Definition - What does Strengite mean?
Strengite refers to a naturally occurring mineral with the chemical formula FePO4·2H2O that is structurally in an orthorhombic-dipyramidal form that contains hydrogen, iron, oxygen and phosphorus. Strengite is used as a constituent of corrosion resistance materials such as phosphate coatings.
Corrosionpedia explains Strengite
Strengite often serves as a passivation layer when used as a protective coating on metal substrates. Spectroscopy studies have shown that the passivation layer of strengite is made up of newberyite, struvite-K and other composites. Rust components may also be present in strengite when it is used as a protective coating on iron. This rust component is in the form of iron-chromium oxide.
Metallic objects or structures used in soil environments display unique chemical reactions for strengite. Carbonates or phosphates present in the soil generate reductive conditions that produce protective layers of yellow brown siderite (FeCO3). Phosphate ions are commonly present in the soil due to the buried organic matter, garbage or other sources of phosphate producers such as fertilizers.