The bonding strength of the coating is related to the cleanliness and roughness of the substrate.

It is an important process in the spraying process that the basic surface cleaning, degreasing, surface roughening and so on. Because some gasoline, acetone degreasing treatment, with a file, fine sandpaper, Whetstone will remove the oxide layer and the fatigue, to expose the metal color.

Then roughening treatment, surface roughening treatment to provide compressive stress, combined with the increased area of coating and the substrate and the purification of the surface stress layer cooling, gear pump, stress relaxation within the coating, it is conducive to the increase of bonding force.

Sand blasting is the most commonly used coarsening process, sand to sharp, hard as well, can choose quartz sand, emery, etc.. After the rough surface is easy to be oxidized or contaminated by the environment, it is necessary to spray in a timely manner, if placed more than 4H to re treatment.

Surface preheating treatment. The temperature difference between the coating and the substrate will cause the coating to produce shrinkage stress, which can lead to cracking and spalling of the coating. Preheating of the substrate surface can reduce and prevent the adverse effects. However, the preheating temperature should not be too high, so as not to cause the substrate surface oxidation and affect the bonding strength between the coating and the substrate surface. Preheating temperature is generally 80-90 degree Celsius, commonly used neutral flame finish.