The density of the coating is one of the key indicators of its performance, which directly affects the protective effect, wear resistance, corrosion resistance and thermal stability of the coating. There are a variety of reasons that affect the density of the coating, and the following are some common factors:

1、Spraying process parameters:

1, spraying distance: too far or too close spraying distance will affect the deposition efficiency of the material and the microstructure of the coating, thus affecting the density.

2, spraying Angle: improper spraying Angle may lead to uneven distribution of materials, the formation of pores and cracks, reduce the density.

3, spraying speed: too fast spraying speed may cause the material to fail to fully melt or cure, forming pores.

4, spray gun power: the power of the spray gun directly affects the degree of melting and deposition efficiency of the material, and insufficient power may lead to the coating is not dense.

2、substrate surface pretreatment:

the cleanliness, roughness and preheating temperature of the substrate surface will affect the density of the coating. Surface pollutants such as grease and oxide hinder the bonding of the material with the matrix and reduce the density; The proper surface roughness can increase the mechanical adhesion between the coating and the substrate and improve the compactness. Preheating can reduce thermal stress and improve the compactness of the coating.

3、Spraying material:

 the chemical composition of the material, particle size distribution, melting point, etc., will affect the density of the coating. Selecting materials with high melting point and uniform particle size distribution can improve the densification of the coating.

4、 environmental conditions: 

the environmental temperature, humidity and cleanliness during the spraying process will also affect the density of the coating. High humidity may cause the material to absorb moisture before spraying, reducing densification; Contaminants in the environment, such as dust, are mixed into the coating to form pores.

5、aftertreatment: 

Post-treatment processes such as cooling rate and heat treatment after spraying will also affect the density of the coating. Rapid cooling may cause the material to shrink to form pores, and appropriate heat treatment can improve the microstructure of the coating and improve the densification.

6、Operator skills: 

The experience and skills of the operator are crucial to the control of the spraying process, and unskilled operation may lead to unstable spraying parameters and affect the density of the coating.

7、equipment performance: 

The performance of the spraying equipment, including the stability of the spray gun and the control accuracy of the spraying system, has a direct impact on the density of the coating. Aging or improper maintenance of equipment can cause fluctuations in spraying parameters and reduce the density of the coating.

In summary, the density of the coating is affected by many factors such as spraying process parameters, substrate surface pretreatment, spraying materials, environmental conditions, post-treatment, operator skills and equipment performance. In practical applications, these factors should be considered comprehensively to improve the density of the coating by optimizing the spraying process and control parameters, so as to ensure the performance and service life of the coating.