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Wrought iron. Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. Rust consists of hydrous iron (III) oxides (Fe 2 O 3 ·nH 2 O) and iron (III) oxide-hydroxide (FeO (OH), Fe (OH) 3), and is typically associated with the corrosion of refined iron.
Pitting corrosion. Appearance. Severe pitting corrosion problems caused by chloride ions on a truss beam of the Nandu River Iron Bridge (Hainan Province, China) leading to the complete rupture of a metallic element. Pitting corrosion, or pitting, is a form of extremely localized corrosion that leads to the random creation of small holes in metal.
v. t. e. Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and preventing corrosion. [1][2]
Cathodic protection (CP; / kæˈθɒdɪk / ⓘ) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. [1] A simple method of protection connects the metal to be protected to a more easily corroded "sacrificial metal" to act as the anode. The sacrificial metal then corrodes instead ...
Phosphate conversion coating. Phosphate conversion coating is a chemical treatment applied to steel parts that creates a thin adhering layer of iron, zinc, or manganese phosphates to improve corrosion resistance or lubrication or as a foundation for subsequent coatings or painting. [1][2][3] It is one of the most common types of conversion ...
Galvanic corrosion. Appearance. Corrosion of an iron nail wrapped in bright copper wire, showing cathodic protection of copper; a ferroxyl indicator solution shows colored chemical indications of two types of ions diffusing through a moist agar medium. Galvanic corrosion (also called bimetallic corrosion or dissimilar metal corrosion) is an ...
Bluing, sometimes spelled as blueing, is a passivation process in which steel is partially protected against rust using a black oxide coating. It is named after the blue-black appearance of the resulting protective finish. Bluing involves an electrochemical conversion coating resulting from an oxidizing chemical reaction with iron on the ...
Galvanization. Galvanized surface with visible spangle. Galvanization or galvanizing (also spelled galvanisation or galvanising) [1] is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which the parts are coated by submerging them in a bath of hot, molten ...