Manufacturing Method Of Metal Powder

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Metal powder refers to a group of metal particles with a size of less than 1 mm. Including single metal powder, alloy powder and some refractory compound powder with metallic properties, it is the main raw material of powder metallurgy.
 
The simple substance of metal is generally silver-white. When the metal is under certain conditions, it is black powder. Most metal powders are black.
 
Preparation method
 
It is usually divided into mechanical method and physical chemical method according to the principle of transformation. It can be obtained directly from solid, liquid and gaseous metals, and can be transformed from metal compounds in different states through reduction, pyrolysis, and electrolysis. Preparation. Refractory metal carbides, nitrides, borides, and silicides can generally be prepared directly by compounding or reduction-compounding methods. Due to different preparation methods, the shape, structure and particle size of the same powder often differ greatly (Figure 2). The powder preparation methods are listed as follows, among which the most widely used are reduction method, atomization method and electrolysis method.

 
Reduction method
 
The reducing agent is used to take the oxygen in the metal oxide powder, and the metal is reduced to powder. Gas reducing agents include hydrogen, ammonia, coal gas, and converted natural gas. Solid reducing agents include carbon and metals such as sodium, calcium and magnesium. Hydrogen or ammonia reduction is commonly used to produce metal powders such as tungsten, molybdenum, iron, copper, nickel, and cobalt. Carbon reduction is often used to produce iron powder. Metal powders such as tantalum, niobium, titanium, zirconium, vanadium, beryllium, thorium, and uranium can be produced by using strong metal reducing agents such as sodium, magnesium, calcium, etc. (see metal thermal reduction). Using high-pressure hydrogen to reduce metal salt aqueous solutions, nickel, copper, cobalt and their alloys or coated powders can be obtained (see hydrometallurgy). Most of the powder particles produced by the reduction method are irregular shapes with a sponge structure. The particle size of the powder mainly depends on factors such as the reduction temperature, time and the particle size of the raw materials. The reduction method can prepare most metal powders and is a widely used method.

Tag: Metal Powder   Elementary  
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