This document is a student project on alloys submitted by Shubham Kourav to his teacher Mrs. Shashi Jharia. It discusses the aim of studying the constituents of alloys and provides information on common alloys such as stainless steel, aluminum, bronze, and brass. It describes their compositions and common uses. The project includes a list of experiments conducted and references used in the project.

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SESSION 2014-2015
INVESTIGATORYPROJECTON -
“CONSTITUENTSOF ALLOYS”
CLASS- 12
SUBMITTED TO SUBMITTED BY
MRs.shashi jharia shubham kourav

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CERTIFICATE
THIS IS TO CERTIFY THAT THE PROJECTENTITLED “CONSTITUENTS OF ALLOYS”WHICHHAS
BEENCOMPLETEDAND SUBMITTEDBY “SHUBHAMKOURAV”STUDENTOFCLASS 12TH
M/S. YEAR
2014-2015 OFADITYA CONVENTSCHOOL,IS A BONAFIEDWORKOF HIM.
SUBMITTED BY
SHUBHAM KOURAV DATE: / /
PRINCIPAL TEACHER
ACKNOWLEDGEMENT
I ACKNOWLEDGE THE VALUABLE SUGGESTION AND ADVICE
BY Mrs. SHASHI JHARIA (CHEMISTRY TEACHER), ADITYA
CONVENT SCHOOL, JABALPUR FOR ENCOURAGING ME FOR

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THIS PROJECT. I TAKE THIS OPPORTUNITY TO EXPRESS MY
GRATITUDE FOR HIS GUIDANCE DURING THE COURSE OF
THIS PROJECT WORK.I AM ALSO GRATEFUL TO THE
RESPECTED PRINCIPAL Mrs. VINITA MAHESHWARI (PRICIPAL)
FOR HER KIND HELP AND COOPERATION EXTENDED FOR ME
DURING THE COURSE OF THE PROJECT.
I CAN’T FORGET TO OFFER MY SINCERE THANKS TO
PARENTS AND ALSO TO MY CLASSMATES WHO HELPED ME
TO CARRY OUT THIS PROJECT WORK SUCCESSFUL AND FOR
THEIR VALUABLE ADVICE AND SUPPORT, WHICH I RECEIVED
FROM THEM TIME TO TIME….
LIST OF CONTENTS:
CERTIFICATE
ACKNOWLEDGEMENT
AIM
INTRODUCTION
LIST OF DIFFERENT ALLOYS AND THEIR USES-
1. STAINLES STEEL
2. ALUMINUM
3. BRONZE
4. BRASS

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5. STEEL
6. AMALGAM
7. PEWTER
8. SOLDER
9. ALNICO
USES OF ALLOYS
EXPERIMENTS
CONCLUSION
BIBLIOGRAPHY
AIM:

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STUDY OF “CONSTITUENTS OF
ALLOYS”
An Alloy is a homogenousmixtureof two or more metals or a non-metal. An alloy of
mercury with another metal is called amalgam. Alloys are usually harder than their
componentsbutvery often less ductile and less malleable. Thus the hardnessof gold
is increased by addition of copper to it. The melting point of an alloy is alwayslower
than the melting pointsof the constituent metals. Other propertiessuch as reactivity

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towardsatmospheric oxygen and moisture, mechanical strength, ductility, colour
etc. also under goesa change when an alloy is madefrom its constituents (metals).
This change of propertiesis very usefuland makesan alloy beneficial.
You might see the word alloy described as a "mixture of metals", but that's a little bit
misleadingbecause somealloys contain only onemetal and it's mixed in with other
substances that are nonmetals(cast iron, for example, is an alloy madeof justone
metal, iron, mixed with one nonmetal, carbon). The best way to think of an alloy is
as a material that's made up of at least two differentchemical elements, one of
which is a metal. The most importantmetallic componentof an alloy (often
representing90 percentor moreof the material) is called the main metal, the parent
metal, or the base metal. The other componentsof an alloy (which are called
alloying agents) can be either metals or nonmetalsand they're presentin much
smaller quantities (sometimes less than 1 percent of the total). Although an alloy
can sometimes be a compound (the elementsit's madefrom are chemically bonded
together), it's usually a solid solution (atoms of the elements are simply intermixed,
like salt mixed with water).
An alloy is a material composed of two or moremetals or a metal and a nonmetal.
An alloy may be a solid solution of the elements (a single phase), a mixtureof
metallic phases (two or moresolutions)or an intermetallic compound withno
distinct boundary between the phases. Solid solution alloysgive a single solid phase
microstructure, while partial solutionsexhibit two or more phases that may or may
not be homogeneousin distribution, dependingon the thermal (heat treatment)
history of the material. An inter-metallic compound hasoneother alloy or pure
metal embedded within another puremetal.
Alloysare used in some applications, where their propertiesare superior to those of
the purecomponentelementsfor a given application. Examplesof alloys are steel,
solder, brass, pewter, phosphor bronzeand an amalgam.
The alloy constituents are usually measured by mass. Alloys are usually classified as
substitutional or interstitial alloys, dependingon the atomic arrangementthat forms
the alloy. They can be further classified as homogeneous(consisting of a single

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phase), or heterogeneous(consisting of two or morephases) or intermetallic
(where there is no distinct boundary between phases).
An alloy is a mixture of either pureor fairly purechemical elements, which formsan
impuresubstance(admixture)that retains the characteristics of a metal. An alloy is
distinct from an impuremetal, such as wrought iron, in that, with an alloy, the added
impuritiesare usually desirable and will typically have some usefulbenefit. Alloys
are madeby mixing two or more elements; at least oneof which being a metal. This
is usually called the primary metalor the base metal, and the name of this metal
may also be the nameof the alloy. The other constituents may or may not be metals
but, when mixed with the molten base, they will be soluble, dissolvinginto the
mixture.
When the alloy cools and solidifies (crystallizes), its mechanical propertieswill often
be quite differentfrom those of its individualconstituents. A metal that is normally
very soft and malleable, such as aluminium, can be altered by alloying it with
another soft metal, like copper. Although both metals are very softand ductile, the
resulting aluminium alloy willbe much harder and stronger. Addingasmall amount
of non-metalliccarbon to iron producesan alloy called steel. Dueto its very-high
strength and toughness(which is much higher than pureiron), and its ability to be
greatly altered by heat treatment, steel is oneof the most common alloysin modern
use. By addingchromium to steel, its resistance to corrosion can be enhanced,
creating stainless steel, while addingsilicon will alter its electrical characteristics,
producingsilicon steel.
Although the elements usually mustbe soluble in the liquid state, they may not
alwaysbe soluble in the solid state. If the metals remain soluble when solid, the
alloy formsa solid solution, becoming a homogeneousstructureconsisting of
identical crystals, called a phase. If the mixturecools and the constituents become
insoluble, they may separate to form two or moredifferenttypesof crystals,
creating a heterogeneousmicrostructureof differentphases. However, in other
alloys, the insoluble elements may not separate untilafter crystallization occurs.
These alloysare called intermetallic alloys because, if cooled very quickly, they first
crystallize as a homogeneousphase, but they are supersaturated with the secondary
constituents. Astime passes, the atoms of these supersaturated alloysseparate
within the crystals, formingintermetallic phases that serve to reinforcethe crystals
internally.
Some alloys occur naturally, such as electrum, which is an alloy that is native to
Earth, consisting of silver and gold. Meteorites are sometimes madeof naturally

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occurringalloys of iron and nickel, but are notnative to the Earth. One of the first
alloys madeby humanswasbronze, which is madeby mixing the metals tin and
copper. Bronzewasan extremely usefulalloy to the ancients, because it is much
stronger and harder than either of its components. Steel wasanother common alloy.
However, in ancient times, it could only be created as an accidental byproductfrom
the heating of iron ore in fires (smelting) duringthe manufactureof iron. Other
ancient alloys includepewter, brass and pig iron. In the modern age, steel can be
created in many forms. Carbon steel can be made by varyingonly the carbon
content, producingsoftalloyslike mild steel or hard alloys like springsteel. Alloy
steels can be madeby addingother elements, such as molybdenum, vanadium or
nickel, resultingin alloys such as high-speed steel or tool steel. Small amountsof
manganeseare usually alloyed with most modern-steelsbecause of its ability to
removeunwanted impurities, likephosphorus, sulfur and oxygen, whichcan have
detrimentaleffects on the alloy. However, most alloys werenot created untilthe
1900s, suchas variousaluminium, titanium, nickel, and magnesium alloys. Some
modern superalloys, suchas incoloy, inconel, and hastelloy, may consist of a
multitudeof differentcomponents.
LIST OF DIFFERENT ALLOYS AND THEIR USES-
1. STAINLESS STEEL

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It is a steel alloy with a minimum of 10.5% chromium contentby mass. Stainless
steel doesnot readily corrode, rust or stain with water as ordinary steel does.
However, it is not fully stain-proof in low-oxygen, high-salinity, or poor air-
circulation environments. Thereare differentgradesand surface finishes of
stainless steel to suitthe environmentthe alloy mustendure. Stainless steel is used
where both the propertiesof steel and corrosion resistance are required.
Stainless steel differsfrom carbon steel by the amountof chromium present.
Unprotected carbon steel rusts readily when exposed to air and moisture. This iron
oxide film (the rust) is active and accelerates corrosion by formingmoreiron oxide;
and, because of the greater volumeof the iron oxide, this tendsto flakeand fall
away. Stainless steels contain sufficientchromium to form a passivefilm of
chromium oxide, which preventsfurther surfacecorrosion by blocking oxygen
diffusion to the steel surfaceand blocks corrosion from spreadinginto the metal's
internalstructure, and, dueto the similar size of the steel and oxideions, they bond
very strongly and remain attached to the surface.
USES
In order to reducecorrosion losses, there are extensive usesof stainless steels.
Stainless steel alloys are used for many commercialapplicationssuch as watch
straps, cutlery etc. Stainless alloys used for making tubes intended for placementon
the bottom of the sea. Stainless Alloysare also widely used in the electronic,

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agricultural, road and rail industries. Stainless steel grades are used for handling
bulk wet materials, tanks, containers, conveyors, chimneysand many others.
2. ALUMINUM
Aluminum isa silverish white metal that has a strongresistance to corrosion and
like gold, is rather malleable. It is a relatively light metal compared to metals such
as steel, nickel, brass, and copper with a specific gravity of 2.7. Aluminum iseasily
machinable and can have a widevariety of surfacefinishes. It also has good
electrical and thermal conductivitiesand is highly reflective to heat and light.
Aluminum alloyshavea strong resistance to corrosion which is a result of an oxide
skin that formsas a result of reactions with the atmosphere. This corrosiveskin
protects aluminum from mostchemicals, weathering conditions, and even many
acids, however alkaline substances are known to penetrate the protective skin and
corrodethe metal.
Aluminum also has a rather high electrical conductivity, makingit usefulas a
conductor. Copper isthe morewidely used conductor, havinga conductivity of
approximately 161% that of aluminum. Aluminum connectorshaveatendency to
become loosened after repeated usage leadingto arcing and fire, which requires
extra precaution and special design when using aluminum wiringin buildings. At
extremely high temperatures(200-250°C)aluminumalloystend to lose some of
their strength.
USES

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Aluminium when combined withother metals gives strength and specific
characteristics for a particular use. Aluminium alloysareextensively used in the
production of cars and engineparts. The vast range of quality Aluminium isused in
variousapplicationslike transport, packaging, electrical application, medicine, and
construction of homes and furniture. Flight at high altitudes would notbe possible
without the strong aluminium alloysused that undergo massamountsof stress and
pressure.
3. BRONZE
It consists copper 60-90%. Bronzeisamixture of copper and other metals like tin.
Copper isnot a strong metal meant for functionaluseand if it is combined with
other metals, it becomes bronzewhich is an alloy that has greater strength known to
last for several years.
Bronze refersto a broad range of copper alloys, usually withtin as the main
additive, but sometimes with other element s such as phosphorus, manganese,
aluminum, or silicon. Typically, bronzeis about 60 percent copper and 40 percent
tin. The use of bronzewas particularly significant for early civilizations, leading to
the name"BronzeAge." Tools, weapons, armor, and buildingmaterials
such as decorative tiles weremadeof bronze, as they were found to be harder and
moredurable than their stone and copper predecessors.
In early use, the natural impurity arsenic sometimes created a superior natural
alloy, called "arsenical bronze."Thoughnot as strong as steel, bronzeis superior to
iron in nearly every application. Bronzedevelopsapatina (a green coating on every
the exposed surface), but it does not oxidizebeyond the surface.
It is considerably less brittle than iron and has a lower casting temperature. Several
bronzealloys resist corrosion (especially by seawater) and metal fatigue better than
steel; they also conductHeat and electricity better than most steels. Bronze has

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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 isthe most popular metal
for top-quality bells and cymbals. Commercial bronze, otherwise known as brass, is
90 percentcopper and 10 percentzinc. It contains no tin.
USES
Bronzewaswidely used for utilitarian and artistic purposesuntil iron became
cheaper and more plentiful. Bronzecontinued to havewideutilitarian uses untilit
became cost prohibitive, now except for a few applications as a bearing metal in the
engineeringand automobile industrieshas fallen out of use. Artistically bronzeis
still widely used in casting sculpturesof all sizes, plaques, and bell founding.
Strictly speaking, bronzeis an alloy of copper and tin. However, bronzeis also used
to describe a wider rangeof copper based alloys. Generally, bronzealloysconsist of
about 12% tin, though somespecialised productsmay contains muchas 20%.
Phosphor bronzes, which contain less than 8% tin, have an addition of phosphor to
improvestrength and hardness. Superior attributes can often be attained through
the addition of other elements to the basic bronzealloy. As well as phosphor, zinc
and lead are the most common additions. A leaded bronzewill generally have better
machining characteristics than an unleaded bronze. Itwill, however, retain a
plasticity that makesit ideal for applications such as the production of bearings, as it
allows slacker tolerances to be absorbed if softer shaft materials are used. This also
preventsthe overheating and seizure of like metals caused by friction.
Adding zinc to bronze alloys results in an alloy commonly known as “gunmetal”.
This derives from the use of this product in early culverins etc., used because of its
hardness and strength. It also has good resistance to corrosion and finds many
applications in the marine industry. Added lead improves the machinability of this
product. Aluminium bronze has become well established in the manufacture of
avionic equipment as well as use in naval and military applications due to its
enhanced corrosion resistance.
4. BRASS

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It consists copper-50-90%. Zinc: 20-40% and smallamountsof tin, lead and iron. A
decorative brass paperweight(left), along with zincand 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 prehistorictimes, long
before zincwas discovered, by melting copper with calamine, a zinc ore. The
amountof zinc in brass varies from 5 to 45 percent, creating a range of brasses,
each with uniqueproperties. By comparison, bronze isprincipally an alloy of
copper and tin. Despitethis distinction, some types of brasses are called bronzes.
Brassis relatively resistant to tarnishing and is often used for decorative purposes.
Its malleability and acoustic properties have madeit the metal of choice for musical
instruments such as the trombone, tuba, trumpet, and euphonium.
Although saxophones and harmonicas are made outof brass, the saxophoneis a
woodwind instrument, and theharmonica, a free reed aero phone. In
organ pipes designed as "reed" pipes, brass strips are used as the "reed."
Aluminum makes brassstronger and morecorrosion-resistant. It formsa
transparent, self-healing, protective layer of aluminum oxide(Al2O3)on the
surface. Tin has a similar effect and findsits use especially in seawater applications
(naval brasses). Combinationsof iron, aluminum, silicon, and manganese make
brass resistant to wear and tear.
USES

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Brasshas countless usesin everyday life, and has been used for thousandsof years.
In ancient times brass was used for armour and weaponry, aswellas for tools like
knives and axes. Nowadaysbrass is used for a widevariety of products. Its acoustic
propertiesmake it ideal for musicalinstruments(brass is a whole orchestra section
includingtrumpets, tubasand trombones).
While its antibacterial propertiesmake it usefulfor things liase. It is very common
in industrialsettings because it does notspark when struck, so fittings for
flammable gasses are made from brass. It is also ductileand easy to machine, so it
can be made into a variety of pipes, tubes, nails and screws. Brass also has very little
friction makingit very usefulin machine parts. In the futurebrass will mostlikely
retain its popularity, becauseit's so useful. It also is nearly 100% recyclable, so
there is no fear of runningoutof brass.
5. STEEL
Every steel is truly an alloy, but notall steels are called "alloy steels". Even the
simplest steels are iron (Fe) (about 99%)alloyed with carbon (C) (about 0.1% to
1%, dependingon type). However, the term "alloy steel" is the standard term
referringto steels with other alloyingelements in additionto the carbon.
Steel is a metal alloy consisting mostly of iron, in addition to small amountsof
carbon, dependingon the gradeand quality of the steel. Alloy steel is any type of
steel to which oneor moreelements besides carbon have been intentionally added,
to producea desired physical property or characteristic. Common elementsthat are
added to makealloy steel are molybdenum, manganese, nickel, silicon, boron,
chromium, and vanadium.

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Alloy steel is often subdivided into two groups: high alloy steels and low alloy steels.
The differencebetween the two is defined somewhatarbitrarily. However, most
agree that any steel that is alloyed with more than eight percent of its weight being
other elements beside iron and carbon, is high alloy steel. Low alloy steels are
slightly morecommon. The physical propertiesof these steels are modified by the
other elements, to give them greater hardness, durability, corrosion resistance, or
toughness as compared to carbon steel. To achieve such properties, these alloys
often requireheat treatment.
USES
Steels are generally used in railways, roads, subways, bridges, other huge buildings
and modern skyscrapers, shipbuilding, cars, armored vehicles, and bulldozers, etc.
Steel alloys, like stainless steel, have become ubiquitousmaterials for constructing
everythingfrom household cookwareto buildings to modern art. The alloy has
many attributes that makeit useful, suchas an excellent shine, a surfacethat resists
corrosion and rust and that is durableunder harsh weather conditions.
6. AMALGAM
Any alloy of mercury iscalled an amalgam. Amalgamsare crystalline in structure,
except for those with high mercury content, which are liquid. Known sinceearly
times, they were mentioned by Pliny the Elder in the 1st century AD. Amalgamsare
commonly used in dental fillings because they have been relatively cheap, easy to
use, and durable. In addition, untilrecently, they have been

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regarded as safe. They are madeby mixing mercury withsilver, copper, tin, and
other metals. The mercury contentof dental fillings has recently
stirred controversy, based on the potentially harmfuleffects of mercury. Mercury
amalgams have also been used in the processof mininggold 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,whereaspuremercury freezes at-38°C.
USES
Amalgamshave several uses. The first is as a silveringagent for mirrors. Amalgams
madeof mercury and silver are used on mirrors. Perhapsthe most popular useof
amalgams is in dentistry, where they are used as fillings for cavities and to cement
tooth restorations. Amalgamsof mercury and tin or copper are most commonly
used in the dental context. As another example, amalgams may also be used to
retrieve tiny amountsof gold and silver from ore.
7. PEWTER
Pewter with little or no lead is of finer quality, and alloys that includeantimony and
bismuth are moredurable and brighter of sheen. Modern pewter isabout 91
percenttin, 7.5 percentantimony, and 1.5 percentcopper; the absence of lead
makes it safe to usefor dishes and drinkingvessels. The surfaceof modern pewter is

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bluish white with either a crisp, bright finish or a soft, satin sheen. It resists tarnish,
retaining its colour and finish indefinitely.
Copper and antimony actas hardenerswhile lead is common in the lower gradesof
pewter, which have a bluish tint. It has a low melting point, around 170–230 °C
(338–446 °F), dependingon the exact mixtureof metals. The word pewter islikely a
variation of the word spelter, aterm for zinc alloys(originally a colloquial name for
zinc).
Pewter work is usually cast, then further finished by hammering, turningon a lathe,
burnishing, and sometimes engraving. Some items, such as snuffboxes, were
constructed from separate pewter pieces and then soldered together. Some modern
pewter work is formed by stampingpresses. Most pewter alloys are quite ductile
and easily worked. Cold-workingdoesnotcausethe metal to harden sufficiently to
requireannealing.
USES
It is used for many other items including porringers, plates, dishes, basins, spoons,
measures, flagons, communion cups, teapots, sugar bowls, beer steins, and cream
jugs. In the early 19th century, changes in fashion caused a declinein the use of
pewter flatware. At the same time, production increased of both cast and spun
pewter tea sets, whale-oil lamps, candlesticks, and so on. Later in the century,
pewter alloys wereoften used as a base metal for silver-plated objects.
In the late 19th century, pewter cameback into fashion with the revivalof medieval
objects for decoration. New replicas of Medievalpewter objects were created, and
collected for decoration. Today, pewter is used in decorative objects, mainly
collectible statuettes and figurines, game figures, aircraft and other models, (replica)
coins, pendants, plated jewellery and so on. Certain athletic contests, such as
the United States FigureSkating Championships, award pewter medalsto the fourth
place finishers.

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8. SOLDER
Solderingis a processin which two or more metal items are joined together by
melting and flowinga filler metal into the joint, the filler metal having a relatively
low melting point.
Soft solder is typically thought of when solder or solderingis mentioned, witha
typical melting range of 90 to 450 °C (190 to 840 °F). It is commonly used
in electronics, plumbing, and assembly of sheet metal parts. Manualsolderinguses
a solderingiron or soldering gun. Alloys that melt between 180 and 190 °C (360 and
370 °F)are the most commonly used. Solderingperformed usingalloyswith a
melting pointabove 450 °C (840 °F) is called 'hard soldering', 'silver soldering',
or brazing.
For electrical and electronics work solder wireis available in a range of thicknesses
for hand-soldering, and with cores containing flux. It is also available as a paste or as
a preformed foilshaped to match the workpiece, moresuitable for
mechanized mass-production. Alloysof lead and tin were universally used in the
past, and are still available; they are particularly convenientfor hand-soldering.
Lead-free solder, somewhat less convenientfor hand-soldering, is often used to
avoid the environmentaleffectof lead.
Plumbersoften use bars of solder, muchthicker than the wire used for electrical
applications. Jewelers often use solder in thin sheets which they cut into snippets.

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USES
A solderingiron is used to melt the alloy between two metal surfaces in the hopes of
connecting them. The use of solderingalloys is beneficial in the manufacturing
businessand for at-home hobbies. Soldering alloys are mostcommonly used in
electronics. They are used in almost every electronic item available from computers
to telephones to televisions. The circuit boards in these items are cluttered with
hundredsof tiny electronic componentswhich were bonded to the board itself with
solder. Plumbersoften use solder to fusetwo pipestogether. Solderingalloys are
very common in jewelry making. Various crafts also use solders. Silversmithing
often makesuse of silver or gold solderingalloysto bond differentpieces together
to create a work of art.
9. ALNICO
Alnico is an acronym referringto a family of iron alloys which in addition to iron are
composed primarily of aluminium (Al), nickel (Ni) and cobalt (Co), hence al-ni-co.
They also include copper, and sometimes titanium. Alnico alloysare ferromagnetic,
with a high coercivity (resistance to loss of magnetism) and are used to
make permanentmagnets. Beforethe developmentof rareearth magnets in the

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1970s, they werethe strongest typeof magnet. Other tradenames for alloys in this
family are: Alni, Alcomax, Hycomax, Columax, and Ticonal.
The composition of alnico alloys is typically 8–12% Al, 15–26% Ni, 5–24% Co,
up to 6% Cu, up to 1% Ti, and the balance is Fe. The developmentof alnico
began in 1931, when T. Mishimain Japan discovered that an alloy of iron,
nickel, and aluminum had a coercivity of 400 oersted (Oe; 32 kA/m), double
that of the best magnet steels of the time.
USES
Alnico magnetsare widely used in industrialand consumer applicationswhere
strong permanentmagnetsare needed; examplesare electric, electric guitar
pickups, microphones, sensors, loudspeakers, magnetron tubes, and cow magnets.
In many applicationsthey are being superseded by rareearth magnets, whose
stronger fields(Br) and larger energy products(BHmax)allow smaller size magnets
to be used for a given application.
USES OF ALLOYS:-
The componentsof variousalloyscontain metallic and non-metallicelements. There
are a large number of possible combination of differentmetals and each has its own
specific set of properties. The Uses for alloysare limitless dependingon the materials
involved and the complexity of the alloy. The alloys are used extensively in fieldsthat
involvebut are notlimited to; aircrafts, military, commercial, industrial, medical,
residential and manufacturingapplications. AlloyslikeAluminium, Copper, Nickel,
Stainless steel, Titanium all have differentusesin variousapplications.
To modify chemical reactivity :-

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When sodium is used as reducingagent it is too reactive to be used but its allay with
mercury, called sodium amalgam can be safely used as reducingagent.
To increase hardness :-
Hardnessof gold is increased by adding copper to it. Also zincis added to copper to
make copper hard in form of brass.
To increase tensile strength :-
Nickeloy, an alloy of Nickel (1%), Copper (4%)and aluminium (95%)hashigh
tensile strength.
To lower the melting point :-
Solder metal which is an alloy of Sn(30%)and Pb(70%)hasvery less meting point
as compared to melting pointsof Sn and Pb.
To modify the colour :-
Aluminium bronzean alloy of Cu and Al has beautifulgolden colour.
To resist corrosion:-
Iron gets rusted and corroded. Its corrosion takes place with time but stainless steel,
an alloy of iron and carbon get not rusted the composition of stainless steel is :Iron -
98% and Carbon - 2%

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AIM-
To analyze a sample of brass.
Requirements:China dish, test-tube funnel, filter paper and common
laboratory reagents.
Theory:
Brassis an alloy of copper and zinc. With the following.
Composition:
Cu = 60-90% and Zn. = 10-40%.
Thus Cu and Zn. form the main constituents of brass. Both these metals dissolved in
50% of nitric acid dueto formation of nitrates which are soluble.
3 Cu + 8HNO3 (Dil) 3 Cu (NO3)2 + 2NO+ 4H2O
or
Cu + 8H+ + 2NO3– 3 Cu+2 + 2NO+ 4H2O
4Zn + 10HNO3 (Dil) 4 Zn (NO2)2 + N2O + 5H2O

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4Zn + 2NO3– + 10H+ 4 Zn+2 + N2O+ 5H2O
The solution is boiled to expelthe oxides of nitrogen and the resultingsolution is
tested for Cu2+ and Zn+2 ions.
Procedure:
1. Place a small piece of brass in a china dish and heat this with minimum quantity of
50% HNO3 so as to dissolvethe piece completely.
2. Continueheating the solution till a dry solid residueis obtained.
3. Dissolvethe solid residuein dil. HCl and filter. Add distilled water to the filtrate.
4. PassH2S gas through the filtrate. A black precipitate of copper sulphideis
obtained. Separate the black ppt. and keep the filtrate for the test of Zn+2 ions
Dissolveblack ppt. by heating them with 50% HNO3. To this solution add ammonium
hydroxidesolution. Appearanceof deep blue coloration in the solution shows the
presenceof copper ionsin the solution.
5. To test Zn+2 ions, boil the filtrate to removeH2Sgas, then add solid NH4Clto this
and heat to dissolve NH4Cl. Add excessof NH4OH so that a solution is ammoniacal.
Now pass H2Sgas through this ammoniacalsolution. Dirty white or grey
precipitation indicate zinc. Separate the precipitates and dissolve it in minimum
amountof dil. HCl. Boil to expel H2S gas and add potassium Ferro cyanidesolution,
white or bluish white ppt. confirm Zn+2 ionsin the solution.
Result:
The given sampleof brass contains copper and zinc. Metals as the main constituents.

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AIM-
To analyze a sample of bronze.
Requirements: Chinadish, test-tube funnel, filter paper and common laboratory
reagents.
Theory:
Bronzeisan alloy of copper and tin with the following.
Composition:
Cu = 88-96% and Sn. = 4-12%.
Thus copper and zinc. form the main constituents of bronze. Boththese metals
dissolved in nitric acid.
3 Cu + 8H+ + 2NO3– 3 Cu2+ + 2NO+ 4H2O
4Sn + NO3– + 10 H+ 4 Sn+2 + NH4+ + 3H2O (Cold and Dil. Acid)
Sn + 4NO3– + 4H+ H2Sn O3 + 2NO2 + H2O (Conc. acid) (Metastannic Acid)

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Excess of nitric acid is removed by heating the solution. The resultingsolution now
would contain Cu+2 ionsand metastannicacid. This solution is acidified with dil. HCl
and H2S gas is passed when the sulphidesof copper and tin are formed.
Cu+2 + S2-CuS(Black ppt.)
H2SnO3 + 2H2SSnS2 (Black ppt.)+ 3H2O
The sulphidesare separated by boiling the ppt. with yellow ammonium sulphide
when SnS2goes into solution as thiostannate where as CuS is not affected.
SnS2 + (NH4)2S(NH4)2 SnS2 (Soluble)
Ammonium thiostannate.
CuS+ (NH4)2SCuS(Unaffected)
Black ppt.
The solubleblack ppt. is tested for Cu+2 ionsand the solution is tested for Sn2+ ions
as in elementary qualitative analysis.
Procedure:
1. Take about 1g. of small pieces of bronzein a china dish and add to it 5-10 ml. of dil.
HNO3.
2. Heat the contentsslowly to dissolvecopper and tin completely and then boil the
contents to a paste to removeexcess of HNO3. All this is carried out in cup board.
3. Dissolvethis dry mass in distilled water containing HCl(1:1)to get a clear solution.
4. Transfer the solution in a test tube and pass H2S in excess i.e. till the precipitation
is complete. Filter and reject the filtrate.

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5. Take the black ppt. in a test tube and add to it 2-3 ml. of yellow ammonium
sulphideand heat. Filter the contents. Black residueis tested for Cu+2 ionsand
filtrate is tested for Sn+2ions.
6. Analysisof black residue:
Transfer a little of the black ppt. into a test tube. Add to it 2-3 ml. of 50%. HNO3 and
boil the contents of the tube. A light blueor green sol. indicates the presenceof Cu+2.
Dividethis sol. into two parts.
(a) To onepart add excess of NH4OH a deep blue coloration confirmsthe presenceof
Cu+2 ions.
(b) Acidify the second part with acetic acid and add K4 [Fe (CN)6] i.e. potassium
ferrocyanidesolution. A reddishbrown ppt. confirmsthe presenceof Cu+2 ions.
7. Analysisof filtrate:
Boil the filtrate with 1 ml. of dil. HCl. A yellow ppt. is obtained. Dissolvein 1 ml. conc.
HCl. To this solution add 0.5 g. of zinc. dustand boil it for 2-3 minutes. Filter and to
filtrate add 1-2 ml. of mercuricchloride solution. A white ppt. turninggrey on
standingconfirmsthe presenceof Sn+4 ions.
Result:
The given sampleof bronzecontains - Cu and Sn as the main constituents.

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CONCLUSION
Brasscontains copper and zinc. Bronzecontainscopper and tin. Alloyshave been
around for a very longtime, even before modern technology. However, the process
in alloy technology only occurred in the last few decades.
An Alloy is a homogenousmixtureof two or more metals or a non-metal. Alloysare
metals made up of morethan oneelement. Alloysserve humankind in amyriad of
ways. An alloy is a solid homogeneoussolution of oneor more elementsin a metal.
Alloysare valuable because they can be madestronger, harder, lighter or better
than pureelements. Alloysoccur in naturewhen metals are mixed with non-metallic
elements to form rock (ore).
Most of the metals we come in contact with in our daily lives are alloys. Alloys can
be made up of two or moremetals, or of metal elements mixed with non-metallic
elements like carbon, sulfur, boron or silicon. For instance, steel is actually an alloy
of iron and carbon, while stainless steel is an alloy of iron, carbon, nickel and
chromium. Very few metals are used today in their pureelementalform. Butone of
them is copper, used in pureform for electrical wiring.
Alloy material has very importantrole in our daily life even there won'tbe a day
passed without usingalloy. Our utensils in the kitchen, vehicles, computers, mobile
phones, chairs etc. are using differenttypeof alloys which means numerous alloys
have been madeand being used by human beings. Most of the engineering and
medical equipments, machineries, tools are madeby Alloys.

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BIBLIOGRAPHY
WWW.GOOGLE.COM
WWW.WIKIPEDIA.COM
WWW.ICBSE.COM
WWW.ALLPROJECTREPORTS.COM
WWW.SLIDESHARE.COM
COMPREHENSIVE CHEMISTRY PRACTICAL CLASS 12TH