How is a sol-gel coating processed?

The process involves: Activation, Filtration, Surface Preparation and Application.

Activation: Prior to activation, the individual components must be mixed thoroughly since there is a tendency for the fillers to settle.

Once properly mixed, components are combined in specific ratios in a mixing vessel for a specific time. During mixing, the chemical reaction causes an increase in the temperature of the mixture. Note: most manufacturers package the components in the proper ratios to help avoid problems.

Filtration: As with any coating, it is necessary to filter the mixed product prior to application.

Surface Prep: The most common substrates used with sol-gel coatings are aluminum and stainless steel. Special primers are under development for the use of this technology on carbon steel and cast iron.

As with any coating, surface preparation is critical, and must be done properly to ensure adhesion. First, the pans must be degreased/cleaned to assure the surface is free of oils, since grit-blasting and other methods do not always remove all the oil. Any oil or grease can contaminate the blasting material and interfere with adhesion, especially with repeated use of the material.

Most pans to be coated with sol-gel have the surface grit-blasted, which roughens the surface and provides more “tooth” for the coating to grab on to. Note: Improper surface preparation can cause problems with performance. If the surface is too smooth, it can negatively affect both adhesion and mechanical performance. If the surface is too rough, it can cause the coating to be drawn into the surface profile, resulting in a dry, rough finish.

At this point, the pans are preheated to a specific temperature, another important step.

Application: With sol-gel coatings, there is a specific time by which the activated and filtered coating should be applied to achieve maximum effectiveness. The coatings are applied via conventional spray equipment. They are available in one- and two-coat systems.

Sol-gels must be applied only to preheated parts that maintain about 50-70°C/120-160°F throughout the spraying process. If parts are not heated and kept at this temperature, the coating could sag, cause wetting defects or dry spray. An IR thermometer can help check the pans to ensure proper temperature.

Another critical step: As with all coatings, there is a required dry-film thickness that must be applied to ensure proper performance. The pans are then cured in conveyor or batch ovens.

 
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Sol-Gel Ceramic Coatings

How is a sol-gel coating processed?

The process involves: Activation, Filtration, Surface Preparation and Application.

Activation: Prior to activation, the individual components must be mixed thoroughly since there is a tendency for the fillers to settle.

Shaft Stirrer

Once properly mixed, components are combined in specific ratios in a mixing vessel for a specific time. During mixing, the chemical reaction causes an increase in the temperature of the mixture. Note: most manufacturers package the components in the proper ratios to help avoid problems.



Filter ExamplesFiltration: As with any coating, it is necessary to filter the mixed product prior to application.

Surface Prep: The most common substrates used with sol-gel coatings are aluminum and stainless steel. Special primers are under development for the use of this technology on carbon steel and cast iron.

As with any coating, surface preparation is critical, and must be done properly to ensure adhesion. First, the pans must be degreased/cleaned to assure the surface is free of oils, since grit-blasting and other methods do not always remove all the oil. Any oil or grease can contaminate the blasting material and interfere with adhesion, especially with repeated use of the material.

Most pans to be coated with sol-gel have the surface grit-blasted, which roughens the surface and provides more “tooth” for the coating to grab on to. Note: Improper surface preparation can cause problems with performance. If the surface is too smooth, it can negatively affect both adhesion and mechanical performance. If the surface is too rough, it can cause the coating to be drawn into the surface profile, resulting in a dry, rough finish.

At this point, the pans are preheated to a specific temperature, another important step.

Application: With sol-gel coatings, there is a specific time by which the activated and filtered coating should be applied to achieve maximum effectiveness. The coatings are applied via conventional spray equipment. They are available in one- and two-coat systems.

Sol-gels must be applied only to preheated parts that maintain about 50-70°C/120-160°F throughout the spraying process. If parts are not heated and kept at this temperature, the coating could sag, cause wetting defects or dry spray. An IR thermometer can help check the pans to ensure proper temperature.

Another critical step: As with all coatings, there is a required dry-film thickness that must be applied to ensure proper performance. The pans are then cured in conveyor or batch ovens.


 

 
 
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