Nickel-based tungsten-doped high-temperature self-lubricating material and preparation method thereof
By adding nickel-plated tungsten powder and rare earth yttrium powder to a Ni-Mo alloy matrix and combining it with plasma sintering, a high-temperature self-lubricating material was prepared. This solved the problem of unstable lubrication performance of existing materials at extreme high temperatures and achieved low friction and wear resistance at high temperatures.
Patent Information
- Application Number
- CN202610219466.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-24
- Publication Date
- 2026-05-08
AI Technical Summary
Existing high-temperature self-lubricating materials cannot maintain stable lubrication and wear resistance under extreme high temperatures and high speeds, making it difficult to apply them on a large scale in aerospace and high-speed transportation fields.
Using Ni-Mo alloy as the matrix, nickel-plated tungsten powder, rare earth Y and CaF2 are added, and spark plasma sintering is combined to prepare nickel-based tungsten-doped high-temperature self-lubricating materials. By introducing solid solution strengthening of tungsten powder and grain refinement of rare earth yttrium powder, a high-temperature lubricating film is formed, which improves the density and self-lubricating properties of the material.
This achieves a low coefficient of friction and low wear rate at high temperatures, improves the material's hardness and wear resistance, enhances its self-lubricating effect, and improves its mechanical properties.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of lubricant preparation technology, specifically relating to a nickel-based tungsten-doped high-temperature self-lubricating material and its preparation method. Background Technology
[0002] High-temperature self-lubricating composite materials, especially those that can maintain good friction and wear performance over a wider or higher temperature range, have become an important research direction. However, most current research is still in the laboratory stage and is difficult to apply on a large scale. In aerospace, high-speed transportation and other fields (such as high-temperature insulated engine bearings and nuclear power valves), there is an urgent need for materials that can maintain stable lubrication and wear resistance under extreme high temperatures and high speeds, which makes the development of new wide-temperature-range friction-reducing and wear-resistant self-lubricating composite materials of great significance.
[0003] In operating conditions where grease lubricants fail, using solid lubricants is an effective method. Therefore, there is a need to develop a Ni-based self-lubricating composite material with excellent overall performance. Summary of the Invention
[0004] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for preparing a nickel-based tungsten-doped high-temperature self-lubricating material. This nickel-based tungsten-doped high-temperature self-lubricating material uses a Ni-Mo alloy as a matrix. By adding nickel-plated tungsten powder and rare earth element Y, its high-temperature strength, wear resistance, and self-lubricating properties are improved. CaF2 is introduced as a composite lubricant to enhance the self-lubricating effect. Combined with a spark plasma sintering process characterized by rapid heating, short sintering time, and controllable microstructure, the density of the nickel-based tungsten-doped high-temperature self-lubricating material is improved, thus providing a high-performance high-temperature self-lubricating composite material.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing a nickel-based tungsten-doped high-temperature self-lubricating material, characterized in that the method includes the following steps: Step 1: Preparation of nickel-plated tungsten powder: Tungsten powder is pretreated with aqua regia, then poured into the electroplating solution and ultrasonically mixed, followed by washing with deionized water, cleaning with ethanol solution and drying to obtain nickel-plated tungsten powder; The electroplating solution uses nickel sulfate as the main salt, sodium hypophosphite as the reducing agent, trisodium citrate and sodium pyrophosphate as buffers, and boric acid as a stabilizer, and the pH is controlled by adding sodium hydroxide. Step 2, Ingredient Preparation: Weigh the nickel-plated tungsten powder obtained in Step 1 with nickel powder, molybdenum powder, rare earth yttrium powder, and calcium fluoride to obtain the composite raw material powder. Step 3, Initial Mixing: Pour the composite raw powder obtained in Step 1 into a container containing ethanol solution and place it on a mechanical stirrer for mixing and stirring to obtain a composite slurry. Then, dry the composite slurry to obtain composite powder. Step 4, Final Mixing: Place the composite powder obtained in Step 3 together with the hard balls into a high-energy ball mill jar, and then place it into a planetary ball mill for ball milling to obtain a uniform composite powder. Step 5, Sintering: The composite powder obtained in Step 4 is loaded into a mold for plasma sintering. After completion, it is cooled with the furnace temperature to obtain a nickel-based tungsten-doped high-temperature self-lubricating material.
[0006] The preparation method of the above-mentioned nickel-based tungsten-doped high-temperature self-lubricating material is characterized in that the tungsten powder particle size in step one is 10μm~15μm; the concentration of nickel sulfate in the electroplating solution is 20g / L~35g / L, the concentration of sodium hypophosphite is 30g / L~50g / L, the concentration of trisodium citrate is 5g / L~10g / L, the concentration of sodium pyrophosphate is 30g / L~60g / L, the concentration of boric acid is 25g / L~45g / L, and the pH is controlled by adding sodium hydroxide to control the pH to 9~13; the ultrasonic mixing time is 10min~30min, followed by washing with deionized water 3~5 times, washing with ethanol solution 3~5 times, and drying in a drying oven at 80℃~120℃.
[0007] The preparation method of the above-mentioned nickel-based tungsten-doped high-temperature self-lubricating material is characterized in that, in step two, by mass percentage, nickel powder is 50%~70%, molybdenum powder is 20%~40%, rare earth yttrium powder is 1%~3%, calcium fluoride is 1%~5%, and nickel-plated tungsten powder is 3%~15%.
[0008] The preparation method of the above-mentioned nickel-based tungsten-doped high-temperature self-lubricating material is characterized in that the mixing and stirring speed in step three is 100 r / min to 180 r / min, and the time is 1 h to 3 h; the drying temperature is 60 ℃ to 90 ℃, and the holding time is 2 h to 5 h.
[0009] The preparation method of the above-mentioned nickel-based tungsten-doped high-temperature self-lubricating material is characterized in that the ball milling in step four uses a ball-to-material ratio of 1:1 to 6:1 and a ball milling time of 6h to 12h.
[0010] The preparation method of the above-mentioned nickel-based tungsten-doped high-temperature self-lubricating material is characterized in that the heating rate of the plasma sintering in step five is 5℃ / min~15℃ / min, the sintering temperature is 850℃~1000℃, and the sintering is carried out under a pressure of 30MPa~100MPa for 5min~25min.
[0011] Meanwhile, the present invention also discloses a nickel-based tungsten-doped high-temperature self-lubricating material, characterized in that it is prepared by the above-described method.
[0012] Typically, the aqua regia in this invention is composed of a mixture of 37% hydrochloric acid and 65%~70% nitric acid in a volume ratio of 3:1.
[0013] Compared with the prior art, the present invention has the following advantages: 1. Compared with traditional high-temperature self-lubricating materials, the nickel-based tungsten-doped high-temperature self-lubricating material of the present invention introduces tungsten powder by adding nickel-plated tungsten powder, which has better compatibility with the nickel-based alloy matrix. At the same time, the good solid solution strengthening effect of tungsten powder reduces the precipitation of hard phase, strengthens the tough matrix, and improves the wear resistance of nickel-based alloy, thereby improving the hardness and friction performance of the nickel-based tungsten-doped high-temperature self-lubricating material.
[0014] 2. The rare earth yttrium powder added to the nickel-based tungsten-doped high-temperature self-lubricating material of the present invention plays a role in refining the grains in the nickel-based alloy, making the grains smaller. When the coating of the nickel-based tungsten-doped high-temperature self-lubricating material is subjected to external force, the plastic deformation is evenly dispersed in more grains, effectively reducing concentrated stress, thereby reducing crack propagation and improving the wear resistance of the nickel-based tungsten-doped high-temperature self-lubricating material.
[0015] 3. The calcium fluoride added to the nickel-based tungsten-doped high-temperature self-lubricating material of the present invention acts as a high-temperature lubricant, forming a good lubricating film at high temperatures, reducing wear on friction surfaces, and enhancing the self-lubricating effect.
[0016] 4. The Ni and Mo elements in the nickel-based tungsten-doped high-temperature self-lubricating material of the present invention are easily oxidized at high temperatures, and a large amount of NiMoO4 and CaMoO4 can be generated at the friction wear marks. These molybdates serve as the main lubricating phase, which makes the nickel-based tungsten-doped high-temperature self-lubricating material have a lower coefficient of friction and wear rate at high temperatures, and exhibits better tribological properties.
[0017] 5. The preparation method of the present invention adopts a dual mixing process of initial mixing and final mixing, which mixes the components in the composite powder, avoids the defect of agglomeration of the same component during subsequent sintering, and improves the mechanical properties of nickel-based tungsten-doped high-temperature self-lubricating materials.
[0018] 6. The preparation method of the present invention uses plasma sintering process, which causes solid solution strengthening in a short time, resulting in higher density of nickel-based tungsten-doped high-temperature self-lubricating material.
[0019] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation
[0020] Example 1 This embodiment includes the following steps: Step 1: Preparation of nickel-plated tungsten powder: Tungsten powder with a particle size of 10μm is pretreated with aqua regia for 1 min, then poured into the electroplating solution and ultrasonically mixed for 10 min. It is then washed three times with deionized water and three times with ethanol solution, and dried in an 80℃ drying oven to obtain nickel-plated tungsten powder. The electroplating solution contains 20 g / L nickel sulfate, 40 g / L sodium hypophosphite, 6 g / L trisodium citrate, 40 g / L sodium pyrophosphate, and 30 g / L boric acid. The pH is controlled to 9 by adding sodium hydroxide. Step 2, Ingredients: Weigh the nickel-plated tungsten powder obtained in Step 1 with nickel powder, molybdenum powder, rare earth yttrium powder, and calcium fluoride in the following proportions by mass percentage: nickel powder 50%, molybdenum powder 40%, rare earth yttrium powder 1%, calcium fluoride 1%, and nickel-plated tungsten powder 8% to obtain the composite raw powder. Step 3, Initial mixing: Pour the composite raw powder obtained in Step 1 into a container containing ethanol solution, and place it on a mechanical stirrer for mixing at a speed of 120 r / min for 2 hours to obtain a composite slurry. Then, dry the composite slurry at a temperature of 75℃ for 4 hours to obtain a composite powder. Step 4, final mixing: The composite powder obtained in step 3 is placed together with hard balls into a high-energy ball mill jar and then into a planetary ball mill for ball milling. The ball-to-powder ratio is 1:1 and the ball milling time is 6 hours to obtain a uniform composite powder. Step 5, Sintering: The composite powder obtained in Step 4 is loaded into a mold for plasma sintering. The heating rate is 10℃ / min, the sintering temperature is 850℃, and the sintering is carried out at a pressure of 85MPa for 6 minutes. After completion, the material is cooled with the furnace temperature to obtain a nickel-based tungsten-doped high-temperature self-lubricating material.
[0021] Example 2 This embodiment includes the following steps: Step 1: Preparation of nickel-plated tungsten powder: Tungsten powder with a particle size of 12μm was pretreated with aqua regia for 3 minutes, then poured into the electroplating solution and ultrasonically mixed for 20 minutes. It was then washed 4 times with deionized water and 4 times with ethanol solution, and dried in an 80℃ drying oven to obtain nickel-plated tungsten powder. The electroplating solution contained nickel sulfate at a concentration of 30 g / L, sodium hypophosphite at a concentration of 40 g / L, trisodium citrate at a concentration of 6 g / L, sodium pyrophosphate at a concentration of 40 g / L, and boric acid at a concentration of 30 g / L. The pH was controlled to 10 by adding sodium hydroxide. Step 2, Ingredients: Weigh the nickel-plated tungsten powder obtained in Step 1 with nickel powder, molybdenum powder, rare earth yttrium powder, and calcium fluoride in the following proportions by mass percentage: 60% nickel powder, 30% molybdenum powder, 2% rare earth yttrium powder, 2% calcium fluoride, and 6% nickel-plated tungsten powder to obtain the composite raw powder. Step 3, Initial mixing: Pour the composite raw powder obtained in Step 1 into a container containing ethanol solution, and place it on a mechanical stirrer for mixing at a speed of 120 r / min for 2 hours to obtain a composite slurry. Then, dry the composite slurry at a temperature of 75℃ for 4 hours to obtain a composite powder. Step 4, Final Mixing: The composite powder obtained in Step 3 is placed together with hard balls into a high-energy ball mill jar and then placed into a planetary ball mill for ball milling. The ball-to-powder ratio is 2:1, and the ball milling time is 7.5 hours to obtain a uniform composite powder. Step 5, Sintering: The composite powder obtained in Step 4 is loaded into a mold for plasma sintering. The heating rate is 5℃ / min, the sintering temperature is 950℃, and the sintering is carried out under a pressure of 90MPa for 6 minutes. After completion, the powder is cooled with the furnace temperature to obtain a nickel-based tungsten-doped high-temperature self-lubricating material.
[0022] Comparative Example 1 The difference between this comparative example and Example 2 is that step one was not performed, and in step two, tungsten powder was directly weighed and mixed with nickel powder, molybdenum powder, rare earth yttrium powder, and calcium fluoride.
[0023] Comparative Example 2 The difference between this comparative example and Example 2 is that rare earth yttrium powder and calcium fluoride were not added during step two of the ingredient preparation.
[0024] Example 3 This embodiment includes the following steps: Step 1: Preparation of nickel-plated tungsten powder: Tungsten powder with a particle size of 15μm was pretreated with aqua regia for 5 minutes, then poured into the electroplating solution and ultrasonically mixed for 30 minutes. It was then washed 5 times with deionized water and 5 times with ethanol solution, and dried in an 80℃ drying oven to obtain nickel-plated tungsten powder. The electroplating solution contained nickel sulfate at a concentration of 35g / L, sodium hypophosphite at a concentration of 40g / L, trisodium citrate at a concentration of 6g / L, sodium pyrophosphate at a concentration of 40g / L, and boric acid at a concentration of 30g / L. The pH was controlled to 11 by adding sodium hydroxide. Step 2, Ingredients: Weigh the nickel-plated tungsten powder obtained in Step 1 with nickel powder, molybdenum powder, rare earth yttrium powder, and calcium fluoride in the following proportions by mass percentage: 70% nickel powder, 20% molybdenum powder, 3% rare earth yttrium powder, 3% calcium fluoride, and 4% nickel-plated tungsten powder to obtain the composite raw powder. Step 3, Initial mixing: Pour the composite raw powder obtained in Step 1 into a container containing ethanol solution, and place it on a mechanical stirrer for mixing at a speed of 120 r / min for 2 hours to obtain a composite slurry. Then, dry the composite slurry at a temperature of 75℃ for 4 hours to obtain a composite powder. Step 4, final mixing: The composite powder obtained in step 3 is placed together with hard balls into a high-energy ball mill jar and then into a planetary ball mill for ball milling. The ball-to-powder ratio is 3:1 and the ball milling time is 10 hours to obtain a uniform composite powder. Step 5, Sintering: The composite powder obtained in Step 4 is loaded into a mold for plasma sintering. The heating rate is 10℃ / min, the sintering temperature is 1000℃, and the sintering is carried out at a pressure of 100MPa for 6 minutes. After completion, the powder is cooled with the furnace temperature to obtain a nickel-based tungsten-doped high-temperature self-lubricating material.
[0025] Example 4 This embodiment includes the following steps: Step 1: Preparation of nickel-plated tungsten powder: Tungsten powder with a particle size of 10μm is pretreated with aqua regia for 1 min, then poured into the electroplating solution and ultrasonically mixed for 10 min. It is then washed three times with deionized water and three times with ethanol solution, and dried in an 80℃ drying oven to obtain nickel-plated tungsten powder. The electroplating solution contains 20 g / L nickel sulfate, 30 g / L sodium hypophosphite, 5 g / L trisodium citrate, 30 g / L sodium pyrophosphate, and 25 g / L boric acid. The pH is controlled to 13 by adding sodium hydroxide. Step 2, Ingredients: Weigh the nickel-plated tungsten powder obtained in Step 1 with nickel powder, molybdenum powder, rare earth yttrium powder, and calcium fluoride in the following proportions by mass percentage: nickel powder 51%, molybdenum powder 40%, rare earth yttrium powder 1%, calcium fluoride 5%, and nickel-plated tungsten powder 3% to obtain the composite raw powder. Step 3, Initial mixing: Pour the composite raw powder obtained in Step 1 into a container containing ethanol solution, and place it on a mechanical stirrer for mixing at a speed of 100 r / min for 1 hour to obtain a composite slurry. Then, dry the composite slurry at a temperature of 60℃ for 2 hours to obtain a composite powder. Step 4, final mixing: The composite powder obtained in step 3 is placed together with hard balls into a high-energy ball mill jar and then into a planetary ball mill for ball milling. The ball-to-powder ratio is 3:1 and the ball milling time is 12 hours to obtain a uniform composite powder. Step 5, Sintering: The composite powder obtained in Step 4 is loaded into a mold for plasma sintering. The heating rate is 15℃ / min, the sintering temperature is 850℃, and the sintering is carried out under a pressure of 30MPa for 5min. After completion, the material is cooled with the furnace temperature to obtain a nickel-based tungsten-doped high-temperature self-lubricating material.
[0026] Example 5 This embodiment includes the following steps: Step 1: Preparation of nickel-plated tungsten powder: Tungsten powder with a particle size of 10μm is pretreated with aqua regia for 1 min, then poured into the electroplating solution and ultrasonically mixed for 10 min. It is then washed three times with deionized water and three times with ethanol solution, and dried in an 80℃ drying oven to obtain nickel-plated tungsten powder. The electroplating solution contains 20 g / L nickel sulfate, 50 g / L sodium hypophosphite, 10 g / L trisodium citrate, 60 g / L sodium pyrophosphate, and 45 g / L boric acid. The pH is controlled to 13 by adding sodium hydroxide. Step 2, Ingredients: Weigh the nickel-plated tungsten powder obtained in Step 1 with nickel powder, molybdenum powder, rare earth yttrium powder, and calcium fluoride in the following proportions by mass percentage: nickel powder 50%, molybdenum powder 29%, rare earth yttrium powder 1%, calcium fluoride 5%, and nickel-plated tungsten powder 15% to obtain the composite raw powder. Step 3, Initial mixing: Pour the composite raw powder obtained in Step 1 into a container containing ethanol solution, and place it on a mechanical stirrer for mixing at a speed of 180 r / min for 3 hours to obtain a composite slurry. Then, dry the composite slurry at a temperature of 90℃ for 5 hours to obtain a composite powder. Step 4, final mixing: The composite powder obtained in step 3 is placed together with hard balls into a high-energy ball mill jar and then placed into a planetary ball mill for ball milling. The ball-to-powder ratio is 6:1 and the ball milling time is 12 hours to obtain a uniform composite powder. Step 5, Sintering: The composite powder obtained in Step 4 is loaded into a mold for plasma sintering. The heating rate is 15℃ / min, the sintering temperature is 850℃, and the sintering is carried out under a pressure of 30MPa for 25min. After completion, the powder is cooled with the furnace temperature to obtain a nickel-based tungsten-doped high-temperature self-lubricating material.
[0027] The properties of the high-temperature self-lubricating materials prepared in Examples 1-5 and Comparative Examples 1-2 of this invention are shown in Table 1 below.
[0028] Table 1
[0029] As shown in Table 1, compared with Comparative Examples 1-2, the nickel-based tungsten-doped high-temperature self-lubricating materials prepared in Examples 1-5 of this invention exhibit significantly improved hardness, flexural strength, and electrical conductivity, while their friction coefficient and wear rate are significantly reduced. The performance of the nickel-based tungsten-doped high-temperature self-lubricating material prepared in Example 2 is particularly well-developed. Meanwhile, compared to Example 2, the material prepared in Comparative Example 1 without nickel plating of the tungsten powder shows a significant decrease in hardness, indicating that this invention introduces tungsten powder by adding nickel-plated tungsten powder, thereby improving the compatibility with the nickel-based alloy matrix and achieving solid solution strengthening, thus enhancing the material's hardness and friction performance. The material prepared in Comparative Example 2, lacking rare earth yttrium powder and calcium fluoride, shows a substantial increase in friction coefficient and a significant decrease in self-lubricating properties, indicating that this invention reduces wear on the friction surface and achieves excellent self-lubricating effects by adding rare earth yttrium powder and calcium fluoride.
[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.
Claims
1. A method for preparing a nickel-based tungsten-doped high-temperature self-lubricating material, characterized in that, The method includes the following steps: Step 1: Preparation of nickel-plated tungsten powder: Tungsten powder is pretreated with aqua regia, then poured into the electroplating solution and ultrasonically mixed, followed by washing with deionized water, cleaning with ethanol solution and drying to obtain nickel-plated tungsten powder; The electroplating solution uses nickel sulfate as the main salt, sodium hypophosphite as the reducing agent, trisodium citrate and sodium pyrophosphate as buffers, and boric acid as a stabilizer, and the pH is controlled by adding sodium hydroxide. Step 2, Ingredient Preparation: Weigh the nickel-plated tungsten powder obtained in Step 1 with nickel powder, molybdenum powder, rare earth yttrium powder, and calcium fluoride to obtain the composite raw material powder. Step 3, Initial Mixing: Pour the composite raw powder obtained in Step 1 into a container containing ethanol solution and place it on a mechanical stirrer for mixing and stirring to obtain a composite slurry. Then, dry the composite slurry to obtain composite powder. Step 4, Final Mixing: Place the composite powder obtained in Step 3 together with the hard balls into a high-energy ball mill jar, and then place it into a planetary ball mill for ball milling to obtain a uniform composite powder. Step 5, Sintering: The composite powder obtained in Step 4 is loaded into a mold for plasma sintering. After completion, it is cooled with the furnace temperature to obtain a nickel-based tungsten-doped high-temperature self-lubricating material.
2. The preparation method of a nickel-based tungsten-doped high-temperature self-lubricating material according to claim 1, characterized in that, The tungsten powder in step one has a particle size of 10μm~15μm; the electroplating solution contains nickel sulfate at a concentration of 20g / L~35g / L, sodium hypophosphite at a concentration of 30g / L~50g / L, trisodium citrate at a concentration of 5g / L~10g / L, sodium pyrophosphate at a concentration of 30g / L~60g / L, and boric acid at a concentration of 25g / L~45g / L, with the pH controlled at 9~13 by adding sodium hydroxide; the ultrasonic mixing time is 10min~30min, followed by washing with deionized water 3~5 times, rinsing with ethanol solution 3~5 times, and then drying in a drying oven at 80℃~120℃.
3. The preparation method of a nickel-based tungsten-doped high-temperature self-lubricating material according to claim 1, characterized in that, In step two, by mass percentage, nickel powder is 50%~70%, molybdenum powder is 20%~40%, rare earth yttrium powder is 1%~3%, calcium fluoride is 1%~5%, and nickel-plated tungsten powder is 3%~15%.
4. The preparation method of a nickel-based tungsten-doped high-temperature self-lubricating material according to claim 1, characterized in that, In step three, the mixing speed is 100 r / min to 180 r / min, and the time is 1 h to 3 h; the drying temperature is 60 ℃ to 90 ℃, and the holding time is 2 h to 5 h.
5. The method for preparing a nickel-based tungsten-doped high-temperature self-lubricating material according to claim 1, characterized in that, The ball-to-material ratio used in step four is 1:1 to 6:1, and the ball milling time is 6 to 12 hours.
6. The method for preparing a nickel-based tungsten-doped high-temperature self-lubricating material according to claim 1, characterized in that, The plasma sintering process described in step five involves a heating rate of 5°C / min to 15°C / min, a sintering temperature of 850°C to 1000°C, and sintering under a pressure of 30MPa to 100MPa for 5 to 25 minutes.
7. A nickel-based tungsten-doped high-temperature self-lubricating material, characterized in that, It is prepared by the method described in any one of claims 1 to 6.