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The long life of copper when exposed to natural waters is a result of its thermodynamic stability, its high resistance to reacting with the environment, and the formation of insoluble corrosion products that insulate the metal from the environment. The corrosion rate of copper in most drinkable waters is less than 2.5 μm/year, at this rate a ...
FAC rates rapidly decrease with increasing water pH. FAC has to be distinguished from erosion corrosion because the fundamental mechanisms for the two corrosion modes are different. FAC does not involve impingement of particles, bubbles, or cavitation which cause the mechanical (often crater-like) wear on the surface. By contrast to mechanical ...
Silver, solid or plated; monel metal; high nickel-copper alloys: −0.15 Nickel, solid or plated; titanium and its alloys; monel: −0.30 Copper, solid or plated; low brasses or bronzes; silver solder; German silvery high copper-nickel alloys; nickel-chromium alloys: −0.35 Brass and bronzes: −0.40 High brasses and bronzes: −0.45
Corrosion removal should not be confused with electropolishing, which removes some layers of the underlying metal to make a smooth surface. For example, phosphoric acid may also be used to electropolish copper but it does this by removing copper, not the products of copper corrosion.
The corrosion rate of copper in most potable waters is less than 2.5 μm/year, at this rate a 15 mm tube with a wall thickness of 0.7 mm would last for about 280 years. [2] In some soft waters the general corrosion rate may increase to 12.5 μm/year, but even at this rate it would take over 50 years to perforate the same tube.
In a neutral pH solution, the pH inside the crevice can drop to 2, a highly acidic condition that accelerates the corrosion of most metals and alloys. For a given crevice type, two factors are important in the initiation of crevice corrosion: the chemical composition of the electrolyte in the crevice and the electrical potential drop into the ...
An alkaline pH has been shown to have a beneficial effect on the corrosion resistance for steel. [6] The mechanism for copper begins the same as for steel, evolution of the inhibitor. Once at the copper surface however, the inhibitor will form a copper benzotriazole complex which is protective. [9]
Aluminum, galvanized/zinc coatings, brass, and copper do not survive well in very alkaline or very acidic pH environments. Copper and brasses do not survive well in high nitrate or ammonia environments. Carbon steels and iron do not survive well in low soil resistivity and high chloride environments. [16]