During the formation of the sprayed layer, the actual bonding points of the particles do not fill the entire contact surface of the particles. At the same time, the temperature and heat of the central and marginal areas of the flame flow are very unevenly distributed, resulting in the heat conditions of the particles are not the same.Also the addition of particles can not have the same thermal and mechanical state, so the grain joints can not To avoid the emergence of pores or loose, which will inevitably affect the coating performance. The sandblasting machine, if coupled with the influence of the thermal stress formed by the coating process, has a certain limit on the binding capacity of the spray coating.

Based on the previous analysis, the combination form of the automatic blasting machine can be summarized as follows:

1, mechanical combination

This is the main form, that is, melting or close to the melting of the particles under the impact of deformation, mosaic, bite and tampon, the final condensation shrinkage, bonding to the substrate surface formed by the combination.

2, the weak non-valence bond interaction (van der Waals force)

That is, on the clean surface, the atomic distance between the particles and the substrate reaches the force of the atomic and molecular distance.

3, chemical bond combination

That is, when the atomic distance on the contact surface reaches the value of the atomic lattice constant, the atomic activation energy can exceed the bond energy to form the chemical bond of the coating atoms with the substrate atoms.

4, micro-diffusion combined

That is, the elements in the sprayed particles interact with the elements in the substrate under certain conditions, and sometimes even the bonding elements are formed by these diffusion elements.