As the definition says, surface treatment or surface finishing is a broad range of industrial processes that alter the surface of a manufactured item to achieve a certain property.
We can classify different surface treatments in four groups:
- Pre-treatment prepares the parts for next step in the process. The most common is process of cleaning such as degreasing – which can be an ultrasonic degreasing – or pickling with or without ultrasound.
- Post-treatment finalizes the process, such as passivation or colouring.
- Changing the metal surface by chemical reaction and acting as the final coating, such as black oxidising (blackening), phosphating, chromating or passivation.
- Varying the metal surface thanks to an action to remove paint or surface removal, such as etching, chemical milling or stripping or ultrasonic paint stripping.