How to avoid delamination and peeling of the coating during tungsten carbide spraying?

How to avoid delamination and peeling of the coating during tungsten carbide spraying?

To avoid delamination and peeling of the coating during tungsten carbide spraying, the following measures can be taken:

Optimize surface pretreatment

Thoroughly remove oil, rust, and scale from the surface of the substrate to ensure a clean and impurity free surface.

Adopting appropriate sandblasting technology to achieve ideal surface roughness and enhance the mechanical bonding between the coating and the substrate.

Control spraying parameters

Accurately adjust parameters such as spraying distance, spray gun movement speed, powder feeding amount, gas flow rate, and pressure. Maintain a stable and appropriate spraying temperature and speed to ensure that the powder particles can fully melt and bond well with the substrate.

Choose the appropriate spraying process

Select the appropriate tungsten carbide spraying process based on the shape, size, usage environment, and performance requirements of the workpiece, such as plasma spraying or supersonic flame spraying.

preheating

Before spraying, preheating the substrate appropriately can reduce the temperature gradient between the coating and the substrate, lower thermal stress, and help improve the bonding strength.

Interlayer processing

When spraying multiple layers, after the previous layer is sprayed, appropriate polishing or roughening treatment should be carried out to remove the surface oxide layer and pollutants, and increase the bonding force between layers.

Material matching

Ensure that the quality and particle size distribution of tungsten carbide powder meet the requirements, and have good compatibility with binders or other additive materials.

Control the spraying environment

Maintain the temperature, humidity, and cleanliness of the spraying work environment within an appropriate range to reduce the impact of external factors on coating quality.

Reasonable cooling

After spraying, use appropriate cooling methods to evenly cool the coating and avoid excessive internal stress caused by uneven cooling.

subsequent processing

After spraying, appropriate heat treatment or mechanical processing should be carried out to improve the microstructure and properties of the coating and enhance its stability.

Strict quality inspection

During and after the spraying process, timely coating quality testing should be carried out, such as combining strength testing, thickness measurement, porosity detection, etc. If problems are found, process parameters should be adjusted or repaired in a timely manner.