Graphene reinforced aluminum carbonaceous slide plate material and preparation method thereof

Abstract

The application relates to a graphene reinforced aluminum-carbon slide plate material and a preparation method thereof. 25-37 wt% tabular corundum particles with a particle size of 2-3 mm and 28-34 wt% tabular corundum particles with a particle size greater than or equal to 1 mm and less than 2 mm are used as aggregates, 27-38 wt% tabular corundum fine powder with a particle size less than 0.088 mm, 2-5 wt% elemental Si powder and 1-3 wt% modified graphene nanosheets are used as a matrix, the aggregates are placed in a stirrer, 4-7 wt% of liquid phenolic resin accounting for the sum of the aggregates and the matrix is added, mixing is carried out, the matrix is added, and uniform stirring is carried out; machine compression molding is carried out, heat treatment is carried out at 200-250 DEG C, heat preservation is carried out at 1220-1400 DEG C and under carbon embedding conditions for 5-8 hours, and natural cooling is carried out, so that the graphene reinforced aluminum-carbon slide plate material is obtained. The slide plate material prepared by the application has the characteristics of good oxidation resistance, excellent slag resistance, high strength and good thermal shock resistance, and can be used in a continuous casting system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of refractory materials. In particular, it relates to a graphene reinforced aluminum-carbon slide plate material and a preparation method thereof. BACKGROUND

[0002] Aluminum-carbon refractory materials have excellent thermal shock resistance and corrosion resistance due to the high thermal conductivity of carbon and poor wetting performance of molten slag, and are widely used to prepare slide plate bricks, water gaps and other key functional devices, playing an important role in continuous casting systems.

[0003] In recent years, there have been some reports on the research and preparation technology of aluminum-carbon slide plate materials. For example, the patent technology "Nanosilicon in-situ generated ceramic phase reinforced aluminum-carbon slide plate and its preparation process" (CN 201911225412.4) uses mullite, sintered corundum, vermiculite, alpha-Al2O3 micro powder, nanosilicon powder and flaky graphite as raw materials to prepare a nanosilicon in-situ generated ceramic phase reinforced aluminum-carbon slide plate material; another example is the patent technology "Slide plate refractory material containing titanium carbonitride and its preparation method" (CN 200710051846.8), which uses corundum, zirconia or zirconia corundum or zirconia mullite, Al2O3 micro powder, titanium dioxide powder, boron carbide powder, silicon carbide powder, metal Al powder, metal Si powder and graphite as raw materials to prepare a slide plate refractory material containing titanium carbonitride; and another example is the patent technology "Magnesium oxide micro powder reinforced aluminum-zirconium-carbon slide plate and its preparation method" (CN 201910612116.3), which uses fused corundum, zirconia mullite, metal Al powder, carbon, binder and MgO micro powder as main raw materials to prepare a magnesium oxide micro powder reinforced aluminum-zirconium-carbon slide plate material.

[0004] However, the existing aluminum-carbon slide plate materials still have some obvious deficiencies: (1) the poor oxidation resistance of carbon itself, which is easily oxidized in the product and forms a pore structure, reducing the strength and slag resistance of the product; (2) the carbon source introduced in the raw materials, especially the nanoscale carbon source, is difficult to disperse uniformly during the preparation process, which has a negative impact on the strength of the product; (3) the poor interfacial bonding between carbon (non-oxide) in the product and corundum aggregate and oxide fine powder in the matrix, resulting in low strength of the product. SUMMARY

[0005] The present application aims to overcome the defects of the prior art, and the purpose is to provide a graphene reinforced aluminum-carbon slide plate material with good oxidation resistance, excellent slag resistance, high strength and good thermal shock resistance, and a preparation method thereof.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0007] Step 1, preparation of modified graphene nanosheets

[0008] Mixing the xylene, the polycarbosilane powder and the graphene nanosheet according to the mass ratio of xylene:polycarbosilane fine powder:graphene nanosheet of 100:(12-18):(2-5), stirring for 5-10 min, and then ultrasonic treatment for 30-60 min, and then vacuum filtration treatment to obtain a mixture; drying the mixture at 200-240℃ for 3-6h to obtain modified graphene nanosheets.

[0009] Step 2, preparation of graphene reinforced aluminum-carbon slide plate material

[0010] The particle size of the plate-shaped corundum particles is 2-3mm, the particle size of the plate-shaped corundum particles is greater than or equal to 1mm and less than 2mm, the particle size of the plate-shaped corundum fine powder is less than 0.088mm, the particle size of the elemental Si powder is less than 4μm, and the content of Si in the elemental Si powder is greater than 98.5wt%.

[0011] According to the ingredients and contents described in step 2, first, the aggregate is placed in a mixer, 4-7wt% of liquid phenolic resin based on the sum of the aggregate and the matrix is added, mixed uniformly, and then the matrix is added and stirred uniformly; then, it is formed by machine pressing under the condition of 180-240MPa, heat treated at 200-250℃ for 24-48 hours, and finally heat treated at 1220-1400℃ under carbon embedding conditions for 5-8 hours, and naturally cooled to obtain the graphene reinforced aluminum-carbon slide plate material.

[0012] The particle size of the polycarbosilane fine powder is less than 75μm.

[0013] The thickness of the graphene nanosheet is less than 10nm, and the C content of the graphene nanosheet is greater than 99.5wt%.

[0014] The particle size of the elemental Si powder is less than 4μm, and the Si content of the elemental Si powder is greater than 98.5wt%.

[0015] The carbon residue rate of the liquid phenolic resin is greater than 40%.

[0016] Compared with the prior art, the present application has the following positive effects:

[0017] (1) The graphene nanosheet introduced in the present application is modified, which can effectively improve the uniformity of the distribution of the graphene nanosheet in the product, and improve the strength and thermal shock resistance of the product.

[0018] The present application utilizes polycarbosilane fine powder to modify graphene nanosheets, so that a large number of polycarbosilane molecules are adsorbed on the surface of the graphene nanosheets, effectively reducing the van der Waals force between the graphene nanosheets, that is, weakening the main driving force for the agglomeration of graphene nanosheets. This helps the graphene nanosheets to be more uniformly dispersed in the product and more easily filled into the micropores inside the product, improving the uniformity of the product structure, not only improving the strength of the product, but also helping the product to absorb and relieve thermal stress, and improving the thermal shock resistance of the product.

[0019] (2) The present application utilizes polycarbosilane fine powder to form pyrolysis product SiC x O y layer on the surface of graphene nanosheets, hindering the oxidation of graphene nanosheets, and improving the oxidation resistance of the product.

[0020] The polycarbosilane fine powder in the present application will pyrolyze on the surface of graphene nanosheets when heated at 1220-1400℃ under carbon-embedded conditions, and the pyrolysis product is mainly a large amount of amorphous SiC x O y layer, accompanied by a small amount of SiC and SiO2 phase. The SiC x O y layer generated on the surface of graphene nanosheets can hinder the contact of graphene nanosheets with oxygen, helping to slow down the oxidation process of graphene nanosheets, and significantly improving the oxidation resistance of the product.

[0021] (3) The present application utilizes polycarbosilane fine powder to modify graphene nanosheets, promoting the generation of SiC whiskers on the surface of graphene nanosheets, and improving the strength and slag resistance of the product.

[0022] The modified graphene nanosheets in the present application have a large amount of polycarbosilane attached to their surface, providing more reaction sites for the generation of SiC whiskers on the surface of graphene nanosheets. When heated at 1220-1400℃ under carbon-embedded conditions, SiO, CO and other gases in the matrix will diffuse to the surface of graphene nanosheets and react with the pyrolysis products of polycarbosilane, generating a large amount of SiC whiskers in situ on the surface of graphene nanosheets. Therefore, SiC whiskers can be distributed between graphene nanosheets and non-oxide particles in the matrix, improving the interfacial compatibility and making the interface more tightly bonded, reducing the penetration path of oxygen and molten slag, and further improving the strength, oxidation resistance and slag resistance of the product.

[0023] At the same time, the pyrolysis products of polycarbosilane on the surface of graphene nanosheets and the in-situ generated SiC whiskers have a synergistic effect, and the reaction with molten slag at high temperature will increase the SiO2 content in the penetrated slag and increase the viscosity of the penetrated slag, slowing down the further erosion and penetration of high-temperature molten slag into the matrix of the product, and thus improving the slag resistance of the product.

[0024] The graphene reinforced aluminum carbonaceous slide plate material prepared by the application has the following characteristics: apparent porosity of 12.1-14.8%; bending strength of 24-31 MPa; good oxidation resistance.

[0025] Therefore, the graphene reinforced aluminum carbonaceous slide plate material prepared by the application has the characteristics of good oxidation resistance, excellent slag resistance, high strength and good thermal shock resistance, and can be used in continuous casting systems. DETAILED DESCRIPTION

[0026] The application will be further described in combination with the specific embodiments, which are not intended to limit the protection scope thereof.

[0027] A graphene reinforced aluminum carbonaceous slide plate material and a preparation method thereof.

[0028] Step 1: Preparation of modified graphene nanosheets

[0029] The mass ratio of dimethylbenzene:polycarbosilane fine powder:graphene nanosheets is 100:(12-18):(2-5), the dimethylbenzene, the polycarbosilane fine powder and the graphene nanosheets are mixed, stirred for 5-10 min, and then ultrasonically treated for 30-60 min, and the mixture is obtained after vacuum filtration treatment; the mixture is dried at 200-240℃ for 3-6h to obtain modified graphene nanosheets.

[0030] Step 2: Preparation of graphene reinforced aluminum carbonaceous slide plate material

[0031] 25-37wt% of plate-shaped corundum particles with a particle size of 2-3mm, 28-34wt% of plate-shaped corundum particles with a particle size of greater than or equal to 1mm and less than 2mm as aggregate, 27-38wt% of plate-shaped corundum fine powder with a particle size of less than 0.088mm, 2-5wt% of elemental Si powder and 1-3wt% of modified graphene nanosheets as matrix.

[0032] According to the components and contents in step 2, first, the aggregate is placed in a stirrer, 4-7wt% of liquid phenolic resin based on the sum of the aggregate and the matrix is added, mixed uniformly, and then the matrix is added and stirred uniformly; then, it is formed by machine pressing under the condition of 180-240MPa, heat treated at 200-250℃ for 24-48 hours, and finally, it is obtained by natural cooling under the condition of 1220-1400℃ and carbon embedding for 5-8 hours.

[0033] In the specific embodiment:

[0034] The particle size of the polycarbosilane fine powder is <75μm;

[0035] The thickness of the graphene nanosheet is < 10 nm; the C content of the graphene nanosheet is > 99.5 wt%;

[0036] The particle size of the elemental Si powder is < 4 μm; the Si content of the elemental Si powder is > 98.5 wt%;

[0037] The carbon residue rate of the liquid phenolic resin is > 40%.

[0038] The embodiments are not described again.

[0039] Embodiment 1

[0040] A graphene reinforced aluminum-carbon slide plate material and a preparation method thereof. The specific steps of the preparation method in the embodiment are as follows:

[0041] Step 1, preparation of modified graphene nanosheet

[0042] The xylene, the polycarbosilane powder and the graphene nanosheet are mixed in a mass ratio of 100:12:2, stirred for 6 min, and then ultrasonically treated for 40 min. After vacuum filtration treatment, a mixture is obtained. The mixture is dried at 230°C for 6 h to obtain the modified graphene nanosheet.

[0043] Step 2, preparation of graphene reinforced aluminum-carbon slide plate material

[0044] The particle size of the plate-shaped corundum particles is 2-3 mm, and the particle size of the plate-shaped corundum particles is greater than or equal to 1 mm and less than 2 mm. The particle size of the plate-shaped corundum fine powder is less than 0.088 mm, the particle size of the elemental Si powder is less than 0.088 mm, and the particle size of the modified graphene nanosheet is less than 0.088 mm.

[0045] According to the components and contents in step 2, the aggregate is first placed in a stirrer, 7 wt% of liquid phenolic resin based on the sum of the aggregate and the matrix is added, and then the matrix is added and stirred uniformly. Then, it is formed by machine pressing under the condition of 180 MPa, heat treated at 230°C for 48 hours, and finally naturally cooled under the condition of 1280°C and carbon embedding for 7 hours to obtain the graphene reinforced aluminum-carbon slide plate material.

[0046] The graphene reinforced aluminum-carbon slide plate material prepared in the embodiment has a porosity of 14.6%, a bending strength of 24 MPa, and good oxidation resistance.

[0047] Embodiment 2

[0048] A graphene reinforced aluminum-carbon slide plate material and a preparation method thereof. The specific steps of the preparation method in the embodiment are as follows:

[0049] Step 1, preparation of modified graphene nanoplatelets

[0050] The xylene, the polycarbosilane powder and the graphene nanoplatelets were mixed in a mass ratio of 100:14:3, stirred for 5 min, then ultrasonic treated for 60 min, and after vacuum filtration treatment, a mixture was obtained; the mixture was dried at 200℃ for 5h to obtain modified graphene nanoplatelets.

[0051] Step 2, preparation of graphene reinforced aluminum-carbon quality slide plate material

[0052] 32.5wt% of plate-shaped corundum particles with a particle size of 2-3mm, 33.8wt% of plate-shaped corundum particles with a particle size greater than or equal to 1mm and less than 2mm as aggregate, 27.2wt% of plate-shaped corundum fine powder with a particle size less than 0.088mm, 3.5wt% of elemental Si powder, 3wt% of modified graphene nanoplatelets as matrix.

[0053] According to the ingredients and their contents described in step 2: first, the aggregate was placed in a blender, 4wt% of liquid phenolic resin based on the sum of the aggregate and the matrix was added, mixed uniformly, then the matrix was added and stirred uniformly; then it was formed under the condition of 200MPa, heat treated at 220℃ for 32 hours, and finally heat treated at 1400℃ and buried in carbon for 5 hours, and naturally cooled to obtain the graphene reinforced aluminum-carbon quality slide plate material.

[0054] The graphene reinforced aluminum-carbon quality slide plate material prepared in this example has an apparent porosity of 13.6%, a bending strength of 28MPa, and good oxidation resistance.

[0055] Example 3

[0056] A graphene reinforced aluminum-carbon quality slide plate material and a preparation method thereof. The specific steps of the preparation method described in this example are:

[0057] Step 1, preparation of modified graphene nanoplatelets

[0058] The xylene, the polycarbosilane powder and the graphene nanoplatelets were mixed in a mass ratio of 100:14:3, stirred for 5 min, then ultrasonic treated for 60 min, and after vacuum filtration treatment, a mixture was obtained; the mixture was dried at 200℃ for 5h to obtain modified graphene nanoplatelets.

[0059] Step 2, preparation of graphene reinforced aluminum-carbon quality slide plate material

[0060] The aggregate consisted of 29.3 wt% of tabular corundum particles with a particle size of 2-3 mm and 28.1 wt% of tabular corundum particles with a particle size greater than or equal to 1 mm and less than 2 mm, with 35.6 wt% of tabular corundum fine powder with a particle size less than 0.088 mm, 5 wt% of elemental Si powder, and 2 wt% of modified graphene nanosheets as the matrix.

[0061] According to the composition and content described in step 2: First, place the aggregate in a mixer, add liquid phenolic resin accounting for 6 wt% of the sum of the aggregate and the matrix, mix evenly, then add the matrix and mix evenly; then press it into shape under 220 MPa, heat treat it at 200℃ for 24 hours, and finally keep it at 1220℃ and under carbon embedding conditions for 8 hours, and cool it naturally to obtain the graphene-reinforced aluminum carbon slide plate material.

[0062] The graphene-reinforced aluminum carbon slide plate material prepared in this embodiment has the following characteristics: apparent porosity of 14.2%; flexural strength of 27.2 MPa; and good oxidation resistance.

[0063] Example 4

[0064] A graphene-reinforced aluminum-carbon sliding plate material and its preparation method. The specific steps of the preparation method described in this embodiment are as follows:

[0065] Step 1: Preparation of modified graphene nanosheets

[0066] The xylene, polycarbosilane powder, and graphene nanosheets were mixed in a mass ratio of 100:16:4, stirred for 10 min, ultrasonically treated for 30 min, and then vacuum filtered to obtain a mixture. The mixture was then dried at 240°C for 4 h to obtain modified graphene nanosheets.

[0067] Step 2: Preparation of graphene-reinforced aluminum-carbon sliding plate material

[0068] The aggregate consisted of 25.2 wt% of tabular corundum particles with a particle size of 2-3 mm and 32.3 wt% of tabular corundum particles with a particle size greater than or equal to 1 mm and less than 2 mm, with 37.9 wt% of tabular corundum fine powder with a particle size less than 0.088 mm, 2 wt% of elemental Si powder, and 2.6 wt% of modified graphene nanosheets as the matrix.

[0069] According to the composition and content described in step 2: First, place the aggregate in a mixer, add liquid phenolic resin accounting for 5 wt% of the sum of the aggregate and the matrix, mix evenly, then add the matrix and mix evenly; then press it into shape under 240 MPa, heat treat it at 250℃ for 40 hours, and finally keep it at 1340℃ and under carbon embedding conditions for 6 hours, and cool it naturally to obtain the graphene-reinforced aluminum carbon slide plate material.

[0070] The graphene reinforced aluminum carbonaceous slide plate material prepared in the embodiment has an apparent porosity of 12.3%, a bending strength of 30 MPa, and good oxidation resistance.

[0071] Compared with the prior art, the embodiment has the following positive effects:

[0072] (1) The graphene nanosheets introduced in the embodiment are modified, which effectively improves the uniformity of the distribution of the graphene nanosheets in the product, and improves the strength and thermal shock resistance of the product.

[0073] The graphene nanosheets are modified by the polycarbosilane fine powder, so that a large number of polycarbosilane molecules are adsorbed on the surface of the graphene nanosheets, effectively reducing the van der Waals force between the graphene nanosheets, that is, weakening the main driving force for the agglomeration of the graphene nanosheets. This helps the graphene nanosheets to be more uniformly dispersed in the product and more easily filled into the micropores inside the product, improves the uniformity of the structure of the product, not only improves the strength of the product, but also helps the product to absorb and relieve thermal stress, and improves the thermal shock resistance of the product.

[0074] (2) The polycarbosilane fine powder in the embodiment forms a pyrolysis product SiC x O y layer on the surface of the graphene nanosheets, which hinders the oxidation of the graphene nanosheets and improves the oxidation resistance of the product.

[0075] The polycarbosilane fine powder in the embodiment will pyrolyze on the surface of the graphene nanosheets when it is kept at 1220-1400℃ under carbon-embedding conditions, and the pyrolysis product mainly includes a large number of amorphous SiC x O y layers and a small amount of SiC and SiO2 phases. The SiC x O y layer generated on the surface of the graphene nanosheets can hinder the contact of the graphene nanosheets with oxygen, which helps to slow down the oxidation process of the graphene nanosheets and significantly improves the oxidation resistance of the product.

[0076] (3) The polycarbosilane fine powder in the embodiment modifies the graphene nanosheets, which promotes the generation of SiC whiskers on the surface of the graphene nanosheets, and improves the strength and slag resistance of the product.

[0077] The modified graphene nanosheet surface in the embodiment is attached with a large amount of polycarbosilane, which provides more reaction sites for the generation of SiC whiskers on the graphene nanosheet surface. When the temperature is kept at 1220-1400℃ under the carbon-embedding condition, SiO and CO in the matrix will diffuse to the surface of the graphene nanosheet and react with the pyrolysis products of polycarbosilane to generate a large amount of SiC whiskers in situ on the surface of the graphene nanosheet. Therefore, the SiC whiskers can be distributed between the graphene nanosheet and the non-oxide particles in the matrix, improve the interface compatibility, make the interface more closely combined, reduce the penetration path of oxygen and slag, and further improve the strength, oxidation resistance and slag resistance of the product.

[0078] Meanwhile, the pyrolysis products of polycarbosilane on the surface of the graphene nanosheet and the in-situ generated SiC whiskers have a synergistic effect, and the reaction with the slag at high temperature will increase the SiO2 content and the viscosity of the penetrated slag, slow down the further erosion and penetration of the high-temperature slag to the matrix part of the product, and further improve the slag resistance of the product.

[0079] The graphene-reinforced aluminum-carbonaceous slide plate material prepared in the embodiment has a porosity of 12.1-14.8%, a bending strength of 24-31MPa, and good oxidation resistance.

[0080] Therefore, the graphene-reinforced aluminum-carbonaceous slide plate material prepared in the embodiment has the characteristics of good oxidation resistance, excellent slag resistance, high strength and good thermal shock resistance, and can be used in the continuous casting system.

Claims

1. A method of making a graphene-reinforced aluminum-carbon slideboard material, characterized by The preparation method comprises the following steps: Step 1, preparation of modified graphene nanosheets The xylene, the polycarbosilane powder and the graphene nanosheets are mixed in a mass ratio of 100: (12-18): (2-5), stirred for 5-10 min, and then ultrasonically treated for 30-60 min, to obtain a mixture after vacuum filtration treatment; the mixture is dried at 200-240℃ for 3-6 h to obtain modified graphene nanosheets; Step 2, preparation of graphene reinforced aluminum-carbon slide plate material The graphene reinforced aluminum-carbon slide plate material is prepared according to the preparation method of the graphene reinforced aluminum-carbon slide plate material in any one of claims 1-5. The particle size of the polycarbosilane powder is <75 μm.

2. The method of making a graphene reinforced aluminum carbonaceous slide plate material of claim 1, wherein The thickness of the graphene nanosheets is <10 nm; and the C content of the graphene nanosheets is >99.5 wt%.

3. The method of making a graphene reinforced aluminum carbonaceous slide plate material of claim 1, wherein The particle size of the elemental Si powder is <4 μm; and the Si content of the elemental Si powder is >98.5 wt%.

4. The method of making a graphene reinforced aluminum carbonaceous slide plate material of claim 1, wherein The carbon residue rate of the liquid phenolic resin is >40%.

5. The method of making a graphene reinforced aluminum carbonaceous slide plate material of claim 1, wherein The graphene reinforced aluminum-carbon slide plate material is prepared according to the preparation method of the graphene reinforced aluminum-carbon slide plate material in any one of claims 1-5.

6. A graphene-reinforced aluminum-carbon slide plate material, characterized by The graphene reinforced aluminum-carbon slide plate material is prepared according to the preparation method of the graphene reinforced aluminum-carbon slide plate material in any one of claims 1-5.