Simulated rain exposures can mimic long-term metal runoff at atmospheric conditions-A case study on naturally and prepatinated zinc sheet

Short- and long-term zinc runoff are studied at field and laboratory conditions to show that a laboratory setup can simulate field conditions and to investigate how prepatination influences the zinc runoff process. Results from four differently patinated zinc surfaces exposed at laboratory conditions, seven consecutive individual 4-h rain events, and exposure at field conditions for 2 years show that the laboratory setup does simulate field conditions provided that the limitations of the laboratory are considered. It is also determined through corrosion product characterization that denser established corrosion products (patina) have a lower runoff than bulky porous or newly formed corrosion products.