WO2020057373A1 - 一种钨合金前驱复合粉体的制备方法、陶瓷氧化铝增强钨合金及其制备方法 - Google Patents

一种钨合金前驱复合粉体的制备方法、陶瓷氧化铝增强钨合金及其制备方法 Download PDF

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WO2020057373A1
WO2020057373A1 PCT/CN2019/104392 CN2019104392W WO2020057373A1 WO 2020057373 A1 WO2020057373 A1 WO 2020057373A1 CN 2019104392 W CN2019104392 W CN 2019104392W WO 2020057373 A1 WO2020057373 A1 WO 2020057373A1
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tungsten alloy
preparing
mixed solution
tungsten
powder
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PCT/CN2019/104392
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English (en)
French (fr)
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魏世忠
潘昆明
王长记
周玉成
陈冲
张程
毛丰
熊美
徐流杰
张国赏
刘伟
李秀青
游龙
汪宙
李洲
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河南科技大学
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Priority to JP2021540353A priority Critical patent/JP7104450B2/ja
Publication of WO2020057373A1 publication Critical patent/WO2020057373A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/045—Alloys based on refractory metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
    • C22C27/04—Alloys based on tungsten or molybdenum

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  • the invention relates to a preparation method of a tungsten alloy precursor composite powder, a ceramic alumina-reinforced tungsten alloy, and a preparation method thereof, and belongs to the technical field of tungsten alloys.
  • the traditional tungsten alloy preparation process is solid + solid (liquid) milling, pressing, and sintering.
  • the tungsten alloy produced by this process generally has an uneven distribution of the second phase, which leads to the aggregation of the second phase in the grains of the tungsten alloy.
  • the problems of growth, coarse grains, and grain boundary segregation, and the sintered tungsten alloy also have defects such as low hardness, low shape, and low strength.
  • High density tungsten alloy is a high density, high strength and high ductility material, which is widely used in military, aerospace, metallurgy, machinery and other fields.
  • Oxides such as La 2 O 3 , Y 2 O 3, etc.
  • carbides such as TaC, ZrC, etc.
  • Cu alloys Al alloy, Mg alloy, W alloy, etc.
  • the dried solid powder is then dried at Calcined at 550 ° C for 4h, and then reduced through two stages of hydrogen reduction (one stage at 600 ° C for 2h and two stages at 900 ° C for 2h) to obtain Al 2 O 3 doped W composite powder. Particle size and good morphology, but due to segregation during precipitation, Al 2 O 3 and W distributions are not uniform.
  • the object of the present invention is to provide a method for preparing a tungsten alloy precursor composite powder, which can improve the uniformity of each component in the powder.
  • the invention also provides a ceramic alumina reinforced tungsten alloy with high density, micro hardness and compressive strength, and a preparation method thereof.
  • the technical scheme adopted in the method for preparing the tungsten alloy precursor composite powder of the present invention is:
  • a method for preparing a tungsten alloy precursor composite powder includes the following steps:
  • the pH is adjusted by using oxalic acid after liquid-liquid mixing. Hydrogen ions and tungstate ions in the solution will react to form a tungstic acid precipitate; oxalate ions and aluminum ions react to form oxalic acid.
  • Aluminum precipitation due to the co-reaction and co-precipitation of tungstic acid and aluminum oxalate, can avoid serious segregation caused by the large mass difference between tungsten and aluminum nucleus, and improve the uniformity between tungstic acid and aluminum oxalate in the obtained powder, so that It achieves molecular-level mixing, which provides a raw material basis for improving the high temperature wear resistance and erosion resistance of tungsten alloys.
  • the mass concentration of ammonium metatungstate in the mixed solution is 1.9 to 3.033 g / mL.
  • the amount of ammonium metatungstate and soluble aluminum salt in the mixed solution can be set according to the composition of the tungsten alloy.
  • the relative content of ammonium metatungstate and soluble aluminum salt in the mixed solution affects the performance of the tungsten alloy.
  • the mass ratio of the tungsten element and the aluminum element in the mixed solution is 97 to 99: 0.529 to 1.588.
  • the above method for preparing a tungsten alloy precursor composite powder further includes calcining the obtained mixed powder, and then reducing it with a reducing gas.
  • the composite powder can be converted into tungsten and aluminum oxides by calcination, and the tungsten oxide can be converted into tungsten by reduction with a reducing gas.
  • Alumina has high hardness, good chemical stability, and can improve the wear resistance, high temperature resistance and corrosion resistance of tungsten alloys.
  • heating the mixed solution can also provide sufficient power for the reaction in the solution, increase the nucleation rate of the precipitation reaction, and achieve the effect of refining the grains.
  • the method for preparing a tungsten alloy precursor composite powder according to the present invention further comprises adding oxalic acid to the mixed solution to adjust the pH, heating the reaction to completion, and then removing the solvent.
  • heating the mixed solution not only the reaction time can be shortened, but also the reaction can be completed to achieve 100% recovery of metal ions.
  • the technical scheme adopted in the preparation method of the ceramic alumina reinforced tungsten alloy of the present invention is:
  • a method for preparing ceramic alumina reinforced tungsten alloy includes the following steps:
  • the preparation method of the ceramic alumina-reinforced tungsten alloy of the present invention adopts a liquid-liquid mixing method to mix ammonium metatungstate and soluble aluminum salt in a solution, and then add oxalic acid to the mixed solution to generate precipitation of tungstic acid and aluminum oxalate.
  • hydrogen ions and tungstate ions will react to form a precipitate of tungstic acid; oxalate ions and aluminum ions react to form a precipitate of aluminum oxalate.
  • the tungsten and aluminum nuclei can be avoided due to their mass Segregation caused by the large gap during the precipitation process greatly improves the uniformity of each component in the mixed powder.
  • the mixed powder is calcined and gas reduced.
  • the tungsten oxide is volatilized and transferred into the atmosphere during the gas reduction.
  • the gas phase is reduced in the form of steam and precipitated on the surface of low-cost tungsten oxide or second-phase ceramic alumina to form a composite tungsten powder with uniform composition distribution.
  • ceramic alumina particles can not only inhibit impurity elements at the tungsten alloy grain boundaries.
  • the dispersed alumina phase is small and uniformly distributed in the tungsten matrix, which solves many problems such as the density of tungsten alloys, the uniformity of the second phase, the strength, and the thermal creep resistance.
  • the method for preparing a ceramic alumina-reinforced tungsten alloy further includes forging or rolling the sintered tungsten alloy.
  • the forging pass deformation is 5-8%.
  • the forging is rotary forging.
  • the rolling pass deformation is 2 to 5%.
  • the mass ratio of the tungsten element and the aluminum element is 97 to 99: 0.529 to 1.588.
  • the technical scheme adopted by the ceramic alumina reinforced tungsten alloy of the present invention is:
  • a ceramic alumina-reinforced tungsten alloy prepared by the method for preparing a ceramic alumina-reinforced tungsten alloy.
  • the ceramic alumina-reinforced tungsten alloy of the present invention is prepared by using the above preparation method.
  • the ceramic alumina second phase in the tungsten alloy not only solves the problem that the traditional second-phase dispersion-enhanced tungsten alloy has coarse grains, uneven distribution of the second phase, It is easy to introduce impurities and other problems, and the high hardness alumina greatly improves the wear resistance and erosion resistance of tungsten alloys. It is the application and application of tungsten alloys under special conditions (such as wear, erosion, corrosion and other conditions). Development provides new directions.
  • the present invention provides a method for preparing a tungsten alloy precursor composite powder, including the following steps:
  • the pH is adjusted by using oxalic acid after liquid-liquid mixing. Hydrogen ions and tungstate ions in the solution will react to form a tungstic acid precipitate; oxalate ions and aluminum ions react to form oxalic acid.
  • Aluminum precipitation due to the co-reaction and co-precipitation of tungstic acid and aluminum oxalate, can avoid serious segregation caused by the large mass difference between tungsten and aluminum nucleus, and improve the uniformity between tungstic acid and aluminum oxalate in the obtained powder, so that It achieves molecular-level mixing, which provides a raw material basis for improving the high temperature wear resistance and erosion resistance of tungsten alloys.
  • the metatungstate in the mixed solution The mass concentration of ammonium is 1.9 to 3.033 g / mL.
  • the amount of ammonium metatungstate and soluble aluminum salt in the mixed solution can be set according to the composition of the tungsten alloy.
  • the relative content of ammonium metatungstate and soluble aluminum salt in the mixed solution affects the performance of the tungsten alloy. In order to improve the performance of the tungsten alloy, it is preferred In the mixed solution, the mass ratio of the tungsten element and the aluminum element is 97 to 99: 0.529 to 1.588.
  • the soluble aluminum salt is at least one of aluminum nitrate, sulfate, and halide.
  • at least one of aluminum sulfate and aluminum nitrate can be selected.
  • the above method for preparing a tungsten alloy precursor composite powder further includes calcining the obtained mixed powder, and then reducing it with a reducing gas.
  • the composite powder can be converted into tungsten and aluminum oxides by calcination, and the tungsten oxide can be converted into tungsten by reduction with a reducing gas.
  • Alumina has high hardness, good chemical stability, and can improve the wear resistance, high temperature resistance and corrosion resistance of tungsten alloys.
  • the calcination temperature is 550-650 ° C, and the calcination time is 0.5-2 hours.
  • the mixed powder is spread into a layer with a thickness of 3 to 6 mm before calcining.
  • the reducing gas used in the reduction is hydrogen.
  • the tungsten oxide is volatilized in the hydrogen atmosphere and transferred to the gas phase. It is reduced in the form of steam and deposited on the surface of low-cost oxide or second-phase ceramic alumina to form a composite tungsten powder with uniform composition. .
  • the number of reductions using hydrogen is two times, the temperature of the first reduction is 580-630 ° C, and the temperature of the second reduction is 880-920 ° C.
  • the first reduction time is 4-7 hours.
  • the second reduction time is 8-12 hours.
  • the thickness of the material layer is controlled to be 3 to 6 mm during the two reduction processes.
  • the mixed solution is heated during the process of adding oxalic acid to the mixed solution.
  • heating the mixed solution also provides sufficient power for the reaction in the solution to increase the nucleation rate of the precipitation reaction and achieve the effect of refining the grains.
  • the temperature for heating the mixed solution is 60 to 100 ° C.
  • the method for preparing a tungsten alloy precursor composite powder according to the present invention further comprises adding oxalic acid to the mixed solution to adjust the pH, heating the reaction to completion, and then removing the solvent.
  • heating the mixed solution not only the reaction time can be shortened, but also the reaction can be completed to achieve 100% recovery of metal ions.
  • Solid-liquid separation can be performed by suction filtration or centrifugation.
  • the invention also provides a method for preparing a ceramic alumina-reinforced tungsten alloy, including the following steps:
  • the preparation method of the ceramic alumina-reinforced tungsten alloy of the present invention adopts a liquid-liquid mixing method to mix ammonium metatungstate and soluble aluminum salt in a solution, and then add oxalic acid to the mixed solution to generate precipitation of tungstic acid and aluminum oxalate.
  • hydrogen ions and tungstate ions will react to form a precipitate of tungstic acid; oxalate ions and aluminum ions react to form a precipitate of aluminum oxalate.
  • the tungsten and aluminum nuclei can be avoided due to their mass Segregation caused by the large gap during the precipitation process greatly improves the uniformity of each component in the mixed powder.
  • the mixed powder is calcined and gas reduced.
  • the tungsten oxide is volatilized and transferred into the atmosphere during the gas reduction.
  • the gas phase is reduced in the form of steam and precipitated on the surface of low-cost tungsten oxide or second-phase ceramic alumina to form a composite tungsten powder with uniform composition distribution.
  • ceramic alumina particles can not only inhibit impurity elements at the tungsten alloy grain boundaries.
  • the pressure and holding time for pressing in step 3) are related to the selected sintering method.
  • the pressure for pressing and forming is 180-200 MPa, and the holding time is 2-5 minutes.
  • the pressure used for press molding is 30 to 60 MPa, and the holding time is determined by the sintering time.
  • Spark plasma sintering (SparkPlasmaSintering or SPS), also known as plasma electric spark sintering, is generally sintered using a discharge plasma sintering furnace.
  • the discharge plasma sintering furnace has the functions of pressure forming and sintering at the same time.
  • a pulse current is first applied. Under the effect of the pulse current, the contact point of the powder particles generates a discharge plasma, and the surface of the particles generates a micro-exothermic phenomenon.
  • the pulse power is turned off, and the sample is heated by resistance heating until the predetermined sintering is achieved.
  • the temperature and the shrinkage of the sample are completed, and the pressure is finally released.
  • the pressure state is maintained during the sintering process until the end of the pressure relief, and the pressure in the pressure state and the initial pressure remain basically unchanged.
  • a sintering method for preparing a tungsten alloy in the prior art may be adopted.
  • the sintering is vacuum intermediate frequency induction sintering or discharge plasma sintering.
  • the temperature of the vacuum intermediate frequency induction sintering is 1400 to 1500 ° C and the time is 4 to 8 hours.
  • the temperature of the discharge plasma sintering is 1180 to 1250 ° C and the time is 3 to 5 minutes. Because of the low temperature and short time of discharge plasma sintering, and the ability to obtain higher density, higher strength, and smaller grain size alloys at lower sintering temperatures, discharge plasma sintering is preferred.
  • the method for preparing a ceramic alumina-reinforced tungsten alloy further includes forging or rolling the sintered tungsten alloy.
  • the forging pass deformation is 5-8%.
  • the forging is rotary forging.
  • the rolling pass deformation is 2 to 5%.
  • Tungsten alloy has a large internal stress after forging or rolling, and internal stress needs to be eliminated by heat treatment to achieve the purpose of stable material performance.
  • the above preparation method further includes heat treatment after forging or rolling; the temperature of the heat treatment is 1100 to 1300 ° C, and the time of the heat treatment is 2 to 4 hours.
  • the mass ratio of the tungsten element and the aluminum element is 97 to 99: 0.529 to 1.588.
  • the invention also provides a ceramic alumina-reinforced tungsten alloy prepared by the above-mentioned preparation method.
  • the ceramic alumina-reinforced tungsten alloy of the present invention is prepared by using the above preparation method.
  • the ceramic alumina second phase in the tungsten alloy not only solves the problem that the traditional second-phase dispersion-enhanced tungsten alloy has coarse grains, uneven distribution of the second phase, It is easy to introduce impurities and other problems, and the high hardness alumina greatly improves the wear resistance and erosion resistance of tungsten alloys. It is the application and application of tungsten alloys under special conditions (such as wear, erosion, corrosion and other conditions). Development provides new directions.
  • Embodiment 2 of a method for preparing a tungsten alloy precursor composite powder
  • the obtained mixed powder is spread into a layer with a thickness of 7 mm, and then calcined at 550 ° C for 2 hours. Then, the calcined product is placed in a tube reduction furnace, and after spreading into a layer with a thickness of 5 mm, hydrogen is passed in at 610. Reduced for 5h at °C, then passed through a 100-mesh sieve, took the sieve and placed it in a tube reduction furnace, spread it into a layer with a thickness of 5mm, passed in hydrogen at 900 ° C for 10h, and then passed through a 100-mesh sieve Net, take out the sieve, and get composite tungsten powder, that is.
  • Example 5 of a method for preparing a tungsten alloy precursor composite powder
  • the obtained mixed powder is spread into a layer with a thickness of 8 mm, and then calcined at 650 ° C for 1 hour. Then, the calcined product is placed in a tube reduction furnace, and after spreading into a layer with a thickness of 6 mm, hydrogen is passed in at 620. Reduced at °C for 4h, then passed through a 100-mesh sieve, took the sieve and placed it in a tube reduction furnace, spread it into a layer with a thickness of 6mm, passed in hydrogen at 920 ° C for 8h, and then passed through a 100-mesh sieve Net, take out the sieve, and get composite tungsten powder, that is.
  • the obtained mixed powder is spread into a layer with a thickness of 7 mm, and then calcined at 550 ° C for 2 hours. Then, the calcined product is placed in a tube reduction furnace, and after spreading into a layer with a thickness of 5 mm, hydrogen is passed in at 610. Reduced for 5h at °C, then passed through a 100-mesh sieve, took the sieve and placed it in a tube reduction furnace, spread it into a layer with a thickness of 5mm, passed in hydrogen at 900 ° C for 10h, and then passed through a 100-mesh sieve Net, take out the sieve, and get composite tungsten powder, that is.
  • the obtained mixed powder is spread into a layer with a thickness of 7 mm, and then calcined at 550 ° C for 2 hours. Then, the calcined product is placed in a tube reduction furnace, and after spreading into a layer with a thickness of 5 mm, hydrogen is passed in at 610. Reduced for 5h at °C, then passed through a 100-mesh sieve, took the sieve and placed it in a tube reduction furnace, spread it into a layer with a thickness of 5mm, passed in hydrogen at 900 ° C for 10h, and passed through a 100-mesh sieve Net, take out the sieve, and get composite tungsten powder, that is.
  • the obtained mixed powder is spread into a layer with a thickness of 7 mm, and then calcined at 550 ° C for 2 hours. Then, the calcined product is placed in a tube reduction furnace, and after spreading into a layer with a thickness of 5 mm, hydrogen is passed in at 610. Reduced for 5h at °C, then passed through a 100-mesh sieve, took the sieve and placed it in a tube reduction furnace, spread it into a layer with a thickness of 5mm, passed in hydrogen at 900 ° C for 10h, and then passed through a 100-mesh sieve Net, take out the sieve, and get composite tungsten powder, that is.
  • Example 1 of a method for preparing a ceramic alumina-reinforced tungsten alloy
  • Example 1 of the method for preparing a tungsten alloy precursor composite powder is placed in a cylindrical soft rubber sleeve, and then placed in an ultra-high pressure room of 180 MPa for cold isostatic pressing.
  • the holding time is 3min, to obtain a cold-pressed green rod, put the green rod into an intermediate frequency induction sintering furnace, pass in hydrogen, and sinter at 2200 ° C for 10h under the protection of hydrogen to obtain a sintered alloy rod;
  • the obtained sintered alloy rod is heated in a hydrogen furnace and then spin-forged to obtain it; during the spin-forging process, the temperature of the spin-forging is controlled to 1480 ° C, and the pass deformation is 5%.
  • Example 2 of a method for preparing a ceramic alumina-reinforced tungsten alloy
  • Example 2 of the method for preparing a tungsten alloy precursor composite powder is placed in a square-shaped soft rubber sleeve, and then placed in an ultra-high pressure chamber of 190 MPa for cold isostatic pressing, and the holding time is 2 min.
  • To obtain a cold-pressed green sheet put the green sheet into an intermediate frequency induction sintering furnace, pass in hydrogen, and sinter it at 2250 ° C for 8 hours under the protection of hydrogen to obtain a sintered alloy sheet;
  • the obtained sintered alloy sheet is heated in a hydrogen furnace and then rolled to obtain it; during the rolling process, the rolling temperature is controlled to 1520 ° C, and the pass deformation is 2%.
  • Example 3 of the method for preparing a tungsten alloy precursor composite powder into a cylindrical soft rubber sleeve, and place it in a 200 MPa ultra-high pressure chamber for cold isostatic pressing.
  • the holding time is 3 minutes.
  • a cold-pressed green rod is obtained, the green rod is placed in an intermediate frequency induction sintering furnace, hydrogen gas is passed in, and sintering is performed at 2300 ° C for 6 hours under the protection of hydrogen to obtain a sintered alloy rod.
  • the sintered alloy rod obtained in Example 3 of the method for preparing a ceramic alumina-reinforced tungsten alloy is heated in a hydrogen furnace and then spin-forged to obtain the spin-forged temperature.
  • the spin-forging temperature is controlled to 1480 ° C.
  • the amount of deformation is 5%.
  • Example 5 of a method for preparing a ceramic alumina-reinforced tungsten alloy
  • the composite tungsten powder prepared in Example 4 of the method for preparing a tungsten alloy precursor composite powder was placed in a square-shaped soft rubber sleeve, and then placed in a 200 MPa ultra-high pressure chamber for cold isostatic pressing, and the holding time was 2 min. Cold press the green sheet, put the green sheet into an intermediate frequency induction sintering furnace, pass in hydrogen, and sinter it at 2300 ° C for 8 hours under the protection of hydrogen to obtain a sintered alloy sheet.
  • Example 6 of a method for preparing a ceramic alumina-reinforced tungsten alloy
  • the sintered alloy sheet obtained in Example 5 of the method for preparing a ceramic alumina-reinforced tungsten alloy is heated in a hydrogen furnace and then rolled to obtain it; during the rolling process, the rolling temperature is controlled to 1600 ° C, and the passes are deformed. The amount is 3%.
  • the composite tungsten powder prepared in Example 5 of the method for preparing a tungsten alloy precursor composite powder was placed in graphite, and then sintered in a discharge plasma sintering furnace.
  • the sintering temperature was 2100 ° C
  • the holding time was 5 minutes
  • the sintering pressure was 30MPa, the alloy is obtained.
  • Example 8 of a method for preparing a ceramic alumina-reinforced tungsten alloy
  • the composite tungsten powder prepared in Example 6 of the method for preparing a tungsten alloy precursor composite powder was placed in graphite and then sintered in a discharge plasma sintering furnace.
  • the sintering temperature was 2000 ° C
  • the holding time was 3 minutes
  • the sintering pressure 40MPa, the alloy is obtained.
  • Example 9 of the method for preparing a ceramic alumina-reinforced tungsten alloy
  • Example 7 of the method for preparing a tungsten alloy precursor composite powder was placed in graphite, and then sintered in a discharge plasma sintering furnace.
  • the sintering temperature was 1950 ° C
  • the holding time was 5 minutes
  • the sintering pressure was 50MPa, the alloy is obtained.
  • Example 10 of a method for preparing a ceramic alumina-reinforced tungsten alloy
  • Example 8 of the method for preparing a tungsten alloy precursor composite powder was placed in graphite, and then sintered in a discharge plasma sintering furnace.
  • the sintering temperature was 1900 ° C
  • the holding time was 5 minutes
  • the sintering pressure 50MPa
  • the composite tungsten powder prepared in Example 9 of the method for preparing a tungsten alloy precursor composite powder was placed in graphite, and then sintered in a discharge plasma sintering furnace.
  • the sintering temperature was 1900 ° C
  • the holding time was 5 minutes
  • the sintering pressure was 50MPa, the alloy is obtained.
  • the ceramic alumina-reinforced tungsten alloy of this embodiment is prepared by using the preparation methods of Examples 1 to 11 of the ceramic alumina-reinforced tungsten alloy preparation method, and details are not described herein again.
  • the method of preparing the tungsten alloy precursor composite powder of the comparative example and the method of preparing the tungsten alloy precursor composite powder of Example 9 differ only in that the temperature of the mixed solution is increased to 75 ° C. and citric acid is added to the mixed solution to the mixed solution.
  • PH 1.0, the rest is exactly the same as in Example 9.
  • the tungsten alloy precursor composite powder prepared in the comparative example was made into a tungsten alloy according to the method for preparing a ceramic alumina-reinforced tungsten alloy in Example 9 of the method for preparing a ceramic-alumina-reinforced tungsten alloy.
  • the tungsten alloys prepared in Examples 1 to 11 and Comparative Examples using the ceramic alumina-reinforced tungsten alloy method were taken, the grain size of the alloy was measured by the intercept method, and the density of the alloy was measured by the Archimedes drainage method. The relative density (relative to the theoretical density) was calculated.
  • the microhardness of the alloy was measured using a HVS-1000A microhardness tester, and the tensile strength of the alloy was measured using a SHIMADZUAG-I250KN precision universal testing machine. The results are shown in Table 1.
  • the tungsten alloys of Examples 1 to 11 have the advantages of fine grains, high density, high compressive strength, and high hardness.

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Abstract

本发明涉及一种钨合金前驱复合粉体的制备方法、陶瓷氧化铝增强钨合金及其制备方法，属于钨合金技术领域。本发明的钨合金前驱复合粉体的制备方法，包括：提供偏钨酸铵、可溶性铝盐的混合溶液，在混合溶液中加草酸至pH不大于1.5，反应完全，然后去除溶剂得到混合粉体。本发明的制备方法通过液-液混合后采用草酸对pH进行调节，溶液中氢离子和钨酸根离子会反应生成钨酸沉淀；草酸根离子和铝离子反应生成草酸铝沉淀，由于钨酸和草酸铝共同反应共同沉淀的原因，能够避免因钨原子核和铝原子核质量差距较大造成的严重偏析，提高所得粉体中钨酸和草酸铝之间的均匀程度，使其达到分子级混合，为提高钨合金的高温耐磨损耐冲蚀性能提供了原料基础。

Description

一种钨合金前驱复合粉体的制备方法、陶瓷氧化铝增强钨合金及其制备方法 技术领域
本发明涉及一种钨合金前驱复合粉体的制备方法、陶瓷氧化铝增强钨合金及其制备方法，属于钨合金技术领域。
背景技术
传统的钨合金制备工艺为固+固(液)制粉、压制、烧结，但是采用该工艺生产的钨合金普遍存在第二相分布不均、导致存在于钨合金晶粒中的第二相聚集长大、晶粒粗大以及存在晶界偏聚的问题，而且烧结态的钨合金也存在硬度值不高、塑形较低、强度低等缺陷。高比重钨合金是一种高密度、高强度、高延展性材料，广泛用于军事、航空航天、冶金、机械等领域，然而由于晶粒粗大、低温脆性、辐射脆性、韧脆转变温度较高、再结晶温度低、高温强度不足等缺点，限制了其更广泛的应用。氧化物(例如La 2O 3、Y 2O 3等)和碳化物(例如TaC、ZrC等)具有熔点高、高温强度高、良好的化学稳定性等特点，因此常被用作合金(Cu合金、Al合金、Mg合金、W合金等)的弥散强化第二相。现有技术中，河南科技大学硕士学位论文《Al 2O 3掺杂钨合金制备、组织与性能研究》(2017年06月)中公开了一种Al 2O 3掺杂钨合金前驱粉体的水热合成法，该方法将偏钨酸铵和硝酸铝的混合溶液在180℃保温20h，然后真空抽滤，将滤渣反复清洗后在120℃保温10h进行干燥，再将干燥后的固体粉末在550℃煅烧4h，然后经过两段氢还原(一段在600℃还原2h，二段在900℃还原2h)，得到Al 2O 3掺杂W复合粉，该方法制得的复合粉虽然具有较小的粒径和较好的形貌，但由于沉淀过程中容易产生偏析，Al 2O 3和W分布不均匀。
发明内容
本发明的目的是提供一种钨合金前驱复合粉体的制备方法，能够提高粉体中各成分的均匀程度。
本发明还提供了一种高密度、显微硬度和抗压强度的陶瓷氧化铝增强钨合金及其制备方法。
为了实现以上目的，本发明的钨合金前驱复合粉体的制备方法所采用的技术方案是：
一种钨合金前驱复合粉体的制备方法，包括以下步骤：
提供偏钨酸铵、可溶性铝盐的混合溶液，在混合溶液中加草酸至pH不大于1.5，反应 完全，然后去除溶剂得到混合粉体。
本发明的钨合金前驱复合粉体的制备方法，通过液-液混合后采用草酸对pH进行调节，溶液中氢离子和钨酸根离子会反应生成钨酸沉淀；草酸根离子和铝离子反应生成草酸铝沉淀，由于钨酸和草酸铝共同反应共同沉淀的原因，能够避免因钨原子核和铝原子核质量差距较大造成的严重偏析，提高所得粉体中钨酸和草酸铝之间的均匀程度，使其达到分子级混合，为提高钨合金的高温耐磨损耐冲蚀性能提供了原料基础。
偏钨酸铵的浓度越高，反应形核率越高、颗粒越细小。为了减小混合粉体中颗粒粒径，同时考虑偏钨酸铵在水中的溶解度，所述混合溶液中偏钨酸铵的质量浓度为1.9～3.033g/mL。
混合溶液中偏钨酸铵和可溶性铝盐的量可根据对钨合金成分进行设置，混合溶液中偏钨酸铵和可溶性铝盐的相对含量影响钨合金的性能，为了提高钨合金的性能，优选的，所述混合溶液中，钨元素和铝元素的质量比为97～99:0.529～1.588。
上述的钨合金前驱复合粉体的制备方法，还包括将所得混合粉体进行煅烧，然后用还原性气体进行还原。通过煅烧可以将复合粉体转化为钨和铝的氧化物，采用还原性气体进行还原可将钨的氧化物转化为钨。氧化铝具有高的硬度、良好的化学稳定性，能够提高钨合金的耐磨性、抗高温性和抗腐蚀能力。
为了进一步缩短制备时间、加快化学反应的进行，并在短时间内使反应完全以达到金属离子的100％回收，优选的，在混合溶液中加草酸的过程中，对混合溶液进行加热；所述加热的温度为60～100℃。另外对混合溶液进行加热还能为溶液中的反应提供了足够的动力，使沉淀反应形核速率增大，可以达到细化晶粒的效果。
本发明的钨合金前驱复合粉体的制备方法，还包括在混合溶液中加入草酸调整pH后，进行加热至反应完全，然后再去除溶剂。通过对混合溶液进行加热不仅能缩短反应时间，还能促进反应完全以达到金属离子的100％回收。
本发明的陶瓷氧化铝增强钨合金的制备方法所采用的技术方案为：
一种陶瓷氧化铝增强钨合金的制备方法，包括以下步骤：
1)提供偏钨酸铵、可溶性铝盐的混合溶液，在混合溶液中加草酸至pH不大于1.5，反应完全，然后去除溶剂得到混合粉体；
2)将所得混合粉体进行煅烧，然后采用还原性气体进行还原，得到复合钨粉；
3)将所得的复合钨粉压制成型，然后烧结，即得。
本发明的陶瓷氧化铝增强钨合金的制备方法，采用液-液混合方法，将偏钨酸铵和可溶 性铝盐在溶液中混匀，然后通过在混合溶液中加入草酸产生钨酸和草酸铝沉淀，溶液中氢离子和钨酸根离子会反应生成钨酸沉淀；草酸根离子和铝离子反应生成草酸铝沉淀，由于钨酸和草酸铝共同反应共同沉淀的原因，能够避免钨原子核和铝原子核因为质量差距较大在沉淀过程中产生的偏析，大大提高了各成分在混合粉体中的均匀程度，将混合粉体进行煅烧、气体还原，气体还原过程中钨的氧化物在气氛中挥发并转入气相，以蒸汽形式被还原并沉淀在低价氧化钨或第二相陶瓷氧化铝表面，形成成分分布均匀的复合钨粉；烧结过程中，陶瓷氧化铝颗粒不仅能抑制杂质元素在钨合金晶界处偏聚，降低合金中的O，P等杂质和晶界偏析，改善钨合金内部元素分布，而且陶瓷氧化铝弥散相细小且在钨基体中均匀分布，解决了钨合金致密度、第二相均匀性、强度及抗热蠕变性能等诸多问题。
上述的陶瓷氧化铝增强钨合金的制备方法，还包括将烧结所得钨合金进行锻造或轧制。通过将烧结态的钨合金通过锻造或轧制，可以进一步提高钨合金的致密度，从而提高其强度、耐磨损和耐冲蚀性能。所述锻造的道次变形量为5～8％。优选的，所述锻造为旋锻。所述轧制的道次变形量为2～5％。
为了提高陶瓷氧化铝增强钨合金的性能，优选的，所述混合溶液中，钨元素和铝元素的质量比为97～99:0.529～1.588。
本发明的陶瓷氧化铝增强钨合金所采用的技术方案为：
一种采用上述的陶瓷氧化铝增强钨合金的制备方法制得的陶瓷氧化铝增强钨合金。
本发明的陶瓷氧化铝增强钨合金，采用上述制备方法制得，钨合金中的陶瓷氧化铝第二相，不仅解决了传统第二相弥散增强钨合金晶粒粗大、第二相分布不均、易引入杂质等问题，而且高硬度氧化铝大幅度提高了钨合金的耐磨损耐冲蚀的性能，为钨合金在特殊工况下(如磨损、冲蚀、腐蚀等工况)的应用和发展提供了新的方向。
具体实施方式
钨合金中各组分的均匀程度对钨合金本身的性能有重要的影响，为了提高钨合金中的性能，本发明提供了一种钨合金前驱复合粉体的制备方法，包括以下步骤：
提供偏钨酸铵、可溶性铝盐的混合溶液，在混合溶液中加草酸至pH不大于1.5，反应完全，然后去除溶剂得到混合粉体。
本发明的钨合金前驱复合粉体的制备方法，通过液-液混合后采用草酸对pH进行调节，溶液中氢离子和钨酸根离子会反应生成钨酸沉淀；草酸根离子和铝离子反应生成草酸铝沉淀，由于钨酸和草酸铝共同反应共同沉淀的原因，能够避免因钨原子核和铝原子核质量差距较大造成的严重偏析，提高所得粉体中钨酸和草酸铝之间的均匀程度，使其达到分子级 混合，为提高钨合金的高温耐磨损耐冲蚀性能提供了原料基础。
偏钨酸铵的浓度越高，反应形核率越高、颗粒越细小，为了减小混合粉体中颗粒粒径，同时考虑偏钨酸铵在水中的溶解度，所述混合溶液中偏钨酸铵的质量浓度为1.9～3.033g/mL。
混合溶液中偏钨酸铵和可溶性铝盐的量可根据钨合金成分进行设置，混合溶液中偏钨酸铵和可溶性铝盐的相对含量影响钨合金的性能，为了提高钨合金的性能，优选的，所述混合溶液中，钨元素和铝元素的质量比为97～99:0.529～1.588。
所述可溶性铝盐为铝的硝酸盐、硫酸盐、卤化物中的至少一种，如可以选择硫酸铝、硝酸铝中的至少一种。
上述的钨合金前驱复合粉体的制备方法，还包括将所得混合粉体进行煅烧，然后用还原性气体进行还原。通过煅烧可以将复合粉体转化为钨和铝的氧化物，采用还原性气体进行还原可将钨的氧化物转化为钨。氧化铝具有高的硬度、良好的化学稳定性，能够提高钨合金的耐磨性、抗高温性和抗腐蚀能力。
为了提高煅烧过程形成氧化物的效率并降低能耗，优选的，所述煅烧的温度为550～650℃，煅烧的时间为0.5～2h。优选的，煅烧前将混合粉料铺展成厚度为3～6mm的料层。
所述还原采用的还原性气体为氢气。采用氢气进行还原的过程中，钨的氧化物在氢气气氛中挥发并转入气相，以蒸汽形式被还原并沉积在低价氧化物或第二相陶瓷氧化铝表面，形成成分均匀的复合钨粉。
采用氢气还原的次数为两次，第一次还原的温度为580～630℃，第二次还原的温度为880～920℃。优选的，所述第一次还原的时间为4～7h。第二次还原的时间为8～12h。为了降低能耗，两次还原过程中，控制料层的厚度为3～6mm。
为了进一步缩短制备时间、加快化学反应的进行，并在短时间内使反应完全以达到金属离子的100％回收，在混合溶液中加草酸的过程中，对混合溶液进行加热。另外对混合溶液进行加热还给溶液中的反应提供了足够的动力，使沉淀反应形核速率增大，可以达到细化晶粒的效果。优选的，在混合溶液中加草酸的过程中，对混合溶液进行加热的温度为60～100℃。
本发明的钨合金前驱复合粉体的制备方法，还包括在混合溶液中加入草酸调整pH后，进行加热至反应完全，然后再去除溶剂。通过对混合溶液进行加热不仅能缩短反应时间，还能促进反应完全以达到金属离子的100％回收。
所述去除溶剂是将反应完全的混合溶液进行固液分离，然后再将所得的固体进行干燥。固液分离可以采用抽滤或离心的方法进行。
本发明还提供了一种陶瓷氧化铝增强钨合金的制备方法，包括以下步骤：
1)提供偏钨酸铵、可溶性铝盐的混合溶液，在混合溶液中加草酸至pH不大于1.5，反应完全，然后去除溶剂得到混合粉体；
2)将所得混合粉体进行煅烧，然后采用还原性气体进行还原，得到复合钨粉；
3)将所得的复合钨粉压制成型，然后烧结，即得。
本发明的陶瓷氧化铝增强钨合金的制备方法，采用液-液混合方法，将偏钨酸铵和可溶性铝盐在溶液中混匀，然后通过在混合溶液中加入草酸产生钨酸和草酸铝沉淀，溶液中氢离子和钨酸根离子会反应生成钨酸沉淀；草酸根离子和铝离子反应生成草酸铝沉淀，由于钨酸和草酸铝共同反应共同沉淀的原因，能够避免钨原子核和铝原子核因为质量差距较大在沉淀过程中产生的偏析，大大提高了各成分在混合粉体中的均匀程度，将混合粉体进行煅烧、气体还原，气体还原过程中钨的氧化物在气氛中挥发并转入气相，以蒸汽形式被还原并沉淀在低价氧化钨或第二相陶瓷氧化铝表面，形成成分分布均匀的复合钨粉；烧结过程中，陶瓷氧化铝颗粒不仅能抑制杂质元素在钨合金晶界处偏聚，降低合金中的O，P等杂质和晶界偏析，改善钨合金内部元素分布，而且陶瓷氧化铝弥散相细小且在钨基体中均匀分布，解决了钨合金致密度、第二相均匀性、强度及抗热蠕变性能等诸多问题。
步骤3)中进行压制成型的压力以及保压时间与选择的烧结方法有关，如采用真空中频感应烧结时，压制成型的压力为180～200MPa，保压时间为2～5min；采用放电等离子体烧结时，压制成型采用的压力为30～60MPa，保压时间由烧结时间决定。
放电等离子体烧结(SparkPlasmaSintering或SPS)，又称为等离子体电火花烧结，一般采用放电等离子烧结炉进行烧结。放电等离子烧结炉同时具备加压成型和烧结的功能，使用时需要向粉体样品施加初始压力(素坯成型)，然后进行烧结。烧结过程中，首先施加脉冲电流，在脉冲电流的作用下，粉末颗粒接触点产生放电等离子，颗粒表面由于活化产生微放热现象，然后关闭脉冲电源，对样品进行电阻加热，直至达到预定的烧结温度并且样品收缩完成为止，最后卸压。一般情况下，烧结过程中一直保持加压状态，直至结束卸压，而且加压状态的压力与初始压力保持基本不变。
步骤3)中进行烧结时，可以采用现有技术中制备钨合金的烧结方法。所述烧结为真空中频感应烧结或放电等离子体烧结。真空中频感应烧结的温度为1400～1500℃，时间为4～8h；放电等离子体烧结的温度为1180～1250℃，时间为3～5min。由于放电等离子体烧结 的温度低、时间短，并且能在较低的烧结温度获得较高致密度、较高强度以及较小晶粒尺寸的合金，优选采用放电等离子体烧结。
上述陶瓷氧化铝增强钨合金的制备方法，还包括将烧结所得钨合金进行锻造或轧制。通过将烧结态的钨合金通过锻造或轧制，可以进一步提高钨合金的致密度，从而提高其强度、耐磨损和耐冲蚀性能。所述锻造的道次变形量为5～8％。优选的，所述锻造为旋锻。所述轧制的道次变形量为2～5％。
钨合金经过锻造或轧制后内部存在很大的应力，需经热处理消除内应力以达到材料性能稳定的目的。优选的，上述的制备方法，还包括在锻造或轧制后进行热处理；所述热处理的温度为1100～1300℃，热处理的时间为2～4h。
为了提高陶瓷氧化铝增强钨合金的性能，优选的，所述混合溶液中，钨元素和铝元素的质量比为97～99:0.529～1.588。
本发明还提供了一种采用上述的制备方法制得的陶瓷氧化铝增强钨合金。
本发明的陶瓷氧化铝增强钨合金，采用上述制备方法制得，钨合金中的陶瓷氧化铝第二相，不仅解决了传统第二相弥散增强钨合金晶粒粗大、第二相分布不均、易引入杂质等问题，而且高硬度氧化铝大幅度提高了钨合金的耐磨损耐冲蚀的性能，为钨合金在特殊工况下(如磨损、冲蚀、腐蚀等工况)的应用和发展提供了新的方向。
以下结合具体实施方式对本发明的技术方案作进一步的说明。
钨合金前驱复合粉体的制备方法的实施例1
本实施例的钨合金前驱复合粉体的制备方法，包括以下步骤：
1)将138.0kg偏钨酸铵(AMT)和1.34kg硫酸铝[Al 2(SO 4) 3]溶于45.5L蒸馏水中，待固体全部溶解之后得到混合溶液；
将所得混合溶液加入草酸调节pH＝1.5，然后采用100℃的水浴进行加热，待混合溶液的温度升至100℃后，继续采用100℃的水浴加热，加热过程中对混合溶液一直进行搅拌，待其反应完全，抽滤、干燥，得到混合粉体；
2)将所得混合粉体铺展成厚度为2mm的料层后在550℃下煅烧1h，然后将煅烧产物置于管式还原炉内，铺展成厚度为3mm的料层后，通入氢气在590℃下还原7h，然后过60目筛网，取筛下物重新置于管式还原炉中，铺展成厚度为3mm的料层后，通入氢气在880℃下还原12h，然后过60目筛网，取筛下物，得到复合钨粉，即得。
钨合金前驱复合粉体的制备方法的实施例2
本实施例的钨合金前驱复合粉体的制备方法，包括以下步骤：
1)将137.45kg偏钨酸铵(AMT)和10.53kg硫酸铝[Al 2(SO 4) 3]溶于49.33L蒸馏水中，待固体全部溶解之后得到混合溶液；
将所得混合溶液加入草酸调节pH＝1.5，然后采用90℃的水浴进行加热，待混合溶液的温度升至90℃后，继续采用90℃的水浴加热，加热过程中对混合溶液一直进行搅拌，待其反应完全，抽滤、干燥，得到混合粉体；
2)将所得混合粉体铺展成厚度为6mm的料层后在550℃下煅烧1.5h，然后将煅烧产物置于管式还原炉内，铺展成厚度为4mm的料层后，通入氢气在600℃下还原6h，然后过80目筛网，取筛下物重新置于管式还原炉中，铺展成厚度为4mm的料层后，通入氢气在890℃下还原11h，然后过80目筛网，取筛下物，得到复合钨粉，即得。
钨合金前驱复合粉体的制备方法的实施例3
本实施例的钨合金前驱复合粉体的制备方法，包括以下步骤：
1)将134.40kg偏钨酸铵(AMT)和22.06kg硝酸铝[Al(NO 3) 3·9H 2O]溶于52.15L蒸馏水中，待固体全部溶解之后得到混合溶液；
将所得混合溶液加入草酸调节pH＝1.0，然后采用90℃的水浴进行加热，待混合溶液的温度升至90℃后，继续采用90℃的水浴加热，加热过程中对混合溶液一直进行搅拌，待其反应完全，抽滤、干燥，得到混合粉体；
2)将所得混合粉体铺展成厚度为7mm的料层后在550℃下煅烧2h，然后将煅烧产物置于管式还原炉内，铺展成厚度为5mm的料层后，通入氢气在610℃下还原5h，然后过100目筛网，取筛下物重新置于管式还原炉中，铺展成厚度为5mm的料层后，通入氢气在900℃下还原10h，然后过100目筛网，取筛下物，得到复合钨粉，即得。
钨合金前驱复合粉体的制备方法的实施例4
本实施例的钨合金前驱复合粉体的制备方法，包括以下步骤：
1)将121.93kg偏钨酸铵(AMT)和36.76kg硝酸铝[Al(NO 3) 3·9H 2O]溶于63L蒸馏水中，待固体全部溶解之后得到混合溶液；
将所得混合溶液加入草酸调节pH＝1.0，然后采用85℃的水浴进行加热，待混合溶液的温度升至85℃后，继续采用85℃的水浴加热，加热过程中对混合溶液一直进行搅拌，待其反应完全，抽滤、干燥，得到混合粉体；
2)将所得混合粉体铺展成厚度为6mm的料层后在600℃下煅烧0.5h，然后将煅烧产物置于管式还原炉内，铺展成厚度为6mm的料层后，通入氢气在620℃下还原5h，然后过120目筛网，取筛下物重新置于管式还原炉中，铺展成厚度为6mm的料层后，通入氢 气在900℃下还原9h，然后过120目筛网，取筛下物，得到复合钨粉，即得。
钨合金前驱复合粉体的制备方法的实施例5
本实施例的钨合金前驱复合粉体的制备方法，包括以下步骤：
1)将135.79kg偏钨酸铵(AMT)和14.71kg硝酸铝[Al(NO 3) 3·9H 2O]溶于50.17L蒸馏水中，待固体全部溶解之后得到混合溶液；
将所得混合溶液加入草酸调节pH＝0.5，然后采用90℃的水浴进行加热，待混合溶液的温度升至90℃后，继续采用90℃的水浴加热，加热过程中对混合溶液一直进行搅拌，待其反应完全，抽滤、干燥，得到混合粉体；
2)将所得混合粉体铺展成厚度为8mm的料层后在650℃下煅烧1h，然后将煅烧产物置于管式还原炉内，铺展成厚度为6mm的料层后，通入氢气在620℃下还原4h，然后过100目筛网，取筛下物重新置于管式还原炉中，铺展成厚度为6mm的料层后，通入氢气在920℃下还原8h，然后过100目筛网，取筛下物，得到复合钨粉，即得。
钨合金前驱复合粉体的制备方法的实施例6
本实施例的钨合金前驱复合粉体的制备方法，包括以下步骤：
1)将136.48kg偏钨酸铵(AMT)和11.03kg硝酸铝[Al(NO 3) 3·9H 2O]溶于49.16L蒸馏水中，待固体全部溶解之后得到混合溶液；
将所得混合溶液加入草酸调节pH＝0.5，然后采用65℃的水浴进行加热，待混合溶液的温度升至65℃后，继续采用65℃的水浴加热，加热过程中对混合溶液一直进行搅拌，待其反应完全，抽滤、干燥，得到混合粉体；
2)将所得混合粉体铺展成厚度为7mm的料层后在550℃下煅烧2h，然后将煅烧产物置于管式还原炉内，铺展成厚度为5mm的料层后，通入氢气在610℃下还原5h，然后过100目筛网，取筛下物重新置于管式还原炉中，铺展成厚度为5mm的料层后，通入氢气在900℃下还原10h，然后过100目筛网，取筛下物，得到复合钨粉，即得。
钨合金前驱复合粉体的制备方法的实施例7
本实施例的钨合金前驱复合粉体的制备方法，包括以下步骤：
1)将137.17kg偏钨酸铵(AMT)和10.06kg硫酸铝[Al 2(SO 4) 3]溶于48.06L蒸馏水中，待固体全部溶解之后得到混合溶液；
将所得混合溶液加入草酸调节pH＝1.0，然后采用75℃的水浴进行加热，待混合溶液的温度升至75℃后，继续采用75℃的水浴加热，加热过程中对混合溶液一直进行搅拌，待其反应完全，抽滤、干燥，得到混合粉体；
2)将所得混合粉体铺展成厚度为6mm的料层后在550℃下煅烧1.5h，然后将煅烧产物置于管式还原炉内，铺展成厚度为4mm的料层后，通入氢气在600℃下还原6h，然后过80目筛网，取筛下物重新置于管式还原炉中，铺展成厚度为4mm的料层后，通入氢气在890℃下还原11h，然后过80目筛网，取筛下物，得到复合钨粉，即得。
钨合金前驱复合粉体的制备方法的实施例8
本实施例的钨合金前驱复合粉体的制备方法，包括以下步骤：
1)将138.21kg偏钨酸铵(AMT)和1.84kg硝酸铝[Al(NO 3) 3·9H 2O]溶于46.68L蒸馏水中，待固体全部溶解之后得到混合溶液；
将所得混合溶液加入草酸调节pH＝0.0，然后采用90℃的水浴进行加热，待混合溶液的温度升至90℃后，继续采用90℃的水浴加热，加热过程中对混合溶液一直进行搅拌，待其反应完全，抽滤、干燥，得到混合粉体；
2)将所得混合粉体铺展成厚度为7mm的料层后在550℃下煅烧2h，然后将煅烧产物置于管式还原炉内，铺展成厚度为5mm的料层后，通入氢气在610℃下还原5h，然后过100目筛网，取筛下物重新置于管式还原炉中，铺展成厚度为5mm的料层后，通入氢气在900℃下还原10h，然后过100目筛网，取筛下物，得到复合钨粉，即得。
钨合金前驱复合粉体的制备方法的实施例9
本实施例的钨合金前驱复合粉体的制备方法，包括以下步骤：
1)将138.21kg偏钨酸铵(AMT)和1.84kg硝酸铝[Al(NO 3) 3·9H 2O]溶于46.68L蒸馏水中，待固体全部溶解之后得到混合溶液；
将所得混合溶液采用90℃的水浴加热至90℃，然后在混合溶液中加入草酸调节pH＝0，继续采用90℃的水浴加热，加热过程中对混合溶液一直进行搅拌，待其反应完全，抽滤、干燥，得到混合粉体；
2)将所得混合粉体铺展成厚度为7mm的料层后在550℃下煅烧2h，然后将煅烧产物置于管式还原炉内，铺展成厚度为5mm的料层后，通入氢气在610℃下还原5h，然后过100目筛网，取筛下物重新置于管式还原炉中，铺展成厚度为5mm的料层后，通入氢气在900℃下还原10h，然后过100目筛网，取筛下物，得到复合钨粉，即得。
陶瓷氧化铝增强钨合金的制备方法的实施例1
本实施例的陶瓷氧化铝增强钨合金的制备方法，包括以下步骤：
1)将钨合金前驱复合粉体的制备方法的实施例1中制得的复合钨粉放入圆筒状软胶套中，再置于180MPa超高压室内进行冷等静压，保压时间为3min，得到冷压生坯棒，将 生坯棒放入中频感应烧结炉中，通入氢气，在氢气的保护下以2200℃烧结10h，得到烧结态合金棒材；
2)将所得的烧结态合金棒材放入氢气炉中加热之后进行旋锻，即得；旋锻过程中控制旋锻温度为1480℃，道次变形量为5％。
陶瓷氧化铝增强钨合金的制备方法的实施例2
本实施例的陶瓷氧化铝增强钨合金的制备方法，包括以下步骤：
1)将钨合金前驱复合粉体的制备方法的实施例2中制得的复合钨粉放入方形状软胶套中，再置于190MPa超高压室内进行冷等静压，保压时间为2min，得到冷压生坯板，将生坯板放入中频感应烧结炉中，通入氢气，在氢气的保护下以2250℃烧结8h，得到烧结态合金板材；
2)将所得的烧结态合金板材放入氢气炉中加热之后进行轧制，即得；轧制过程中控制轧制温度为1520℃，道次变形量为2％。
陶瓷氧化铝增强钨合金的制备方法的实施例3
本实施例的钨合金前驱复合粉体的制备方法，包括以下步骤：
将钨合金前驱复合粉体的制备方法的实施例3中制得的复合钨粉放入圆筒状软胶套中，再置于200MPa超高压室内进行冷等静压，保压时间为3min，得到冷压生坯棒，将生坯棒放入中频感应烧结炉中，通入氢气，在氢气的保护下以2300℃烧结6h，得到烧结态合金棒材，即得。
陶瓷氧化铝增强钨合金的制备方法的实施例4
本实施例的陶瓷氧化铝增强钨合金的制备方法，包括以下步骤：
将陶瓷氧化铝增强钨合金的制备方法的实施例3中得到的烧结态合金棒材放入氢气炉中加热之后进行旋锻，即得；旋锻过程中控制旋锻温度为1480℃，道次变形量为5％。
陶瓷氧化铝增强钨合金的制备方法的实施例5
本实施例的钨合金前驱复合粉体的制备方法，包括以下步骤：
将钨合金前驱复合粉体的制备方法的实施例4中制得的复合钨粉放入方形状软胶套中，再置于200MPa超高压室内进行冷等静压，保压时间为2min，得到冷压生坯板，将生坯板放入中频感应烧结炉中，通入氢气，在氢气的保护下以2300℃烧结8h，得到烧结态合金板材，即得。
陶瓷氧化铝增强钨合金的制备方法的实施例6
本实施例的陶瓷氧化铝增强钨合金的制备方法，包括以下步骤：
将陶瓷氧化铝增强钨合金的制备方法的实施例5中得到的烧结态合金板材放入氢气炉中加热之后进行轧制，即得；轧制过程中控制轧制温度为1600℃，道次变形量为3％。
陶瓷氧化铝增强钨合金的制备方法的实施例7
本实施例的陶瓷氧化铝增强钨合金的制备方法，包括以下步骤：
将钨合金前驱复合粉体的制备方法的实施例5中制得的复合钨粉放入石墨中，再置于放电等离子烧结炉中进行烧结，烧结温度为2100℃，保温时间为5min，烧结压力30MPa，即得合金。
陶瓷氧化铝增强钨合金的制备方法的实施例8
本实施例的陶瓷氧化铝增强钨合金的制备方法，包括以下步骤：
将钨合金前驱复合粉体的制备方法的实施例6中制得的复合钨粉放入石墨中，再置于放电等离子烧结炉中进行烧结，烧结温度为2000℃，保温时间为3min，烧结压力40MPa，即得合金。
陶瓷氧化铝增强钨合金的制备方法的实施例9
本实施例的陶瓷氧化铝增强钨合金的制备方法，包括以下步骤：
将钨合金前驱复合粉体的制备方法的实施例7中制得的复合钨粉放入石墨中，再置于放电等离子烧结炉中进行烧结，烧结温度为1950℃，保温时间为5min，烧结压力50MPa，即得合金。
陶瓷氧化铝增强钨合金的制备方法的实施例10
本实施例的陶瓷氧化铝增强钨合金的制备方法，包括以下步骤：
将钨合金前驱复合粉体的制备方法的实施例8中制得的复合钨粉放入石墨中，再置于放电等离子烧结炉中进行烧结，烧结温度为1900℃，保温时间为5min，烧结压力50MPa，即得合金。
陶瓷氧化铝增强钨合金的制备方法的实施例11
本实施例的陶瓷氧化铝增强钨合金的制备方法，包括以下步骤：
将钨合金前驱复合粉体的制备方法的实施例9中制得的复合钨粉放入石墨中，再置于放电等离子烧结炉中进行烧结，烧结温度为1900℃，保温时间为5min，烧结压力50MPa，即得合金。
陶瓷氧化铝增强钨合金的实施例
本实施例的陶瓷氧化铝增强钨合金分别是采用陶瓷氧化铝增强钨合金的制备方法的实施例1～11的制备方法制得的，此处不再赘述。
对比例
对比例的钨合金前驱复合粉体的制备方法与钨合金前驱复合粉体的制备方法的实施例9的区别仅在于待混合溶液的温度升至75℃后在混合溶液中加柠檬酸至混合溶液的pH＝1.0，其余完全同实施例9。
将对比例制得的钨合金前驱复合粉体按照陶瓷氧化铝增强钨合金的制备方法的实施例9中陶瓷氧化铝增强钨合金的制备方法制成钨合金。
实验例
取采用陶瓷氧化铝增强钨合金的制备方法的实施例1～11的及对比例中的制得的钨合金，采用截线法测定合金的晶粒大小，采用阿基米德排水法测定合金密度并计算相对密度(相对于理论密度)，采用HVS-1000A显微硬度计测定合金的显微硬度，同时采用SHIMADZUAG-I250KN精密万能试验机测定合金的抗拉强度，结果见表1。
表1 钨合金的性能测试结果
Figure PCTCN2019104392-appb-000001
由表1可知，相较于对比例，实施例1～11的钨合金，具有晶粒细小、致密度高、高的抗压强度和高硬度的优点。

Claims (21)

  1. 一种钨合金前驱复合粉体的制备方法，其特征在于：包括以下步骤：
    提供偏钨酸铵、可溶性铝盐的混合溶液，在混合溶液中加草酸至pH不大于1.5，反应完全，然后去除溶剂得到混合粉体。
  2. 根据权利要求1所述的钨合金前驱复合粉体的制备方法，其特征在于：所述混合溶液中偏钨酸铵的质量浓度为1.9～3.033g/mL。
  3. 根据权利要求1所述的钨合金前驱复合粉体的制备方法，其特征在于：所述混合溶液中，钨元素和铝元素的质量比为97～99:0.529～1.588。
  4. 根据权利要求1所述的钨合金前驱复合粉体的制备方法，其特征在于：所述可溶性铝盐为铝的硝酸盐、硫酸盐、卤化物中的至少一种。
  5. 根据权利要求1所述的钨合金前驱复合粉体的制备方法，其特征在于：还包括将所得混合粉体进行煅烧，然后用还原性气体进行还原。
  6. 根据权利要求5所述的钨合金前驱复合粉体的制备方法，其特征在于：所述还原采用的还原性气体为氢气；采用氢气还原的次数为两次；第一次还原的温度为580～630℃，时间为4～7h；第二次还原的温度为880～920℃，时间为8～12h。
  7. 根据权利要求5所述的钨合金前驱复合粉体的制备方法，其特征在于：所述煅烧的温度为550～650℃，煅烧的时间为0.5～2h。
  8. 根据权利要求1所述的钨合金前驱复合粉体的制备方法，其特征在于：在混合溶液中加草酸的过程中，对混合溶液进行加热；所述加热的温度为60～100℃。
  9. 一种陶瓷氧化铝增强钨合金的制备方法，其特征在于：包括以下步骤：
    1)提供偏钨酸铵、可溶性铝盐的混合溶液，在混合溶液中加草酸至pH不大于1.5，反应完全，然后去除溶剂得到混合粉体；
    2)将所得混合粉体进行煅烧，然后采用还原性气体进行还原，得到复合钨粉；
    3)将所得的复合钨粉压制成型，然后烧结，即得。
  10. 根据权利要求9所述的陶瓷氧化铝增强钨合金的制备方法，其特征在于：所述混合溶液中偏钨酸铵的质量浓度为1.9～3.033g/mL。
  11. 根据权利要求9所述的陶瓷氧化铝增强钨合金的制备方法，其特征在于：所述可溶性铝盐为铝的硝酸盐、硫酸盐、卤化物中的至少一种。
  12. 根据权利要求9所述的陶瓷氧化铝增强钨合金的制备方法，其特征在于：所述还 原采用的还原性气体为氢气；采用氢气还原的次数为两次；第一次还原的温度为580～630℃，时间为4～7h；第二次还原的温度为880～920℃，时间为8～12h。
  13. 根据权利要求9所述的陶瓷氧化铝增强钨合金的制备方法，其特征在于：所述煅烧的温度为550～650℃，煅烧的时间为0.5～2h。
  14. 根据权利要求9所述的陶瓷氧化铝增强钨合金的制备方法，其特征在于：在混合溶液中加草酸的过程中，对混合溶液进行加热；所述加热的温度为60～100℃。
  15. 根据权利要求9所述的陶瓷氧化铝增强钨合金的制备方法，其特征在于：所述压制成型的压力为180～200MPa，保压时间为2～5min；所述烧结为真空中频感应烧结，烧结温度为1180～1250℃，时间为3～5min。
  16. 根据权利要求9所述的陶瓷氧化铝增强钨合金的制备方法，其特征在于：还包括将烧结所得钨合金进行锻造或轧制。
  17. 根据权利要求16所述的陶瓷氧化铝增强钨合金的制备方法，其特征在于：所述锻造的道次变形量为5～8％。
  18. 根据权利要求16所述的陶瓷氧化铝增强钨合金的制备方法，其特征在于：所述轧制的道次变形量为2～5％。
  19. 根据权利要求16所述的陶瓷氧化铝增强钨合金的制备方法，其特征在于：还包括在锻造或轧制后进行热处理；所述热处理的温度为1100～1300℃，热处理的时间为2～4h。
  20. 根据权利要求9所述的陶瓷氧化铝增强钨合金的制备方法，其特征在于：所述混合溶液中，钨元素和铝元素的质量比为97～99:0.529～1.588。
  21. 一种采用如权利要求9所述的陶瓷氧化铝增强钨合金的制备方法制得的陶瓷氧化铝增强钨合金。
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