Titanium powder generally includes three aspects, namely purity, particle size and particle shape. The purity of titanium powder is related to its particle size. For products of the same specification, the smaller the particle size, the lower the purity. Titanium powder size is divided into 4 levels, the size of 1000-50pm is a coarse powder, 50-10pm is a fine powder, 10-0.5pm is a fine powder, and less than 0.5pm is ultrafine powder. In grades. Except for special purpose requirements, they are generally classified by oxygen content, that is, the lower the oxygen content, the better the quality and the higher the grade. Those with oxygen content less than 0.15% are high-quality titanium powder.
Physical properties: Titanium powder is a dark gray amorphous powder, boiling point ≤ 3000 ℃, melting point 1668 ℃ ± 2 ℃, insoluble in water and organic solvents at room temperature. It is a non-magnetic metal and will not be magnetized in a large magnetic field. It is non-toxic and tasteless. It has good compatibility with human tissues and blood.
Chemical properties: It does not react with water, dilute sulfuric acid, dilute hydrochloric acid and nitric acid at room temperature, but can be corroded by hydrofluoric acid, phosphoric acid, and molten alkali. Titanium can be dissolved in hot hydrochloric acid and hot sulfuric acid, as well as hydrofluoric acid. Or in a mixture of hydrofluoric acid and hydrochloric acid (sulfuric acid). Titanium powder will increase the content of N, H, O, and C in the atmosphere. Mixing with strong oxides can cause an explosion.
Titanium powder has good corrosion resistance and is mostly used in the aerospace industry, chemical corrosion-resistant materials, electric vacuum materials, alloy additives, etc. Titanium powder refers to titanium metal powder with a size less than 1mm and irregular shape, usually black-gray. Its performance combines the characteristics of the metal titanium block and the commonality of the powder. Titanium powder has a large surface free energy. Therefore, it is more active than metal titanium blocks, and it is easier to react with other elements or compounds, and oxidize, burn, and explode. It is a dangerous product. Its purity and performance largely depend on the preparation method and its process conditions.
There are four main methods for industrial production of titanium and titanium alloy powder:
(1) Hydrodehydrogenation method. Titanium powder and its alloy powder with good quality and fine particle size can be obtained through the hydrogenation dehydrogenation process, but the batch is small and the price is more expensive. Now, this method is more commonly used.
(2) Metal reduction method. This kind of powder has a large output, low price, good plasticity, suitable for cold forming. It is the main raw material for the production of general corrosion-resistant products. Because it contains high sodium and chloride ions, it is easy to contaminate equipment and deteriorate the welding performance of the material during sintering.
(3) Centrifugal atomization method. The US Nuclear Metals Corporation first adopted electricity in the 1960s.
(4) Electrolysis method. The purity is higher than that of sodium-reduced titanium sponge powder, but the formability of electrolytic titanium powder is worse than that of titanium sponge wire powder.
Titanium powder and titanium alloy powder are usually light gray, and darken as the particle size becomes smaller. The coarse powder has a metallic luster, the fine powder is gray, and superfine powder is black. Titanium dihydride powder is generally grayish brown and darker in color than titanium powder. Outer titanium powder is mainly used as a grain refiner for cast aluminum and a deflagration agent for fireworks and fireworks. Grade titanium powder has different uses according to different purity and particle size. It is mainly used as a raw material for powder metallurgy to prepare titanium or titanium-containing alloys. Other applications are as electric vacuum getters, raw materials for solid mercury sources in electric vacuum, and surface coating materials.
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