Difference between revisions of "Alloy" - New World Encyclopedia

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=== Nickel silver (German silver) ===
 
=== Nickel silver (German silver) ===
  
'''Nickel silver''' is a metal [[alloy]] of [[copper]] with [[nickel]] and often but not always [[zinc]]. It is named for its silvery appearance, and contains no elemental [[silver]]. Other common names for this alloy are '''German Silver''', '''Paktong''', '''New Silver''' and '''Alpacca''' (or '''Alpaca''').
+
Nickel silver is an alloy of [[copper]], [[nickel]], and often (but not always) [[zinc]]. It is named for its silvery appearance and contains no elemental [[silver]]. Other common names for this alloy are '''German silver''', '''Paktong''', '''New Silver''', and '''Alpacca''' (or '''Alpaca''').
  
There are many different formulations of alloys which fall within the general term of "Nickel Silver". All contain [[copper]], [[nickel]] and [[zinc]], while some formulations may additionally include [[antimony]], [[tin]], [[lead]] or [[cadmium]]. A representative industrial formulation (Alloy No.752) is 65% copper, 18% nickel, 17% zinc. In metallurgical science, such alloys would be more properly termed '''nickel [[bronze]]'''.  
+
Many different formulations of alloys fall in the general category of "nickel silver". Besides containing [[copper]], [[nickel]], and [[zinc]], some formulations may include [[antimony]], [[tin]], [[lead]], or [[cadmium]]. A representative industrial formulation (Alloy No.752) is 65% copper, 18% nickel, 17% zinc. In metallurgical science, such alloys would be more properly termed '''nickel bronze'''.
  
 
Some nickel silver alloys, especially those containing high proportions of zinc, are [[stainless]].
 
Some nickel silver alloys, especially those containing high proportions of zinc, are [[stainless]].
  
Nickel-silver alloys are commonly named by listing their percentages of copper and nickel, thus "Nickel Silver 55-18" would contain 55% copper, 18% nickel, and 27% other elements, most probably entirely zinc. A two-element alloy may be named for its nickel content alone, thus NS-12 is 88% copper and 12% nickel.
+
Nickel-silver alloys are commonly named by listing their percentages of copper and nickel, thus "Nickel Silver 55-18" would contain 55% copper, 18% nickel, and 27% other elements, most probably zinc. A two-element alloy may be named for its nickel content alone, thus NS-12 is 88% copper and 12% nickel.
  
  
Nickel silver first became popular as a base metal for silver plated [[cutlery]] and other [[silverware]], notably the [[electroplating|electroplate]]d wares called [[EPNS]] (Electro-plated Nickel Silver).
+
Nickel silver first became popular as a base metal for silver-plated [[cutlery]] and other [[silverware]], notably the electroplated wares called [[EPNS]]* (Electro-plated Nickel Silver). It is used in [[zippers]]*, costume [[jewelry]]*, and musical instruments (such as [[cymbal]]*s), and is valuable for electrically-powered [[model railway]] layouts as its [[oxide]] is conductive. Also, after about 1920, its use became widespread for pocketknife [[bolsters]], due to its machinability and corrosion resistance. Prior to this point, most common was [[iron]].
 
 
It is used in [[zippers]], costume [[jewellery]], for making musical instruments (e.g., [[cymbal]]s), and is valuable for electrically-powered [[model railway]] layouts as its [[oxide]] is conductive. Also, after about 1920, its use became widespread for pocketknife [[bolsters]], due to its machinability and corrosion resistance. Prior to this point, most common was [[iron]].
 
  
 
It is widely used in the production of [[coin]]s (e.g. [[GDR]] [[East German mark |marks]], [[Portuguese escudo]]).
 
It is widely used in the production of [[coin]]s (e.g. [[GDR]] [[East German mark |marks]], [[Portuguese escudo]]).
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Its industrial and technical uses include marine fittings and plumbing fixtures for its corrosion resistance, and heating coils for its high electrical resistance.
 
Its industrial and technical uses include marine fittings and plumbing fixtures for its corrosion resistance, and heating coils for its high electrical resistance.
  
It was used in the construction of the arly tricone [[resophonic guitar]].
 
  
 
====History====
 
====History====
Nickel silver is first known in [[China]], and was known in the west from imported wares called ''Paktong'' or ''Pakfong'' where the silvery metal colour was used to imitate [[sterling silver]]. It was discovered to be a copper-nickel-zinc alloy in the 18th century. In [[1770]] the [[Suhl]] (Germany) metalworks were able to produce a similar alloy and in [[1823]] a competition was initiated to perfect the production process by creating an alloy that possessed the closest visual similarity to silver. The brothers Henniger in [[Berlin]] and A. Geitner in [[Schneeberg]] independently achieved this goal. '''Alpacca''' became a widely known name in northern Europe for nickel silver after it was used as a trademark brand by the manufacturer Berndorf.
+
 
 +
The earliest use of nickel silver appears to have been in [[China]]. It became known to the West from imported wares called ''Paktong'' or ''Pakfong'', where the silvery metal color was used to imitate [[sterling silver]]*. It was discovered to be a copper-nickel-zinc alloy in the eighteenth century. In [[1770]] the [[Suhl]] (Germany) metalworks were able to produce a similar alloy and in [[1823]] a competition was initiated to perfect the production process by creating an alloy that possessed the closest visual similarity to silver. The brothers Henniger in [[Berlin]] and A. Geitner in [[Schneeberg]] independently achieved this goal. '''Alpacca''' became a widely known name in northern Europe for nickel silver after it was used as a trademark brand by the manufacturer Berndorf.
  
 
Nickel silver became widely used after 1840 with the development of electoplating, as it formed an ideal strong and bright substrate for the plating process. It was also used unplated in applications such as cheaper grades of [[cutlery]].
 
Nickel silver became widely used after 1840 with the development of electoplating, as it formed an ideal strong and bright substrate for the plating process. It was also used unplated in applications such as cheaper grades of [[cutlery]].
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*[http://www.metalwalltiles.net/bronzeTiles.htm Information about Bronze Tiles]
 
*[http://www.metalwalltiles.net/bronzeTiles.htm Information about Bronze Tiles]
 
* [http://www.danforthpewter.com/crafting-of-holloware.html How Pewter Pieces are Produced on a Lathe: Danforth Pewterers]
 
* [http://www.danforthpewter.com/crafting-of-holloware.html How Pewter Pieces are Produced on a Lathe: Danforth Pewterers]
 +
*[http://www.npi.gov.au/database/substance-info/profiles/27.html National Pollutant Inventory - Copper and compounds fact sheet]
 +
*[http://pages.zoom.co.uk/leveridge/nickel1.html Nickel Silver, German Silver, and related alloys]
 +
  
 
[[Category:Physical sciences]]
 
[[Category:Physical sciences]]

Revision as of 20:13, 22 September 2006

If a metal is combined with other chemical elements (metallic or nonmetallic) to form a solution or compound, and if the combination has metallic properties, the resulting material is called an alloy. Generally, a number of properties of the alloy are significantly different from those of its components. An alloy with two components is called a binary alloy; one with three is a ternary alloy; one with four is a quaternary alloy.

Steel is an extremely useful alloy, with iron as its major component and a carbon content between 0.02% and 1.7% by weight.

Some common alloys are brass, bronze, and steel. Some alloys are named after their primary constituent. For example, the "silver" used in jewelry and the "aluminum" used as a structural building material are actually alloys. Alloys of gold are rated on a scale of carats—for instance, 14 carat gold is 58% gold. The term "alloy" is sometimes used loosely as a synonym for "aluminum alloy," such as when referring to "alloy wheels" fitted on automobiles.

General properties

Alloys are usually designed to have properties that are more desirable than those of their constituents. For instance, steel is stronger than iron, its main element. The alloy "inherits" some of the characteristics of the elements it was made from—usually properties such as density, reactivity, and electrical and thermal conductivity. By contrast, properties such as tensile strength, Young's modulus, and shear strength can differ vastly from those of its constituent materials. These differences are caused by various factors, including the packing of atoms of differing sizes within the alloy. Larger atoms exert a compressive force on neighboring atoms, and smaller atoms exert a tensile force on their neighbors. Consequently, an alloy tends to resist deformation more than a pure metal, in which the atoms are freer to move.

Unlike pure metals, most alloys do not have a sharp melting point. Instead, they melt over a temperature range in which the material is a mixture of the solid and liquid phases. The temperature at which melting begins is called the solidus, and that at which melting is complete is called the liquidus. For most pairs of elements, however, there is a single, sharp melting point when the elements are in a particular ratio, called a eutectic mixture.

Some common alloys

Amalgam

Any alloy of mercury is called an amalgam. Most metals are soluble in mercury, but some (such as iron) are not. Amalgams are commonly used in dental fillings because they have been relatively cheap, easy to use, and durable. In addition, until recently, they have been regarded as safe. They are made by mixing mercury with silver, copper, tin, and other metals. The mercury content of dental fillings has recently stirred controversy, based on the potentially harmful effects of mercury.

Mercury amalgams have also been used in the process of mining gold and silver, because of the ease with which mercury amalgamates with them. In addition, thallium amalgam is used as the liquid material in thermometers, because it freezes at -58°C, whereas pure mercury freezes at -38°C.

Brass

A decorative brass paperweight (left), along with zinc and copper samples.

Brass is the term used for alloys of copper and zinc in a solid solution. It has a yellow color, somewhat similar to gold. It was produced in prehistoric times, long before zinc was discovered, by melting copper with calamine, a zinc ore.

The amount of zinc in brass varies from 5 to 45 percent, to create a range of brasses each with unique properties[1]. By comparison, bronze is principally an alloy of copper and tin.[2]. Despite this distinction, some types of brasses are called bronzes.

Brass is relatively resistant to tarnishing and is often used for decorative purposes. Its malleability and acoustic properties have made it the metal of choice for brass musical instruments such as the trombone, tuba, trumpet, and euphonium. Although saxophones and harmonicas are made out of brass, the saxophone is a woodwind instrument, and the harmonica, a free reed aerophone. In organ pipes designed as "reed" pipes, brass strips are used as the "reed".

Aluminum makes brass stronger and more corrosion resistant. It forms a transparent, self-healing, protective layer of aluminum oxide (Al2O3) on the surface. Tin has a similar effect and finds its use especially in seawater applications (naval brasses). Combinations of iron, aluminium, silicon and manganese make brass resistant to wear and tear.

Bronze

Assorted ancient bronze castings found as part of a cache.

Bronze refers to a broad range of copper alloys, usually with tin as the main additive, but sometimes with other elements such as phosphorus, manganese, aluminum, or silicon. Typically, bronze is about 60% copper and 40% tin.

The use of bronze was particularly significant for early civilizations, leading to the name Bronze Age. Tools, weapons, armor, and building materials such as decorative tiles were made of bronze, as they were found to be harder and more durable than their stone and copper predecessors. In early use, the natural impurity arsenic sometimes created a superior natural alloy, called arsenical bronze.

Though not as strong as steel, bronze is superior to iron in nearly every application. Bronze develops a patina, but it does not oxidize beyond the surface. It is considerably less brittle than iron and has a lower casting temperature. Several bronze alloys are resist corrosion (especially by seawater) and metal fatigue better than steel, and they conduct heat and electricity better than most steels.

Bronze has myriad uses in industry. It is widely used today for springs, bearings, bushings, and similar fittings, and is particularly common in the bearings of small electric motors. It is also widely used for cast metal sculpture and is the most popular metal for top-quality bells and cymbals.

Commercial bronze (otherwise known as brass) is 90% copper and 10% zinc. It contains no tin.

Pewter

Pewter plate

Pewter is traditionally composed of 85–99 percent tin, with the remainder consisting of copper, which acts as a hardener. Lead is added for the lower grades of pewter and a bluish tint.

Traditionally, there were three grades of pewter: fine, for eatingware, with 96-99 percent tin and 1-4 percent copper; trifle, also for eating and drinking utensils but duller in appearance, with 92 percent tin, 1-4 percent copper, and up to 4 percent lead; and lay or ley metal, not for eating or drinking utensils, which could contain up to 15 percent lead. Modern pewter mixes the tin with copper, antimony, and/or bismuth rather than lead.

Physically, pewter is a bright, shiny metal that is similar in appearance to silver. Like silver, it oxidizes to a dull gray over time, if left untreated. It is a very malleable alloy, being soft enough to carve with hand tools. It also takes good impressions from punches or presses. Given this inherent softness and malleability, pewter cannot be used to make tools. Some types of pewter pieces, such as candlesticks, were turned on a metal lathe, and these items are sometimes referred to as "holloware." Pewter has a low melting point (around 225-240°C), depending on the exact mixture of metals. Duplication by casting gives excellent results.

The use of pewter was common from the Middle Ages up until the various developments in glass-making during the eighteenth and nineteenth centuries. Pewter was the chief tableware until the making of china. With the mass production of glass products, glass has universally replaced pewter in day-to-day life. Today, pewter is mainly used for decorative objects such as collectible statuettes and figurines, replica coins, and pendants.

Nickel silver (German silver)

Nickel silver is an alloy of copper, nickel, and often (but not always) zinc. It is named for its silvery appearance and contains no elemental silver. Other common names for this alloy are German silver, Paktong, New Silver, and Alpacca (or Alpaca).

Many different formulations of alloys fall in the general category of "nickel silver". Besides containing copper, nickel, and zinc, some formulations may include antimony, tin, lead, or cadmium. A representative industrial formulation (Alloy No.752) is 65% copper, 18% nickel, 17% zinc. In metallurgical science, such alloys would be more properly termed nickel bronze.

Some nickel silver alloys, especially those containing high proportions of zinc, are stainless.

Nickel-silver alloys are commonly named by listing their percentages of copper and nickel, thus "Nickel Silver 55-18" would contain 55% copper, 18% nickel, and 27% other elements, most probably zinc. A two-element alloy may be named for its nickel content alone, thus NS-12 is 88% copper and 12% nickel.


Nickel silver first became popular as a base metal for silver-plated cutlery and other silverware, notably the electroplated wares called EPNS (Electro-plated Nickel Silver). It is used in zippers, costume jewelry, and musical instruments (such as cymbals), and is valuable for electrically-powered model railway layouts as its oxide is conductive. Also, after about 1920, its use became widespread for pocketknife bolsters, due to its machinability and corrosion resistance. Prior to this point, most common was iron.

It is widely used in the production of coins (e.g. GDR marks, Portuguese escudo).

Its industrial and technical uses include marine fittings and plumbing fixtures for its corrosion resistance, and heating coils for its high electrical resistance.


History

The earliest use of nickel silver appears to have been in China. It became known to the West from imported wares called Paktong or Pakfong, where the silvery metal color was used to imitate sterling silver. It was discovered to be a copper-nickel-zinc alloy in the eighteenth century. In 1770 the Suhl (Germany) metalworks were able to produce a similar alloy and in 1823 a competition was initiated to perfect the production process by creating an alloy that possessed the closest visual similarity to silver. The brothers Henniger in Berlin and A. Geitner in Schneeberg independently achieved this goal. Alpacca became a widely known name in northern Europe for nickel silver after it was used as a trademark brand by the manufacturer Berndorf.

Nickel silver became widely used after 1840 with the development of electoplating, as it formed an ideal strong and bright substrate for the plating process. It was also used unplated in applications such as cheaper grades of cutlery.

Steel

List of alloys

This is a list of alloys grouped by the main metallic constituent, in order of increasing atomic number of the main metal. Under these headings, the alloys are in no particular order. Some of the main alloying elements are optionally listed after the alloy names.

Alloys of aluminum

Alloys of potassium

Alloys of iron

Alloys of cobalt

Alloys of nickel

Alloys of copper

Alloys of gallium

  • Galinstan

Alloys of silver

Alloys of tin

Rare earth alloys

  • Mischmetal (various rare earths)

Alloys of gold

Alloys of mercury

Alloys of lead

Alloys of bismuth

  • Wood's metal
  • Rose metal
  • Field's metal
  • Cerrobend

Alloys of zirconium

  • Zircaloy

See also

References
ISBN links support NWE through referral fees

  1. Engineering Designer, v 30, n 3, May-June 2004, 6-9
  2. Machinery Handbook, Industrial Press Inc, New York, Edition 24, page 501

External links

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