A Nb@ZrO 2 Core-shell structure material and preparation method thereof

Abstract

The present invention discloses a Nb@ZrO2 core-shell structure material and a preparation method thereof. The preparation method comprises the following steps: S1. Mix SDS, Nb and water, stir, and ultrasonically disperse to form a first suspension; then carry out suction filtration, drying, calcination, then washing, suction filtration and drying to obtain a first powder; S2. Mix CTAB, ZrO2 and water, stir, and ultrasonically disperse to form a second suspension; then carry out suction filtration, drying, calcination, then washing, suction filtration and drying to obtain a second powder; S3. Add the first powder to a granulating agent for granulation, then mix the obtained granular material with the second powder, and then add CTAB and water and mix, and mechanically stir to prepare a slurry coating the granular material; S4. Dry and calcine the slurry coating the granular material to obtain the Nb@ZrO2 core-shell structure material. The Nb@ZrO2 core-shell structure material prepared by the present invention constructs a stable core-shell system and avoids the oxidation of Nb by contacting air.

Description

Technical Field

[0001] The present invention relates to the technical field of cemented carbide, and in particular to a Nb@ZrO 2 Core-shell structure material and preparation method thereof. Background Art

[0002] Nb is a refractory metal (melting point 2463℃), which is widely used in aerospace and other fields due to its good mechanical properties at high temperatures. Nb is chemically stable at room temperature, but with the increase of temperature, it oxidizes severely in the air, which limits the application of Nb and its alloys.

[0003] Core-shell nanoparticles are a composite structure formed by coating several layers of uniform nanofilm on the surface of a particle with a size ranging from micrometers to nanometers. The core and shell are connected to each other through physical or chemical action. The chemical inertness of the coating layer in the core-shell composite material can improve the stability of the nanoparticles. Therefore, the core-shell structure material exhibits better physical and chemical properties than a single core particle, and has a wide range of application prospects.

[0004] The document "Study on the Preparation Technology of Surface Coating Modification of Nb and Nb / Si Powder" (Author: Ke Li; Huazhong University of Science and Technology, January 2011) records that the high temperature oxidizability of Nb seriously restricts the preparation and use of Nb-based composite materials under aerobic conditions. By surface modification of Nb powder, a protective layer is formed on the surface of the powder particles. However, at present, the sol-gel method is used to realize ZrO 2 The coating effect of micron Nb powder is still not very ideal. The colloid obtained by the sol-gel method still needs to be calcined at 900℃ after drying. Argon is used for protection during the calcination process, but there is still air in the colloid. After calcination at 900℃, Nb is severely oxidized. Therefore, high-temperature calcination should be avoided under the condition that Nb is exposed to air. Summary of the invention

[0005] In view of this, in order to solve the above technical problems, the present invention aims to provide a Nb@ZrO 2 Core-shell structure material and preparation method thereof, prepared Nb@ZrO 2 The core-shell structure material constructs a stable core-shell system with zirconium oxide ZrO 2 Coating Nb prevents Nb from being oxidized by contact with air.

[0006] The technical solutions adopted are:

[0007] A Nb@ZrO 2 The method for preparing a core-shell structure material comprises the following steps:

[0008] S1. SDS, Nb and water are mixed, mechanically stirred, and ultrasonically dispersed into a first suspension; the first suspension is filtered, dried, calcined, washed, filtered, and dried to obtain a first powder;

[0009] S2. CTAB, ZrO 2 Mixing with water, mechanically stirring, and ultrasonically dispersing into a second suspension; filtering the second suspension, drying, calcining, and then washing, filtering, and drying to obtain a second powder;

[0010] S3. The first powder is added to the molding agent for granulation, and the obtained granular material is mixed with the second powder, and then CTAB and water are added and mixed, and mechanically stirred to prepare a slurry of the coated granular material;

[0011] S4. Dry and calcine the slurry of the coated granular material to obtain a Nb@ZrO2 core-shell structure material.

[0012] Furthermore, in S1, SDS is 2 mmol / L, Nb is 2.5-3.5 g, and water is 150-210 mL.

[0013] Furthermore, in S2, CTAB is 4 mmol / L, ZrO 2 The amount of iodine is 1.5-2.5g, and the amount of water is 90-150mL.

[0014] Furthermore, in S3, CTAB is 4 mmol / L and water is 40-50 mL.

[0015] Furthermore, in S3, the molding agent consists of 10wt%-15wt% of rapeseed oil, 75wt%-80wt% of xylene and 10wt%-15wt% of polyisobutylene.

[0016] Furthermore, the calcination in S4 is carried out in a three-temperature zone tubular electric furnace, with a heating rate of 3-10°C / min, a holding calcination temperature of 150-220°C, a holding time of 1-3h, and an argon atmosphere.

[0017] Furthermore, the calcination temperature is 200°C, the heating rate is 8°C / min, and the holding time is 2h.

[0018] Furthermore, the washing and filtration in S1-S2 are all performed by washing with distilled water and alcohol followed by filtration.

[0019] Further, in S4, after calcination, the mixture is washed, filtered, dried, and sieved through 200 meshes to obtain a Nb@ZrO2 core-shell structure material.

[0020] A Nb@ZrO 2 The core-shell structure material is prepared by the preparation method described in the above scheme.

[0021] The beneficial effects of the present invention are:

[0022] The present invention dries and calcines the slurry of the coated granular material to obtain a Nb@ZrO2 core-shell structure material. The prepared Nb@ZrO2 core-shell structure material has Nb as the core and ZrO as the core. 2 The granular material is coated with the slurry layer by layer to construct a stable core-shell system and obtain a good core-shell structure.

[0023] The present invention uses zirconium oxide ZrO 2 The coating of Nb prevents Nb from being oxidized by contact with air. The core-shell structure material exhibits better physical and chemical properties than the single core particle, laying a solid foundation for improving the mechanical properties and other specific properties of the material, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings involved in the description of the embodiments are briefly introduced below.

[0025] Figure 1 The Nb@ZrO prepared in Example 1 2 XRD pattern of core-shell structure materials.

[0026] Figure 2 The Nb@ZrO prepared in Example 1 2 TEM image of core-shell structure material.

[0027] Figure 3 The Nb@ZrO prepared in Example 2 2 SEM image of core-shell structure material.

[0028] Figure 4 The Nb@ZrO prepared in Example 3 2 SEM image of core-shell structure material. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only partial embodiments of the present invention, not all embodiments. 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.

[0030] Example 1

[0031] A Nb@ZrO 2 The method for preparing a core-shell structure material comprises the following steps:

[0032] S1. 2.5 g of Nb powder and 2 mmol / L SDS dispersant after ball milling were added to a beaker containing 150 mL of distilled water for mechanical ultrasonic stirring, and distilled water was used as a dispersion medium; after dispersion for 2 h, a first suspension was prepared; the first suspension was filtered, dried, calcined at 180 ° C, and the holding time was 2 h. The calcination atmosphere was argon atmosphere, and then washed, filtered, and dried to obtain a first powder;

[0033] S2. 2.5 g ZrO 2 The powder and dispersant 4mmol / L CTAB were added into a beaker containing 150mL distilled water and ultrasonically stirred. After 2.5h of dispersion, the second suspension was prepared. The ZrO 2 The content is 50wt%; the second suspension is filtered, dried, calcined at 180°C, the holding time is 2h, the calcination atmosphere is argon atmosphere, and then washed, filtered, dried, to obtain a second powder;

[0034] S3. Add the first powder to a molding agent for granulation, wherein the molding agent is composed of 15wt% rapeseed oil, 75wt% xylene and 10wt% polyisobutylene. Then, the obtained granular material is mixed with the second powder, and then 4mmol / L CTAB and 50mL water are added to mix, and mechanically stirred to prepare a slurry for coating the granular material;

[0035] S4. The slurry of the coated granular material was dried, the heating rate was 8°C / min, and it was calcined at 200°C for 2h, washed with distilled water and alcohol, filtered 4 times, dried, and sieved through 200 mesh to obtain Nb@ZrO 2 Core-shell structural materials.

[0036] Prepared Nb@ZrO 2 See the XRD diagram of core-shell structure materials for Figure 1 As shown, TEM images refer to Figure 2 shown.

[0037] Example 2

[0038] A Nb@ZrO 2 The method for preparing a core-shell structure material comprises the following steps:

[0039] S1. 3 g of Nb powder after ball milling and 2 mmol / L SDS dispersant were added to a beaker containing 180 mL of distilled water for mechanical ultrasonic stirring, and distilled water was used as a dispersion medium; after dispersion for 2 h, a first suspension was prepared; the first suspension was filtered, dried, calcined at 180 ° C, and the holding time was 2 h. The calcination atmosphere was argon atmosphere, and then washed, filtered, and dried to obtain a first powder;

[0040] S2. 2g ZrO 2The powder and dispersant 4mmol / L CTAB were added into a beaker containing 120mL distilled water and ultrasonically stirred. After 2.5h of dispersion, the second suspension was prepared. The ZrO 2 The content is 40wt%; the second suspension is filtered, dried, calcined at 180°C, the holding time is 2h, the calcination atmosphere is argon atmosphere, and then washed, filtered, dried, to obtain a second powder;

[0041] S3. Add the first powder to a molding agent for granulation, wherein the molding agent is composed of 15wt% rapeseed oil, 75wt% xylene and 10wt% polyisobutylene. Then, the obtained granular material is mixed with the second powder, and then 4mmol / L CTAB and 50mL water are added to mix, and mechanically stirred to prepare a slurry for coating the granular material;

[0042] S4. The slurry of the coated granular material was dried, the heating rate was 8°C / min, and it was calcined at 200°C for 2h, washed with distilled water and alcohol, filtered 4 times, dried, and sieved through 200 mesh to obtain Nb@ZrO 2 Core-shell structural materials.

[0043] Prepared Nb@ZrO 2 See the SEM images of core-shell structure materials for Figure 3 shown.

[0044] Example 3

[0045] A Nb@ZrO 2 The method for preparing a core-shell structure material comprises the following steps:

[0046] S1. 3.5 g of Nb powder and 2 mmol / L SDS dispersant after ball milling were added to a beaker containing 210 mL of distilled water for mechanical ultrasonic stirring, and distilled water was used as a dispersion medium; after dispersion for 2 h, a first suspension was prepared; the first suspension was filtered, dried, calcined at 180 ° C, and the holding time was 2 h. The calcination atmosphere was argon atmosphere, and then washed, filtered, and dried to obtain a first powder;

[0047] S2. 1.5 g ZrO 2 The powder and dispersant 4mmol / L CTAB were added into a beaker containing 90mL distilled water and ultrasonically stirred. After 2.5h of dispersion, the second suspension was prepared. The ZrO 2 The content is 30wt%; the second suspension is filtered, dried, calcined at 180°C, the holding time is 2h, the calcination atmosphere is argon atmosphere, and then washed, filtered, dried, to obtain a second powder;

[0048] S3. Add the first powder to a molding agent for granulation, wherein the molding agent is composed of 15wt% rapeseed oil, 75wt% xylene and 10wt% polyisobutylene. Then, the obtained granular material is mixed with the second powder, and then 4mmol / L CTAB and 50mL water are added to mix, and mechanically stirred to prepare a slurry for coating the granular material;

[0049] S4. The slurry of the coated granular material was dried, the heating rate was 8°C / min, and it was calcined at 200°C for 2h, washed with distilled water and alcohol, filtered 4 times, dried, and sieved through 200 mesh to obtain Nb@ZrO 2 Core-shell structural materials.

[0050] Prepared Nb@ZrO 2 See the SEM images of core-shell structure materials for Figure 4 shown.

[0051] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A Nb@ZrO 2 Preparation method of core-shell structure material, It is characterized in that The steps include: S1. SDS, Nb and water are mixed, mechanically stirred, and ultrasonically dispersed into a first suspension; the first suspension is filtered, dried, calcined, washed, filtered, and dried to obtain a first powder; S2. CTAB, ZrO 2 Mixing with water, mechanically stirring, and ultrasonically dispersing into a second suspension; filtering the second suspension, drying, calcining, and then washing, filtering, and drying to obtain a second powder; S3. The first powder is added to the molding agent for granulation, and the obtained granular material is mixed with the second powder, and then CTAB and water are added and mixed, and mechanically stirred to prepare a slurry of the coated granular material; S4. Dry and calcine the slurry of coated granular material to obtain Nb@ZrO 2 Core-shell structural materials.

2. Nb@ZrO according to claim 1 2 Preparation method of core-shell structure material, It is characterized in that In S1, SDS is 2mmol / L, Nb is 2.5-3.5g, and water is 150-210mL.

3. Nb@ZrO according to claim 1 2 Preparation method of core-shell structure material, It is characterized in that In S2, CTAB is 4mmol / L, ZrO 2 The amount of iodine is 1.5-2.5g, and the amount of water is 90-150mL.

4. Nb@ZrO according to claim 1 2 Preparation method of core-shell structure material, It is characterized in that In S3, CTAB is 4 mmol / L and water is 40-50 mL.

5. Nb@ZrO according to claim 1 2 Preparation method of core-shell structure material, It is characterized in that In S3, the molding agent consists of 10wt%-15wt% of rapeseed oil, 75wt%-80wt% of xylene and 10wt%-15wt% of polyisobutylene.

6. Nb@ZrO according to claim 1 2 Preparation method of core-shell structure material, It is characterized in that The calcination in S4 is carried out in a three-temperature zone tubular electric furnace, with a heating rate of 3-10°C / min, a heat preservation calcination temperature of 150-220°C, a heat preservation time of 1-3h, and an argon atmosphere.

7. Nb@ZrO according to claim 6 2 Preparation method of core-shell structure material, It is characterized in that The calcination temperature was 200°C, the heating rate was 8°C / min, and the holding time was 2h.

8. Nb@ZrO according to claim 1 2 Preparation method of core-shell structure material, It is characterized in that The washing and filtration in S1-S2 are all washed with distilled water and alcohol before filtration.

9. Nb@ZrO according to claim 1 2 Preparation method of core-shell structure material, It is characterized in that In S4, after calcination, washing, filtration, drying, and sieving through 200 mesh, Nb@ZrO 2 Core-shell structural materials.

10. A Nb@ZrO 2 A core-shell structure material, which is prepared by the preparation method described in any one of claims 1-9.

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