Neutral Passivation
Neutral passivation is a post-treatment process using alkaline or neutral solutions to stabilize metal surfaces and prevent flash rust.
Physicochemical Working Principle
Neutral passivation uses aqueous solutions with pH values between 6 and 8 to remove oxygen from the surface. This forms a thin layer of oxidized metal that prevents corrosion.
Metallurgical Relevance & Welding Risks
This method is especially helpful for stiff steels and aluminum alloys because it protects the surface and increases the service life of parts. However, wrong solution concentration or too long storage can lead to over-passivation, which contaminates the metal and degrades its mechanical properties.
Workshop Practice & Instructions
Use a pH measurement to set up the solution. A concentration of 5-10 g/L is typical. Storage time is usually 30 minutes after the metal has been dried. Make sure to check and renew the solution regularly.