CN108163821A - The preparation method of spherical titanium nitride - Google Patents

Abstract

The invention relates to a preparation method of spherical titanium nitride, in particular to a method for preparing spherical titanium nitride by using radio frequency plasma powder production equipment. The technical problem solved by the invention is to provide a method for preparing spherical titanium nitride with high spheroidization rate. The method of the present invention adopts radio frequency plasma equipment as a reaction device, uses titanium hydride powder as a raw material, and uses nitrogen as a reaction gas to prepare titanium nitride powder in one step. The process flow is short and the reaction time is extremely short, which greatly improves production efficiency and obtains The product has no impurity pollution, simple preparation process, and low requirements for raw materials, which lays the foundation for the industrial production of spherical titanium nitride powder. The spherical titanium nitride powder prepared by the method of the invention has high spheroidization rate and nitriding rate. The preparation of raw materials does not require a lot of crushing, and the particle size of the product is small.

Description

Preparation method of spherical titanium nitride

technical field

The invention relates to a preparation method of spherical titanium nitride, in particular to a method for preparing spherical titanium nitride by using radio frequency plasma powder production equipment.

Background technique

The metal compound TiN has many excellent physical and chemical properties. It has excellent corrosion resistance, wear resistance and oxidation resistance, and has a high melting point (3205°C) and a hardness of 1990 (×9.8N/mm ² ). TiN deposition on jewelry and lamps can not only achieve aesthetic effect, but also enhance wear resistance. It is a potential material to replace WC, which is widely used at present, and can greatly reduce the cost of material application. TiN compounds have high biocompatibility, and also have high application value in clinical medicine and stomatology. In addition, TiN can also be used to make crucibles, cutting tools, additives, etc. The breadth and depth of application of TiN powder are not commensurate with its excellent properties. It needs to be researched and developed by people. It can be predicted that titanium nitride powder will become a new material of the century.

With the continuous deepening of research on TiN, there are more and more methods for preparing TiN powder. Traditional TiN powder preparation methods, such as: metal titanium powder nitriding method, titanium dioxide carbothermal reduction nitriding method, gas phase method, etc., obtain TiN powder with irregular shape, poor fluidity, greatly reduced performance, and low nitriding rate. High, the nitriding time is longer, the particle size range is wider, and the energy consumption is large. So far, there is no effective solution that covers the above problems.

Compared with non-spherical titanium nitride powder, the mechanical properties of spherical titanium nitride are the same in all directions, and it is easier to obtain products with excellent performance in powder metallurgy and 3D printing. Therefore, there is an urgent need for a method for preparing spherical titanium nitride with simple preparation process and high spheroidization rate.

Patent 200410072553.4 discloses a method for reactive plasma spraying nanocrystalline titanium nitride powder, using a plasma spray gun for spraying, specifically including the main steps: titanium powder into the powder feeder, into the mixed ion gas, into the reaction chamber Nitrogen is passed through, titanium powder is sent into the flame flow, sprayed and collected in a container containing water, and titanium nitride powder particles with a diameter of 30-100nm can be obtained by using this method. However, this method requires pure titanium powder as a raw material. In the early stage, it is necessary to prepare titanium powder particles of different particle sizes, and then carry out nitriding. The preparation process is complicated and the equipment requirements are high. More importantly, pure titanium powder is easily oxidized in air to form titanium oxide. This is disadvantageous for nitriding. In addition, the danger of spontaneous combustion of pure titanium powder is much greater, and the safety requirements for production are higher. Sending titanium powder into the flame flow, spraying and collecting in the water container, the energy loss is large. Moreover, the sphericity of the obtained titanium nitride is not good, and the spheroidization rate needs to be further improved.

Contents of the invention

In view of the above defects, the technical problem to be solved by the present invention is to provide a method for preparing spherical titanium nitride with simple preparation process and high spheroidization rate.

The preparation method of spherical titanium nitride of the present invention is prepared by radio frequency plasma equipment, and specifically comprises the following steps:

a. Arcing: Argon is used as the ionized gas to start the arc, and nitrogen is introduced from the protective gas inlet of the radio frequency plasma equipment at the same time; the working voltage of the radio frequency plasma equipment is controlled to be 5-15kV, and the power is 30-200kW;

b. Feeding: After the arc is stabilized, the flow ratio of argon gas and nitrogen gas is controlled to be 1:20-10:1, and then titanium hydride powder is fed by the feeding device to obtain spherical titanium nitride.

Preferably, in step a, after the arc is stabilized, the ionized gas is changed to a mixed gas of argon and nitrogen.

Preferably, in the mixed gas of argon and nitrogen, the volume ratio of argon and nitrogen is 1:5˜10:1.

Further preferably, in the mixed gas of argon and nitrogen, preferably, the volume ratio of argon and nitrogen is 1:2˜3:1.

Preferably, in step b, the particle size of the titanium hydride powder is 10-400 μm.

Further preferably, the titanium hydride powder is fed by vibration with an amplitude of 10-80%.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention uses radio frequency plasma equipment as the reaction device, uses titanium hydride powder as the raw material, and nitrogen as the reaction gas to prepare titanium nitride powder in one step. The process flow is short and the reaction time is extremely short, which greatly improves the production efficiency and obtains The product has no impurity pollution, simple preparation process and low requirements on raw materials, which lays a foundation for realizing the industrialized production of spherical titanium nitride powder.

The spherical titanium nitride powder prepared by the method of the invention has high spheroidization rate and nitriding rate. The preparation of raw materials does not require a lot of crushing, and the particle size of the product is small.

The invention is not only applicable to the preparation of spherical titanium nitride powder, but also applicable to the preparation of spherical zirconium nitride powder and other nitride spherical powders.

Description of drawings

Figure 1 is an XRD pattern of titanium nitride prepared in the present invention.

Fig. 2 is an SEM image of titanium nitride prepared in the present invention.

Detailed ways

The preparation method of spherical titanium nitride of the present invention is prepared by radio frequency plasma equipment, and specifically comprises the following steps:

a. Arcing: Argon is used as the ionized gas to start the arc, and nitrogen is introduced from the protective gas inlet of the radio frequency plasma equipment at the same time; the working voltage of the radio frequency plasma equipment is controlled to be 5-15kV, and the power is 30-200kW;

b. Feeding: After the arc is stabilized, the flow ratio of argon gas and nitrogen gas is controlled to be 1:20-10:1, and then the titanium hydride powder is fed by the feeding device, and the titanium hydride powder is dehydrogenated in the plasma torch. Direct nitriding while spheroidizing to obtain semi-molten titanium nitride;

c. Spheroidization: Under the action of surface tension, the semi-molten titanium nitride is cooled and solidified into a spherical shape.

The radio frequency plasma powder spheroidization technology is an existing technology. The principle is that under the action of a high frequency power supply, the inert gas is ionized to form a stable high temperature inert gas plasma; and the raw materials with irregular shapes are sent into the plasma through the feeding device. In the torch, a large amount of heat is absorbed in the high-temperature plasma, and the surface is rapidly melted, and enters the reactor at a very high speed, and is rapidly cooled in an inert atmosphere. Under the action of surface tension, it is cooled and solidified into a spherical powder. However, the present invention realizes direct nitriding while dehydrogenating and spheroidizing titanium hydride powder in the plasma torch by controlling the voltage and power of the radio-frequency plasma equipment, and introducing specific types of gas and specific gas flow rates to obtain a spherical shape. Titanium nitride. Its reaction principle is:

TiH ₂ =Ti+H ₂

2Ti+N ₂ =2TiN

In the method of the present invention, the above two-step reactions are all carried out in the next step under the condition of a high-temperature radio frequency plasma field fed with argon and nitrogen. First, the argon gas is introduced from the center of the radio frequency plasma equipment, that is, the ionized gas inlet, and the nitrogen gas is passed from the edge of the radio frequency plasma equipment, that is, the shielding gas inlet. In this way, the argon flow is easy to generate a plasma flow, and the titanium hydride material is pyrolyzed. Nitrogen is introduced from the edge of the RF plasma powder production equipment to make the nitriding reaction more complete. The titanium nitride spheroidization rate and nitriding rate obtained by the method are high, and the spheroidization and nitriding are carried out simultaneously, which greatly improves the production efficiency.

In order to improve the spheroidization rate, preferably, in step a, use argon as the ionized gas to start the arc to obtain an argon arc. After the argon arc is stabilized, change the ionized gas into a mixed gas of argon and nitrogen. At this time, the An arc of argon and nitrogen is formed. Nitrogen ionization in the plasma torch acts as a reaction heat source and as a reactant at the same time, reacting with titanium powder at high temperature to directly obtain spherical titanium nitride powder, which can not only save reaction energy consumption, but also improve product purity and spheroidization rate.

More preferably, in the mixed gas of argon and nitrogen, the volume ratio of argon to nitrogen is 1:5 to 10:1, more preferably, the volume ratio of argon to nitrogen is 1:2 to 3:1 . When the ionized gas is a mixed gas, it is still necessary to control the flow ratio of the total argon gas and the total nitrogen gas to be 1:20-10:1. In the present invention, regardless of nitrogen or argon, the flow unit is m ³ /h.

The particle size of commonly used titanium hydride powder is suitable for the present invention. Preferably, in step b, the particle size of titanium hydride powder is 40-100 μm.

As a preferred solution, the titanium hydride powder is fed by vibration with an amplitude of 10-80%, which can make the reaction of the titanium hydride powder more complete and increase the nitriding rate.

The specific implementation of the present invention will be further described below in conjunction with the examples, and the present invention is not limited to the scope of the examples.

Example 1

Spherical titanium nitride powder is produced by radio frequency plasma powder production equipment. The amplitude of the feeding device of the radio frequency plasma powder production equipment is set at 20%, the operating voltage is 10.5kV, and the power is 48kW. "Side gas" (that is, the protective gas inlet) is fed with nitrogen, and "middle gas" (that is, the ionized gas inlet) is first fed with argon to start the arc, and then the mixed gas of argon and nitrogen is fed into the arc after the arc is stable to control the nitrogen flow The ratio of the flow rate to the argon gas is 2:1, and the material is fed and reacted for 5 minutes to receive the material, and the spherical titanium nitride powder is prepared. Its XRD spectrum is shown in Figure 1, and its SEM spectrum is shown in Figure 2. The spheroidization rate reaches 80%, and the nitriding rate is 83%.

Among them, the spheroidization rate is obtained by observing the spheroidization number by scanning electron microscope. The nitriding rate is obtained by measuring the surface of the sample with an energy spectrometer and combining with the analysis results of an X-ray diffractometer.

Example 2

Spherical titanium nitride powder is produced by radio frequency plasma powder production equipment. The amplitude of the feeding device of the radio frequency plasma powder production equipment is set at 22%, the operating voltage is 11.5kV, and the power is 55kW. The "edge gas" (that is, the protective gas inlet) is fed with nitrogen, and the "middle gas" (that is, the ionized gas inlet) is fed with argon to start the arc. The ratio of nitrogen flow to argon flow is 1:1. After the arc is stabilized, titanium hydride is fed in, and the feeding reaction takes 5 minutes to collect. The mass of titanium nitride powder is measured to be 27g. Its XRD pattern is similar to Figure 1, and its SEM pattern is similar to Figure 2. The spheroidization rate reaches 82%, and the nitriding rate is 76%.

Example 3

Spherical titanium nitride powder is produced by radio frequency plasma powder production equipment. The amplitude of the feeding device of the radio frequency plasma powder production equipment is set at 24%, the operating voltage is 8kV, and the power is 40kW. "Side gas" (i.e. the inlet of protective gas) is fed with nitrogen, "middle gas" (i.e. the inlet of ionized gas) is firstly fed with argon gas to start the arc, and then the mixed gas of argon and nitrogen is fed in after the arc is stable. The flow rate of nitrogen gas is the same as that of The flow ratio of argon gas is 3:2, and the feeding reaction takes 5 minutes to receive the material, and the measured mass of titanium nitride powder is 28g. Its XRD pattern is similar to Figure 1, and its SEM pattern is similar to Figure 2. The spheroidization rate reaches 88%, and the nitriding rate is 78%.

Example 4

Spherical titanium nitride powder is produced by radio frequency plasma powder production equipment. The amplitude of the feeding device of the radio frequency plasma powder production equipment is set to be 10%, the working voltage is 15kV, and the power is 200kW. "Side gas" (i.e. the inlet of protective gas) is fed with nitrogen, "middle gas" (i.e. the inlet of ionized gas) is firstly fed with argon gas to start the arc, and then the mixed gas of argon and nitrogen is fed in after the arc is stable. The flow rate of nitrogen gas is the same as that of The flow ratio of argon gas was 3:20, and the feeding reaction was 5 minutes to receive the material. The mass of titanium nitride powder was measured to be 19g. Its XRD pattern is similar to Figure 1, and its SEM pattern is similar to Figure 2. The spheroidization rate reaches 91%, and the nitriding rate is 56%.

Example 5

Spherical titanium nitride powder is produced by radio frequency plasma powder production equipment. The amplitude of the feeding device of the radio frequency plasma powder production equipment is set at 80%, the operating voltage is 12kV, and the power is 60kW. "Side gas" (i.e. the inlet of protective gas) is fed with nitrogen, "middle gas" (i.e. the inlet of ionized gas) is firstly fed with argon gas to start the arc, and then the mixed gas of argon and nitrogen is fed in after the arc is stable. The flow rate of nitrogen gas is the same as that of The flow ratio of argon gas is 9:10, and the feeding reaction takes 5 minutes to receive the material. The mass of titanium nitride powder is measured to be 42g. Its XRD pattern is similar to Figure 1, and its SEM pattern is similar to Figure 2. The spheroidization rate reaches 81%, and the nitriding rate is 68%.

Claims (6)

1. the preparation method of spherical titanium nitride, it is characterised in that：Be prepared using radio frequency plasma equipment, specifically include as Lower step：

A, the starting the arc：Using argon gas as the ionized gas starting the arc, while by nitrogen at the gas atmosphere inlet of radio frequency plasma equipment It is passed through；The operating voltage for controlling radio frequency plasma equipment is 5~15kV, and power is 30~200kW；

B, feeding：After arc stabilization, it is 1 to control the flow-rate ratio of the argon gas being passed through and nitrogen:20~10:1, then by feed device Hydride powder is sent into, obtains spherical titanium nitride.

2. the preparation method of spherical shape titanium nitride according to claim 1, it is characterised in that：In a steps, after arc stabilization, Ionized gas is become to the mixed gas of argon gas and nitrogen.

3. the preparation method of spherical shape titanium nitride according to claim 2, it is characterised in that：The mixing of the argon gas and nitrogen In gas, the volume ratio of argon gas and nitrogen is 1:5~10:1.

4. the preparation method of spherical shape titanium nitride according to claim 3, it is characterised in that：The mixing of the argon gas and nitrogen In gas, preferably the volume ratio of argon gas and nitrogen is 1:2~3:1.

5. according to the preparation method of Claims 1 to 4 any one of them spherical shape titanium nitride, it is characterised in that：In b step, hydrogen The grain size for changing titanium valve is 10~400 μm.

6. according to the preparation method of Claims 1 to 5 any one of them spherical shape titanium nitride, it is characterised in that：The titantium hydride Powder is fed using vibration, and amplitude is 10~80%.