Q&A about powder metallurgy press (4)

Question:

What is the basic principle of using specific surface adsorption method to test powder particle size?

Answer: 

Due to the large total surface area and the unbalanced atomic force field of the powder, the powder has an adsorption effect on the gas. In the liquid nitrogen temperature area, the adsorption of the substance to the gas is mainly the adsorption of physical properties (no chemical reaction). 

After mathematical processing, if the total adsorption capacity is known. The volume of the gas, converted into the number of molecules of the gas, is divided by the volume of one gas molecule, that is, the surface area of the powder is obtained, which is usually measured by one gram of powder, so we define the surface area of one gram of powder as the specific surface area, When we know the value of the total surface area, we can assume that the powder is spherical, and then obtain the average particle size of the powder based on the relationship between the equivalent diameter of the sphere and the surface area (shape factor). 

In order to obtain as accurate measurement data as possible, the adsorbed gas is usually an inert gas. Such a method of measuring the total surface area of a certain mass of powder and then calculating the average particle size of the powder is the basic principle of calculating the powder particle size by testing the specific surface area of the powder.

Geepro Machinery has been one of the professional Powder Metallurgy Press manufacturer and supplier in China since 2007. Let's go through some common questions that customers cared about together, and hope this will help with your production.