What is the role of hydrogen as a secondary working gas?

       (1) Hydrogen (H2) is a diatomic gas. In the process of thermal ionization, it is first decomposed into single atoms by absorbing heat, and then ionized. Hydrogen absorbs a lot of heat in the process of dissociation and ionization, so hydrogen as a plasma gas has a high enthalpy value.



     (2) The thermal conductivity of hydrogen is the highest in the gas, which helps the powder to melt in the plasma gas. In plasma spraying, a certain amount of hydrogen is generally added to argon, which can improve the thermal energy and heat transfer of the plasma arc. Hydrogen is an indispensable gas when spraying powders with high melting points.

     (3) For most metal materials, hydrogen is a reducing gas, so adding hydrogen to the working gas can effectively prevent the oxidation of the material and improve the quality of the coating.

     In addition, adding a certain amount of hydrogen into the spray gun can effectively increase the voltage and power of the plasma arc.