Doped tungsten oxide composite material and preparation method and application thereof

Abstract

The invention belongs to the technical field of tungsten and tungsten products, and particularly relates to a doped tungsten oxide composite material and a preparation method and application thereof. The invention provides a method for preparing doped tungsten oxide by a chemical precipitation method, which comprises the following steps: dispersing two aqueous solutions in the form of tiny liquid drops in an atomization manner, and carrying out chemical reaction at the moment of contact and mixing, so that rare earth element cations are rapidly combined with hydroxyl anions in an alkaline environment; the preparation method comprises the following steps: adding ammonium paratungstate into an ammonium paratungstate precursor, quickly drying at high temperature, nucleating to obtain the doped ammonium paratungstate precursor, realizing uniform distribution of rare earth elements, and calcining at high temperature to obtain the doped tungsten oxide composite material with uniform particle size. The invention aims to provide a preparation method of a short-process doped composite material powder which can be efficiently industrialized and is uniform in nanoscale particle size.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tungsten and tungsten products, and particularly relates to a doped tungsten oxide composite material and a preparation method and application thereof. BACKGROUND

[0002] Tungsten has good physical and chemical properties, such as a high melting point, high thermal conductivity and high high-temperature strength. The particle size and uniformity of the original tungsten powder have a great influence on the performance of tungsten alloy. In addition, tungsten powder is the most important raw material for preparing cemented carbide. The addition of rare earth elements in tungsten alloy and cemented carbide can improve the performance of the alloy. The traditional method is to add rare earth oxide powder and tungsten powder or tungsten carbide powder for composite ball milling to realize the addition of rare earth oxides, but this method cannot guarantee the uniformity of the addition of rare earth elements. SUMMARY

[0003] The application aims to provide a doped tungsten oxide composite material and a preparation method and application thereof.

[0004] In order to achieve the above-mentioned purpose, the application provides the following technical scheme: The application provides a preparation method of a doped tungsten oxide composite material, comprising the following steps: The tungsten salt solution and the rare earth metal salt solution are respectively atomized, and the atomized mist droplets are compounded to obtain a doped ammonium paratungstate precursor; the compounding environment temperature is not higher than 300 DEG C; The doped ammonium paratungstate precursor is calcined to obtain the doped tungsten oxide composite material.

[0005] Preferably, the tungsten salt solution comprises at least one of ammonium tungstate solution and ammonium metatungstate solution.

[0006] Preferably, the rare earth metal salt solution comprises at least one of cerium salt solution, lanthanum salt solution, yttrium salt solution and ytterbium salt solution.

[0007] Preferably, the content of WO3 in the tungsten salt solution is 100-370 g / L. The content of the rare earth metal salt in the rare earth metal salt solution is not higher than 10 g / L.

[0008] Preferably, the volume ratio of the tungsten salt solution to the rare earth metal salt solution is 1:1.

[0009] Preferably, the compounding environment temperature is 120-300 DEG C.

[0010] Preferably, the atomization frequency is 1000-20000 Hz.

[0011] Preferably, the temperature of the calcination is 600-1100℃, and the atmosphere of the calcination is air.

[0012] The application further provides the doped tungsten oxide composite material prepared by the preparation method.

[0013] The application further provides application of the doped tungsten oxide composite material in preparation of an alloy.

[0014] The application provides a preparation method of a doped tungsten oxide composite material, comprising the following steps: atomizing a tungsten salt solution and a rare earth metal salt solution respectively, and compounding the atomized mist drops to obtain a doped ammonium paratungstate precursor; the compounding is performed at an ambient temperature of no higher than 300℃; and the doped ammonium paratungstate precursor is calcined to obtain the doped tungsten oxide composite material.

[0015] Since the tungsten salt is generally alkaline, the rare earth metal ions in the rare earth metal salt solution will immediately form rare earth hydroxide precipitates when directly mixed with the hydroxyl ions in the tungsten salt, resulting in uneven distribution of the rare earth elements. Therefore, the application provides a method for preparing a doped tungsten oxide composite material by a chemical precipitation method, in which the two aqueous solutions are dispersedly distributed in the form of tiny droplets and chemically react in the instant of contact and mixing, the rare earth element cations rapidly combine with the hydroxyl anions in the alkaline environment, and rapidly dry and nucleate under the action of high temperature to obtain the doped ammonium paratungstate precursor, realizing uniform distribution of the rare earth elements. Subsequently, high-temperature calcination can obtain the nanoscale doped tungsten oxide composite material with uniform particle size, and the nanoscale rare earth-tungsten composite oxide is uniformly distributed at the grain boundaries. The application is dedicated to providing a preparation method of a doped composite material powder with efficient industrialization, nanoscale uniform particle size and a short process. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 SEM image of the doped ammonium paratungstate precursor prepared for Example 2; Figure 2 XRD image of the doped ammonium paratungstate precursor prepared for Example 2; Figure 3 SEM and EDS images of the doped tungsten oxide composite material obtained from Example 2; Figure 4 XRD image of the doped tungsten oxide composite material obtained from Example 2; Figure 5 Fracture morphology and force-displacement curve of the hard alloy prepared from the doped tungsten oxide composite material of Example 2. DETAILED DESCRIPTION

[0017] The application provides a preparation method of a doped tungsten oxide composite material, comprising the following steps: The tungsten salt solution and the rare earth metal salt solution are atomized respectively, and the atomized mist droplets are compounded to obtain a doped ammonium paratungstate precursor. The doped ammonium paratungstate precursor is calcined to obtain the doped tungsten oxide composite material.

[0018] The application atomizes the tungsten salt solution and the rare earth metal salt solution respectively, and compounds the atomized mist droplets to obtain a doped ammonium paratungstate precursor.

[0019] In the application, the tungsten salt solution preferably comprises at least one of an ammonium tungstate solution and an ammonium metatungstate solution; the content of WO3 in the tungsten salt solution is preferably 100-370 g / L, and can be specifically 100 g / L, 150 g / L, 200 g / L, 250 g / L, 300 g / L, 350 g / L or 370 g / L.

[0020] In the application, the rare earth metal salt solution preferably comprises at least one of a cerium salt solution, a lanthanum salt solution, a yttrium salt solution and a ytterbium salt solution. In the application, the content of the rare earth metal salt in the rare earth metal salt solution is preferably not higher than 10 g / L. In the application, the cerium salt solution preferably comprises a cerium nitrate solution.

[0021] In the application, the volume ratio of the tungsten salt solution to the rare earth metal salt solution is preferably 1:1.

[0022] The application does not have special limitations on the atomization process, and the process well known to those skilled in the art can be adopted. In the application, the frequency of atomization is preferably 1000-20000 Hz, and can be specifically 1000 Hz, 5000 Hz, 10000 Hz, 15000 Hz or 20000 Hz. In the application, the atomization environment temperature is the same as the compounding environment temperature, and will not be described here.

[0023] In the application, the compounding environment temperature is not higher than 300 DEG C, and is preferably 120-300 DEG C, and can be specifically 120 DEG C, 180 DEG C, 200 DEG C, 250 DEG C or 300 DEG C. In the compounding process, the droplets chemically react in the instant of contact and mixing, the rare earth element cations combine with the hydroxyl anions in the alkaline environment rapidly, and the doped ammonium paratungstate precursor is obtained through rapid drying and nucleation under the action of high temperature.

[0024] After obtaining the doped ammonium paratungstate precursor, the application calcines the doped ammonium paratungstate precursor to obtain the doped tungsten oxide composite material.

[0025] In the present application, the temperature of the calcination is preferably 600-1100℃, and can be specifically 600℃, 700℃, 800℃, 900℃, 1000℃, or 1100℃; the time of the calcination is preferably 4h; and the atmosphere of the calcination is preferably air.

[0026] The present application also provides a doped tungsten oxide composite material prepared by the preparation method described above, which comprises a micron-sized tungsten oxide matrix and a nanometer-sized rare earth-tungsten composite oxide doped at the grain boundaries of the micron-sized tungsten oxide matrix. In the present application, the chemical composition of the nanometer-sized rare earth-tungsten composite oxide is preferably Ce4W9O 33 In the present application, the mass percentage of the rare earth element in the doped tungsten oxide composite material is preferably not higher than 3%.

[0027] The present application also provides an application of the doped tungsten oxide composite material described above in the preparation of alloys.

[0028] Unless otherwise specified, the materials and equipment used in the present application are commercially available in the art.

[0029] The technical solutions in the present application will be clearly and completely described below in combination with the embodiments in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative efforts fall within the scope of the present application.

[0030] Embodiment 1 An ammonium tungstate aqueous solution (the WO3 content is 370g / L) and a cerium nitrate solution (the cerium nitrate content is 5g / L) with a volume ratio of 1:1 are respectively atomized, and the obtained mist droplets are combined to obtain a doped ammonium paratungstate precursor, wherein the atomization frequency is 20000Hz, and the environmental temperature is 180℃. The obtained doped ammonium paratungstate precursor is calcined at 800℃ in an air atmosphere for 4h to obtain a doped tungsten oxide composite material, wherein the mass percentage of the rare earth cerium is 2.2%.

[0031] Embodiment 2 An ammonium tungstate aqueous solution (the WO3 content is 370g / L) and a cerium nitrate solution (the cerium nitrate content is 2.2g / L) with a volume ratio of 1:1 are respectively atomized, and the obtained mist droplets are combined to obtain a doped ammonium paratungstate precursor, wherein the atomization frequency is 20000Hz, and the environmental temperature is 220℃. The obtained doped ammonium paratungstate precursor is calcined at 800℃ in an air atmosphere for 4h to obtain a doped tungsten oxide composite material, wherein the mass percentage of the rare earth cerium is 0.9%.

[0032] Performance test Test example 1 Figure 1 and Figure 2 respectively are SEM and XRD diagrams of the doped ammonium paratungstate precursor prepared in example 2, it can be seen that the doped ammonium paratungstate precursor obtained by the present application is a tetrahydrate compound structure, and the spherical particle size is micron level.

[0033] Figure 3 are SEM and EDS diagrams of the doped tungsten oxide composite material obtained in example 2, Figure 4 is an XRD diagram of the doped tungsten oxide composite material obtained in example 2, it can be seen that after calcination, the rare earth elements are uniformly distributed on the tungsten oxide matrix, and after calcination, the composite material forms a uniformly distributed Ce4W9O 33 phase.

[0034] Test example 2 The doped tungsten oxide composite material obtained in example 2 is used to prepare WC-6.5Co cemented carbide; The specific process is: the doped tungsten oxide composite material is subjected to hydrogen reduction, carbonization and sintering in sequence, wherein the temperature of hydrogen reduction is 900℃, the time is 1h; the temperature of carbonization is 1400℃, the time is 2h; the temperature of sintering is 1410℃, the time is 1h, and the pressure is 9MPa; The obtained WC-6.5Co cemented carbide is subjected to performance test according to GB / T385-12015; and untreated tungsten powder is used as a control; Figure 5 (a) of which is the fracture morphology of the WC-6.5Co cemented carbide obtained in example 2, Figure 5 (b) of which is the fracture morphology of the WC-6.5Co cemented carbide obtained from untreated tungsten powder, Figure 5 (c) of which is the force-displacement curve; The specific results are shown in table 1; Table 1 Performance results of the alloy prepared by the composite material of example 2

[0035] It can be seen that the mechanical properties of the rare earth doped alloy are obviously improved.

[0036] Although the above examples make a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the present embodiments without creativity, which all belong to the protection scope of the present application.

Claims

1. A method for preparing a doped tungsten oxide composite material, characterized in that, Includes the following steps: Tungsten salt solution and rare earth metal salt solution are atomized separately, and the atomized droplets are combined to obtain a doped ammonium paratungstate precursor; the ambient temperature for the combination is not higher than 300℃. The doped ammonium paratungstate precursor was calcined to obtain the doped tungsten oxide composite material.

2. The preparation method according to claim 1, characterized in that, The tungsten salt solution includes at least one of ammonium tungstate solution and ammonium metatungstate solution.

3. The preparation method according to claim 1, characterized in that, The rare earth metal salt solution includes at least one of cerium salt solution, lanthanum salt solution, yttrium salt solution, and ytterbium salt solution.

4. The preparation method according to claim 1, characterized in that, The WO3 content in the tungsten salt solution is 100~370g / L; The content of rare earth metal salts in the rare earth metal salt solution is not higher than 10 g / L.

5. The preparation method according to claim 4, characterized in that, The volume ratio of the tungsten salt solution to the rare earth metal salt solution is 1:

1.

6. The preparation method according to claim 1, characterized in that, The ambient temperature of the composite is 120~300℃.

7. The preparation method according to claim 1, characterized in that, The atomization frequency is 1000~20000Hz.

8. The preparation method according to claim 1, characterized in that, The calcination temperature is 600~1100℃, and the calcination atmosphere is air.

9. The doped tungsten oxide composite material prepared by the preparation method according to any one of claims 1 to 8, characterized in that, It includes a micron-sized tungsten oxide matrix and nano-sized rare earth-tungsten composite oxides doped at the grain boundaries of the micron-sized tungsten oxide matrix.

10. The application of the doped tungsten oxide composite material according to claim 9 in the preparation of alloys.

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