Thermal spraying is widely used to improve surface properties such as wear resistance, corrosion protection, and thermal performance. Regardless of the coating type or application, correct surface preparation is essential to achieving reliable adhesion and consistent coating performance. Poor preparation can compromise even advanced thermal spray processes.
Why surface preparation matters
Thermal spray coating, like the examples seen here https://www.poeton.co.uk/surface-treatments/thermal-metal-sprays/, is a technique that relies on mechanical interlocking rather than metallurgical bonding. For this to occur, the substrate surface must be clean and suitably roughened. Contaminants such as oil, grease, moisture, or oxides act as barriers, preventing proper adhesion and increasing the risk of coating failure. This principle applies across all spray methods, including flame spray, HVOF, and thermal plasma spray systems.
Cleaning and degreasing
Surface preparation begins with thorough cleaning to remove any contaminants. Degreasing methods vary depending on the substrate material and application requirements, but commonly include solvent cleaning or alkaline washing. Effective degreasing ensures the coating particles can make direct contact with the substrate during application.
Grit blasting and surface profiling
Once cleaned, the surface is typically grit blasted to create an appropriate profile. Abrasive particles are projected at high velocity to roughen the substrate while removing remaining residues. This process creates a textured surface that supports strong mechanical bonding. Abrasive type and particle size are selected according to substrate hardness and coating specification.
In conclusion, careful surface preparation is fundamental to achieving durable adhesion, coating integrity, and long-term performance in thermal spraying across industrial applications where reliability and consistency are essential requirements.