chemistry-investigatory-project-on-consistuents-of-alloys

1. Certificate of Authenticity
This is to certify that “Parvez Hassan
Ansari”a student of class 12th ‘A’ has
successfully completed the research project on
the topic “Study of constituents of ALLOYS”
under the guidance of Mr.R.N.Chauhan.
This project is absolutely genuine and does not
indulge in plagiarism of any kind. The
references taken in making this project have
been declared at the end of this project.
Signature (subject teacher) Signature (examiner)

2. Acknowledgement
I feel proud to present my investigatory project in
chemistry on the “Study of Constituents of Alloys”
This project would not have been feasible without the
proper rigorous guidance of chemistry teacher
Mr.R.N.Chauhan who guided me throughout this project
in every possible way. An investigatory project involves
various difficult lab experiments, which have to obtain
the observations and conclude the reports on a
meaningful note. These experiments are very critical
and in the case of failure may result in disastrous
consequences. Thereby, I would like to thanks both
Mr.R.N.Chauhan and lab assistant Mr.Damoder for
guiding me on a systematic basis and ensuring that
in completed all my experiments with ease.Rigorous
hard work has put in this project to ensure that it proves
to be the best. I hope that it proves to be the best. I hope
that this project will prove to be a breeding ground for
the next generation of students and will guide them in
every possible way.

3. Aim
Study Of Constituents
Of Alloys

4. Introduction
An alloy(through the Fr. aloyer, from Lat. alligare, to combine), is a
partial or complete solid solution of one or more elements in a
metallic matrix. Complete solid solution alloys give single solid phase
microstructure, while partial solutions give two or more phases that
may be homogeneous in distribution depending on thermal (heat
treatment) history. Alloys usually have different properties from
those of the component elements. Alloying one metal with other
metal(s) or non metal(s) often enhances its properties. For instance,
steel is stronger than iron, its primary element. The physical
properties, such as density, reactivity, Young's modulus, and
electrical and thermal conductivity, of an alloy may not differ
greatly from those of its elements, but engineering properties, such
as tensile strength and shear strength may be substantially different
from those of the constituent materials. This is sometimes due to
the sizes of the atoms in the alloy, since larger atoms exert a
compressive force on neighboring atoms, and smaller atoms exert a
tensile force on their neighbors, helping the alloy resist
deformation. Alloys may exhibit marked differences in behavior
even when small amounts of one element occur. For example,
impurities in semi-conducting ferromagnetic alloys lead to different
properties, as first predicted by White, Hogan, Suhl, Tian Abrie and
Nakamura. Some alloys are made by melting and mixing two or more
metals. Brass is an alloy made from copper and zinc. Bronze, used
for bearings, statues, ornaments and church bells, is an alloy of
copper and tin. Unlike pure metals, most alloys do not have a single
melting point. Instead, they have a melting range in which the
material is a mixture of solid and liquid phases. The temperature at
which melting begins is called the solidus and the temperature when
melting is complete is called the liquidus. However, for most alloys
there is a particular proportion of constituents (in rare cases two)
which has a single melting point. This is called the alloy's eutectic
mixture.

5. Some Common Alloys And Their Uses
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, creating a range of brasses, each
with unique properties. By comparison, bronze is principally an alloy
of copper and tin. 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 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

6. finds its use especially in seawater applications (naval brasses).
Combinations of iron, aluminum, silicon, and manganese make brass
resistant to wear and tear.
Bronze-
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 percent copper and 40 percent 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 (a green coating on the exposed surface),
but it does not oxidize beyond the surface. It is considerably less
brittle than iron and has a lower casting temperature. Several
bronze alloys resist corrosion (especially by seawater) and metal
fatigue better than steel; they also 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 percent copper and 10
percent zinc. It contains no tin.

7. Pewter-
Pewter plate:-
Pewter is traditionally composed of 85 to 99 percent tin, with the
remainder consisting of copper, which acts as a hardener. Lead is
added to lower grades of pewter, giving a bluish tint. Traditionally,
there were three grades of pewter: fine, for eatingware, with 96 to
99 percent tin and 1 to 4 percent copper; trifle, also for eating and
drinking utensils but duller in appearance, with 92 percent tin, 1 to 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, beingsoft
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 to 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 daily life. Today, pewter is mainly
used for decorative objects such as collectible statuettes and
figurines, replica coins, and pendants.

8. 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 percent copper, 18 percent nickel,
and 17 percent 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.
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 an alloy composed of copper, nickel,
and zinc in the eighteenth century. Nickel silver first became
popular as a base metal for silverplated cutlery and other silverware,
notably the electroplated wares called "E.P.N.S." (electro-plated
nickel silver). It is used in zippers, costume jewelry, and musical
instruments (such as cymbals). After about 1920, its use became
widespread for pocketknife bolsters, due to its machinability and
corrosion resistance. In some countries, it is used in the production
of coins. Its industrial and technical uses include marine fittings
and plumbing fixtures for its corrosion resistance, and heating coils
for its high electrical resistance.

9. Steel-
Steel is an alloy composed mainly of iron, with carbon content
between 0.02 and 1.7 percent by weight. Carbon is the most
costeffective alloying material for iron, but many other alloying
elements are also used. Carbon and other elements act as hardening
agents, preventing iron atoms in the crystal lattice from sliding past
one another. By varying the amount of alloying elements and their
distribution in the steel, one can control its qualities such as
hardness, elasticity, ductility, and tensile strength. Steel with
increased carbon content can be made harder and stronger than
iron, but it is also more brittle. The maximum solubility of carbon in
iron is 1.7 percent by weight, occurring at 1130 °C. Higher
concentrations of carbon or lower temperatures produce
cementite, which reduces the material's strength. Alloys with higher
carbon content than this are known as cast iron because of their
lower melting point. Steel should also be distinguished from
wrought iron, with little or no carbon (usually less than 0.035
percent). Currently, there are several classes of steels in which
carbon is replaced with other alloying materials, and carbon, if
present, is undesired. More recently, steels have been defined as
iron-based alloys that can be plastically formed—pounded, rolled,
and so forth.

10. Experiment - 1
Aim : To analyze a sample of brass qualitatively.
Requirements : China dish, test-tube funnel, filter paper and common
laboratory reagents.
Theory : Brass is 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 due to 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
4Zn + 2NO+ 10H 4 Zn+2 + N2O + 5H2O
The solution is boiled to expel the oxides of nitrogen and the resulting
solution 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 dissolve the piece completely.
2. Continue heating the solution till a dry solid residue is obtained.
3. Dissolve the solid residue in dil. HCl and filter. Add distilled water to
the filtrate.
4. Pass H2S gas through the filtrate. A black precipitate of copper
sulphide is obtained. Separate the black ppt. and keep the filtrate for
the test of Zn+2 ions Dissolve black ppt. by heating them with 50%
HNO3. To this solution add ammonium hydroxide solution. Appearance
of deep blue colouration in the solution shows the presence of copper
ions in the solution.
5. To test Zn+2 ions, boil the filtrate to remove H2S gas, then add solid
NH4Cl to this and heat to dissolve NH4Cl. Add excess of NH4OH so
that a solution is ammoniacal. Now pass H2S gas through this ammoniacal
solution. Separate the precipitates and dissolve it in minimum amount of
dil. HCl. Boil to expel H2S gas and add potassium Ferro cyanide solution,
white or bluish white ppt. confirm Zn+2 ions in the solution.
Result :
The given sample of brass contains copper and zinc. metals as the
main constituents.

11. Experiment - 2
Aim : To analyze a sample of bronze qualitatively.
Requirements : China dish, test-tube funnel, filter paper and common
laboratory reagents.
Theory : Bronze is an 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. Both
these 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)
Excess of nitric acid is removed by heating the solution. The resulting
solution now would contain Cu+2 ions and metastannic acid. This
solution is acidified with dil. HCl and H2S gas is passed when the
sulphides of copper and tin are formed.
Cu+2 + S2- CuS (Black ppt.)
H2SnO3 + 2H2S SnS2 (Black ppt.) + 3H2O
The sulphides are separated by boiling the ppt. with yellow ammonium
sulphide when SnS2 goes into solution as thiostannate where as CuS is
not affected.
SnS2 + (NH4)2S (NH4)2 SnS2 (Soluble)
Ammonium thiostannate.
CuS + (NH4)2S CuS (Unaffected)
Black ppt.
The soluble black ppt. is tested for Cu+2 ions and the solution is
tested for Sn2+ ions as in elementary qualitative analysis.
Procedure :
1. Take about 1g. of small pieces of bronze in a china dish and add
to it 5-10 ml. of dil. HNO3.
2. Heat the contents slowly to dissolve copper and tin completely
and then boil the contents to a paste to remove excess of HNO3.
All this is carried out in cup board.
3. Dissolve this dry mass in distilled water containing HCl (1:1) to get a
clear solution.

12. 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.
5. Take the black ppt. in a test tube and add to it 2-3 ml. of yellow
ammonium sulphide and heat. Filter the contents. Black residue is tested
for Cu+2 ions and filtrate is tested for Sn+2 ions.
6. Analysis of 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 blue or green sol.
indicates the presence of Cu+2. Divide this sol. Into two parts.
(a) To one part add excess of NH4OH a deep blue colouration confirms
the presence of Cu+2 ions.
(b) Acidify the second part with acetic acid and add K4 [Fe (CN)6] i.e.
potassium ferrocyanide solution. A reddish brown ppt. confirms the
presence of Cu+2 ions.
7. Analysis of filtrate :
Boil the filtrate with 1 ml. of dil. HCl. A yellow ppt. is obtained. Dissolve
in 1 ml. conc. HCl. To this solution add 0.5 g. of zinc. Dust and boil it for
2-3 minutes. Filter and to filtrate add 1-2 ml. of mercuric chloride
solution. A white ppt. turning grey on standing confirms the presence of
Sn+4 ions.
Result :
The given sample of bronze contains - Cu and Sn as the main
constituents.

13. Bibliography
Comprehensive Chemistry Practical ClassXII.
http://www.icbse.com
www.google.com
www.wikipedia.org
www.allprojectreports.com
www.chemistryprojects.com