Does Bronze Rust?
Bronze does not rust because rust is iron oxide, and bronze is primarily a copper alloy, most often copper combined with tin and sometimes small amounts of other elements. While it does not form red rust like steel, bronze can still corrode over time. Instead of rust, it typically develops a surface patina that can range from brown to green, caused by copper oxides and other copper compounds that form when the metal is exposed to air, moisture, and contaminants.
In many environments, that patina is protective and helps slow further corrosion, which is why bronze is commonly used for marine hardware, bearings, and architectural details. In harsh conditions such as saltwater exposure, stagnant moisture, or chloride contamination, bronze can experience more aggressive corrosion like pitting, and outdoor surfaces may show green staining. If you ever see reddish rust spots on bronze, it is often from iron particles or steel fasteners nearby rather than the bronze itself.
