Surface treatment before spraying

       In order to improve the bonding strength of coating and substrate surface, it is an important process of plasma spraying to clean, remove oil and roughen the substrate surface before spraying.

1.Clean and remove grease from the surface of the base

*Alkaline washing method is to put the surface of the substrate into alkaline
solution such as sodium hydroxide or sodium carbonate, dissolve the grease
on the surface of the substrate, and then rinse it with water.

*Solution washing method USES volatile solutions, such as acetone, ethanol,
gasoline, ethylene trichloride and ethylene perchlorinated ethane, etc. Their
main function is to dissolve the mineral oil on the surface of the substrate, and
then remove it.
*Steam cleaning method is the use of trichloroethylene steam cleaning,
although this method cleaning effect is good, but is harmful to the human body.

2.Clean and remove oil on the surface of loose matrix
It is difficult to clean and remove oil on the surface of the loose matrix (such as cast iron). Although the grease is not on the surface, when spraying, the grease in the loose hole will penetrate into the surface of the matrix due to the increase of the temperature on the surface of the matrix.Therefore, after cleaning and deoiling the loose matrix surface, it is necessary to heat the surface to about 250 degrees Celsius, try to exude the grease on the surface, and then remove it.