Zinc brass

Lead(ll) azide Calcium stearate, copper, zinc, brass, carbon disulfide... 

Copper and Copper Alloys. The coppers are divided into oxygen-bearing and oxygen-free coppers. Numerous copper alloys are of commercial importance, including those alloys with zinc (brasses), with tin (phosphor bronzes), and with aluminum (aluminum bronzes) all are weldable. 

The composition of the builders in an alkaline cleaner is dependent on the metal substrate from which the soil is to be removed. For steel (qv) or stainless steel aggressive, ie, high pH, alkaline salts such as sodium or potassium hydroxide can be used as the main alkaline builder. For aluminum, zinc, brass, or tin plate, less aggressive (lower pH) builders such as sodium or potassium siUcates, mono- and diphosphates, borates, and bicarbonates are used. 

Copper—Zinc Brasses. Copper—zinc alloys have been the most widely used copper alloy during the 1990s. It is no accident that the word brass is included in the name of many copper alloy manufacturers. The manufacture of brass buttons and other brass artifacts was the principal reason for the estabhshment of the U.S. copper alloy industry in Connecticut during the 1800s. 

Table 16 illustrates the property enhancements and tradeoffs seen when tin is added to a copper—zinc brass base composition. The most commonly used alloys for electrical connectors are the Cu—10 Zn—Sn brasses, such as C411, C422, and C425. These lower level zinc—tin alloys offer good corrosion resistance along with the good formabiHty, conductivity, and strength levels of brass. 

Bronzes are somewhat similar to brasses in mechanical properties and to high-zinc brasses in corrosion resistance (except that bronzes are not affected by stress cracking). Aluminum and silicon bronzes are very popiilar in the process industries because they combine good strength with corrosion resistance. 

Copper-alloy corrosion behavior depends on the alloying elements added. Alloying copper with zinc increases corrosion rates in caustic solutions whereas nickel additions decrease corrosion rates. Silicon bronzes containing between 95% and 98% copper have corrosion rates as low as 2 mil/y (0.051 mm/y) at 140°F (60°C) in 30% caustic solutions. Figure 8.2 shows the corrosion rate in a 50% caustic soda evaporator as a function of nickel content. As is obvious, the corrosion rate falls to even lower values as nickel concentration increases. Caustic solutions attack zinc brasses at rates of 2 to 20 mil/y (0.051 to 0.51 mm/y). 

Zinc brasses are corroded much more rapidly by ammonium hydroxide than by caustic solutions. Corrosion rates approaching 240 mil/y (6.1 mm/y) have been measured at room temperature in two normal ammonium-hydroxide solutions. Corrosion rates in hot, concentrated caustic solutions may be as high as 70 mil/y (1.8 mm/y). 

The resistance of a metal to erosion-corrosion is based principally on the tenacity of the coating of corrosion products it forms in the environment to which it is exposed. Zinc (brasses), aluminum (aluminum brass), and nickel (cupronickel) alloyed with copper increase the coating s tenacity. An addition of V2 to 1)4% iron to cupronickel can greatly increase its erosion-corrosion resistance for the same reason. Similarly, chromium added to iron-base alloys and molybdenum added to austenitic stainless steels will increase resistance to erosion-corrosion. 

Zinc brasses containing phosphorus, antimony, and/or arsenic dezinc-ify much less readily than brasses free of these elements. Brasses containing less than 15% zinc are virtually immune to attack, and those containing more than 32% zinc are readily dealloyed. 

Layer-type dezincification is easy to recognize visually. The original component shape and dimensions are usually preserved, but the metal color changes from the golden yellow of zinc brass to the red of ele-... 

The outstanding properties of copper-base materials are high electrical and thermal conductivity, good durabihty in mildly corrosive chemical environments and excellent ductility for forming complex shapes. As a relatively weak material, copper is often alloyed with zinc (brasses), tin (bronzes), aluminum and nickel to improve its mechanical properties and corrosion resistance. 

The development of new solutions for established alloys for example the replacement of fluoborate for lead-zinc brasses. 

Percy, J. (1861), Metallurgy The Art of Extracting Metals from their Ores and Adapting Them to Various Purposes of Manufacture, Murray, London reprint in two parts (ca. 1985) Vol. 1, Fuel Fire-Clays Copper Zinc Brass, etc. Vol. 2, Iron Steel, De Archaeologische Pers Nederland, Eindhoven. 

Lead(II) azide Lead chromate Lead dioxide Calcium stearate, copper, zinc, brass, carbon disulfide Iron hexacyanoferrate(4-) Aluminum carbide, hydrogen peroxide, hydrogen sulfide, hydroxylamine, ni-troalkanes, nitrogen compounds, nonmetal halides, peroxoformic acid, phosphorus, phosphorus trichloride, potassium, sulfur, sulfur dioxide, sulfides,... 

Copper-zinc brasses, 7 753 modified, 7 757-758 Coprecipitation, 14 196 Coproduction... 

Zinc antimonide, 3 44, 53—54 Zinc atomizing process, 26 598 Zinc baths, 9 828-829, 830t Zincblende semiconductors, 22 141 band structure of, 22 142-144 transport properties of, 22 148, 149t Zinc borates, 4 282-283 Zinc brass... 

Percy, J. (1861). Metallurgy. Volume I Fuel Fire-Clays Copper, Zinc Brass. Murray, London. 

Table 6.3 Average analyses of low Zinc brasses (<28% Zn ) classified by country. The majority date from before AD 1560.

Silver items, however, are also relatively rare in the archaeological record. The most common metal found is either copper, usually alloyed with either tin (bronze) or, in the later periods, zinc (brass), or iron. The latter contains very little lead and, because of severe corrosion problems, its survival rate is often low (but see Degryse et al., 2007). Fortunately, copper can also be characterized from its lead isotope signature, since the primary ore of copper is chalcopyrite (CuFeS2), which often co-occurs with galena (PbS) and sphalerite (ZnS). Even if the ore used is a secondary mineral formed by the oxidation of the primary deposit, the copper smelted from such a deposit would normally be expected to... 

Despite the good performance characteristics of HMTD, it had several significant faults. As mentioned earlier, the peroxide bond is very reactive. This made HMTD incompatible with most metals. It actively attacked aluminum, tin, zinc, brass, copper, iron, and lead. HMTD was also very unstable when stored, exhibiting tremendous weight loss over short periods of time. In the end, it was judged both too reactive and too thermally unstable for any practical usage. It fell into obscurity in the explosives community in the early 1950s. 

Reactions with metals. When mercury fulminate is boiled with water containing metallic suspensions, the majority of metals (e.g. aluminium, zinc, copper), form their fulminates and mercury is precipitated. Reaction can also occur at room temperature, except with nickel. Other metals may be ranged according to increasing reactivity silver, tin, bismuth, cadmium, iron, lead, copper, zinc, brass, aluminium. With aluminium, the reaction takes only a few hours, yielding a large amount of A1203. 

Prior to the Civil War, engineers were pretty well limited to working with only a few materials, such as iron, copper, tin, zinc, brass and bronze and, of course, wood. Steel became more readily available shortly after the Civil War through the wider use of the recently discovered Bessemer and open-hearth processes and the subsequent discovery of alloy steels. And around the turn of the century, aluminum was becoming available in commercial quantities. 

Season cracking of high zinc brasses is a severe form of embrittlement resulting in cracking or disintegration. Somewhat similar forms of stress-corrosion cracking occur in many other metals and alloys. Embrittlement of boiler plate, discussed below, may be considered a special case. 

The history of zinc is interesting in that it was long used in the form of alloys before it came to be recognized as an element in 1746. For hundreds of years prior to that date, however, alloys of copper and zinc (brasses) were produced by the smelting of ores containing compounds... 

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