Adherence

Definition: The strength of the bond between a coating and the metal underneath.

• Adhesion vs. Adherence: Adhesion is just the molecular attraction; Adherence is the mechanical toughness of the whole system.

• Why it matters: High adherence keeps a zinc coating attached to a steel pipe even when it is bent, heated, or scratched.

• How to improve it: Roughen the surface for better "grip," allow chemicals to mix between layers, and ensure the coating "wets" the metal perfectly.