Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal. However, since "bronze" is a somewhat imprecise term, and historical pieces have variable compositions, in particular with an unclear boundary with brass, modern museum and scholarly descriptions of older objects increasingly use the more cautious and inclusive term "copper alloy" instead.

The word Bronze is believed to be cognate with the and , perhaps ultimately taken from the Persian word for brass, birinj; or possibly from the Latin name of the city of Brindisi (aes Brundusinum—Pliny).

History

The discovery of bronze enabled people to create metal objects which were better than previously possible. Tools, weapons, armor, and various building materials, like decorative tiles, made of bronze were harder and more durable than their stone and copper ("Chalcolithic") predecessors. Initially bronze was made out of copper and arsenic to form arsenic bronze. It was only later that tin was used, becoming the sole type of bronze in the late 3rd millennium BC. Tin bronze was superior to arsenic bronze in that the alloying process itself could more easily be controlled (as tin was available as a metal) and the alloy was stronger and easier to cast. Also, unlike arsenic, tin is not toxic.

The earliest tin-alloy bronzes date to the late 4th millennium BC in Susa (Iran) and some ancient sites in China, Luristan (Iran) and Mesopotamia (Iraq).

Copper and tin ores are rarely found together (exceptions include one ancient site in Thailand and one in Iran), so serious bronze work has always involved trade. In Europe, the major source for tin was Great Britain's deposits of ore in Cornwall, which were traded as far as Phoenicia in the Eastern Mediterranean.

Though bronze is generally harder than wrought iron, with Vickers hardness of 60–258 vs. 30–80, the Bronze Age gave way to the Iron Age; this happened because iron was easier to find and easier to process. Bronze was still used during the Iron Age, for example officers in the Roman army had bronze swords while foot soldiers had iron, but, for many purposes, the weaker wrought iron was found to be sufficiently strong. Archaeologists suspect that a serious disruption of the tin trade precipitated the transition. The population migrations around 1200–1100 BC reduced the shipping of tin around the Mediterranean (and from Great Britain), limiting supplies and raising prices. As ironworking improved, iron became cheaper; and as cultures advanced from wrought iron to forged iron, they learned how to make steel, which is stronger than bronze and holds a sharper edge longer.

Composition

There are many different bronze alloys but modern bronze is typically 88% copper and 12% tin. Alpha bronze consists of the alpha solid solution of tin in copper. Alpha bronze alloys of 4–5% tin are used to make coins, springs, turbines and blades. Historical "bronzes" are highly variable in composition, as most metalworkers probably used whatever scrap was to hand; the metal of the 12th century English Gloucester Candlestick is bronze containing a mixture of copper, zinc, tin, lead, nickel, iron, antimony, arsenic with an unusually large amount of silver - between 22.5% in the base and 5.76% in the pan below the candle. The proportions of this mixture may suggest that the candlestick was made from a hoard of old coins. The Benin Bronzes are really brass, and the Romanesque Baptismal font at St Bartholomew's Church, Liège is described as both bronze and brass.

Commercial bronze (90% copper and 10% zinc) and Architectural bronze (57% Copper, 3% Lead, 40% Zinc) are more properly regarded as brass alloys because they contain zinc as the main alloying ingredient. They are commonly used in architectural applications.

Bismuth bronze is a bronze alloy with a composition of 52% copper, 30% nickel, 12% zinc, 5% lead, 1% bismuth. It is able to hold a good polish and so is sometimes used in light reflectors and mirrors.

Other bronze alloys include aluminium bronze, phosphor bronze, manganese bronze, bell metal, arsenical bronze, speculum metal and cymbal alloys.

Properties

Bronze is considerably less brittle than iron. Typically bronze only oxidizes superficially; once a copper oxide (eventually becoming copper carbonate) layer is formed, the underlying metal is protected from further corrosion. However, if copper chlorides are formed, a corrosion-mode called "bronze disease" will eventually completely destroy it. Copper-based alloys have lower melting points than steel or iron, and are more readily produced from their constituent metals. They are generally about 10 percent heavier than steel, although alloys using aluminum or silicon may be slightly less dense. Bronzes are softer and weaker than steel—bronze springs, for example, are less stiff (and so store less energy) for the same bulk. Bronze resists corrosion (especially seawater corrosion) and metal fatigue more than steel and is also a better conductor of heat and electricity than most steels. The cost of copper-base alloys is generally higher than that of steels but lower than that of nickel-base alloys.

Copper and its alloys have a huge variety of uses that reflect their versatile physical, mechanical, and chemical properties. Some common examples are the high electrical conductivity of pure copper, the excellent deep drawing qualities of cartridge case brass, the low-friction properties of bearing bronze, the resonant qualities of bell bronze, and the resistance to corrosion by sea water of several bronze alloys.

The melting point of Bronze varies depending on the actual ratio of the alloy components and is about .

Bronze is nonmagnetic.

Uses

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.

In the twentieth century, silicon was introduced as the primary alloying element, creating an alloy with wide application in industry and the major form used in contemporary statuary. Sculptors may prefer silicon bronze because of the ready availability of silicon bronze brazing rod, which allows color-matched repair of defects in castings. Aluminum is also used for the structural metal aluminum bronze.

It is also widely used for cast bronze sculpture. Many common bronze alloys have the unusual and very desirable property of expanding slightly just before they set, thus filling in the finest details of a mold. Bronze parts are tough and typically used for bearings, clips, electrical connectors and springs.

Spring bronze weatherstripping comes in rolls of thin sheets and is nailed or stapled to wood windows and doors. There are two types, flat and v-strip. It has been used for hundreds of years because it has low friction, seals well and is long lasting. It is used in building restoration and custom construction.

Bronze also has very low metal-on-metal friction, which made it invaluable for the building of cannon where iron cannonballs would otherwise stick in the barrel. It is still widely used today for springs, bearings, bushings, automobile transmission pilot bearings, and similar fittings, and is particularly common in the bearings of small electric motors. Phosphor bronze is particularly suited to precision-grade bearings and springs. It is also used in guitar and piano strings.

Unlike steel, bronze struck against a hard surface will not generate sparks, so it (along with beryllium copper) is used to make hammers, mallets, wrenches and other durable tools to be used in explosive atmospheres or in the presence of flammable vapors.

Bronze is used to make bronze wool for woodworking applications where steel wool would discolor oak.

Bronze statues

Indian Hindu artisans from the period of the Chola empire in Tamil Nadu, used bronze to create intricate statues via the lost wax casting method with ornate detailing depicting the Gods of Hinduism mostly, but also the lifestyle of the period. The art form survives to this day, with many silpis, craftsmen, working in the areas of Swamimalai and Chennai.

In antiquity other cultures also produced works of high art using bronze. For example: in Africa, the bronze heads of the Kingdom of Benin; in Europe, Grecian bronzes typically of figures from Greek mythology; in east Asia, Chinese bronzes of the Shang and Zhou dynasty — more often ceremonial vessels but including some figurine examples.

Bronze continues into modern times as one of the materials of choice for monumental statuary.

Musical instruments

Bronze is the most popular metal for top-quality bells, particularly bell metal, which is about 23% tin.

Nearly all professional cymbals are made from a bronze alloy. The alloy used in drum kit cymbal bronze is unique in the desired balance of durability and timbre.

Modern cymbals consist of several types of bronze, the most common being B20 bronze, which is roughly 20% tin, 80% copper, with traces of silver. Zildjian and Sabian use this alloy for their professional lines. A Swiss company, Paiste, uses a softer B8 bronze which is made from 8% tin and 92% copper in nearly all of their cymbals. Zildjian and Sabian use this metal too, in their budget priced cymbals.

As the tin content in a bell or cymbal rises, the timbre drops. As well as B8 and B20, Meinl Percussion uses B10 (10% tin) and B12 (12% tin) alloys for cymbals, which have timbres roughly between B8 and B20.

Bronze is also used for the windings of steel strings of various stringed instruments such as the double bass, piano, harpsichord, and the guitar, replacing former gut and nylon strings. Bronze strings are commonly reserved on pianoforte for the lower pitch tones, as they possess a superior sustain quality to that of high-tensile steel.

Bronzes of various metallurgical properties are widely used in struck idiophones around the world, notably in South East Asia, and most famously for the Javanese gamelan and other glockenspiel-like musical instruments. The earliest bronze archeological finds in Indonesia date from 1–2 BCE, including flat plates probably suspended and struck by a wooden or bone mallet.

Some companies are now making saxophones from phosphor bronze (3.5 to 10% tin and up to 1% phosphorus content).

Medals

thumb|200px|right|A large bronze cast medallion, some 9.5 by 8.7 centimetres in measurement, created by the celebrated medalist Valerio Belli in the sixteenth century. Bronze has been used in the manufacture of various types of medals for centuries, and are known in contemporary times for being awarded to the second-runner up in sporting competitions and other events. The later usage was in part attributed to the choices of Gold, Silver and Bronze to represent the first three Ages of Man in Greek mythology: the Golden Age, when men lived among the gods; the Silver age, where youth lasted a hundred years; and the Bronze Age, the era of heroes, and was first adopted at the 1904 Summer Olympics. At the 1896 event, silver was awarded to winners and bronze to runners-up, while at 1900 other prizes were given, not medals.

See also

List of copper alloys

Art object

Bronze medal

Bronze sculpture

Bronzing

Chinese bronze inscriptions‎

French Empire mantel clock

Seagram Building

DZR Dezincification Resistant Brass

UNS C69100

References

External links

Bronze bells

"Lost Wax, Found Bronze": lost-wax casting explained

Viking Bronze - Ancient and Early Medieval bronze casting

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name	Kim Kardashian Humphries
birth name	Kimberly Noel Kardashian
birth date	October 21, 1980
birth place	Los Angeles, California, US
nationality	American
ethnicity	Armenian, Dutch, Scottish
net worth	$35million
years active	2007–present
known for	Reality show Keeping Up with the Kardashians and Kourtney and Kim Take New York
occupation	Entrepreneur, actress, model, socialite
height
measurements	35D-26-40
spouse	Damon Thomas (2000-2004) Kris Humphries (2011-present)
parents	Robert Kardashian (father)Kris Jenner (mother)Bruce Jenner (stepfather)
relatives	Kourtney Kardashian (sister)Khloé Kardashian (sister)Robert Kardashian Jr. (brother)Kylie Jenner (half-sister)Kendall Jenner (half-sister)
website	http://kimkardashian.celebuzz.com/ }}

Kimberly "Kim" Kardashian Humphries (née Kimberly Noel Kardashian; October 21, 1980) is an American socialite, television personality, model, and actress. She is the daughter of late attorney Robert Kardashian, and is known for a sex tape with her former boyfriend Ray J as well as her E! reality series that she shares with her family, Keeping Up with the Kardashians. Kardashian's prominence has increased as of January 2011 with the premiere of Kourtney and Kim Take New York, the second spin-off of Keeping Up with the Kardashians (the first being Kourtney and Khloé Take Miami), debuting on E!, with the series following Kim and sister Kourtney Kardashian as they leave Los Angeles to open a third D-A-S-H store in New York City.

Kardashian has launched multiple fragrances, guest starred on numerous shows, competed on ABC's Dancing with the Stars, and has had roles in movies such as Disaster Movie and Deep in the Valley. In 2010, Kardashian, along with her sisters Kourtney and Khloé, released an autobiography, Kardashian Konfidential.

Early life

Kardashian was born in Los Angeles, California, the daughter of late attorney Robert Kardashian and Kris Jenner (née Houghton). Her father was a third generation Armenian American and her mother is of Dutch and Scottish descent. Her paternal great-grandparents immigrated to Los Angeles from historic Armenia (then part of the Ottoman Empire, now in Turkey). Her last name in Armenian (spelled Քարտաշեան in Armenian) means "son of a stonemason." Although only half Armenian, she states that she "was raised with a huge Armenian influence, always hearing stories of Armenia, eating Armenian food and celebrating Armenian holidays".

Kardashian has two sisters, Kourtney and Khloé, and one brother, Robert. She has stepbrothers Burton Jenner, Brandon Jenner, and reality TV star Brody Jenner, step-sister Casey Jenner, and half-sisters Kendall Jenner and Kylie Jenner.

She attended Marymount High School. During high school, Kardashian worked at her father's music marketing firm, Movie Tunes.

Career

2007–present: Reality television

Kardashian first rose to fame in February 2007 when she starred in a sex tape with R&B; singer Ray J. In October 2007 she along with her two sisters, mother, brother, half-sisters, and stepfather starred in the E! television series, Keeping Up with the Kardashians. The series has aired five seasons to date, with two spin-off series.

Her first acting role was in the television series Beyond the Break. She then starred in the 2008 disaster film spoof Disaster Movie as Lisa. Kardashian appeared in the How I Met Your Mother episode "Benefits". She also appeared on the Season 3 premiere of the series 90210 with her sisters Khloé and Kourtney; they all played themselves. Kardashian was a guest hostess of WrestleMania XXIV and appeared as a guest judge during Cycle 13 of America's Next Top Model. On December 16, 2009, Kardashian made a guest star appearance on CBS's CSI: NY with Vanessa Minnillo.

Kardashian was one of 13 participants on the seventh season of Dancing with the Stars. She was partnered with Mark Ballas and was the third contestant voted off the show on September 30, 2008, finishing in 11th place overall.

2007–2010: Modeling and retail

Kardashian co-owns a clothing boutique called D-A-S-H with her sisters Kourtney and Khloé.

In December 2007, Kardashian posed nude for Playboy. She has also featured in numerous international editions of FHM, including the cover of the April 2010 Australian edition and the UK March 2011 edition. In February 2008, Bongo Jeans announced that Kardashian would be their face model. She also models for Balenciaga shoes, Carl's Jr. fast food, Sugar Factory lollipops, and various other products.

Kardashian released her own fragrance product in 2010.

In March 2009, Kardashian launched an endorsement with ShoeDazzle shopping, of which she is the co-founder and chief fashion stylist.. The following month on April 9, 2009, Kardashian released a workout DVD series, Fit In Your Jeans By Friday, with trainers Jennifer Galardi and Patrick Goudeau. In September 2009, Fusion Beauty and Seven Bar Foundation launched "Kiss Away Poverty", with Kardashian as the face of the campaign. For every LipFusion lipgloss sold, $1 went to the Foundation to fund women entrepreneurs in the US.

Famous Cupcakes, a Los Angeles bakery, created a vanilla cupcake mix for Kardashian. The cupcake flavor is called Va-Va-Va-Nilla.

Kardashian has also created jewelry along with her sisters, Khloé and Kourtney. They produced a collection for Virgins, Saints, and Angels in 2010.

Again with her sisters, Kardashian has released various clothing lines. One called K-Dash was to be sold on QVC in 2010, and in the same year they produced a range for Bebe. As of August 2011 they are creating another for Sears, called the Kardashian Kollection.

In addition, Kardashian and her sisters created a sunless tanner called Kardashian Glamour Tan in 2010.

On July 1, 2010, the New York City branch of Madame Tussauds revealed a wax figure of Kardashian.

2010–present

Kardashian is the producer of The Spin Crowd, a reality television show about Command PR, a New York City public relations firm, run by Jonathan Cheban and Simon Huck. The show follows them as they settle into their new offices in Los Angeles. Kardashian is friends with both, specifically Cheban, and frequently appears on her reality shows. She also appeared at the 2010 MTV VMAs on September 12, 2010. She also appeared in and was the subject and judge of a task on the ninth episode of Season 10 of The Apprentice in 2010; the two teams had to create an in-store display for her new perfume line, to be sold at Perfumania.

Kim, Kourtney, and Khloé wrote an autobiography entitled Kardashian Konfidential. The book was released in stores on November 23, 2010.

In December 2010, Kardashian filmed a music video for a song titled "Jam (Turn It Up)," the video was directed by Hype Williams; Kanye West makes a cameo in the video. Kardashian premiered the song during a New Year's Eve party at TAO Las Vegas on December 31, 2010. The song was produced by The-Dream and Tricky Stewart. Kardashian said that she was forced into doing the song by friends such as Ciara, Kanye West, and "Turn It Up" producer The-Dream. When asked if an album is in the works, Kardashian replied: "There's no album in the works or anything – just one song we did for Kourtney and Kim Take New York, and a video Hype Williams directed, half of the proceeds we're giving away to a cancer foundation, because The-Dream's and one of my parents passed away from cancer. It's just all having fun – with a good cause". Jim Farber, writing for the Daily News, called the song a "dead-brained piece of generic dance music, without a single distinguishing feature," and suggested that the single made Kardashian the "worst singer in the reality TV universe."

Kardashian's 2010 earnings were the highest of any other reality star at $6 million.

A mainstream UK national newspaper, The Guardian, has commented on her ability to attract payments of up to US$10,000 from sponsors for each tweet that she broadcasts, noting that she is "an American reality TV star whose sole talent lies in her large rump".

Personal life

Relationships

In 2000, Kardashian married music producer Damon Thomas; their relationship ended in divorce in 2004. Subsequently she dated R&B; singer Ray J, NFL star Reggie Bush and Dallas Cowboys wide receiver Miles Austin. She was also seen with model Gabriel Aubry. Kardashian then began dating NBA player Kris Humphries of the New Jersey Nets; they married on August 20, 2011 in Montecito, California. Kardashian and Humphries made $17.9 million on nuptials.

Sex tape

In February 2007, a pornographic home video she made with singer Ray J was leaked. Vivid Entertainment bought the rights for $1 million and released the film as Kim Kardashian: Superstar on February 21. Kardashian sued Vivid for ownership of the tape. In late April 2007, Kardashian dropped the suit and settled with Vivid Entertainment for $5 million.

Cookie Diet lawsuit

Dr. Sanford Siegal, the creator of the Cookie Diet, sued Kardashian, claiming she defamed him on Twitter. According to Siegal, Kardashian tweeted in October that he was "falsely promoting" that she was on the cookie diet. Siegal filed a claim in a Florida state court claiming the statements are false and defamatory. He also alleges that Kardashian was on QuickTrim's payroll when she posted the tweet. Kardashian's tweet appears to stem from an article on CookieDiet.com, that named Kardashian as one of many celebrities who saw positive results on the diet. Kardashian sent a cease-and-desist order to Siegal, demanding the link be removed.

Activism

Kardashian has supported the recognition of the Armenian Genocide on numerous occasions and has encouraged Barack Obama and the United States government to consider its acknowledgement. On April 21, 2011, a few days before the 96th anniversary of the Armenian Genocide, she has written about the issue on her blog in an effort to put it under spotlight and has also sent a tweet to her fans urging its recognition.

On April 1, 2010, Kardashian joined Cyndi Lauper in the launch of her Give a Damn campaign to create a wider awareness of discrimination against the LGBT community as part of her True Colors Fund.

However, she has also been on the receiving end of activism. Animal rights organization PETA has criticized her for repeatedly wearing fur coats, and named her as one of the five worst people or organizations of 2010 when it came to animal welfare.

Filmography

2007–present: Keeping Up with the Kardashians as Herself

2008: Dancing with the Stars as Herself

2008: Disaster Movie as Calvin's girlfriend, Lisa Taylor

2009: CSI: NY as Debbie Fallon (1 episode)

2009: Deep in the Valley as Summa Eve

2009: How I Met Your Mother as herself (1 episode)

2009: Beyond the Break as Elle (4 episodes)

2010: 90210 as herself (season 3 premiere)

2011–present: Kourtney and Kim Take New York

References

External links

Official website

Kardashians join forces with Australian designer at Mediasearch

Category:1980 births Category:American actors Category:American female models Category:American film actors Category:American people of Armenian descent Category:American people of Dutch descent Category:American people of Scottish descent Category:American socialites Category:Businesspeople in fashion Category:Kardashian family Category:Living people Category:People from Los Angeles, California

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