Titanium Diboride(TiB2): A New Type of Industrial Ceramic Material

DATE :Dec 06, 2021
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1. What is titanium diboride
Among many compounds, metal borides have better high temperature performance than metal carbides. For example, titanium diboride (TiB2) cermet products are more suitable than titanium carbide (TiC) and tungsten carbide (WC) cermet products while using under high temperature and high corrosive working conditions. Titanium diboride powder is gray (or gray-black) and ranks sixth among the top ten materials with the highest melting point in the world currently known . The anti-oxidation temperature in the air can reach 1100℃. As a new type of ceramic material, it has excellent physical and chemical properties. In addition to the extremely high melting point, the hardness is also large, chemical stability, electrical and thermal conductivity, and mechanical properties at high temperatures. 
The characteristics of titanium diboride as structural materials and functional materials:
①In terms of structural materials. The high strength and hardness of titanium boride make it possible to make tools, wire-drawing films, sandblasting nozzles and hard tool materials. At the same time, it can also be an additive to composite materials.
②In terms of functional materials. The resistivity of titanium boride and pure iron is very similar, so its application in functional materials is very useful. Through the electrical properties of titanium boride, flexible PTC materials can be made.
2. Preparation method of titanium diboride
The current methods for preparing titanium diboride raw materials mainly include carbothermic reduction method, self-propagating high temperature and synthesis method, mechanochemical reaction method, vapor deposition method, ball milling method, etc.
①Carbothermal reduction method
Using titanium and boron oxides as raw materials, carbon black as reducing agent, long-term high-temperature carbon reduction treatment in a carbon tube furnace, the purity of the synthesized titanium diboride powder depends on the purity of the raw material powder. This method is a process that is frequently used in industrial production. The disadvantage is that the obtained titanium diboride powder has a large particle size and a relatively high impurity content.
②Self-propagating high-temperature synthesis (SHS)
This method is generally to press the raw material mixture to be reacted into a block, and then ignite one end of the block to ignite the reaction. The huge heat released by the reaction causes the adjacent materials to react, and finally a combustion wave spreading at a speed v is formed. Finally, as the combustion wave advances, the raw material mixture is transformed into the final product. Due to the self-purification effect of the self-propagating high-temperature synthesis process, the product purity is high, so the obtained powder is easy to be further sintered, and the external energy consumption is low. If combined with other special technical means, dense titanium diboride can be directly prepared Material.
③Mechanochemical reaction method (MR)
In this method, the reactant powder is placed in a high-energy ball mill, and the powder is repeatedly deformed to broken under the action of the squeezing and shearing of the grinding ball. The violent friction and collision of the ball milling medium causes the mechanical energy to be converted into chemical energy, thereby synthesizing the required reactants. Compared with the first two methods to prepare titanium diboride, the mechanochemical reaction method has the advantages of low synthesis temperature, wide source of raw materials and low cost.
The application direction of titanium diboride
Titanium diboride and its composite materials can be combined with other metals and ceramic-based polymers to form a series of new materials with commercial application value.
①Titanium diboride can be used as a grain refinement and particle strengthening additive. It can be mixed into aluminum-based, copper-based titanium-aluminum alloy and iron-based materials to greatly improve the mechanical and physical properties of the material. This grain refinement and particle strengthening effect will increase as the purity and fineness of the titanium diboride powder increase.
②Titanium diboride can be composited with silicon carbide, aluminum nitride, boron nitride, titanium carbide and other non-oxide ceramics, and can also be composited with alumina and other oxide ceramic materials. A large number of experimental studies have shown that the prepared The new composite material has more excellent mechanical strength and fracture toughness, and can be one of the high-quality materials for making armor protection materials.
③Titanium diboride particles mixed with high-performance resin can be made into PTC heating ceramics and head-type PTC materials, which have the characteristics of safety, power saving, reliability, and easy processing and molding. They are electric irons, electric blankets, electric ovens, and air conditioners. A key high-tech for the upgrading of household appliances such as hot-air heating rooms. 
④Titanium diboride has excellent electrical conductivity and excellent resistance to molten metal corrosion. It can be used to make evaporating vessels, molten metal crucibles, aluminum electrolytic cell cathodes, spark plugs and other electrode and contact head materials.
⑤ Due to the good wettability of titanium diboride and metal aluminum liquid, using titanium diboride as the cathode coating material of the aluminum electrolytic cell can reduce the power consumption of the aluminum electrolytic cell and prolong the life of the electrolytic cell.
⑥ Titanium diboride can be used to make ceramic cutting tools and molds. It can manufacture finishing tools, wire drawing dies, extrusion dies, sandblasting nozzles, sealing components, etc.