400 ℃, nitriding time is 1h.

3) Preparation of "Embedded Bonding Layer"

The preparation of "embedded bonding layer" on the surface and subsurface of the substrate includes three steps:

Firstly, using metal vacuum vapor ion source (MEVVA), a certain amount of Ti element is pre-implanted on the substrate surface after nitriding treatment, the pre-implantation voltage is 8.2kV, the beam current is 5A, and the implantation dose is 5.6×10 ¹⁴ /cm ² ; then close the metal vacuum vapor ion source, utilize the magnetic filter vacuum arc deposition system (FCVA) to deposit a layer of nano-scale metal Ti on the surface of the substrate, the substrate bias of the deposited nano-Ti layer is-200V, and the duty cycle is 90 %, the arcing current is 100mA, the magnetic filter electric field current is 2.0A, the voltage is 24.2V, and the deposition time is 10s; finally, the metal vacuum vapor ion source (MEVVA) is used to increase the injection voltage, and inject A large dose of Ti element is used to finally form an "embedded bonding layer" that improves the bonding force of the membrane base. At this time, the implantation voltage of Ti ions is 12kV, the beam current is 5.8mA, and the implantation dose is 8.2×10 ¹⁴ /cm ² .

4) Metal transition Ti layer deposition

The metal Ti transition layer was deposited on the "embedded bonding layer" using a magnetic filter vacuum arc deposition (FCVA) system. The specific process parameters are as follows: magnetic filter current: 2.0A, voltage: 24.2V, vacuum degree: 8.0×10 ^{- 4} Pa, the starting current is 100A, the negative bias is -200V, the duty cycle is 90%, the beam intensity is 700mA, and the deposition time is 15min;

5) Ti→TiN gradient structure deposition

A magnetic filtered vacuum arc deposition (FCVA) system is used to continuously control the input _N2 flow through a programmable flow controller in real time, and a gradient structure gradually transforming from metallic Ti to ceramic TiN is deposited on the metal transition layer. The specific process parameters are as follows: the degree of vacuum is 8.0×10 ^-4 ~5.0×10 ^-3 Pa, the arcing current is 100A, the negative bias voltage is 200V, the duty cycle is 90%, the beam intensity is 700mA, and the _N2 flow rate is The form of the proportional function y=0.0144t (t represents the deposition time) gradually increases from 0 sccm to 26 sccm, and the deposition time is 30 min.

6) TiN/Ti nano multilayer structure deposition

Utilize the magnetic filtration vacuum arc deposition (FCVA) system, through the compilable flow controller, realize the step type cycle switch between 26sccm and 0sccm _two kinds of flows to the input N flow, the specific process parameters are as follows: the vacuum degree is 1.0 ×10 ^-4 ～5.0×10 ^-3 Pa, the arcing current is 100A, the negative bias voltage is 200V, the duty cycle is 90%, the beam current intensity is 700～800mA, and the deposition time of each nano-Ti layer is 12s, The deposition time of each nano-TiN layer is 48s, and the total deposition time of the TiN/Ti nano-multilayer structure is 45min.

7) Cyclic superposition of modulation period

The process cycle in steps (4)-(6) is operated twice.

In addition, Ti ion sputtering was carried out every 40 minutes during deposition of other film layers except surface nitriding and ion implantation. On the one hand, this process can release the internal stress in the deposited film. On the other hand, Ti ions hit the substrate at high speed, which can increase the temperature of the substrate to reduce the generation of subsequent internal stress, thereby improving the overall toughness and other mechanical properties of the film. The specific process parameters are as follows: arcing current: 110mA, magnetic filter current: 2.0A, voltage: 24.2V, the substrate bias voltage was adjusted to -800V, -600V and -400V in turn, and sputtering was performed under each bias voltage for 30s.

Example 3:

1) Polishing and cleaning of the substrate

Use 400-600, 800-1000, 1200 and 2000 mesh sandpaper in sequence to rough and finely grind the TC4 matrix sample, and then use polishing flannelette and diamond polishing paste to polish the finely ground sample until the surface of the sample is rough The degree reaches Ra=0.02±0.005μm.

After polishing, the substrate must be ultrasonically cleaned with absolute ethanol and acetone for 10 minutes before clamping and coating, and then quickly dried with high-purity nitrogen.

2) surface nitriding treatment

The process of nitriding the surface of the substrate is as follows: using glow plasma nitriding technology, nitriding the surface of the substrate, the nitriding gas is NH ₃ , the glow voltage is 800V, the current is 13A, and the vacuum in the furnace is 100Pa , Nitriding temperature is 400 ℃, nitriding time is 1h.

3) Preparation of "Embedded Bonding Layer"

The preparation of "embedded bonding layer" on the surface and subsurface of the substrate includes three steps:

Firstly, using metal vacuum vapor ion source (MEVVA), a certain amount of Ti element is pre-implanted on the substrate surface after nitriding treatment, the pre-implantation voltage is 8.2kV, the beam current is 5A, and the implantation dose is 5.6×10 ¹⁴ /cm ² ; then close the metal vacuum vapor ion source, utilize the magnetic filter vacuum arc deposition system (FCVA) to deposit a layer of nano-scale metal Ti on the surface of the substrate, the substrate bias of the deposited nano-Ti layer is-200V, and the duty cycle is 90 %, the arcing current is 100mA, the magnetic filter electric field current is 2.0A, the voltage is 24.2V, and the deposition time is 10s; finally, the metal vacuum vapor ion source (MEVVA) is used to increase the injection voltage, and inject A large dose of Ti element is used to finally form an "embedded bonding layer" that improves the bonding force of the membrane base. At this time, the implantation voltage of Ti ions is 12kV, the beam current is 5.8mA, and the implantation dose is 8.2×10 ¹⁴ /cm ² .

4) Metal transition Ti layer deposition

The metal Ti transition layer was deposited on the "embedded bonding layer" using a magnetic filter vacuum arc deposition (FCVA) system. The specific process parameters are as follows: magnetic filter current: 2.0A, voltage: 24.2V, vacuum degree: 8.0×10 ^{- 4} Pa, the starting current is 100A, the negative bias is -200V, the duty cycle is 90%, the beam intensity is 700mA, and the deposition time is 10min;

5) Ti→TiN gradient structure deposition

A magnetic filtered vacuum arc deposition (FCVA) system is used to continuously control the input _N2 flow in real time through a programmable flow controller, and a gradient structure gradually transforming from metallic Ti to ceramic TiN is deposited on the metal transition layer. The specific process parameters are as follows: the degree of vacuum is 8.0×10 ^-4 ~ 5.0×10 ^-3 Pa, the arcing current is 100A, the negative bias voltage is 200V, the duty cycle is 90%, the beam intensity is 700mA, and the _N2 flow rate is The form of the proportional function y=0.0144t (t represents the deposition time) gradually increases from 0 sccm to 26 sccm, and the deposition time is 20 min.

6) TiN/Ti nano multilayer structure deposition

Utilize the magnetic filtration vacuum arc deposition (FCVA) system, through the compilable flow controller, realize the step type cycle switch between 26sccm and 0sccm _two kinds of flows to the input N flow, the specific process parameters are as follows: the vacuum degree is 1.0 ×10 ^-4 ～5.0×10 ^-3 Pa, the arcing current is 100A, the negative bias voltage is 200V, the duty cycle is 90%, the beam current intensity is 700～800mA, and the deposition time of each nano-Ti layer is 12s, The deposition time of each nano-TiN layer is 48s, and the total deposition time of the TiN/Ti nano-multilayer structure is 30min.

7) Cyclic superposition of modulation period

According to the process in steps (4)-(6), the operation is circulated for 4 times in total.

In addition, Ti ion sputtering was carried out every 40 minutes during deposition of other film layers except surface nitriding and ion implantation. On the one hand, this process can release the internal stress in the deposited film. On the other hand, Ti ions hit the substrate at high speed, which can increase the temperature of the substrate to reduce the generation of subsequent internal stress, thereby improving the overall toughness and other mechanical properties of the film. The specific process parameters are as follows: arcing current: 110mA, magnetic filter current: 2.0A, voltage: 24.2V, the substrate bias voltage was adjusted to -800V, -600V and -400V in turn, and sputtering was performed under each bias voltage for 30s.

Comparative example 1 (the preparation method of certain traditional multi-layer coating):

1) Polishing and cleaning of the substrate

Use 400-600, 800-1000, 1200 and 2000 mesh sandpaper in turn to rough and finely grind the TC4 substrate sample until there are no obvious horizontal and vertical grinding marks, and then use polishing flannelette and diamond polishing paste to polish the finely ground sample Process until the surface roughness of the sample reaches Ra=0.02±0.005 μm.

The polished substrate must be ultrasonically cleaned twice with absolute ethanol and acetone before clamping and coating, each time for 10 minutes, and quickly dried with high-purity nitrogen.

2) Metal transition Ti layer deposition

The metal Ti transition layer was deposited on the "embedded bonding layer" using a magnetic filter vacuum arc deposition (FCVA) system. The specific process parameters are as follows: magnetic filter current: 2.0A, voltage: 24.2V, vacuum degree: 8.0×10 ^{- 4} Pa, the starting current is 100A, the negative bias is -200V, the duty cycle is 90%, the beam intensity is 700mA, and the deposition time is 10mins;

3) TiN ceramic layer deposition

A TiN ceramic layer was deposited on the Ti→TiN gradient structure using a magnetic filtered vacuum arc deposition (FCVA) system with the input N flow rate kept constant at ₂₆ sccm by a programmable flow controller. The specific process parameters are as follows: vacuum degree not less than 8×10 ^-3 Pa, substrate bias voltage: -200V, duty cycle: 90%, arcing current: 100mA, magnetic filter current: 2.0A, voltage: 24.2V, deposition The duration is 40 minutes.

4) Cyclic superposition of modulation period

According to the process in steps (4)-(6), the operation is circulated for 4 times in total.

It should be noted that, for the sake of simple description, the above-mentioned embodiments are expressed as a combination of a series of steps according to specific implementation modes, but it cannot be assumed that the specific implementation modes of the present invention are limited thereto. Within the spirit and principles of the present invention, those skilled in the art can make various modifications and improvements on the basis of the above-mentioned embodiments, and these modifications and improvements fall within the protection scope of the present invention. Those skilled in the art should understand that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily necessary for the present invention, and in the case of no conflict, the embodiments of the present invention and the features can be combined with each other. In addition, the base material selected in this embodiment is TC4 titanium alloy used for processing the blades of aero-engine compressors, but the base in the embodiment of the present invention is not limited to TC4 bases, but can also be TC11, stainless steel and other commonly used aero-engine compressor blades. s material. The protection scope of the present invention is defined by the claims and their equivalents.

Claims (10)

1. A kind of anti-erosion coating structure of nanometer multi-layer gradient composite, it is characterized in that: The coating structure includes a nitriding structure, an "embedded bonding layer", a nanometer multi-layer structure and a gradient structure. From the substrate to the surface of the coating, there are nitrided layer, ion implanted layer, and a repeating structure composed of Ti metal layer, Ti→TiN gradient layer and TiN/Ti nano-multilayer structure. An anti-erosion coating structure with gradient layers; the repeating structure is stacked n times repeatedly, and the value range of n is a positive integer greater than 0. 2. the anti-erosion coating structure of nanometer multilayer gradient composite as claimed in claim 1, is characterized in that: The depth of the surface nitriding layer is 20-50um; the implantation depth of the embedded bonding layer is 60-200nm, preferably 100-160nm. 3. the anti-erosion coating structure of nanometer multilayer gradient composite as claimed in claim 1, is characterized in that: In one or more repeating structures of the composite coating structure, the thickness ratio of the metal Ti layer, the Ti→TiN gradient layer and the TiN/Ti nano-multilayer structure is 1: (0.5-3): (0.5-9) . 4. the anti-erosion coating structure of nanometer multilayer gradient composite as claimed in claim 1, is characterized in that: In the TiN/Ti nano multilayer structure, the thicknesses of the Ti layer and the TiN layer are both greater than 10 nm and not more than 100 nm, and the thickness ratio is 1: (0.5-9). 5. the anti-erosion coating structure of nanometer multi-layer gradient composite as claimed in claim 1, is characterized in that: The total thickness of the composite coating structure is 18-24um. 6. the anti-erosion coating structure of nanometer multilayer gradient composite as claimed in claim 1, is characterized in that: In the composite coating structure, a repeating structure composed of Ti metal layer, Ti→TiN gradient layer, and TiN/Ti nanometer multi-layer sequential cyclic stacking is stacked n times, and the value range of n is 0<n A positive integer ≤10. 7. gradient multilayer composite coating structure as claimed in claim 1, is characterized in that: The substrate is one or more of stainless steel, TC11 and TC4 substrates. 8. The preparation method of the anti-erosion coating structure of nanometer multi-layer gradient composite as claimed in any one of claims 1 to 7, characterized in that: Combining surface nitriding, metal vacuum vapor ion source implantation, magnetic filtration vacuum cathode arc deposition, magnetic filtration vacuum cathode arc sputtering and compilable flow controller and other technologies, the surface nitriding technology can make the substrate surface and subsurface The material properties are similar to those of the coating material to alleviate the stress concentration phenomenon at the junction of the film and substrate; the metal vacuum vapor ion source implantation method is used to perform ion implantation on the substrate surface after nitriding to form an "embedded bonding layer"; combined with magnetic filtration Vacuum cathodic arc deposition method and compilable flow controller, by continuously controlling the input N2 flow rate, Ti metal layer, Ti→TiN gradient layer, TiN ceramic layer and TiN/Ti nano-layer structure can be sequentially prepared; magnetic filter vacuum cathodic arc Sputtering technology is to avoid excessive internal stress inside the coating and affect its overall performance. 9. the preparation method of the anti-erosion coating structure of nanometer multilayer gradient composite as claimed in claim 8, is characterized in that: 1) The specific preparation method of each layer structure includes the following steps using glow plasma nitriding technology to carry out surface nitriding treatment on the substrate, the nitriding gas is NH ₃ , the glow voltage is 700-1000V, and the current is 12-15A. The vacuum degree in the furnace is 100-150Pa, the nitriding temperature is 300°C, and the nitriding time is 1-4h; if the following parameters can be optimized, please give the preferred range. 2) The ion implantation bonding layer is prepared by metal vacuum vapor ion source implantation method, which is characterized in that: the degree of vacuum is 1.0×10 ^-4 ~ 1.0×10 ^-3 Pa, the implantation voltage is 8~15kV, and the beam intensity is 4~8mA , the total dose of implanted ions is 1.0×10 ¹⁵ ~1.0×10 ¹⁶ /cm ^-2 ; 3) The Ti metal layer is prepared by magnetic filtration vacuum cathodic arc deposition method, which is characterized in that: a 90° magnetic filtration elbow is used, the magnetic field current is 2 to 4A, and the vacuum degree is 1.0×10 ^-4 to 1.0×10 ^-3 Pa. The arc current is 100-110A, the negative bias voltage is 200-250V, the duty cycle is 85%-90%, and the beam current intensity is 700-800mA; 4) Combining the magnetic filtration vacuum cathodic arc deposition method and the compilable flow controller, the metal Ti _→ TiN gradient structure is prepared by continuously controlling the input N flow rate, which is characterized in that: a 90° magnetic filtration elbow is used, and the vacuum degree is 1.0 ×10 ^-4 ～5.0×10 ^-3 Pa, the arcing current is 100～110A, the negative bias voltage is 200～250V, the duty cycle is 85%～90%, the beam current intensity is 700～800mA, and the N ₂ flow rate is above Proportional function (y=kt, k>0), quadratic function (incremental part y=at ² , a>0) or sine function (incremental part y=nsin2πft, n=20～32, ) gradually increases from 0sccm to 20-32sccm, and the preferred flow rate is 26sccm; 5) Combining the magnetic filtration vacuum cathodic arc deposition method and the programmable flow controller, by controlling the N ₂ flow rate to switch between the maximum flow rate (20-32 sccm) and 0 sccm in a rapid cycle. Preparation of TiN/Ti nano multi-layer structure, characterized in that: using a 90° magnetic filter elbow, the vacuum degree is 1.0×10 ^-4 ~ 5.0×10 ^-3 Pa, the arcing current is 100 ~ 110A, and the negative bias is 200 ～250V, duty cycle 85%～90%, beam intensity 700～800mA; 6) In the preparation process, in order to avoid the formation of excessive internal stress inside the coating and affect its erosion resistance, in the preparation process except surface nitriding and ion implantation, the method of magnetic filter cathode vacuum arc sputtering is adopted , Ti sputtering is carried out every 30 to 40 minutes, the _N2 flow rate during sputtering is 0sccm, the arcing current is 110 to 120A, the negative bias voltage is -800V, -600V and -400V in turn, and the duty cycle is 85% ~90%, and keep for 30~40s under each negative bias. 10. the preparation method of the anti-erosion coating structure of nanometer multilayer gradient composite as claimed in claim 8, is characterized in that: Use 400-600, 800-1000, 1200 and 2000 mesh sandpaper in turn to rough and finely grind the TC4 matrix sample until there are no obvious horizontal and vertical grinding marks, and then use polishing flannelette and diamond polishing paste to grind the finely ground sample. Polishing treatment until the surface roughness of the sample reaches Ra=0.02±0.005μm; The polished substrate must be ultrasonically cleaned twice with absolute ethanol and acetone before clamping and coating, each time for 10 minutes, and quickly dried with high-purity nitrogen.