What happens to an aluminum paste over time?

Aluminum paste, when used in roofing materials, undergoes a process of oxidation over time. This oxidation results in the formation of a thin layer of aluminum oxide on the surface, which causes the initially bright, reflective surface to become dull. The process reduces its reflectivity, which can affect the energy efficiency of buildings as the reflective properties contribute to reducing heat absorption. This characteristic behavior is particularly important in roofing applications where maintaining reflectivity can support thermal performance and longevity.

In contrast, aluminum paste does not become more reflective or evaporate completely; it also does not typically harden and strengthen significantly. Over time, the surface's primary change is the oxidation process that leads to a loss of sheen and reflectivity. Understanding this behavior is crucial for assessing the long-term performance of roofing materials that incorporate aluminum paste.