Definition - What does Rust Bloom mean?
A rust bloom is a visual identification of the onset of corrosion that is characterized by a localized brownish/orange discoloration on a metallic surface. Exposure to moisture or causative chemicals will initiate the onset of a rust bloom, which can eventually lead to material failure.
Corrosionpedia explains Rust Bloom
A rust bloom is indicative of the chemical formation of new rust. It can be either localized or uniform and widely spread across a surface. There are two main types: flash rust and rust back.
Adequate coating practices such as painting or spraying with water resistant substances may be used as a means to prevent rust bloom. Ideally, lowering the humidity of the environment is also advised if possible.