CN116752099A - NiTiAl-X multi-element alloy coating and preparation method and application thereof - Google Patents

Abstract

This application relates to the technical field of metal coatings, specifically to a NiTiAl-X multi-component alloy coating and its preparation method and application. The coating is made of NiTiAl‑X quaternary alloy material, where X is selected from one of the transition metals Nb, Mo, Cu or V. The atomic ratio of Ni, Ti, Al and X in the coating material is: 45～50:45～50:0.5～4:0.5～4. The preparation method of the coating includes first using vacuum arc melting technology to prepare NiTiAl-X multi-component alloy ingots, and then using magnetron sputtering to form a NiTiAl-X multi-component alloy coating on the substrate based on the alloy target. The NiTiAl-X multi-element alloy coating prepared by this application has both high cavitation corrosion resistance and erosion resistance, and has excellent cavitation corrosion resistance and erosion resistance. It can be used in marine, shipbuilding, transportation, nuclear power and other fields, and is effective Improve the service life of high-pressure pipelines, propellers, turbines and other flow-passing components.

Description

A NiTiAl-X multi-component alloy coating and its preparation method and application

Technical field

The present application relates to the technical field of metal coatings, and in particular to a NiTiAl-X multi-component alloy coating and its preparation method and application.

Background technique

When the propellers of ocean ships, runner blades, guide blades, top rings and bottom ring bushings of water turbines and other flow-passing components run in sand-containing water flows, they will produce corrosion due to cavitation erosion, slurry erosion and the combined effect of the two. Severe damage. Therefore, using appropriate surface engineering technology to enhance the cavitation and erosion resistance of flow-passing components is the key to improving the service life of flow-passing components.

Cavitation erosion is also called cavitation erosion. Its principle is that when liquid flows, when the pressure in a local area suddenly drops while the temperature remains basically unchanged, bubbles are formed. The bubbles suddenly collapse when they enter the high-pressure area from the low-pressure area. After the bubbles collapse, The generated high-speed jet continuously impacts the material surface, causing material damage to the flow-passing components and even surface erosion. The erosion effect of sediment belongs to hydrodynamic abrasive wear. The sandy water flow will have a huge impact on the high-speed running turbine, and the solid particles in the water will collide with and cut the flow channel, causing wear on the surface of the flow-passing parts.

At present, the method of preparing coatings on flow-passing components such as hydraulic turbines is often used at home and abroad to improve their anti-cavitation and anti-erosion properties. According to materials, commonly used coatings include metallic coatings and non-metallic coatings. Although non-metallic coatings such as epoxy resin and polyurethane have lower costs and simple processes, they have problems such as low bonding strength with the substrate and easy peeling under long-term pulsating negative pressure in strong cavitation zones. The metal coating mainly uses thermal spraying process, surfacing and laser cladding technology: The thermal spraying cermet coating mainly relies on mechanical bonding with the matrix and ceramic powder particles. There are pores in the structure, so the bonding strength is not high; the cladding process There are problems such as uneven thickness of the weld layer, brittleness of the fusion zone, and prone to cracks. The processing allowance is large and the weldability requirements of the base material are high. The laser cladding coating has high bonding strength, uniform structure, and excellent abrasion resistance. , but there is still the problem of cracks easily occurring during the cladding process.

Among metal coatings, NiTi alloy has good superelasticity and shape memory effects, can absorb the huge energy generated when cavitation bubbles collapse, and has excellent cavitation corrosion resistance. However, NiTi alloy has low hardness, resulting in poor wear resistance. Therefore, alloying elements can be used to strengthen the NiTi matrix phase to prepare a composite coating material with both cavitation resistance and wear resistance.

Contents of the invention

Relevant studies have shown that when the NiTi coating with added alloying elements is in the martensitic state, its overall corrosion resistance is better. Adding Al to NiTi alloy, NiTiAl alloy retains the shape memory effect while also having high yield strength and certain elasticity. This is because after adding Al element, the martensitic transformation temperature point of NiTi alloy drops significantly. The addition of a small amount of Al can make it in the martensite state at room temperature. During the cavitation corrosion process, the local pressure generated by bubble collapse can reach 1.2GPa. Such a high pressure can induce the formation of martensite twins in the NiTi phase, thereby absorbing energy and reducing damage to the alloy surface. NiTiAl alloy can withstand cyclic stress up to 1.7GPa under compression and exhibits a recoverable elastic strain of more than 5%. Therefore, NiTiAl alloy has both cavitation corrosion resistance and wear resistance properties, and shows certain application potential in the fields of cavitation corrosion resistance and erosion resistance. However, due to the expensive price of NiTi series alloys and poor cold working properties, NiTiAl alloys have problems such as grain boundary precipitation phases and element segregation. Currently, they have no application in resisting cavitation corrosion and erosion wear on the surfaces of propellers and turbine flow-passing parts. The use of coating materials can alleviate the problems of expensive bulk materials and difficult processing to a certain extent. By adding alloy elements, the overall performance of the coating materials can be further controlled, and problems such as segregation and inclusions in the materials can be reduced to a certain extent. .

In view of this, the first purpose of this application is to provide a NiTiAl-X multi-component alloy coating with both cavitation and erosion resistance. This coating has excellent cavitation and erosion resistance and can It is used in marine, shipbuilding, transportation, nuclear power and other fields to effectively improve the service life of high-pressure pipelines, propellers, turbines and other flow-passing components.

The second purpose of this application is to optimize the coating preparation process based on the above-mentioned coating and provide a method for preparing the above-mentioned NiTiAl-X multi-component alloy coating.

In order to achieve the above purpose, this application adopts the following technical solutions:

In the first aspect, this application provides a NiTiAl-X multi-component alloy coating, which improves the NiTi alloy cavitation corrosion resistance coating in related technologies. By adding 0.5 to 4at.% Al element, it plays the role of solid solution strengthening. Enhanced the wear resistance and yield strength of the coating. Furthermore, on the basis of NiTiAl alloy, the microstructure of the material is controlled by adding transition elements Nb, Mo, Cu or V, thereby improving the fatigue damage of the coating caused by the grain boundary precipitation phase of the NiTiAl alloy coating, and at the same time improving the coating's The bonding force with the matrix further improves the cavitation corrosion and erosion resistance of the alloy.

Specifically, the NiTiAl-X multi-component alloy coating is made of NiTiAl-X quaternary alloy material, where X is selected from one of the transition metals Nb, Mo, Cu or V, and Ni, The atomic ratio of Ti, Al, and X is: 45～50:45～50:0.5～4:0.5～4.

Preferably, when Nb is selected as the X element, Ni:Ti:Al:Nb=47.5~50:45~47.5:1~3:2~4; when Mo is selected as the ~47:47~50:4:1~4; when Cu is selected as the X element, Ni:Ti:Al:Cu=45~50:45~50:1~2:3~4; when V is selected as the X element , Ni:Ti:Al:V=47.5～49.5:47.5～48.5:0.5～2.5:0.5～2.5.

In a second aspect, this application provides a method for preparing the NiTiAl-X multi-component alloy coating of the first aspect. First, an ingot of the NiTiAl-X multi-component alloy is prepared through alloy smelting technology, and a target material is obtained by cutting from the ingot. The NiTiAl-X multi-component alloy coating is obtained by depositing the target material on the surface of the base material through magnetron sputtering technology.

Specifically, the preparation method includes the following steps:

(1) Preparation of NiTiAl-X multicomponent alloy ingots:

Use Ti source, Ni source, Al source and pure X source with a purity greater than 99wt.% to prepare NiTiAl-X with an atomic ratio of Ni:Ti:Al:X= 45～50:45～50:0.5～4:0.5～4 Multi-component alloy ingots; the reason for using the above-mentioned high-purity Ti, Ni, Al, and

(2) Preparation of magnetron sputtering target:

The NiTiAl-X multi-component alloy ingot obtained in step (1) is used as the raw material, and the NiTiAl-X alloy target is obtained by cutting and processing; preferably, the above-mentioned NiTiAl can be obtained by cutting from the NiTiAl-X multi-component alloy ingot using wire electric discharge cutting. -X alloy target material is processed by wire EDM because the cutting edge of the target material after processing is very small, which greatly improves the material utilization rate and reduces the material cost.

(3) Preparation of NiTiAl-X multi-component alloy coating:

Using the NiTiAl-X alloy target obtained in step (2), use magnetron sputtering equipment to deposit a NiTiAl-X multi-component alloy coating on the substrate.

Preferably, in step (1), the NiTiAl-X multicomponent alloy ingot is prepared by vacuum arc melting technology, and each alloy ingot needs to be turned over and melted at least four times to obtain an alloy ingot with uniform composition and microstructure. The reason why vacuum arc melting technology is used to prepare alloy ingots is that the prepared alloy ingots have uniform composition, no oxidation, few pollutants, and short preparation time.

Preferably, before preparing the coating, the surface of the substrate used in step (3) is cleaned and sandblasted to enhance the bonding force between the coating and the substrate.

Preferably, in step (3), the substrate pressure during the magnetron sputtering process is 5×10 ^-6 Pa, and the deposition pressure is fixed at 5.0×10 ^-1 Pa by controlling the argon flow rate in the deposition chamber; The deposition power of the NiTiAl-X multi-element alloy coating is 1000 W, and the sputtering time is 5 to 6 hours; the substrate temperature is maintained at 600°C during the sputtering process, and the furnace is cooled to 150°C after the sputtering is completed. The reason for setting the above magnetron sputtering parameters is that the coating prepared by these parameters has a uniform and dense structure, good bonding, and is not easy to crack. The coating thickness is moderate, which avoids the decrease in cavitation corrosion resistance and erosion performance caused by insufficient thickness.

In a third aspect, the present application provides an application of the NiTiAl-X multi-component alloy coating of the first aspect in current-passing components.

The beneficial effects of this application are:

(1) Compared with the existing technology, the NiTiAl-X multi-component alloy coating of the present invention has both good anti-cavitation and anti-erosion properties. Under standard cavitation and erosion test conditions, its average cavitation erosion rate is It can be as low as 0.2MDE/μm, and the average erosion rate can be as low as 1.3MDE/μm; at the same time, the NiTiAl-X coating of the present invention also has higher wear resistance, high compressive strength and high corrosion resistance. Especially suitable for parts with current flow;

(2) The NiTiAl-X coating prepared by the magnetron sputtering technology used in the present invention has high bonding strength with the base material, is not easily separated from the base material, has uniform coating thickness, no pores, and no cracks;

(3) In addition, compared with the high-hardness ceramic phase particle-reinforced NiTi matrix phase composite coating, the NiTiAl-X coating of this application has a simpler process and a more stable composition.

Description of the drawings

Figure 1 shows a schematic structural diagram of the ASTM G32-10 standard cavitation erosion experimental device according to an embodiment of the present application;

Figure 2 shows an SEM microstructure photograph of the Ni ₅₀ Ti ₄₅ Al ₂ Cu ₃ coating according to Example 1 of the present application;

Figure 3 shows an SEM microstructure photograph of the Ni _48.5 Ti _48.5 Al _2.5 V _0.5 coating according to Example 2 of the present application;

Figure 4 shows the SEM micromorphology of the Ni ₅₀ Ti ₄₅ Al ₃ Nb ₂ coating according to Example 3 of the present application;

Figure 5 shows a cross-sectional SEM micromorphology image of the Ni ₄₅ Ti ₄₈ Al ₄ Mo ₃ coating according to Example 4 of the present application;

Reference signs:

1. Power supply; 2. Constant temperature device; 3. Ultrasonic generator; 4. Test sample; 5. Test liquid; 6. Support device.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail below. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that can be purchased commercially.

In industrial production, transition metals are often used as alloying elements to improve the physical and chemical properties of the original metals. In the field of cavitation corrosion and erosion, there have been relevant studies proving that NiTi alloys have better cavitation corrosion and erosion resistance after adding alloying elements. On the basis of NiTi alloy, the present invention improves the wear resistance of the material by adding an appropriate amount of Al, and further controls the microstructure of the material and the bonding strength of the coating by adding transition elements Nb, Mo, Cu or V, and here Based on this, the coating preparation process is optimized and designed to obtain a NiTiAl-X alloy coating with good cavitation corrosion resistance and erosion performance.

The solutions of the present invention will be explained below with reference to examples. Those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. If no specific technology or conditions are specified, the general conditions or technologies in this field will be followed.

Example 1

Example 1 intends to prepare six NiTiAl-Cu coatings with different atomic ratios. The atomic ratios of the six different composition coatings are: Ni ₄₅ Ti ₅₀ Al ₁ Cu ₄ , Ni _47.5 Ti _47.5 Al ₁ Cu ₄ , Ni ₅₀ Ti ₄₅ Al ₁ Cu ₄ , Ni ₄₅ Ti ₅₀ Al ₂ Cu ₃ , Ni _47.5 Ti _47.5 Al ₂ Cu ₃ , Ni ₅₀ Ti ₄₅ Al ₂ Cu ₃ . In addition, a coating with the composition of Ni ₅₀ Ti ₄₅ Al _0.5 Cu _4.5 and Ni ₅₀ Ti ₄₅ Al ₃ Cu ₂ was also prepared as Comparative Example 1.

The following takes the composition of Ni ₅₀ Ti ₄₅ Al ₂ Cu ₃ as an example to briefly describe the preparation method of NiTiAl-Cu alloy coating. The steps not specifically stated are applicable to other components in this example/comparative example. The specific method is as follows:

(1) Preliminary preparation: Cut 30×30×6 304 stainless steel as the base body, clean and sandblast the surface of the base body to facilitate subsequent coating combination.

(2) Preparation of alloy ingots: high-purity titanium sponge (purity 99.76 wt.%), high-purity nickel block (purity 99.95wt.%), high-purity aluminum (purity 99.99 wt.%) and Cu with a purity of 99.9wt.% or above A NiTiAl-Cu alloy ingot with an atomic ratio of 50:45:2:3 was prepared. The alloy ingot was prepared by arc melting technology on a water-cooled copper crucible in an Ar atmosphere. The furnace cavity was evacuated to 3×10 ^-3 Pa and then backfilled with high-purity Ar gas (99.99 wt.%) to a pressure of 0.05 MPa. Each alloy ingot was turned over and melted four times to obtain a NiTiAl-Cu alloy ingot with uniform composition and microstructure.

(3) Target material preparation: NiTiAl-Cu alloy ingot is used as raw material, and a target material with a size of 101.6 (diameter) × 5 mm (thickness) is cut from the alloy ingot using wire EDM.

(4) Coating preparation: Use the cut NiTiAl-Cu alloy ingot as the target material, and use M600 magnetron sputtering equipment to deposit a NiTiAl-Cu film on the substrate. The substrate pressure is 5×10 ^-6 Pa, and the pressure of the deposition process is fixed at 5.0×10 ^-1 Pa by controlling the argon flow rate in the deposition chamber. During the magnetron sputtering deposition process, the deposition power of the NiTiAl-Cu film was 1000 W, and the sputtering time was 5.5 hours. During the sputtering process, the substrate temperature was maintained at 600°C. After sputtering was completed, the furnace was cooled to 150°C and the sample was taken out. The obtained coating target thickness is 15μm

(5) Performance test: Use SEM microscope to measure the bonding quality of coating and substrate. A standard cavitation corrosion testing machine was used to conduct a 2-h cavitation corrosion test on the prepared sample, and the cumulative mass loss of cavitation corrosion of the sample was measured. Please refer to Figure 1, which is a schematic structural diagram of the ASTM G32-10 standard cavitation corrosion test device, which includes 1. Power supply; 2. Constant temperature device; 3. Ultrasonic generator; 4. Test sample; 5. Test liquid; 6. Support device . The test principle is: the sound energy of the ultrasonic generator 3 will be converted into mechanical vibration waves, and the liquid at the solid-liquid contact surface will vibrate at high speed, causing the hydrostatic pressure at the solid-liquid contact surface to decrease at a certain moment, and the liquid will rapidly impact the test in the form of a micro-jet. The surface of the sample will be exposed to controlled cavitation erosion damage. The average erosion rate MDR is defined as the cumulative mass loss of cavitation divided by the product of cavitation area and material density, that is . Taking the cavitation erosion generating device probe as the center, take a circular area with a radius of 8 mm as the cavitation erosion area in the formula. The liquid/solid erosion test is conducted in accordance with the ASTM G73-10 standard test method. In the liquid-solid erosion test, a high-speed water jet with a speed of 100m/s is ejected from a nozzle with a diameter of 4mm, and vertically impacts the sample 15mm away from the nozzle. The impact area of the sample is approximately 25mm². The test results are listed in Table 1.

Table 1 Performance test results of each coating in Example 1/Comparative Example 1

Example 1/Comparative Example 1 uses a NiTiAl-Cu alloy coating prepared by magnetron sputtering deposition technology. The average thickness of the NiTiAl-Cu coating is 14.7 μm. Figure 2 is a microstructure photo of the Ni ₅₀ Ti ₄₅ Al ₂ Cu ₃ coating in this example. The coating matrix structure is a NiTi phase with solid solution of Al and a small amount of Ti ₂ Ni phase. In addition, white massive and short rod-shaped Ni ₃ Ti phases and gray massive copper-rich Ti (Ni, Cu) ₂ phases were also observed to precipitate. When the copper content is low, Cu element tends to precipitate in the precipitation phase. In NiTi alloys, Cu can improve the plasticity of the coating, reduce the friction between the lattice interfaces, and also reduce the sensitivity of the NiTi alloy phase transformation temperature to changes in the NiTi atomic ratio. In addition, the addition of Cu element reduces the tendency of Al element to segregate at grain boundaries. Cu element can also reduce the diffusivity of Fe element, thereby reducing the impact of Fe element in 304 stainless steel on NiTi coating.

For NiTiAl-Cu coatings, compared with the 304 stainless steel substrate, the cavitation corrosion resistance and erosion resistance of all sample coatings are improved to a certain extent, among which the alloy coating with Ni ₅₀ Ti ₄₅ Al ₂ Cu ₃ composition is the best. .

According to the test results of the applicant, when the Al element content in the material is ≤2at.% and the Cu content is between 3 and 4.5at.%, the NiTiAl-Cu coating has better cavitation and erosion resistance. This is because A small amount of Cu element can improve the plasticity of the coating, reduce the tendency of Al element to segregate at the grain boundaries, and coordinate the grain deformation of the coating surface under cavitation erosion impact. When the Cu content in the material is greater than 4.5 at.%, the cavitation corrosion resistance and erosion resistance of the coating deteriorate. This is due to the interaction between excess Cu element and Al element, which will lead to an increase in the volume of the precipitated phase and large precipitation The phase will cause local stress concentration, thereby reducing the mechanical properties of NiTiAl alloy. Comparing the test results of Example 1 and Comparative Example 1, this application controls the Al content in the NiTiAl-Cu coating material between 1-2at.% and the Cu content between 3-4at.%.

Example 2

Example 2 intends to prepare six NiTiAl-V coatings with different atomic ratios. The atomic ratios of the six different composition coatings are: Ni _47.5 Ti _47.5 Al _2.5 V _2.5 , Ni _48.5 Ti _48.5 Al _1.5 V _1.5 , Ni _48.5 Ti _48.5 Al _2.5 V _0.5 , Ni _48.5 Ti _{48.5 Al} 0.5 V _2.5 , Ni _48.5 Ti _47.5 Al _2.5 V _1.5 , Ni _49.5 Ti _47.5 Al _2.5 V _0.5 . In addition, a coating with the composition of Ni _46.5 Ti _47.5 Al _2.5 V _3.5 , Ni _46.5 Ti _48.5 Al _1.5 V _3.5 , and Ni _46.5 Ti _49.5 Al _0.5 V _3.5 was also prepared as Comparative Example 2.

The specific preparation method and performance testing method are consistent with Example 1. The performance test results of the nine coatings are listed in Table 2.

Table 2 Performance test results of each coating in Example 2/Comparative Example 2

Example 2 and Comparative Example 2 used magnetron sputtering technology to prepare a NiTiAl-V alloy coating under an inert atmosphere. The average thickness of the NiTiAl-V coating was 15.2 μm. The matrix structure of the coating is NiTi phase. As the V element increases, the coating grains are slightly refined and the coating toughness increases. When the V content is 0.5at.%, the structure morphology is shown in Figure 3. B19' phase and Ti ₂ Ni phase appear in the coating, and V is solid dissolved in the B19' phase, replacing the position of Ni atoms and playing the role of solid solution strengthening. When the V content is greater than 0.5at.%, the coating consists of the B19' phase, the Ti ₂ Ni phase and the softer V ₉ (Ni, Ti) phase precipitated at the grain boundaries. As the V content increases, the richness of V increases. Agglomerates increasingly accumulate at grain boundaries, resulting in a decrease in the wear resistance of the coating. The precipitation of the second phase at the grain boundary will lead to a reduction in the bonding force of the grain boundary, and the surface grains are easily peeled off during the cavitation etching process, resulting in aggravation of cavitation etching. Combining the test results of the coatings in Example 2 and Comparative Example 2, this application controls the V content in the NiTiAl-V coating material to be between 0.5-2.5at.%.

For the NiTiAl-V coating, compared with the 304 stainless steel substrate, the cavitation corrosion resistance and erosion resistance of all sample coatings are improved to a certain extent, among which Ni _48.5 Ti _48.5 Al _2.5 V _0.5 is the best.

Example 3

Example 3 intends to prepare six NiTiAl-Nb coatings with different atomic ratios. The atomic ratios of the six different composition coatings are: Ni ₅₀ Ti ₄₅ Al ₁ Nb ₄ , Ni ₅₀ Ti ₄₅ Al ₂ Nb ₃ , Ni ₅₀ Ti ₄₅ Al ₃ Nb ₂ , Ni _47.5 Ti _47.5 Al ₂ Nb ₃ , Ni _47.5 Ti _47.5 Al ₁ Nb ₄ , Ni _47.5 Ti _47.5 Al ₃ Nb ₂ . In addition, a coating with a composition of Ni ₄₅ Ti ₅₀ Al ₂ Nb ₃ was also prepared as Comparative Example 3.

Taking the composition of Ni _47.5 Ti _47.5 Al ₃ Nb ₂ as an example, the following is a brief description of the NiTiAl-Nb alloy coating method. The steps not specifically stated are applicable to other components in this example/comparative example. The specific method is as follows:

(1) Preliminary preparation: Cut 30×30×6 304 stainless steel as the base body, clean and sandblast the surface of the base body to facilitate subsequent coating combination.

(2) Preparation of alloy ingots: Use high-purity titanium sponge (99.76 wt.%), high-purity nickel block (99.95 wt.%), high-purity aluminum (99.99 wt.%) and Nb with a purity of more than 99.9wt.% to prepare the atomic ratio It is an alloy ingot of 47.5:47.5:3:2. The alloy ingot was prepared by arc melting technology on a water-cooled copper crucible in an Ar atmosphere. The furnace cavity was evacuated to 3×10 ^-3 Pa and then backfilled with high-purity Ar gas (99.99 wt.%) to a pressure of 0.05 MPa. Each alloy ingot was turned over and melted four times to obtain compositionally and microstructurally homogeneous alloy ingots.

(3) Target material preparation: NiTiAl-Nb alloy ingot is used as raw material, and a target material with a size of 101.6 (diameter) × 5 mm (thickness) is cut from the alloy ingot using wire EDM.

(4) Coating preparation: Use the cut NiTiAl-Nb alloy ingot as the target material, and use M600 magnetron sputtering equipment to deposit a NiTiAl-Nb film on the substrate. The substrate pressure is 5×10 ^-6 Pa, and the pressure of the deposition process is fixed at 5.0×10 ^-1 Pa by controlling the argon flow rate in the deposition chamber. During the magnetron sputtering deposition process, the deposition power of the NiTiAl-Nb film was 1000 W, and the sputtering time was 6 hours. During the sputtering process, the substrate temperature was maintained at 600°C. After sputtering was completed, the furnace was cooled to 150°C and the sample was taken out. The target thickness of the coating obtained was 17 μm.

(5) The performance testing method is consistent with Example 1. The test results are listed in Table 3.

Table 3 Performance test results of each coating in Example 3 and Comparative Example 3

The above embodiments and comparative examples adopt NiTiAl-Nb alloy coatings prepared by magnetron sputtering deposition technology. The average thickness of the NiTiAl-Nb coating is 16.2 μm. The addition of Nb increases the NiTi (Al, Nb) precipitated phase in the coating, and the solid solution strengthening effect brought by the dispersed fine precipitated phases can greatly increase the yield strength of the coating.

Figure 4 shows the SEM micromorphology of the Ni ₅₀ Ti ₄₅ Al ₃ Nb ₂ magnetron sputtered film. In the alloy containing 2at.%Nb, dark gray TiNi matrix and precipitated white TiNi (Al, Nb) phase and black Ti ₂ Ni phase can be observed. As the Nb content increases, the amounts of TiNi (Al, Nb) and Nb-rich Ti ₂ Ni phases increase, and the amount of TiNi matrix decreases. Excessive precipitation has a negative effect on the cavitation corrosion resistance of the coating, because a large amount of second phase will bring stress concentration, leading to the generation of tip cracks and subsequent peeling of the coating structure. For Ni-NiTi-rich alloys, Nb plays a solid solution strengthening role, while promoting the dispersion and precipitation of the Ni ₂ TiAl phase to improve the coating strength. For NiTi alloys with equiatomic ratios, Nb will segregate in the alloy and precipitate high-strength Nb-rich phases, increasing the coating strength and erosion resistance. For Ti-NiTi-rich alloys, although the addition of Nb will increase its room temperature yield strength to a certain extent, it will reduce the solubility of Ti in the matrix, causing coarse Ti ₂ Ni to precipitate within the crystal and deteriorating the material's cavitation corrosion resistance. Combined with the test results of the coating in Comparative Example 3, in this application, the content of Ni and Ti in the NiTiAl-Nb coating material is controlled between 47.5~50:45~47.5, thereby ensuring that the Ni/Ti ratio is ≥1, and the Nb The content is controlled between 2 and 4at.%.

Example 4

Example 4 intends to prepare six NiTiAl-Mo coatings with different atomic ratios. The atomic ratios of the six different composition coatings are: Ni ₄₅ Ti ₅₀ Al ₄ Mo ₁ , Ni ₄₅ Ti ₄₉ Al ₄ Mo ₂ , Ni ₄₅ Ti ₄₈ Al ₄ Mo ₃ , Ni ₄₅ Ti ₄₇ Al ₄ Mo ₄ , Ni ₄₆ Ti ₄₈ Al ₄ Mo ₂ , Ni ₄₇ Ti ₄₇ Al ₄ Mo ₂ . In addition, a coating with the composition of Ni ₅₀ Ti ₄₅ Al ₄ Mo ₁ , Ni ₄₉ Ti ₄₅ Al ₄ Mo ₂ , Ni ₄₈ Ti ₄₅ Al ₄ Mo ₃ , and Ni ₄₇ Ti ₄₅ Al ₄ Mo ₄ was also prepared as Comparative Example 4.

The specific preparation method and performance testing method are consistent with Example 3. The test results are listed in Table 4.

Table 4 Performance test results of each coating in Example 4/Comparative Example 4

Figure 5 is a cross-sectional SEM micromorphology picture of the Ni ₄₅ Ti ₄₈ Al ₄ Mo ₃ coating in this embodiment. It can be seen from the picture that the coating and the cross section are well combined. The average thickness of the NiTiAl-Mo coating is 15.8 μm. When the Mo content is 1at.%, the coating matrix structure is NiTi phase, with a small amount of Ti ₂ Ni phase at the grain boundaries. As the Mo content increases, fine granular white phases precipitate at the grain boundaries. Mo element is mainly solid dissolved in the NiTi matrix. When the Ni/Ti ratio in the coating material is less than 1, the Al atoms in the coating preferentially occupy Ti sites, resulting in excess Ti atoms in the NiTi matrix, and Ti and Mo form The stable Ti-Mo bond is conducive to the solid solution of Mo element, and the solid solution strengthening effect is optimal at this time; when the Ni/Ti ratio in the coating material is greater than 1, the solid solution strengthening effect of Mo element is greatly reduced, and when Mo When the content is greater than 3at.%, a larger-sized Mo-rich phase will precipitate in the coating matrix, which is not conducive to the cavitation corrosion resistance of the coating. Therefore, based on the test results of Example 4 and Comparative Example 4, in this application, the content of Ni and Ti in the NiTiAl-Mo coating is controlled between 45~47:47~50, thereby ensuring that the Ni/Ti ratio is ≤1 , control the Mo content between 1 and 4at.%.

Comparative example 5

NiTi coating: Refer to the coating preparation method of Example 3 to prepare NiTi alloy coatings with three different components: Ni ₄₇ Ti ₅₃ , Ni ₅₀ Ti ₅₀ , and Ni ₅₃ Ti ₄₇ , as the NiTiAl- Comparative example of X alloy coating. After 6 hours of magnetron sputtering, the average thickness of the NiTi coating is 16.4 μm. In standard cavitation and erosion test experiments, the Ni ₅₃ Ti ₄₇ coating experienced severe coating cracking, resulting in large-area peeling of the coating. The Ni ₄₇ Ti ₅₃ and Ni ₅₀ Ti ₅₀ coatings have local weak connections, but the coatings did not crack during standard cavitation and erosion test experiments. The standard cavitation and erosion test results of Ni ₄₇ Ti ₅₃ and Ni ₅₀ Ti ₅₀ coatings are listed in the table below.

Table 5 Performance test results of each coating in Comparative Example 5

Comparative example 6

NiTiAl coating (Al between 0.5-4at.%): Referring to the coating preparation method in Example 3, the components are Ni _49.75 Ti _49.75 Al _0.5 , Ni _49.5 Ti _49.5 Al ₁ , Ni ₄₉ Ti ₄₉ Al ₂ , A NiTiAl alloy coating of Ni ₄₈ Ti ₄₈ Al ₄ is used as a comparative example of the NiTiAl-X alloy coating according to the present invention. After 6 hours of magnetron sputtering, the average thickness of the NiTiAl coating is 16.1 μm. With the addition of Al element, the martensitic twin content of NiTi alloy coating increases, and the wear resistance of the coating increases. When the Al content is less than 2 at.%, the Al element is solidly dissolved inside the NiTi matrix; when the Al content is between 2 and 4 at.%, a small amount of dispersed Ti ₂ Al strengthening phase precipitates in the coating. The addition of Al element effectively improves the erosion resistance of NiTi coating. The experimental results of the erosion test of Ni _49.75 Ti _49.75 Al _0.5 , Ni _49.5 Ti _49.5 Al ₁ , Ni ₄₉ Ti ₄₉ Al ₂ and Ni ₄₈ Ti ₄₈ Al ₄ coatings are listed in the table below.

Table 6 Performance test results of each coating in Comparative Example 6

Comparative example 7

NiTiAl coating (Al<0.5at.%): Referring to the coating preparation method of Example 3, a NiTiAl alloy coating with a composition of Ni _49.9 Ti _49.9 Al _0.2 was prepared as the NiTiAl-X alloy coating of the present invention. comparison ratio. Since the Al content is too low, the Al element is completely dissolved in the NiTi coating matrix, and its cavitation corrosion and erosion resistance are not much different from those of Ni ₅₀ Ti ₅₀ alloy.

Comparative example 8

NiTiAl coating (Al>4at.%): Referring to the coating preparation method of Example 3, a NiTiAl alloy coating composed of Ni ₄₇ Ti ₄₇ Al ₆ and Ni ₄₆ Ti ₄₆ Al ₈ was prepared as the coating of the present invention. Comparative example of NiTiAl-X alloy coating. After 6 hours of magnetron sputtering, the average thickness of the NiTiAl coating is 16.5 μm. With the addition of a large amount of Al element, the hardness of NiTiAl coating increases significantly, but the toughness of the coating decreases. In addition, a large number of Al-containing precipitates were observed at the grain boundaries of the coating. These precipitates will become the source of cavitation cracks during the cavitation erosion process, causing the coating grains to fall off and reducing the cavitation corrosion resistance of the coating. NiTiAl alloy coatings composed of Ni ₄₇ Ti ₄₇ Al ₆ and Ni ₄₆ Ti ₄₆ Al ₈ showed coating damage in standard cavitation corrosion experiments.

Combining Comparative Examples 5 and 6, it can be seen that by adding Al to NiTi alloy, the hardness and wear resistance of the coating can be appropriately improved; further combining Comparative Examples 6 to 8, it can be obtained that when the Al content in NiTiAl alloy When the composition is <0.5at.%, the Al content is very small and is completely dissolved in the NiTi matrix. The performance of the NiTiAl coating is not much different from that of the NiTi coating. When the composition of Al in the NiTiAl alloy is >4at.%, the hardness of the coating Significantly increased, the toughness decreased, and the grain boundary precipitated phase increased, resulting in the deterioration of the coating's cavitation corrosion resistance. Combined with the above analysis, this application controls the Al content in the coating material between 0.5-4at.%.

In addition, compared with the TIG method, the coating prepared by the magnetron sputtering method in the embodiment of the present application has the characteristics of a denser coating, significantly reduced inclusions and holes, and better cavitation corrosion resistance and erosion resistance; compared with Compared with vacuum plasma spraying + laser remelting treatment, the cost of the prepared coating is lower and the process is simpler. The coating alloy composition of the present invention is also suitable for preparation by plasma spraying method.

The above are only examples of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of the present invention, or directly or indirectly applied to other related technologies fields are equally included in the scope of patent protection of this application.

Claims (10)

1. A NiTiAl-X multi-component alloy coating, characterized in that the coating is made of NiTiAl-X quaternary alloy material, wherein X is selected from one of the transition metals Nb, Mo, Cu or V , and the atomic ratio of Ni, Ti, Al, and X in the coating is: 45~50:45~50:0.5~4:0.5~4; under standard cavitation and erosion test conditions, the coating The average erosion rate of cavitation erosion is ≤12.7MDE/μm, and the average erosion rate of erosion is ≤9.9MDE/μm. 2. The NiTiAl-X multi-component alloy coating according to claim 1, characterized in that when Nb is selected as X, Ni:Ti:Al:Nb=47.5～50:45～47.5:1～3:2～ 4. And the ratio of Ni/Ti is ≥1; under standard cavitation and erosion test conditions, the average cavitation erosion rate of this coating is ≤11.1MDE/μm, and the average erosion rate is ≤9.9MDE/μm. 3. The NiTiAl-X multi-component alloy coating according to claim 1, characterized in that when Mo is selected as X, Ni:Ti:Al:Mo=45~47:47~50:4:1~4, And the ratio of Ni/Ti is ≤1; under standard cavitation and erosion test conditions, the average cavitation erosion rate of this coating is ≤6.0MDE/μm, and the average erosion rate is ≤5.1MDE/μm. 4. The NiTiAl-X multi-component alloy coating according to claim 1, characterized in that when Cu is selected as X, Ni:Ti:Al:Cu=45～50:45～50:1～2:3～ 4; Under standard cavitation and erosion test conditions, the average cavitation erosion rate of the coating is ≤12.7MDE/μm, and the average erosion rate is ≤8.9MDE/μm. 5. The NiTiAl-X multi-component alloy coating according to claim 1, characterized in that when V is selected as X, Ni:Ti:Al:V=47.5~49.5:47.5~48.5:0.5~2.5:0.5~ 2.5; Under standard cavitation and erosion test conditions, the average cavitation erosion rate of the coating is ≤9.6MDE/μm, and the average erosion rate is ≤9.5MDE/μm. 6. The preparation method of the NiTiAl-X multi-component alloy coating according to any one of claims 1 to 5, characterized in that it includes the following steps: (1) Preparation of NiTiAl-X multicomponent alloy ingots: Use Ti source, Ni source, Al source and X source with a purity greater than 99wt.% to prepare NiTiAl-X multi-component with an atomic ratio of Ni:Ti:Al:X= 45～50:45～50:0.5～4:0.5～4 alloy ingots; (2) Preparation of magnetron sputtering target: Using the NiTiAl-X multicomponent alloy ingot obtained in step (1) as the raw material, cut and process to obtain the NiTiAl-X alloy target; (3) Preparation of NiTiAl-X multi-component alloy coating: Using the NiTiAl-X alloy target obtained in step (2), use magnetron sputtering equipment to deposit a NiTiAl-X multi-component alloy coating on the substrate. 7. The preparation method according to claim 6, characterized in that the thickness of the NiTiAl-X multi-component alloy coating is 12-17 μm. 8. The preparation method according to claim 6, characterized in that in the step (1), NiTiAl-X multi-component alloy ingots are prepared by vacuum arc melting technology, and each alloy ingot needs to be turned over and melted at least four times. . 9. The preparation method according to claim 6, characterized in that, in the step (3), the substrate pressure during the magnetron sputtering process is 5×10 ^-6 Pa, and the argon gas flow rate in the deposition chamber is controlled. The deposition pressure is fixed at 5.0×10 ^-1 Pa; the substrate temperature is maintained at 600°C during the sputtering process, and is cooled to 150°C in the furnace after sputtering is completed. 10. Application of the NiTiAl-X multicomponent alloy coating according to any one of claims 1 to 5 in current-passing components.