KR950005295B1 - Method of preparing a titanium conpound - Google Patents

Abstract

The invention relates to manufacture of Ti-Ni or Ti-Al compound, TiC, TiB2, TiBi, TiCN, TiN or TiH2 by self propagating high temperature synthesis process. The producing method comprises mixing Ti powder and at least one element selected from nickel, aluminium and silica in a reactor, and heating the mixed materials under inactive gas atmosphere with a heating element sticking to the reactor, to make it possible to generate the exothermic reaction.

Description

Method for preparing titanium compound

1 is a self-heating process synthesis process according to the invention.

2 is a titanium compound manufacturing apparatus according to the present invention.

* Explanation of symbols for main parts of the drawings

1: heating element 2: produced titanium metal compound

3: Zone of Structurization 4: Zone of Combustion

5: Zone of Heating 6: Initial reactant

7: vacuum pump 8,11: pressure gauge

9: argon or hydrogen or nitrogen gas cylinder 10 gas stabilizer

12 outlet 13 transformer

14: calorimeter 15: process control computer

16: power 17: recorder

18: Packing 19: Cooling water outlet

20: motor 21: specimen

23 temperature measuring instrument 24 tungsten filament

25: cooling water inlet 26: hydraulic device

The present invention is an intermetallic compound such as titanium-nickel (TiNi), titanium-aluminum (TiAl), or titanium carbide (TiC) manufactured by self propagating high temperature synthesis using titanium metal powder. ), Titanium boride (TiB _z ), titanium silicate (TiSi), titanium cyanide (TiCN), titanium nitride (TiN), titanium halide (TiH ₂ ).

Conventionally, in order to synthesize a titanium compound, a titanium metal and a powder of carbon or boron are mixed, put into an electric furnace, heated to melt at a temperature of 1800 ° C. or more for a long time, cooled, and ground to a powder. Also, a large amount of energy was consumed to adjust the particle size of this compound. In addition, hydride and nitride, which are solid-gas reactions, were heated by evaporation of a metal plate or coarse particles placed in a vacuum reactor, and nitrogen or hydrogen gas was injected therein to synthesize a compound or produce a powder.

All of these reactions consume a lot of energy and are costly reactions for a long time. Conventionally, new-ceramic, intermetallic compounds, etc. have been operated in a concept of causing a reaction by transferring a substance in a molten state in a high temperature furnace. Therefore, a large amount of energy must be consumed, and the mass and mass of bulk metals and nonmetals have been difficult to control, which makes it difficult to obtain the desired physical properties and has difficulty in consistent quality control. For example, in the case of the shape memory alloy, which is an intermetallic compound, when the content of Ni is changed by 0.1%, the shape memory temperature is changed by 10-20 ° C. In addition, segregation occurs when the alloy is melted in an electric furnace due to the large specific gravity difference between Ti and Ni.

There is an innovative reaction method that solves all the problems described above, which can be named as self-heating synthesis (hereinafter referred to as SHS process).

The principle is that a mixture of metal and nonmetal or metal powder is put into a mold and compressed to form a green compact (6), and heated by a heating element (1) to heat a part of the green compact to ignite. Strong exothermic reactions occur. Although there is a difference in temperature depending on the material to be synthesized, a high temperature of 700 to 4,000 ° C. is mostly formed, and the heat of reaction is then propagated in turn, and then the structured zone (3), the combustion zone (4), and the heating zone ( The reaction layer formed by 5) moves and the reaction is completed in a moment. However, this method is different from the conventional method and requires the use of fine powder.

The advantages of this method are: 1. Very little energy cost 2. Short response time in seconds 3. Simple device. That is, they are made from very brittle and sintered or ingots.

In the present invention, the carbon nitride and boron nitride are formed by mixing titanium metal powder and carbon or boron, respectively, in a mold, and reacting with each other by heating and igniting with a tungsten wire at the top or bottom of the molded product having a diameter of several centimeters and several tens of centimeters in height. The reaction heat is completed in a few seconds by the mechanism that causes the reaction heat to propagate to the next layer and the heat generation amount is high, so the temperature of the reaction layer rises, and impurities (especially alkali metals) are volatilized. There is a feature of manufacturing without the need for a large device. The resulting product is made into powder by a grinder.

Since the reaction between titanium and hydrogen or nitrogen is a solid-gas reaction, titanium powder is placed in a high pressure resistant reactor and evacuated under vacuum, and then hydrogen or nitrogen is discharged from low pressure (below atmospheric pressure) to 400 MPa (mega pascal) or liquid in case of nitrogen. The reaction heat generated by adding nitrogen to the reactor and heating and igniting with a tungsten wire at the top or bottom of titanium also propagates to the next layer and the next layer and completes the reaction within a few seconds.

In this case, unlike solid-solid systems, a high pressure reactor is required, but there is little energy supply.

As such, the method of lowering the production price and producing a high-purity product is different from the prior art.

The starting material used in the present invention is Ti metal powder.

The Ti powder is mixed well with the solid powder of any one of carbon, boron, titanium, aluminum, and silicon and put into a mold to form a green compact, which is a reaction product (6). When one end of the green compact is heated and ignited, the reaction is completed by self propagation with self-heat of reaction generated during the reaction. That is, the reaction proceeds as the reactant propagates the heat of reaction continuously. At this time, in order to control the reaction rate, the product to be obtained is mixed with the reactions in an appropriate ratio and compacted, and this synthesis reaction causes a significant decrease in the reaction rate and a product of the desired physical property. The reaction scheme of the above materials is as follows.

Here, (s) represents a solid powder state and (g) represents a gas state.

The new technology is that all starting materials are powders and the reaction method is the use of self-heating reactions. In addition, it is possible to control the reaction rate by adding an appropriate amount of the product in advance to make a green compact and react.

When the powder is compacted to produce a compound by using the reaction heat method, an accurate and stoichiometric material can be made at will, thereby obtaining exactly the properties we want from the compound. It takes very little energy and the reaction time is instantaneous. By controlling the reaction rate, the final product can be freely shaped, i.e., powder, sintered body, and ingot.

Therefore, very high quality compounds can be obtained quickly and easily, which can energize any industry that needs this material.

When the fine powder of titanium metal and solid mixture such as carbon, nickel and aluminum or a mixture of gas such as hydrogen and nitrogen is ignited at about 2,000 to 4,000 ° C, such as the Thermit reaction, a high-temperature reduction method of metal oxide by aluminum, A fierce exothermic reaction occurs with heat and light. This combustion is not a combination of oxygen, but a solid powder or a solid powder and a gas that generates heat between itself. Therefore, this method is a low-energy process in which the manufacturing process is simple and has a self-refining effect, not only to produce a high purity product but also to spontaneously react in a short time (within a few seconds). The reaction is ignited as in Figure 1, allowing the reaction to proceed from one end of the specimen to the other.

Ignition of the reactants is performed for only 0.05 to 4.0 seconds, and the combustion wave formed by the ignition is sustained by the high reaction heat to form a compound. Therefore, energy is hardly consumed compared with the conventional synthesis method.

Referring to the present invention in detail according to the drawings Figure 1 shows a process diagram of the self-heating reaction according to the present invention, the initial reactant (6) in the drawing shows the visual acuity before the reaction, the specimen is composed only of the initial reactant before the reaction, but the self heating element When the reaction is initiated by heating to (1), these reactants undergo a reaction in which the target titanium metal compound (2) is changed through the heating zone (5), the combustion zone (4), and the structuring zone (3). Upon completion the initial reactants 6 are all converted to titanium metal compounds 2.

2 is a view illustrating an apparatus for manufacturing a titanium compound according to the present invention. The initial reactant 6 in FIG. 1 is described as a specimen 21 in FIG. 2 for convenience.

In the present embodiment, the interior of the reactor means a space partitioned by the packing 18, the cooling water outlet 19, and the cooling water inlet 25, and is the same as the self heating element 1 in FIG. 1 of tungsten filament 24. .

An embodiment of the present invention will be described as follows.

EXAMPLE

Example 1

Synthesis of Titanium Carbide (TiC _x )

Mix the fine Ti metal powder and carbon powder (Carbon Black) in mol ratio (for example, in case of TiC, mix Ti and C in mol ratio of 1: 1, _and in case of TiC _{z · 8} , mix Ti and C in 1: 1 ratio And then pressure molded into a columnar shape, and the isomer is placed in a reactor to which a heating element is attached, and the inside of the reactor is made into an inert atmosphere (vacuum or inert gas atmosphere). When one part of the mixed molded body is heated to about 2,000 ° C. or more with a heating element, and the part reaches the reaction temperature, the reaction mixture causes an exothermic reaction by itself, and the reaction heat generated in the reaction is not reacted. The reaction proceeds spontaneously, eventually forming TiC _x in seconds.

Example 2

Synthesis of Titanium Boride (TiB ₂ )

Ti metal powder and boron are mixed in a mol ratio of 1: 2, and press-molded into a columnar shape. Then, the molded body is put into a reactor and heated and reacted as in Example 1 to obtain TiB ₂ fine powder within seconds.

Example 3

Synthesis of Titanium Nitride (TiN)

The Ti metal powder was press-molded in a columnar shape, and then the molded body was placed in a reactor and filled with nitrogen at 1,000 KPa to 20,000 KPa (Kilo pascal) to make the reactor into a nitrogen atmosphere or to place the molded product on the liquid nitrogen cylinder in the reactor. After evaporation to make the inside of the reactor into a nitrogen atmosphere, it is heated and reacted as in Example 1 to obtain a fine TiN powder within a few seconds.

Example 4

Synthesis of Titanium Carbonitride (TiC _x N _y )

The Ti metal powder and carbon are mixed according to the application and press-molded into a columnar shape. Then, the molded body is placed in a reactor and filled with nitrogen at a pressure between 100 KPa and 20,000 KPa (for example, according to the x value of TiC _x N _y) . Mix Ti and C and assemble nitrogen pressure according to y value). Subsequently, heating and reacting as in Example 1 to obtain a fine TiC _x N _y powder in a few seconds.

Claims (1)

Titanium metal powder and any one selected from boron, carbon, nitrogen, hydrogen, nickle, aluminum and silica are mixed in the reactor with an inert gas atmosphere and a heating element attached or carbon and nitrogen are mixed together ( Heats the mixed mixture with a heating element attached to the reactor to cause the mixed material to generate an exothermic reaction, and the self-heating reaction propagates as self propagating high temperature synthesis method. Tide (TiB ₂ ), titanium carbide (TiC), titanium nitride (TiN), titanium halide (TiH ₂ ), titanium-nickel (TiNi), titanium aluminum (TiAl), titanium silicate (TiSi), titanium cyanide ( A method for producing a titanium compound such as TiCN).