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Properties and preparation method of titanium diboride

wallpapers Tech 2020-05-20
Titanium diboride (TiB2) is the most stable compound of boron and titanium and is mainly used to prepare composite ceramic products. Because it can resist hot metal corrosion, it can be used in the manufacture of molten metal crucibles and electrolytic cell electrodes.

Properties of titanium diboride

Titanium diboride is a C32 type structure, combined in the form of its valence bond, and belongs to the hexagonal metalloid compound. The boron atomic surface and the titanium nuclear surface in the crystal structure alternately form a two-dimensional network structure. B and the other three B are covalently bonded, and an extra electron forms a large π bond. The layered structure of boron atoms similar to graphite and the outer particles of Ti determine that TiB2 has good conductivity and metallic luster, and the Ti-B bond between the boron atom surface and titanium atom surface determines the high hardness of this material And brittleness.

Titanium diboride powder is gray (or gray-black), ranking sixth in the world's top ten highest melting materials currently known. The anti-oxidation temperature in the air can reach 1100 ℃, as a new type of ceramic material, it has very excellent physical and chemical properties, in addition to the extremely high melting point, the hardness is also significant, the chemical stability, electrical and thermal conductivity, mechanical properties at elevated temperatures Are all excellent.

Preparation technology of titanium diboride

1. Direct synthesis

Reaction formula: Ti + 2B = TiB2
Put the T powder and B powder in the high-temperature reactor to directly combine to form titanium diboride. The reaction temperature of this method is above 2000 ° C, the raw material price is high, the process is not easy to control, the reaction is incomplete, the purity of the generated TiB2 is low, and other compounds such as TiB and Ti2B are easy to be generated.

2. Boron method

Reaction formula: TiO2 + 4B = TiB2 + B2O2
The experiment used TiO2 (purity higher than 99%, anatase structure, particle size 0.2-0.3μm) and non-product (92%, particle size 0.2-0.3μm) as raw materials. The mixing ratio in the ball mill is Ti: B = 1: 4, the weight ratio of the ball to the powder is 40: 1, and the ball milling process is completed under vacuum. The reaction temperature does not exceed 1100 ° C.

3. Melt electrolysis

Titanium oxide and alkali (or alkaline earth) metal borates and fluorides generate titanium diboride under melt electrolysis conditions.

4. Auxiliary immersion metal method
 
Reaction formula: Ti + 2B + Al = TiB2 + AI (or Cu, Sn, etc.)

5. Carbothermal
 
(1) Carbothermal reduction method
Reaction formula: 2TiO2 + 5C + B2O3 = 2TiB2 + 5CO ↑
 
(2) Boron carbide method
Reaction formula: 2TiO2 + 3C + B4C = 2TiB2 + 4CO ↑
Or 2TiO2 + C + B4C = 2TiB2 + 2CO2 ↑

6. Spontaneous combustion method

Reaction formula: TiO2 + 5Mg + B2O3 = TiB2 + 5MgO
TiB2 + MgO + 2HNO3 = TiB2 + Mg (NO3) 2 + H2O

7. Vapor deposition

Reaction formula: TiCl4 + 2BCI3 + 5H2 = TiB2 + 10HCI ↑

8. Sol-gel method

Titanium diboride can also be prepared by using the sol-gel method with inorganic salts of Ti and B as raw materials.

Trunnano is a company specializing in the production of titanium diboride. If you are interested in titanium diboride, please consult Leo Manager, email: brad@ihpa.net.

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