Definition - What does Primer Degradation mean?
Primer degradation refers to the occurrence of wear and tear of a base chemical protectant used on the outer surface of a substrate before painting. Primer application is typically the first step when applying corrosion preventative coatings. Degradation of primers occurs due to prolonged exposure to external elements and chemical reactions.
Corrosionpedia explains Primer Degradation
Primers are used to protect a substrate's surface and ensure better adherence of paint to the outer surface of the metal object. They always contain pigments and are used to prevent attack on the substrate by air, water or other elements.
Metal primers must provide an excellent bond by technical anchorage. Modern corrosion-resistant covering systems used over metal contain inorganic or natural zinc oxide. The zinc is assaulted by an electrochemical deterioration process preferentially before metal, and therefore defends the metal substrate with this sacrificial property. However, when a primer is degraded it may no longer be able to provide effective protection.