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Bronze disease is an irreversible and nearly inexorable corrosion process that occurs when chlorides come into contact with bronze or other copper-bearing alloys. [1] It can occur as both a dark green coating, or as a much lighter whitish fuzzy or furry green coating. [ 1 ]
Bismuth-tin bronze is not easily corroded by water; preliminary bismuth is not easily oxidized. Used in faucets, pump components, pipe fittings, plumbing goods, water pump impellers, housings and small gears, Alloy C89835 Bismuth-Tin Bronze has density 0.321 lb/in 3 , [ 10 ] while Alloy C89844 (which is used for fittings or valves for potable ...
Protective elements for bronze fountains are particularly important, since water is one of the leading causes for alterations or corrosion in a bronze. [2] Bronze sculptures incorporated in fountains will need more layers of wax, because the spray of water will cause deterioration of the wax at a faster pace than would normally happen.
Bronze, or bronze-like alloys and mixtures, were used for coins over a longer period. Bronze was especially suitable for use in boat and ship fittings prior to the wide employment of stainless steel owing to its combination of toughness and resistance to salt water corrosion. Bronze is still commonly used in ship propellers and submerged bearings.
Tarnish does not always result from the sole effects of oxygen in the air. For example, silver needs hydrogen sulfide to tarnish, although it may tarnish with oxygen over time. It often appears as a dull, gray or black film or coating over metal. Tarnish is a surface phenomenon that is self-limiting, unlike rust. Only the top few layers of the ...
Aluminium bronzes are most valued for their higher strength and corrosion resistance as compared to other bronze alloys. These alloys are tarnish-resistant and show low rates of corrosion in atmospheric conditions, low oxidation rates at high temperatures, and low reactivity with sulfurous compounds and other exhaust products of combustion.
Gunmetal ingot is a related alloy in which the zinc is replaced by 2% lead; this makes the alloy easier to cast but it has less strength. [2]Modified gunmetal contains lead in addition to the zinc; it is typically composed of 86% copper, 9.5% tin, 2.5% lead, and 2% zinc.
The items should be stored in rooms that are protected from polluted air, dust, ultraviolet radiation, and excessive relative humidity – ideal values are temperature of 16–20 °C and up to 40% (35–55% according to recent Canadian Conservation Institute recommendations) relative humidity, noting that if metal is combined with organic ...