NCIDQ IDFX Practice Exam

What happens to brass and bronze over time when exposed to moisture?

1. They become more durable

2. They do not change color

3. They change color with age

4. They become less dense

The correct answer is: They change color with age

Brass and bronze undergo chemical reactions when exposed to moisture over time, leading to visual changes in their appearance. This process is often referred to as patination. When moisture interacts with the copper content in these alloys, it can trigger oxidation, which causes the surface to develop a greenish patina, particularly in the case of bronze, known as verdigris. Brass may also change color, typically developing a darker or different hue as it oxidizes. This color change is a natural aging process that can provide a distinct aesthetic, often valued in artistic and architectural applications. The process not only alters the visual characteristics of the metals but can also affect their protective qualities, sometimes enhancing their durability in certain conditions. However, this does not imply an increase in overall structural integrity, rather it is the surface appearance that is primarily affected.