Raw material composition of titanium nitride, titanium nitride and preparation method of titanium nitride

Abstract

The invention discloses a raw material composition of titanium nitride, titanium nitride and a preparation method of the titanium nitride. The raw material composition of the titanium nitride comprises the following components in percentage by mass: 5-15% of a titanium source, 3-8% of a nitrogen source, 0.5-3% of a dispersing agent and 80-90% of an organic solvent, the dispersing agent is one or more of polyvinylpyrrolidone, lauryl sodium sulfate and polyethylene glycol. The preparation method of the titanium nitride is simple, efficient and low in cost. The prepared titanium nitride not only has high purity and small average particle size, but also has the advantages of good dispersity, high crystallinity and the like.

Description

Technical Field

[0001] The invention relates to a raw material composition of titanium nitride, titanium nitride and a preparation method thereof. Background Art

[0002] Nano-titanium nitride has the advantages of high hardness, high melting point, good chemical stability, good electrical and thermal conductivity, and unique optical properties, and has shown great application potential in many fields such as cutting tool coatings, electronic devices, and optical films. However, the existing nano-titanium nitride synthesis methods have many shortcomings, such as complex synthesis process, harsh reaction conditions, low product purity, and uneven particle size distribution, which limit the large-scale production and wide application of nano-titanium nitride.

[0003] Therefore, it is of great practical significance to develop an efficient, simple and synthetic method for preparing high-quality nano-titanium nitride. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art that the synthesis process of titanium nitride is complicated, the product quality of the obtained titanium nitride is poor, especially the purity is not high, and the particle size is large, and provide a raw material composition of titanium nitride, titanium nitride and a preparation method thereof. The preparation method of titanium nitride of the present invention is simple, efficient and low in cost. The obtained titanium nitride not only has high purity and small average particle size, but also has the advantages of good dispersibility and high crystallinity.

[0005] The present invention adopts the following technical solutions to solve the above technical problems.

[0006] The present invention provides a raw material composition of titanium nitride, which comprises the following components in percentage by mass:

[0007] 5-15% titanium source, 3-8% nitrogen source, 0.5-3% dispersant and 80-90% organic solvent;

[0008] The dispersant is one or more of polyvinyl pyrrolidone, sodium lauryl sulfate and polyethylene glycol.

[0009] In the present invention, the type of the titanium source can be conventional in the art, preferably including one or more of titanium tetrachloride, tetraisobutyl titanate, tetra-n-butyl titanate and titanium isopropoxide, such as titanium tetrachloride or tetra-n-butyl titanate.

[0010] In the present invention, the type of the nitrogen source can be conventional in the art, and preferably includes one or more of ammonia, urea and sodium azide, such as ammonia and / or urea.

[0011] In the present invention, the dispersant is preferably polyvinyl pyrrolidone and / or sodium lauryl sulfate.

[0012] In the present invention, the organic solvent may be any conventional organic solvent in the art that can dissolve the titanium source, nitrogen source and dispersant, preferably including one or more of anhydrous ethanol, toluene and xylene, such as anhydrous ethanol or toluene.

[0013] In the present invention, in the raw material composition of titanium nitride, the mass percentage of the titanium source is preferably 8-12%, such as 9.38% or 10.39%.

[0014] In the present invention, in the raw material composition of titanium nitride, the mass percentage of the nitrogen source is preferably 4-8%, such as 5.54% or 7.82%.

[0015] In the present invention, in the raw material composition of titanium nitride, the mass percentage of the dispersant is preferably 1-2.5%, such as 1.56% or 2.08%.

[0016] In the present invention, in the raw material composition of titanium nitride, the mass percentage of the organic solvent is preferably 80-88%, such as 81.24% or 81.99%.

[0017] In a preferred embodiment, the raw material composition of titanium nitride includes the following components in percentage by mass: 10.39% titanium source, 5.54% nitrogen source, 2.08% dispersant and 81.99% organic solvent; the dispersant is polyvinyl pyrrolidone.

[0018] In a preferred embodiment, the raw material composition of titanium nitride includes the following components in percentage by mass: 9.38% titanium source, 7.82% nitrogen source, 1.56% dispersant and 81.24% organic solvent; the dispersant is sodium dodecyl sulfate.

[0019] The present invention also provides a method for preparing titanium nitride, which comprises the following steps:

[0020] S1. Mix the raw material composition of titanium nitride as described above, and carry out nitridation reaction in an ammonia atmosphere to obtain a first product; the temperature of the nitridation reaction is 150-300° C.;

[0021] S2. Annealing the first product in an inert atmosphere to obtain the titanium nitride; the annealing is performed in an inert atmosphere; the annealing temperature is 600-800°C.

[0022] In the present invention, the step of mixing the raw material composition of titanium nitride is preferably carried out by mixing the titanium source and the organic solvent, adding the dispersant under stirring conditions, and continuing stirring.

[0023] Wherein, the stirring speed may be 200-400 r / min, for example, 300 r / min.

[0024] The continuous stirring time may be 30-60 min, for example 45 min.

[0025] Wherein, when the nitrogen source is solid, the nitrogen source is preferably added simultaneously with the dispersant. When the nitrogen source is gas, the nitrogen source is directly introduced into the reactor.

[0026] In the present invention, the temperature of the nitridation reaction is preferably 180-280°C, such as 200, 220, 250 or 260°C.

[0027] In the present invention, the nitridation reaction time may be 3-8 h, preferably 4-7 h, such as 5 or 6 h.

[0028] In the present invention, during the nitridation reaction, the pressure of the system may be 0.5-2 MPa, such as 1 or 1.5 MPa.

[0029] In the present invention, during the nitridation reaction, it is preferred to perform a stirring operation, and the stirring speed may be 200-500 r / min, such as 300 or 400 r / min.

[0030] In the present invention, after the nitridation reaction and before the annealing treatment, it is preferred to further perform cooling, separation, washing and drying steps.

[0031] The cooling method may be natural cooling, and the cooling end point may be room temperature, generally 20-30°C.

[0032] The separation method may be conventional in the art, such as centrifugal separation.

[0033] The washing method may be conventional in the art, such as washing with deionized water and anhydrous ethanol alternately for 3-5 times, for example, 4 times.

[0034] The drying method may be conventional in the art, such as drying in a vacuum drying oven. The drying temperature may be 50-80° C., such as 60 or 70° C. The drying time may be 6-12 h, such as 8 or 10 h.

[0035] In the present invention, the temperature of the annealing treatment is preferably 700-800°C, such as 750°C.

[0036] In the present invention, the annealing treatment time may be 1-3 hours, preferably 1.5-2.5 hours, such as 2 hours.

[0037] In the present invention, the inert atmosphere may be any conventional atmosphere in the art, preferably nitrogen.

[0038] The present invention also provides titanium nitride, which is prepared by the above-mentioned preparation method of titanium nitride.

[0039] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0040] The reagents and raw materials used in the present invention are commercially available.

[0041] The positive and progressive effects of the present invention are:

[0042] (1) The present invention precisely controls the reaction conditions and uses a dispersant of a suitable type and amount, so that the titanium nitride obtained not only has high purity and a small average particle size, but also has the advantages of high crystallinity and good dispersibility, and can fully exert its excellent performance in various fields.

[0043] (2) The raw materials used in the preparation of titanium nitride of the present invention are widely available and relatively inexpensive. At the same time, the preparation method of titanium nitride of the present invention does not require complicated equipment and cumbersome operating steps, the reaction conditions are relatively mild, the energy consumption is low, the reaction process is easy to control, the cost is low, and it is conducive to large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the XRD pattern of titanium nitride prepared in Example 1.

[0045] Figure 2 This is the SEM image of the titanium nitride prepared in Example 1.

[0046] Figure 3 This is the XRD pattern of titanium dioxide prepared in Comparative Example 2.

[0047] Figure 4 This is the SEM image of titanium nitride prepared in Comparative Example 6. DETAILED DESCRIPTION

[0048] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0049] Example 1

[0050] S1. (1) Preparation of raw material composition of titanium nitride: Weigh 15 g of tetrabutyl titanate as a titanium source, 8 g of urea as a nitrogen source, 3 g of polyvinyl pyrrolidone (PVP) as a dispersant, and 150 mL of anhydrous ethanol (density 0.7893 g / mL) as an organic solvent. The mass percentage of the titanium source is 10.39%, the mass percentage of the nitrogen source is 5.54%, the mass percentage of the dispersant is 2.08%, and the mass percentage of the organic solvent is 81.99%.

[0051] (2) Solution preparation: Dissolve 15 g of tetra-n-butyl titanate in 150 mL of anhydrous ethanol. Slowly add 8 g of urea and 3 g of PVP while stirring at a speed of 300 r / min. Continue stirring for 45 minutes to form a uniform mixed solution.

[0052] (3) Nitriding reaction: The mixed solution was transferred to a reactor, and ammonia gas was introduced into the reactor at a flow rate of 0.2 L / min (ammonia gas serves as both a nitrogen source and a protective gas). The pressure in the reactor was controlled to be 1 MPa, the temperature to be 200 °C, the reaction time to be 5 hours, and the stirring speed to be 300 r / min to obtain the first product.

[0053] S2. (1) Product separation and washing: After the reaction is completed, the reactor is naturally cooled to room temperature and the reaction product is taken out. The product is separated by centrifugation and washed alternately with deionized water and anhydrous ethanol for 4 times.

[0054] (2) Drying and annealing treatment: The washed product was placed in a vacuum drying oven and dried at 60°C for 8 hours, then placed in a tubular furnace and annealed at 700°C for 2 hours under a nitrogen protective atmosphere to obtain a titanium nitride product.

[0055] Its XRD pattern is as follows Figure 1 ( Figure 1 The black curve is the XRD pattern of titanium nitride prepared in Example 1, and the blue curve is the standard XRD pattern of titanium nitride). Figure 2 .Depend on Figure 2 It can be seen that the titanium nitride prepared in Example 1 has uniform size, and the average particle size is about 40 nm.

[0056] Example 2

[0057] S1. (1) Raw material composition of titanium nitride: 12 g titanium tetrachloride as titanium source, 10 g ammonia (introduced into the reaction system in gaseous form) as nitrogen source, 2 g sodium dodecyl sulfate (SDS) as dispersant, and 120 mL toluene (density 0.866 g / mL) as organic solvent. The mass percentage of the titanium source is 9.38%, the mass percentage of the nitrogen source is 7.82%, the mass percentage of the dispersant is 1.56%, and the mass percentage of the organic solvent is 81.24%.

[0058] (2) Solution preparation: Slowly drop titanium tetrachloride into 120 mL of toluene, stirring while dropping, and continue stirring for 30 minutes after the dropwise addition is complete. Then add 2 g of SDS and stir until it is completely dissolved to obtain a mixed solution.

[0059] (3) Nitriding reaction: The mixed solution was transferred to a reactor and ammonia gas was introduced at a flow rate of 0.2 L / min. The pressure was controlled at 1.5 MPa and the temperature was 250 °C. The reaction was carried out for 6 hours at a stirring speed of 400 r / min.

[0060] S2. (1) Product separation and washing: After the reaction is completed and cooled, the product is separated by centrifugation and washed alternately with deionized water and anhydrous ethanol for 5 times.

[0061] (2) Drying and annealing: The washed product was dried in a vacuum drying oven at 70°C for 10 hours, and then annealed in a tubular furnace at 800°C for 1.5 hours under nitrogen protection.

[0062] Example 3

[0063] The difference from Example 2 is that the temperature of the nitridation reaction in S1 (3) is lowered to 180°C, the product crystallinity is low, and the reaction is incomplete.

[0064] Comparative Example 1

[0065] Nano-titanium nitride was synthesized according to the method of Example 1, except that the dispersant PVP was not added.

[0066] After the reaction, the product was difficult to separate and the agglomeration phenomenon was serious. After testing, the product purity was 90%, the average particle size was 100nm, and the particle size distribution was uneven.

[0067] Comparative Example 2

[0068] The difference from Example 1 is that no nitrogen source is added in S1 (1), and no ammonia is introduced into the reactor in S1 (3). The XRD results of the prepared product are as follows: Figure 3 ( Figure 3 The red curve is the XRD diagram of the product obtained in Comparative Example 2, and the blue curve is the standard XRD diagram of titanium dioxide. Figure 3 It can be seen that comparative example 2 generates titanium dioxide particles instead of titanium nitride.

[0069] Comparative Example 3

[0070] The difference from Example 1 is that in S2 (2), the annealing treatment is not performed under nitrogen protection, resulting in the product being oxidized and having an uneven particle size distribution.

[0071] Comparative Example 4

[0072] The difference from Example 2 is that in S1 (1), toluene is not used as the solvent, but water is used as the solvent. As a result, the titanium tetrachloride is not completely dispersed and the product size is larger.

[0073] Comparative Example 5

[0074] Nano titanium nitride is synthesized by traditional high-temperature solid-phase reaction method. Titanium powder and boron nitride are used as raw materials, mixed in a molar ratio of 3:2, and reacted at a high temperature of 1500℃ for 10 hours. The synthesis process has high energy consumption, and the product contains many impurities, with a purity of only 92%, an average particle size of 150nm, and a wide particle size distribution range.

[0075] Comparative Example 6

[0076] The only difference from Example 1 is that PVP is replaced by sodium carboxymethyl cellulose (CMC) in S1 (1).

[0077] In this comparative example, CMC interferes with the combination of titanium ions and nitrogen sources, resulting in the appearance of impurity phases in the product, and cannot effectively prevent the agglomeration of titanium nitride particles, resulting in a larger particle size of the titanium nitride powder finally obtained.

[0078] The SEM image of the titanium nitride prepared in this comparative example is as follows: Figure 4 .Depend on Figure 4 It can be seen that the titanium nitride particles are seriously agglomerated.

[0079] Comparative Example 7

[0080] Nano-titanium nitride was synthesized according to the method of Example 1, except that the amount of dispersant PVP added in S1 (1) was 5%.

[0081] After the reaction, it can be seen that the bottom of the reactor has obvious particle sedimentation and serious agglomeration. After testing, the product purity is 95% and the average particle size is above 300nm, mainly because excessive dispersant will induce the generated product to agglomerate on its surface.

[0082] Comparative Example 8

[0083] Nano-titanium nitride was synthesized according to the method of Example 1, except that the temperature of the nitridation reaction in S1 (3) was 320°C.

[0084] After the reaction, the product purity was 98% as determined by XRD, and the particle size increased significantly by TEM, with an average particle size of more than 200 nm, mainly due to excessive crystal growth during the nitridation process.

[0085] Comparative Example 9

[0086] Nano-titanium nitride was synthesized according to the method of Example 1, except that the annealing temperature in S2 (2) was 900°C.

[0087] After the reaction, the product purity was 99% as determined by XRD, and the particle size increased significantly as determined by TEM, with an average particle size of more than 300 nm, mainly due to excessive crystal growth during the annealing process.

[0088] Effect Example 1

[0089] The titanium nitride obtained in the above Examples 1-3 and Comparative Examples 1-9 was tested for purity, average particle size, crystallinity and dispersibility.

[0090] The purity test method is as follows: the XRD spectrum of titanium nitride prepared in the embodiment or comparative example is compared with the standard spectrum of titanium nitride, and the purity and impurity phase of titanium nitride are determined according to the intensity and position of the characteristic peaks. If the impurity phase exists, additional non-titanium nitride characteristic peaks will appear, and the impurity content can be semi-quantitatively analyzed according to the peak intensity, etc. The intensity ratio of the diffraction peaks of titanium nitride and the impurity phase is the purity value of titanium nitride.

[0091] The average particle size was tested by scanning electron microscopy (SEM). The titanium nitride prepared in the above-mentioned embodiment and comparative example was dispersed in ethyl acetate solvent to prepare a solution with a mass concentration of 0.1%. The solution was dropped on a copper mesh, and observed and photographed with SEM. The particle sizes of more than 50 points were measured and then ImageJ was used to perform data statistics and the average value was taken as the average particle size.

[0092] The test method for crystallinity is to judge based on the sharpness and intensity of the XRD diffraction peak. The sharper the peak and the higher the intensity, the better the crystallinity. Use JADE software to directly fit the XRD peak to calculate the crystallinity. The crystallinity calculation is based on the area of ​​the crystallization peak and the proportion of the total peak area.

[0093] The test method of dispersibility is: directly observe the distribution state of titanium nitride obtained in the embodiment or comparative example. If there is obvious stacking between particles, it means that the dispersibility is poor. If there is no obvious stacking between particles, it means that the dispersion is good.

[0094] The test results are shown in Table 1.

[0095] Table 1

[0096]

[0097] It can be clearly seen from the comparison between Examples 1-3 and Comparative Examples 1-9 that the titanium nitride prepared by the preparation method of the present invention has high purity, small average particle size, high crystallinity, good dispersibility, and has good application prospects.

Claims

1. A raw material composition of titanium nitride, characterized in that: The raw material composition of titanium nitride includes the following components in percentage by mass: 5-15% titanium source, 3-8% nitrogen source, 0.5-3% dispersant and 80-90% organic solvent; The dispersant is one or more of polyvinyl pyrrolidone, sodium lauryl sulfate and polyethylene glycol.

2. The titanium nitride raw material composition according to claim 1, characterized in that The raw material composition of titanium nitride meets one or more of the following conditions: (1) The titanium source includes one or more of titanium tetrachloride, tetraisobutyl titanate, tetra-n-butyl titanate and titanium isopropoxide, such as titanium tetrachloride or tetra-n-butyl titanate; (2) The nitrogen source includes one or more of ammonia, urea and sodium azide, such as ammonia and / or urea; (3) The type of the dispersant: polyvinyl pyrrolidone and / or sodium lauryl sulfate; (4) The organic solvent includes one or more of anhydrous ethanol, toluene and xylene, such as anhydrous ethanol or toluene.

3. The titanium nitride raw material composition according to claim 1, characterized in that The raw material composition of titanium nitride meets one or more of the following conditions: (1) In the raw material composition of titanium nitride, the mass percentage of the titanium source is 8-12%, for example, 9.38% or 10.39%; (2) In the raw material composition of titanium nitride, the mass percentage of the nitrogen source is 4-8%, for example, 5.54% or 7.82%; (3) In the raw material composition of titanium nitride, the mass percentage of the dispersant is 1-2.5%, for example, 1.56% or 2.08%; (4) In the titanium nitride raw material composition, the mass percentage of the organic solvent is 80-88%, for example, 81.24% or 81.99%.

4. The titanium nitride raw material composition according to claim 1, characterized in that The raw material composition of titanium nitride includes the following components in percentage by mass: 10.39% titanium source, 5.54% nitrogen source, 2.08% dispersant and 81.99% organic solvent; the dispersant is polyvinyl pyrrolidone; Alternatively, the raw material composition of titanium nitride includes the following components in percentage by mass: 9.38% titanium source, 7.82% nitrogen source, 1.56% dispersant and 81.24% organic solvent; the dispersant is sodium dodecyl sulfate.

5. A method for preparing titanium nitride, characterized in that: It includes the following steps: S1. Mixing the raw material composition of titanium nitride according to any one of claims 1 to 4, and performing a nitridation reaction under an ammonia atmosphere to obtain a first product; the temperature of the nitridation reaction is 150-300° C.; S2. Annealing the first product in an inert atmosphere to obtain the titanium nitride; the annealing is performed in an inert atmosphere; the annealing temperature is 600-800°C.

6. The method for preparing titanium nitride as claimed in claim 5, characterized in that: The step of mixing the titanium nitride raw material composition comprises: mixing the titanium source and the organic solvent, adding the dispersant under stirring conditions, and continuously stirring; Wherein, the stirring speed is preferably 200-400r / min, for example 300r / min; The continuous stirring time is preferably 30-60 min, for example 45 min; Wherein, when the nitrogen source is solid, the nitrogen source is preferably added simultaneously with the dispersant; when the nitrogen source is gas, the nitrogen source is directly introduced into the reactor.

7. The method for preparing titanium nitride as claimed in claim 5, characterized in that: The preparation method of titanium nitride meets one or more of the following conditions: (1) The temperature of the nitridation reaction is 180-280°C, for example, 200, 220, 250 or 260°C; (2) The nitridation reaction time is 3-8 h, preferably 4-7 h, for example 5 or 6 h; (3) During the nitridation reaction, the pressure of the system is 0.5-2 MPa, for example, 1 or 1.5 MPa.

8. The method for preparing titanium nitride as claimed in claim 5, characterized in that: The preparation method of titanium nitride meets one or more of the following conditions: (1) During the nitridation reaction, stirring is also performed; the stirring speed is preferably 200-500 r / min, such as 300 or 400 r / min; (2) After the nitridation reaction and before the annealing treatment, cooling, separation, washing and drying steps are performed; Wherein, the cooling method is preferably natural cooling; the cooling end point is preferably room temperature, generally 20-30°C; Wherein, the separation method is, for example, centrifugal separation; The washing method includes, for example, washing with deionized water and anhydrous ethanol alternately for 3-5 times, for example, 4 times; The drying method is, for example, drying in a vacuum drying oven; the drying temperature is preferably 50-80° C., such as 60 or 70° C.; the drying time is preferably 6-12 h, such as 8 or 10 h.

9. The method for preparing titanium nitride as claimed in claim 5, characterized in that: The preparation method of titanium nitride meets one or more of the following conditions: (1) The annealing temperature is 700-800°C, for example 750°C; (2) The annealing time is 1-3 hours, preferably 1.5-2.5 hours, for example 2 hours; (3) The inert atmosphere is nitrogen.

10. A titanium nitride, characterized in that: It is prepared by the preparation method of titanium nitride as described in any one of claims 5 to 9.

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