Super wear-resistant tungsten carbide composite TiSiN / DLC / t-ZrO2 coating technology and preparation method thereof

Abstract

The invention relates to a super wear-resistant tungsten carbide composite TiSiN / DLC / t-ZrO2 coating technology and a preparation method thereof, and aims to improve the performance of equipment under extreme working conditions. By combining a novel mixed TiSiN / DLC / t-ZrO2 coating technology, the hardness and wear resistance of the coating are remarkably improved, the fracture toughness is enhanced, the brittleness is reduced, and the impact resistance is improved. The preparation method comprises the following specific steps: preparing alpha-WC nano powder and t-ZrO2 powder, optimizing the dispersity and uniformity of the powder by adopting ultrasonic treatment and fine grinding, then adding a DLC layer on a TiSiN intermediate layer, and finally coating the surface of a base material with the powder through a cold spraying technology. Tests show that the prepared coating has excellent performances in the aspects of hardness, fracture toughness, wear resistance, high-temperature stability and the like, meets the requirements of high-performance materials, and is suitable for being applied in high-temperature, high-pressure and corrosive environments.

Description

Technical Field

[0005] The invention relates to the field of fluid power and engineering, and specifically combines a novel mixed TiSiN / DLC / t-ZrO2 coating, and relates to a super wear-resistant tungsten carbide composite TiSiN / DLC / t-ZrO2 coating technology and a preparation method thereof. Background Art

[0006] As an advanced material with excellent performance, tungsten carbide has attracted widespread attention in the field of fluid power and engineering due to its outstanding high temperature resistance, wear resistance and corrosion resistance. Compared with traditional materials, tungsten carbide has lower application cost in high temperature and high pressure environments and has better reliability and durability. Equipment in the field of fluid power and engineering, such as pumps, valves, seals, etc., can significantly improve work efficiency and equipment life by using carbide materials. The high hardness and wear resistance of tungsten carbide make it excellent in abrasives and wear-resistant linings in the fields of chemical, energy, mining, etc. Its environmental protection and energy-saving characteristics make it have broad application prospects in green manufacturing and waste gas treatment equipment. With the advancement of technology and the continuous reduction of production costs, the market potential of tungsten carbide in these fields will continue to expand.

[0007] Although tungsten carbide has demonstrated its superior performance in the field of fluid power and engineering, traditional tungsten carbide coatings may face performance problems in some extreme working conditions, especially durability and stability in high temperature, high pressure and corrosive environments. In these cases, the use of tungsten carbide alone may not meet the application requirements.

[0008] This ultra-wear-resistant tungsten carbide composite TiSiN / DLC / t-ZrO2 coating preparation technology is in urgent demand in the field of fluid power. It provides a breakthrough solution to the defects of traditional materials under high temperature and high pressure conditions, and meets the industry's urgent demand for high-performance materials. Summary of the invention

[0009] The purpose of the present invention is to improve the performance of the equipment under extreme working conditions, combining a new mixed TiSiN / DLC / t-ZrO2 coating technology. The present invention can improve the hardness and wear resistance of the coating, and the addition of nanopowder can enhance the fracture toughness of the coating, reduce brittleness, improve impact resistance, and enhance the adhesion of the coating, so that it performs well in high temperature and high pressure environments, significantly extending the life of the equipment.

[0010] In order to achieve the above purpose, the technical solutions adopted are as follows:

[0011] A super wear-resistant tungsten carbide composite TiSiN / DLC / t-ZrO2 coating technology includes the following steps:

[0012] (1) α-WC nanopowder and t-ZrO2 powder are prepared, and then ultrasonically treated in isopropanol, and the mixed suspension is uniformly stirred to obtain nanopowder.

[0013] (2) Preparation of TiSiN / DLC coatings. DLC was added to the top surface and TiSiN was used as the intermediate layer. TiSiN coatings were deposited on WC-Co substrates using a multi-cathode arc system. The deposition target contained pure titanium and TiSi alloy. In the deposition chamber, the Ti and TiSi cathodes were located on opposite sides. The substrate coating temperature was maintained at 480 °C. The deposition process started with a 5-min deposition of pure titanium, as Figure 4 shown.

[0014] (3) The two powders are sprayed onto the surface of the substrate using cold spraying technology to obtain an ultra-wear-resistant tungsten carbide composite TiSiN / DLC / t-ZrO2 coating.

[0015] According to the above scheme, the preparation process of the α-WC nanopowder in step 1 includes the following steps:

[0016] Tungsten powder and graphite powder are mixed in a 1:1 ratio and evenly distributed in a high-temperature plasma at 2200-2400°C for full reaction. After the reaction is completed, the cooling rate is controlled by adjusting the helium flow rate. The airflow separation method is used to separate the fine powder from the gas using a high-speed airflow. The α-WC nanopowder is collected by a cyclone separator to obtain an α-WC nanopowder with a particle size of 95nm. The specific operation is as follows: Figure 1 shown.

[0017] According to the above scheme, the α-WC nanopowder and t-ZrO2 powder described in step 1 both have a particle size of 95nm. The specific operation of preparing t-ZrO2 powder is as follows: Figure 2 shown.

[0018] According to the above scheme, the ultrasonic treatment described in step 1 is to add 3% t-ZrO2 to isopropanol, perform ultrasonic treatment for 5 minutes, then add appropriate amount of α-WC nanopowder and isopropanol, and perform ultrasonic treatment for another 10 minutes.

[0019] According to the above scheme, the uniform stirring in step 1 refers to stirring at a speed of 150 rpm for 16 hours in a Fritsch powder-isette 6 planetary mill, with a rest of 1 minute every hour to prevent overheating and loss of grinding media.

[0020] According to the above scheme, the DLC coating in step 2 was sputtered onto the substrate using DC magnetron sputtering to sputter the Ti intermediate layer as a glue layer. The substrate temperature was 170 °C, the distance between the substrate and the Ti target was kept at 80 mm, and the base pressure was set to 3.0 × 10 3, perform argon ion etching for 20 minutes and deposition for 200 minutes.

[0021] According to the above scheme, in step 2, in order to maintain the uniformity of the coating, the substrate is continuously rotated at a constant speed of 20 revolutions per minute (rpT).

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] The present invention prepares nano-scale α-WC and submicron-scale t-ZrO2 powders respectively by plasma synthesis and gas phase carbonization, thereby ensuring high purity and precise particle size control, optimizing powder particle size and dispersibility, and further reducing the degree of powder agglomeration by ultrasonic treatment and fine grinding, thereby improving the dispersibility and uniformity of the powder.

[0024] Secondly, the present invention combines a novel hybrid titanium nitride / DLC coating to reduce surface roughness and enhance structural performance, thereby improving the mechanical properties and durability of the alloy.

[0025] In addition, the cold spraying technology is used to coat the powder on the substrate surface, and then high-temperature sintering treatment can form a high-quality coating. Compared with the single DLC coating, the hardness, fracture toughness and adhesion strength of the TiSiN / DLC / t-ZrO2 coating are significantly enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 : Schematic diagram of preparing α-WC nanopowder in step 1

[0027] Figure 2 Schematic diagram of preparing submicron t-ZrO2 powder in step 1

[0028] Figure 3 : Schematic diagram of preparing nanopowders in step 1

[0029] Figure 4 : Schematic diagram of TiSiN / DLC coating in step 2 DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] The present invention is further described in detail below through specific embodiments:

[0033] Preparation of ultra-wear-resistant tungsten carbide composite TiSiN / DLC / t-ZrO2 coating, including the following steps:

[0034] S1. First, tungsten powder and graphite powder are mixed in a ratio of 1:1, evenly distributed in a high-temperature plasma at 2200°C for full reaction, and α-WC nanopowder with a particle size of 95nm is collected by airflow separation. High-purity zirconium titanate and 3% yttrium oxide are selected as raw materials, mixed in a mass ratio of 97:3, and the powder is fully and evenly dispersed by ultrasonic treatment. The precursor is prepared by sol-gel method, and the powder is formed after drying. It is calcined at 800°C to 1000°C in nitrogen for 2 to 4 hours, and spheroidal graphite is performed using zirconium oxide balls for 10 to 20 hours. Submicron t-ZrO2-3% Y2O3 powder is obtained by sieving;

[0035] S2. After the preparation in step S1 is completed, the fiber material is guided through a yarn guide device and treated in a heated mold at 120°C. At the same time, the traction machine is started at a speed of 1m / min to make the fiber move evenly, and then the mandrel is fed into the heated mold at a speed of 0.5mm / s to ensure the correct arrangement of the material. 1% t-ZrO2 powder is added to isopropanol by ultrasonic mixing and ultrasonic treatment is performed for 5 minutes. Then 0.5g of WC powder and additional isopropanol are added and ultrasonic treatment is performed for 10 minutes to reduce powder agglomeration;

[0036] S3. Select high-purity alumina grinding bottles and alumina balls (1.6 mm in diameter, 100 g in weight) as grinding bottles and media. Use a Fritsch powder-isette 6 planetary mill, stirring at 150 rpm for 16 hours, resting for 1 minute every hour to prevent overheating;

[0037] S4. Prepare TiSiN / DLC coating, add DLC to the top surface, use TiSiN as the intermediate layer, and use a multi-cathode arc system to deposit TiSiN coating on a WC-Co substrate. The deposition target contains pure titanium (purity of 99.95%) and a TiSi alloy with a diameter of 10 cm (containing titanium and silicon in a ratio of 4:1). In the deposition chamber, the Ti and TiSi cathodes are located on opposite sides. The substrate coating temperature is maintained at 480°C. The deposition process starts with a 5-minute deposition of pure titanium. At this stage, the substrate bias voltage is set to -200V, and the T cathode current ranges from 120 to 140A. Subsequently, the top TiSiN layer is deposited for 90 minutes, the Tisi cathode arc current is 120 to 140A, and the bias voltage is 8 to 130A;

[0038] S5. After mixing the mixed powder with 5% synthetic sodium butene rubber solution, a columnar sample with a diameter of 10 mm and a height of 20 mm was prepared, and a high-temperature sintering was performed in a vacuum for 1 hour at a sintering temperature of 1340°C to adjust the porosity to 68%. In the cold spraying stage, the spraying parameters were adjusted to a temperature of 400°C and a spraying pressure of 3 bar to ensure the coating quality and performance.

[0039] Example 2

[0040] S1. First, tungsten powder and graphite powder are mixed in a ratio of 1:1, evenly distributed in a high-temperature plasma at 2300°C for full reaction, and α-WC nanopowder with a particle size of 95nm is collected by airflow separation. High-purity zirconium titanate and 3% yttrium oxide are selected as raw materials, mixed in a mass ratio of 97:3, and the powder is fully and evenly dispersed by ultrasonic treatment. The precursor is prepared by sol-gel method, and the powder is formed after drying. It is calcined at 800°C to 1000°C in nitrogen for 2 to 4 hours, and spheroidal graphite is performed using zirconium oxide balls for 10-20 hours. Submicron t-ZrO2-3% Y2O3 powder is obtained by sieving;

[0041] S2. After the preparation in step S1 is completed, the fiber material is guided through a yarn guide device and treated in a heated mold at 120°C. At the same time, the traction machine is started at a speed of 1m / min to make the fiber move evenly, and then the mandrel is fed into the heated mold at a speed of 0.5mm / s to ensure the correct arrangement of the material. 3% t-ZrO2 powder is added to isopropanol by ultrasonic mixing and ultrasonic treatment is performed for 5 minutes. Then 0.5g of WC powder and additional isopropanol are added and ultrasonic treatment is performed for 10 minutes to reduce powder agglomeration;

[0042] S3. Select high-purity alumina grinding bottles and alumina balls (1.6 mm in diameter, 100 g in weight) as grinding bottles and media. Use a Fritsch powder-isette 6 planetary mill, stirring at 150 rpm for 16 hours, resting for 1 minute every hour to prevent overheating;

[0043] S4. Prepare TiSiN / DLC coating, add DLC to the top surface, use TiSiN as the intermediate layer, and use a multi-cathode arc system to deposit TiSiN coating on a WC-Co substrate. The deposition target contains pure titanium (purity of 99.95%) and a TiSi alloy with a diameter of 10 cm (containing titanium and silicon in a ratio of 4:1). In the deposition chamber, the Ti and TiSi cathodes are located on opposite sides. The substrate coating temperature is maintained at 480°C. The deposition process starts with a 5-minute deposition of pure titanium. At this stage, the substrate bias voltage is set to -200V, and the T cathode current ranges from 120 to 140A. Subsequently, the top TiSiN layer is deposited for 90 minutes, the Tisi cathode arc current is 120 to 140A, and the bias voltage is 8 to 130A;

[0044] S5. After mixing the mixed powder with 5% synthetic sodium butene rubber solution, a columnar sample with a diameter of 10 mm and a height of 20 mm was prepared, and a high-temperature sintering was performed in a vacuum for 1 hour at a sintering temperature of 1440°C to adjust the porosity to 68%. In the cold spraying stage, the spraying parameters were adjusted to a temperature of 400°C and a spraying pressure of 3 bar to ensure the coating quality and performance.

[0045] Example 3

[0046] S1. First, tungsten powder and graphite powder are mixed in a ratio of 1:1, evenly distributed in a high-temperature plasma at 2300°C for full reaction, and α-WC nanopowder with a particle size of 95nm is collected by airflow separation. High-purity zirconium titanate and 3% yttrium oxide are selected as raw materials, mixed in a mass ratio of 97:3, and the powder is fully and evenly dispersed by ultrasonic treatment. The precursor is prepared by sol-gel method, and the powder is formed after drying. It is calcined at 800°C to 1000°C in nitrogen for 2 to 4 hours, and spheroidal graphite is performed using zirconium oxide balls for 10-20 hours. Submicron t-ZrO2-3% Y2O3 powder is obtained by sieving;

[0047] S2. After the preparation in step S1 is completed, the fiber material is guided through a yarn guide device and treated in a heated mold at 120°C. At the same time, the traction machine is started at a speed of 1m / min to make the fiber move evenly, and then the mandrel is fed into the heated mold at a speed of 0.5mm / s to ensure the correct arrangement of the material. 3% t-ZrO2 powder is added to isopropanol by ultrasonic mixing and ultrasonic treatment is performed for 5 minutes. Then 0.5g of WC powder and additional isopropanol are added and ultrasonic treatment is performed for 10 minutes to reduce powder agglomeration;

[0048] S3. Select high-purity alumina grinding bottles and alumina balls (1.6 mm in diameter, 100 g in weight) as grinding bottles and media. Use a Fritsch powder-isette 6 planetary mill, stirring at 150 rpm for 16 hours, resting for 1 minute every hour to prevent overheating;

[0049] S4. Prepare the DLC coating and sputter the Ti intermediate layer as a glue layer onto the substrate using DC magnetron sputtering. The temperature of the substrate is set to 170°C, and the distance between the substrate and the target is kept at 80 mm. The vacuum chamber is evacuated to a base pressure of 3.0×10 3 The substrate was subjected to argon ion etching for 20 minutes to remove possible contaminants. During the deposition process, the cathode was operated at a DC arc current of 60 to 100 A for 200 minutes.

[0050] S5. After mixing the mixed powder with 5% synthetic sodium butene rubber solution, a columnar sample with a diameter of 10 mm and a height of 20 mm was prepared, and a high-temperature sintering was performed in a vacuum for 1 hour at a sintering temperature of 1440°C to adjust the porosity to 68%. In the cold spraying stage, the spraying parameters were adjusted to a temperature of 400°C and a spraying pressure of 3 bar to ensure the coating quality and performance.

[0051] Test Method

[0052] When evaluating the performance of the prepared WC coating, tests on hardness, toughness, wear resistance and other indicators were comprehensively conducted.

[0053] (1) Hardness test Compared with the single DLC coating, the hardness of the prepared WC coating is significantly improved, reaching 36.2GPa, and the elastic modulus reaches 320GPa

[0054] (2) Fracture toughness test The fracture toughness was measured by three-point bending test. The results of Example 1 showed that the fracture toughness of the sample was 12MPa·m^0.5. The fracture toughness of the sample of Example 2 was 11MPa·m^0.5. The fracture toughness of the sample of Example 3 was 10MPa·m^0.5. The fracture toughness of Example 1 was the highest, indicating that it had good toughness and crack resistance when subjected to external impact or stress. The fracture toughness of Examples 2 and 3 gradually decreased, which may be due to the influence of the particle size distribution of the powder on the toughness. Larger particle size may lead to more defects, thereby reducing toughness.

[0055] (3) Wear resistance test Scanning electron microscopy and atomic force microscopy analysis show that the surface roughness is reduced and the structure is smooth and dense

[0056] (4) High temperature stability test

[0057] At 1500℃, the hardness change of the coating was recorded as ±5%, indicating that the coating has good stability in high temperature environment. The three sample WC coatings prepared all showed excellent performance in high temperature resistance and other aspects, meeting the requirements of high-performance applications.

Claims

1. A super wear-resistant tungsten carbide composite TiSiN / DLC / t-ZrO2 coating technology and its preparation method, characterized in that: The method specifically comprises the following steps: (1) preparing α-WC nanopowder and t-ZrO2 powder, wherein the particle size of the α-WC nanopowder is 95 nm, and the particle size of the t-ZrO2 powder is 95 nm, and the above powders are ultrasonically treated in isopropanol to obtain a uniform suspension; (2) Preparation of TiSiN / DLC coatings, in which TiSiN is used as the middle layer and DLC is used as the top layer, and the TiSiN coating is deposited on a WC-Co substrate using a multi-cathode arc system; (3) The mixed powder is sprayed onto the surface of the substrate by cold spraying technology to form an ultra-wear-resistant tungsten carbide composite TiSiN / DLC / t-ZrO2 coating.

2. The preparation method according to claim 1, characterized in that: The tungsten powder and graphite powder are mixed in a doping ratio of 1:

1.

3. The preparation method according to claim 1, characterized in that: The process parameters include sufficient reaction in a high temperature plasma at 2200°C.

4. The preparation method according to claim 1, characterized in that: The raw materials of high-purity cobalt titanate and 3% yttrium oxide are mixed in a mass ratio of 97:

3.

5. The preparation method according to claim 1, characterized in that: The raw materials are uniformly dispersed by ultrasonic treatment and calcined in nitrogen. The process parameters include: the calcination temperature is 800°C to 1000°C.

6. The preparation method according to claim 1, characterized in that: The baking gas includes at least one of nitrogen and argon, preferably nitrogen.

7. The coating technology according to claim 2, characterized in that: A DLC layer is added to the top surface, TiSiN is used as an intermediate layer, a coating is deposited on the substrate using a multi-cathode arc system, the deposition target contains pure titanium and TiSi alloy, and the process parameters include: a deposition substrate temperature of 480°.

8. The coating technology according to claim 3, wherein the process parameters include a spraying temperature of 400°C and a spraying pressure of 3 bar.

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