A preparation method of NiB2 compound and its application

Abstract

The present invention provides a preparation method and application of a NiB2 compound, wherein the preparation method comprises the following steps: weighing the required nickel powder and boron powder as reaction raw materials, wherein the molar ratio of nickel powder to boron powder is 1:(2.2-2.5); grinding the reaction raw materials into a mixed powder of nickel powder and boron powder under an atmosphere of inert gas; filling the mixed powder after grinding into a crucible, and performing a compacting process under a preset pressure to obtain a blank; placing the blank in a sintering furnace for sintering to obtain a NiB2 compound. The preparation method of the NiB2 compound provided by the present invention, compared with the preparation process of 12Cr2AlMoV alloy in the prior art, does not need to be smelted in an electric furnace, the preparation process is simple, and the production cost is low; in addition, the molar ratio of nickel powder to boron powder is limited to meet a certain range, so as to avoid too much boron powder or nickel powder remaining, and ensure the preparation of a NiB2 compound with higher purity.

Description

Technical Field

[0001] The present invention relates to the technical field of material chemistry, and in particular to a preparation method of a NiB2 compound and an application thereof. Background Art

[0002] With the development of industrial technology, the corrosion of power pipelines, oil pipelines and gas carrier components has brought huge consumption to the national economy, and the requirements for the corrosion resistance of corrosion-resistant components are getting higher and higher. In the prior art, the commonly used materials for H2S corrosion-resistant components are 12Cr2AlMoV alloy, and the preparation of 12Cr2AlMoV alloy adopts electric furnace smelting.

[0003] Among them, 12Cr2AlMoV alloy still has the following shortcomings: on the one hand, the corrosion resistance of corrosion-resistant parts made of 12Cr2AlMoV alloy is poor, which requires shutdown for maintenance or replacement of parts, which not only reduces the working efficiency of the equipment, but also may cause safety hazards if the defects of the parts are not discovered during timely maintenance; on the other hand, the preparation of 12Cr2AlMoV alloy adopts electric furnace smelting, which has complex process and high production cost. The large amount of consumption each year will bring huge losses to my country's economy. Therefore, how to obtain corrosion-resistant materials with low cost and high corrosion resistance is of great significance to industrial engineering. Summary of the invention

[0004] The invention provides a method for preparing a NiB2 compound, which is used to solve the technical problem of poor corrosion resistance of 12Cr2AlMoV alloy in the prior art.

[0005] The present invention provides a method for preparing a NiB2 compound, comprising the following steps:

[0006] Weighing: Weigh the required nickel powder and boron powder as reaction raw materials, wherein the molar ratio of nickel powder to boron powder is 1:(2.2-2.5);

[0007] Grinding: Grinding the reaction raw materials into a mixed powder of nickel powder and boron powder under an inert gas atmosphere;

[0008] Compacting: filling the ground mixed powder into a crucible, and performing compacting at a preset pressure to obtain a blank;

[0009] Sintering: The blank is placed in a sintering furnace for sintering to obtain a NiB2 compound.

[0010] Compared with the preparation process of 12Cr2AlMoV alloy in the prior art, the preparation method of the NiB2 compound provided by the present invention does not require electric furnace smelting, has a simple preparation process and low production cost; in addition, the molar ratio of nickel powder and boron powder is limited to a certain range to avoid excessive boron powder or nickel powder remaining, thereby ensuring the preparation of NiB2 compounds with higher purity.

[0011] Furthermore, the placing of the blank into a sintering furnace for sintering includes: placing a crucible containing the blank into a plasma activated sintering furnace for plasma activated sintering;

[0012] The process conditions of the plasma activated sintering treatment are: first gradually heating to 300°C-500°C, then keeping the temperature for 0.8h-1.2h, then gradually heating to 850°C-1200°C, and then keeping the temperature for 0.5h-5h;

[0013] During the heating and insulation process, the sintering pressure is between 150MPa and 300MPa.

[0014] The present invention adopts plasma activated sintering of a mixed powder of nickel powder and boron powder, which has the technical effects of fast heating, short sintering time, and the ability to improve the sintering efficiency of the mixed powder. It can also improve the performance of the sintered body of the mixed powder, making the structure of the sintered body of the mixed powder fine and uniform, and high in density.

[0015] Furthermore, the temperature is gradually increased to 300℃-500℃ at a first preset heating rate, and then gradually increased to 850℃-1200℃ at a second preset heating rate, wherein the first preset heating rate is between 80℃ / h-120℃ / h, and the second preset heating rate is between 140℃ / h-160℃ / h.

[0016] Furthermore, grinding the reaction raw materials into a mixed powder of nickel powder and boron powder under an inert gas atmosphere includes: placing the reaction raw materials in a ball mill, evacuating the ball mill and filling the ball mill with inert gas; placing the ball mill containing the reaction raw materials in a ball mill for ball milling, wherein the ball milling time is between 5h and 120h.

[0017] The embodiment of the present invention ball-mills the reaction raw materials to improve the dispersion of nickel powder and boron powder, fully mix the nickel powder and sulfur powder, reduce the particle size of the nickel powder and sulfur powder, thereby improving the formability and sinterability of the nickel powder and sulfur powder, and also reduce the sintering temperature to save energy; in addition, the sintering density can also be increased.

[0018] Furthermore, the vacuum degree of the ball mill is ≤10 -1 Pa; the purity of the inert gas is ≥99.9%.

[0019] Furthermore, the inert gas is argon.

[0020] Furthermore, the preset pressure ranges from 50 MPa to 500 MPa.

[0021] Furthermore, the purity of the nickel powder and the boron powder is ≥99%.

[0022] Furthermore, after the step of placing the blank into a sintering furnace for sintering to obtain the NiB2 compound, the step further includes: cooling the NiB2 compound along with the sintering furnace.

[0023] The present invention also provides an application of a NiB2 compound. The NiB2 compound is obtained by applying the above-mentioned preparation method, and the NiB2 compound is coated on the inner surface of a pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of a process flow of a method for preparing a NiB2 compound provided in an embodiment of the present invention;

[0025] Figure 2 A fracture morphology photograph of a NiB2 bulk sample obtained by a method for preparing a NiB2 compound provided in an embodiment of the present invention; DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the following is a brief description of the present invention in conjunction with the attached drawings. Figure 1 and Figure 2 The specific embodiments of the present invention are described in detail.

[0027] See attached Figure 1 The present invention provides a method for preparing a NiB2 compound, comprising the following steps:

[0028] Weighing: Weigh the required nickel powder and boron powder as reaction raw materials, wherein the molar ratio of nickel powder to boron powder is 1:(2.2-2.5);

[0029] Grinding: Grinding the reaction raw materials into a mixed powder of nickel powder and boron powder under an inert gas atmosphere;

[0030] Compacting: Filling the ground mixed powder into a crucible, and performing compacting at a preset pressure to obtain a blank;

[0031] Sintering: The blank is placed in a sintering furnace for sintering to obtain a NiB2 compound.

[0032] It should be noted that grinding is performed in an inert gas atmosphere to prevent oxidation of nickel powder and boron powder.

[0033] It should be noted that the NiB2 compound can be in the form of blocks, powders, filaments, strips or sheets.

[0034] Compared with the preparation process of 12Cr2AlMoV alloy in the prior art, the preparation method of NiB2 compound provided in the embodiment of the present invention does not require electric furnace smelting, has a simple preparation process and low production cost; in addition, the molar ratio of nickel powder and boron powder is limited to a certain range to avoid excessive boron powder or nickel powder remaining, thereby ensuring the preparation of NiB2 compound with higher purity.

[0035] It should be noted that the types of sintering include conventional sintering, atmosphere pressure sintering, hot pressing sintering, microwave sintering and plasma activated sintering, among which the main feature of plasma activated sintering is the use of heating and surface activation to achieve ultra-fast densification sintering of materials, which has the advantages of fast heating rate, short sintering time, low sintering temperature, uniform heating, high production efficiency and energy saving. In addition, due to the combined effect of plasma activation and rapid temperature rise sintering, the growth of grains is inhibited and the microstructure of the original particles is maintained, thereby essentially improving the performance of the sintered body, and making the final product have the characteristics of fine and uniform structure, the ability to maintain the natural state of the raw materials, and high density.

[0036] In the embodiment of the present invention, placing the blank into a sintering furnace for sintering includes: placing a crucible containing the blank into a plasma activated sintering furnace for plasma activated sintering.

[0037] It should be noted that the crucible can be a graphite crucible, a corundum crucible or a metal crucible.

[0038] Therefore, the embodiment of the present invention uses plasma activated sintering of a mixed powder of nickel powder and boron powder, which has the technical effects of fast heating, short sintering time, and the ability to improve the sintering efficiency of the mixed powder. It can also improve the performance of the sintered body of the mixed powder, making the structure of the sintered body of the mixed powder fine and uniform, and high in density.

[0039] In the embodiment of the present invention, optionally, the process conditions of the plasma activated sintering treatment are: first gradually heating to 300°C-500°C, then keeping warm for 0.8h-1.2h, then gradually heating to 850°C-1200°C, and then keeping warm for 0.5h-5h; preferably, first gradually heating to 350°C-500°C, then keeping warm for 0.85h-1.15h, then gradually heating to 900°C-1200°C, and then keeping warm for 1h-4h; more preferably, first gradually heating to 400°C-500°C, then keeping warm for 0.9h-1.1h, then gradually heating to 1000°C-1200°C, and then keeping warm for 1.5h-3.5h;

[0040] In the embodiment of the present invention, optionally, during the heating and heat preservation process, the sintering pressure is between 150 MPa and 300 MPa, preferably, the sintering pressure is between 180 MPa and 280 MPa, and more preferably, the sintering pressure is between 200 MPa and 250 MPa.

[0041] In an embodiment of the present invention, preferably, the temperature is gradually increased to 300℃-500℃ at a first preset heating rate, and then gradually increased to 850℃-1200℃ at a second preset heating rate, wherein the first preset heating rate is between 80℃ / h-120℃ / h, and the second preset heating rate is between 140℃ / h-160℃ / h; more preferably, the first preset heating rate is 100℃ / h, and the second preset heating rate is 150℃ / h.

[0042] In an embodiment of the present invention, the reaction raw materials are ground into a mixed powder of nickel powder and boron powder under an inert gas atmosphere, including: placing the reaction raw materials in a ball mill, evacuating the ball mill and filling the ball mill with an inert gas; placing the ball mill containing the reaction raw materials in a ball mill for ball milling, wherein the ball milling time is between 5h-120h; preferably, the ball milling time is between 20h-100h; more preferably, the ball milling time is between 30h-80h.

[0043] It should be noted that the type of ball mill is not limited, and it can be a short-barrel ball mill, a long-barrel ball mill, a tube mill or a conical mill.

[0044] The embodiment of the present invention ball-mills the reaction raw materials to improve the dispersion of nickel powder and boron powder, fully mix the nickel powder and sulfur powder, reduce the particle size of the nickel powder and sulfur powder, thereby improving the formability and sinterability of the nickel powder and sulfur powder, and also reduce the sintering temperature to save energy; in addition, the sintering density can also be increased.

[0045] In the embodiment of the present invention, the vacuum degree of the ball mill is ≤10 -1 Pa; the purity of inert gas is ≥99.9%.

[0046] In the embodiment of the present invention, the inert gas is argon.

[0047] In the embodiment of the present invention, in the green sheet forming step, the preset pressure ranges from 50 MPa to 500 MPa, preferably, the preset pressure ranges from 100 MPa to 400 MPa, and more preferably, the preset pressure ranges from 200 MPa to 300 MPa.

[0048] In the embodiment of the present invention, optionally, the purity of the nickel powder and the boron powder are both ≥99%; preferably, the purity of the nickel powder and the boron powder are both ≥99.5%; more preferably, the purity of the nickel powder and the boron powder are both ≥99.9%.

[0049] In the embodiment of the present invention, after the step of placing the blank into a sintering furnace for sintering to obtain the NiB2 compound, the step further includes: cooling the NiB2 compound along with the sintering furnace.

[0050] It should be noted that the sintering furnace is cooled to room temperature.

[0051] An embodiment of the present invention also provides an application of a NiB2 compound. The NiB2 compound is obtained by applying the above-mentioned preparation method. The NiB2 compound is coated on the inner surface of a pipeline to improve the corrosion resistance of the inner surface of the pipeline and extend the service life of the pipeline.

[0052] In order to further illustrate the present invention, the preparation method and application of the NiB2 compound provided by the present invention are described in more detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0053] Embodiment 1

[0054] Step 1: Weighing: Weighing the required nickel powder and boron powder as reaction raw materials, wherein the molar ratio of nickel powder to boron powder is 1:2.2, and the purity of nickel powder and boron powder is 99.9%;

[0055] Step 2: Grinding: Place the raw materials in step 1 into a ball mill, evacuate the ball mill and fill it with argon, place the ball mill containing the raw materials into a ball mill and grind it into a mixed powder of nickel powder and boron powder, wherein the vacuum degree of the ball mill is 10 -1 Pa, the purity of argon was 99.9%, and the ball milling time was 5 h;

[0056] Step 3: green compaction: the mixed powder of nickel powder and boron powder in step 2 is filled into a graphite crucible, and green compaction is performed under a preset pressure to obtain a green compact, wherein the preset pressure is 50 MPa;

[0057] Step 4: Sintering: Put the blank and the graphite crucible in step 3 into a plasma activated sintering furnace without separation for plasma activated sintering treatment to obtain NiB2 compound; wherein, the process conditions of the plasma activated sintering treatment are: heating from room temperature to 300°C at a first preset heating rate of 100°C / h, and then keeping warm for 1 hour, and then heating from 500°C to 850°C at a second predicted heating rate of 150°C / h, and then keeping warm for 5 hours; during the heating and keeping warm process, the blank is pressurized all the time, and the sintering pressure is 500MPa.

[0058] Step 5: Cooling: The NiB2 compound in step 4 is cooled in the plasma activated sintering furnace.

[0059] See Table 1 and Table 2, density measurement and corrosion test: Corrosion tests were carried out on the comparison example 12Cr2AlMoV alloy and the NiB2 compound block obtained in Example 1. Specifically, the NiB2 compound block sample obtained in Example 1 had a test size of 50 mm in diameter and 30 mm in length. The density of the NiB2 compound block obtained in Example 1 was tested by the drainage method and was found to be approximately 98.2%.

[0060] The comparative example 12Cr2AlMoV alloy and the NiB2 compound block obtained in Example 1 were placed in a tubular container filled with H2S, and the H2S corrosion resistance test was carried out at 700°C. The results showed that the volume corrosion amount of the NiB2 compound was 6.6 mm 3 / h, the volume corrosion amount of 12Cr2AlMoV alloy is 21.2mmm 3 / h, the volume corrosion amount of NiB2 compound is about 31.1% of the volume corrosion amount of 12Cr2AlMoV alloy.

[0061] Embodiment 2

[0062] Step 1: Weighing: Weighing the required nickel powder and boron powder as reaction raw materials, wherein the molar ratio of nickel powder to boron powder is 1:2.5, and the purity of nickel powder and boron powder is ≥99.9%;

[0063] Step 2: Grinding: Place the raw materials in step 1 into a ball mill, evacuate the ball mill and fill it with argon, place the ball mill containing the raw materials into a ball mill and grind it into a mixed powder of nickel powder and boron powder, wherein the vacuum degree of the ball mill is 10 -3 Pa, the purity of argon is 99.99%, and the ball milling time is 120 h;

[0064] Step 3: green compaction: the mixed powder of nickel powder and boron powder in step 2 is filled into a graphite crucible, and green compaction is performed under a preset pressure to obtain a green compact, wherein the preset pressure is 500 MPa;

[0065] Step 4: Sintering: Put the blank and graphite crucible in step 3 into a plasma activated sintering furnace without separation for plasma activated sintering treatment to obtain NiB2 compound; wherein, the process conditions of the plasma activated sintering treatment are: heating from room temperature to 500°C at a first preset heating rate of 100°C / h, and then keeping warm for 1 hour, and then heating from 500°C to 1200°C at a second predicted heating rate of 150°C / h, and then keeping warm for 0.5 hour; during the heating and keeping warm process, the blank is pressurized all the time, and the sintering pressure is 150MPa.

[0066] Step 5: Cooling: The NiB2 compound in step 4 is cooled in the plasma activated sintering furnace.

[0067] See Table 1 and Table 2, density measurement and corrosion test: Corrosion tests were carried out on the comparison example 12Cr2AlMoV alloy and the NiB2 compound block obtained in Example 1. Specifically, the NiB2 compound block sample obtained in Example 1 had a test size of 50 mm in diameter and 30 mm in length. The density of the NiB2 compound block obtained in Example 1 was tested by the drainage method and was found to be approximately 99.4%.

[0068] The comparative example 12Cr2AlMoV alloy and the NiB2 compound block obtained in Example 1 were placed in a tubular container filled with H2S, and the H2S corrosion resistance test was carried out at 700°C. The results showed that the volume corrosion amount of the NiB2 compound was 5.8 mm 3 / h, the volume corrosion amount of 12Cr2AlMoV alloy is 21.2mmm 3 / h, the volume corrosion amount of NiB2 compound is about 27.4% of the volume corrosion amount of 12Cr2AlMoV alloy.

[0069] Embodiment 3

[0070] Step 1: Weighing: Weighing the required nickel powder and boron powder as reaction raw materials, wherein the molar ratio of nickel powder to boron powder is 1:2.4, and the purity of nickel powder and boron powder is ≥99.9%;

[0071] Step 2: Grinding: Place the raw materials in step 1 into a ball mill, evacuate the ball mill and fill it with argon, place the ball mill containing the raw materials into a ball mill and grind it into a mixed powder of nickel powder and boron powder, wherein the vacuum degree of the ball mill is 10 -3 Pa, the purity of argon is 99.9%, and the ball milling time is 75 h;

[0072] Step 3: green compaction: the mixed powder of nickel powder and boron powder in step 2 is filled into a graphite crucible, and green compaction is performed under a preset pressure to obtain a green compact, wherein the preset pressure is 300 MPa;

[0073] Step 4: Sintering: Put the blank and graphite crucible in step 3 into a plasma activated sintering furnace without separation for plasma activated sintering treatment to obtain NiB2 compound; wherein, the process conditions of plasma activated sintering treatment are: heating from room temperature to 400°C at a first preset heating rate of 100°C / h, and then keeping warm for 1 hour, and then heating from 500°C to 950°C at a second predicted heating rate of 150°C / h, and then keeping warm for 3 hours; during the heating and keeping warm process, the blank is pressurized all the time, and the sintering pressure is 300MPa.

[0074] Step 5: Cooling: The NiB2 compound in step 4 is cooled in the plasma activated sintering furnace.

[0075] See Table 1 and Table 2, density measurement and corrosion test: Corrosion tests were carried out on the comparison example 12Cr2AlMoV alloy and the NiB2 compound block obtained in Example 1. Specifically, the NiB2 compound block sample obtained in Example 1 had a test size of 50 mm in diameter and 30 mm in length. The density of the NiB2 compound block obtained in Example 1 was tested by the drainage method and was found to be approximately 99.0%.

[0076] The comparative example 12Cr2AlMoV alloy and the NiB2 compound block obtained in Example 1 were placed in a tubular container filled with H2S, and the H2S corrosion resistance test was carried out at 700°C. The results showed that the volume corrosion amount of the NiB2 compound was 6.3 mm 3 / h, the volume corrosion amount of 12Cr2AlMoV alloy is 21.2mmm 3 / h, the volume corrosion amount of NiB2 compound is about 29.7% of the volume corrosion amount.

[0077] Table 1: Density table of NiB2 compounds in various embodiments.

[0078]

[0079]

[0080] Table 2: Comparison of volume corrosion of NiB2 compounds in various embodiments and 12Cr2AlMoV alloy in comparative example.

[0081]

[0082] In summary, the preparation method of the Ni3B4 compound provided in the embodiment of the present invention is simple in process compared with the preparation method of the 12Cr2AlMoV alloy in the prior art, and the production cost per kilogram is only 60-85% of that of the 12Cr2AlMoV alloy, which can significantly save costs. The prepared NiB2 compound, compared with the 12Cr2AlMoV alloy used in the prior art, has a volume corrosion amount of about 30% of the volume corrosion amount of the 12Cr2AlMoV alloy, and the corrosion resistance is further improved. The method is suitable for promotion and use in industrial equipment, improves the corrosion resistance of the equipment, extends the life of the equipment and related components, reduces the maintenance cost and maintenance time of the equipment and related components, improves the production efficiency of the equipment, and reduces the loss of the national economy.

[0083] Finally, it should be noted that, in this article, terms such as "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0084] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to the embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a NiB2 compound, characterized in that: Includes steps: Weighing: Weigh the required nickel powder and boron powder as reaction raw materials, wherein the molar ratio of nickel powder to boron powder is 1:(2.2-2.5); Grinding: placing the reaction raw materials into a ball mill, evacuating the ball mill and filling the ball mill with inert gas; placing the ball mill containing the reaction raw materials into a ball mill and grinding the mixture into a mixed powder of nickel powder and boron powder, wherein the ball milling time is between 5h and 120h; Compacting: filling the ground mixed powder into a crucible, and performing compacting at a preset pressure to obtain a blank; Sintering: placing the blank into a sintering furnace for sintering to obtain a NiB2 compound; The step of placing the blank into a sintering furnace for sintering includes: placing a crucible containing the blank into a plasma activated sintering furnace for plasma activated sintering; The process conditions of the plasma activated sintering treatment are: first gradually heating up to 300°C-500°C, then keeping the temperature for 0.8h-1.2h, then gradually heating up to 850°C-1200°C, and then keeping the temperature for 0.5h-5h; during the heating and keeping process, the sintering pressure is between 150MPa-300MPa.

2. The method for preparing the NiB2 compound according to claim 1, characterized in that: First, the temperature is gradually increased to 300°C-500°C at a first preset heating rate, and then the temperature is gradually increased to 850°C-1200°C at a second preset heating rate, wherein the first preset heating rate is between 80°C / h-120°C / h, and the second preset heating rate is between 140°C / h-160°C / h.

3. The method for preparing the NiB2 compound according to claim 1, characterized in that: The vacuum degree of the ball mill is ≤10 -1 Pa; the purity of the inert gas is ≥99.9%.

4. The method for preparing the NiB2 compound according to claim 1, characterized in that: The inert gas is argon.

5. The method for preparing the NiB2 compound according to claim 1, characterized in that: In the green sheet forming step, the preset pressure has a value range of 50 MPa-500 MPa.

6. The method for preparing the NiB2 compound according to claim 1, characterized in that: The purity of the nickel powder and the boron powder is ≥99%.

7. The method for preparing the NiB2 compound according to any one of claims 1 to 6, characterized in that: After the step of placing the blank into a sintering furnace for sintering to obtain the NiB2 compound, the method further includes: cooling: cooling the NiB2 compound along with the sintering furnace.

8. An application of a NiB2 compound, characterized in that: A NiB2 compound is obtained by applying the preparation method described in any one of claims 1 to 7, and the NiB2 compound is coated on the inner surface of a pipe.

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