阅读说明：本技术 一种纳米二硼化钛粉体的制备方法 (Preparation method of nano titanium diboride powder ) 是由 王开新 韩成良 周正 曹显志 郭秀凤 于 2019-12-15 设计创作，主要内容包括：一种纳米二硼化钛粉体的制备方法,涉及高熔点硼化物粉体的制备技术领域。取硝酸钛、镁粉、三溴化硼置于密封的高压反应釜中进行反应,反应产物经过洗涤、过滤、干燥获得二硼化钛粗粉,粗粉中含部分氮化钛杂质；将装有二硼化钛粗粉和助磨剂的球磨罐放入到等离子体球磨机中,设置好转速和球磨时间后进行球磨处理；待球磨结束后,取出反应产物并通过分级处理即可得到不同粒度分布的二硼化钛纳米粉体。球磨过程中不会产生有害物质,有利于环境保护。同时,在球磨过程中引入一定强度的等离子体,使粉体颗粒表面活性增强,诱导原料中的杂相进一步反应,进一步控制粉体的结构缺陷,从而纯化了产品,同时也加速了球磨进程。(A preparation method of nano titanium diboride powder relates to the technical field of preparation of high-melting-point boride powder. Placing titanium nitrate, magnesium powder and boron tribromide in a sealed high-pressure reaction kettle for reaction, washing, filtering and drying a reaction product to obtain titanium diboride coarse powder, wherein the coarse powder contains part of titanium nitride impurities; putting the ball milling tank filled with the titanium diboride coarse powder and the grinding aid into a plasma ball mill, setting the rotating speed and the ball milling time, and then carrying out ball milling treatment; after the ball milling is finished, taking out the reaction product and carrying out grading treatment to obtain the titanium diboride nano powder with different particle size distributions. No harmful substance is generated in the ball milling process, which is beneficial to environmental protection. Meanwhile, plasma with certain strength is introduced in the ball milling process, so that the surface activity of powder particles is enhanced, the heterogeneous phase in the raw materials is induced to further react, and the structural defects of the powder are further controlled, so that the product is purified, and the ball milling process is accelerated.)

1. A preparation method of nano titanium diboride powder is characterized by comprising the following steps:

step one, preparing titanium diboride coarse powder

Placing titanium nitrate, magnesium powder and boron tribromide in a sealed high-pressure reaction kettle for reaction, washing, filtering and drying a reaction product to obtain titanium diboride coarse powder, wherein the coarse powder contains part of titanium nitride impurities;

step two, ball milling preparation of nano titanium diboride powder

Putting the ball milling tank filled with the titanium diboride coarse powder and the grinding aid into a plasma ball mill, setting the rotating speed and the ball milling time, and then carrying out ball milling treatment;

after the ball milling is finished, taking out the reaction product and carrying out grading treatment to obtain the titanium diboride nano powder with different particle size distributions.

2. The method according to claim 1, wherein the weight ratio of the titanium nitrate, the magnesium powder and the boron tribromide in the first step is 1: 3-5: 2 to 3.

3. The method of claim 1, wherein the reaction is carried out at 200 to 300 ℃ for 1 to 5 hours in the first step.

4. The method of claim 1, wherein the weight ratio of the titanium diboride coarse powder to the grinding aid in step two is 1: 1.

5. the method of claim 1 or 4, wherein in step two the grinding aid is ethylene glycol.

6. The method according to claim 1, wherein the rotation speed of the ball mill in the second step is 300-600 rpm, and the ball milling time is 4-15 hours.

Technical Field

The invention relates to the technical field of preparation of high-melting-point boride powder, in particular to a preparation method of nano titanium diboride powder.

Background

Transition metal borides having high melting points, high strength, good wear resistance and chemical stability, high electrical and thermal conductivity have been the focus of research in recent years. Titanium diboride (TiB)₂) Is an important boride material, is a diboride of a group IVB metal and has the same hexagonal planar network structure. Titanium diboride (TiB)₂) Besides good physicochemical properties of transition metal boride, the titanium boride (TiB) has excellent electrical properties, oxidation resistance and high-temperature creep resistance₂) The method has wide application in the fields of structural materials, functional materials and ultrahigh temperature materials.

The current common boride synthesis methods include an arc melting method, a reduction reaction method, a mechanochemical method and the like. The arc melting method is that the high melting point electrode generates electric arc to melt metal, and the temperature is reduced after power failure, and the metal is solidified into ingot. In addition, TiCl is present₄And NaBH₄The reaction raw material is subjected to reduction reaction (500-700 ℃) in inert gas (Ar) to obtain TiB with uniform particle size (20nm)₂The produced hydrogen chloride gas has environmental pollution and the prepared powder has poor dispersibility. The traditional mechanochemical method mainly thins raw material particles by ball milling, improves the surface energy of powder, reduces reaction temperature, has the advantages of simple and convenient process, high production efficiency and the like, but the synthesized powder has uneven particle size distribution and more structural defects and is still the aspect needing further improvement.

Disclosure of Invention

Aiming at the defects of the preparation of the titanium diboride powder, the invention provides the preparation method of the nano titanium diboride powder, which has the advantages of low process energy consumption, simple and convenient process and higher purity of the prepared powder.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a preparation method of nano titanium diboride powder comprises the following steps:

step one, preparing titanium diboride coarse powder

Placing titanium nitrate, magnesium powder and boron tribromide in a sealed high-pressure reaction kettle for reaction, washing, filtering and drying a reaction product to obtain titanium diboride coarse powder, wherein the coarse powder contains part of titanium nitride impurities;

step two, ball milling preparation of nano titanium diboride powder

Putting the ball milling tank filled with the titanium diboride coarse powder and the grinding aid into a plasma ball mill, setting the rotating speed and the ball milling time, and then carrying out ball milling treatment;

after the ball milling is finished, taking out the reaction product and carrying out grading treatment to obtain the titanium diboride nano powder with different particle size distributions.

As the preferred technical scheme of the invention, the preparation method of the nano titanium diboride powder comprises the following steps:

in the first step, the weight ratio of titanium nitrate to magnesium powder to boron tribromide is 1: 3-5: 2-3, reacting for 1-5 hours at 200-300 ℃.

In the second step, the weight ratio of the titanium diboride coarse powder to the grinding aid is 1: 1, the grinding aid is glycol. The rotating speed of the ball mill is 300-600 revolutions per minute, and the ball milling time is 4-15 hours.

Compared with the prior art, the invention has the beneficial effects that:

1) the preparation method realizes the preparation of the titanium diboride powder by the titanium nitrate, the magnesium powder and the boron tribromide, simultaneously improves the purity of the product by utilizing a ball milling process, and the adopted process has the advantages of simplicity, convenience, low cost and the like, and can be used for large-scale production. The prepared product has the advantages of uniform particle size distribution, high product purity and the like.

2) The prepared titanium diboride coarse powder and the grinding aid are selected as reaction raw materials in the ball milling process, so that no harmful substances are generated in the ball milling process, and the environment protection is facilitated. Meanwhile, plasma with certain strength is introduced in the ball milling process, so that the surface activity of powder particles is enhanced, the heterogeneous phase in the raw materials is induced to further react, and the structural defects of the powder are further controlled, so that the product is purified, and the ball milling process is accelerated.

Drawings

FIG. 1 is an XRD pattern of titanium diboride coarse powder prepared in step one and three titanium diboride powders prepared in step two;

FIG. 2 is SEM images of the preparation of titanium diboride coarse powder (a) in the first step and three kinds of titanium diboride powder (b, c and d are ball milled for 4, 8 and 12 hours respectively) in the second step.

Detailed Description

The invention provides a preparation method of nano titanium diboride powder, which comprises the following steps:

step one, preparing titanium diboride coarse powder

According to the weight ratio of 1: 3-5: and 2-3, placing titanium nitrate, magnesium powder and boron tribromide in a sealed high-pressure reaction kettle, reacting for 1-5 hours at 200-300 ℃, washing the reaction product with acid to remove impurities, filtering and drying to obtain titanium diboride coarse powder, wherein the coarse powder contains part of titanium nitride impurities (titanium nitride cannot be removed by acid washing).

Step two, ball milling preparation of nano titanium diboride powder

And (2) putting the ball milling tank filled with the titanium diboride coarse powder and grinding aid ethylene glycol (the weight ratio of the titanium diboride coarse powder to the grinding aid ethylene glycol is 1: 1) into a plasma ball mill, setting the rotating speed to 300-600 revolutions per minute and the ball milling time (4, 8 and 12 hours), and then carrying out ball milling treatment.

After the ball milling is finished, taking out the reaction product and carrying out grading treatment to obtain the titanium diboride nano powder with different particle size distributions.

FIG. 1 is an XRD (X-ray diffraction) diagram of titanium diboride coarse powder prepared in the first step and three titanium diboride powders prepared in the second step, and it can be seen from FIG. 1 that TiB without ball milling treatment is adopted₂The coarse powder contains a certain amount of TiN phase, and the existence of diffraction characteristic peak of the TiN phase can be obviously observed. However, as the ball milling time was prolonged, the peak height of the diffraction characteristic peak of TiN tended to be gentle, and the peak intensity of the diffraction peak of the entire reaction product gradually increased, indicating that TiB₂The crystallinity of the nano powder is gradually increased along with the prolonging of the ball milling time.

FIG. 2 is an SEM image of titanium diboride coarse powder prepared in the first step (a) and three titanium diboride powders prepared in the second step (b, c and d are respectively subjected to ball milling for 4, 8 and 12 hours), and the microscopic appearances of four groups of reaction products are analyzed through the SEM image in FIG. 2, and the influence of the ball milling time on the particle size of the powders is analyzed:

when TiB₂When the coarse powder is not subjected to ball milling treatment, as can be seen from fig. 2a, the obtained product is irregular in shape and is composed of a plurality of primary particles, and the particle size of the particles is mainly distributed between 20 and 80 μm; when ball milling treatment is carried out for 4h, as can be seen from fig. 2b, the shape of the product is still random and mainly consists of primary particles and part of secondary particles, and the size of the primary particles is large (about 1-2 μm); when the ball milling time is 8 hours, as can be seen from fig. 2c, the shape of the reaction product is spheroidal, and the reaction product is still composed of primary particles and secondary particles, and the size of the primary particles constituting the secondary particles is large (about 500-900 nm); continuing ball milling for 12h, as can be seen from FIG. 2d, the reaction product is mainly composed of a plurality of primary particles and a part of secondary particles, the shape is also spheroidal, the size of the primary particles is the smallest (about 20-100 nm), and the size of the primary particles constituting the secondary particles is larger (about 200-800 nm).

The analysis and the test of the X-ray powder diffraction and the field emission scanning electron microscope are combined to obtain the conclusion:

the ball milling time is controlled to be 0h, 4h, 8h and 12h respectively, the particle size of titanium diboride powder particles can be obviously observed to be gradually reduced along with the prolonging of the ball milling time, the particle size is changed from a micron level to a nanometer level, and when the ball milling time is 12h, the average particle size of the titanium diboride powder particles is at least 20-100 nm. Meanwhile, under the action of the plasma generator, the impurity phase (such as TiN) in the raw material is converted to a target product through a series of chemical reactions, so that the purity of the reaction product is improved (the purity of the finally prepared titanium diboride can reach more than 99.5 percent).

The preparation method of the nano titanium diboride powder is further described by combining the embodiment.