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The Effect of Voltage on Copper
Electroplating |
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Researched by Nathaniel
H. |
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The purpose of this experiment was to determine the amount of voltage that would be the most suitable for copper electroplating.
I became interested in this idea when I learned that electroplating was important in manufacturing and I wanted to learn what the best way of electroplating was.
The information gained from this experiment could benefit manufacturers everywhere so they would know the amount of voltage that would be the most fitting for copper electroplating.
My hypothesis was that 4.8 volts would be the most suitable for copper electroplating.
I based my hypothesis on Microsoft Encarta Encyclopedia Deluxe 2001, which said, “A steady direct current of low voltage, usually from 1 to 6 V, is required for the process”, and that led me to believe that 4.8 volts would be the best for copper electroplating because it was the most volts in this range that my power source could provide and probably would be the most effective.
The constants in this study were:
• Type of metal (copper)
• Electrolyte used during testing
• Item being plated
• Weight of the item being plated
• Length of copper metal
• Time of the electroplating process (25 minutes)
• Testing procedure
• Weight of copper metal
• Electrical source
• Triple beam balance
The manipulated variable was the amount of voltage used during the electroplating process.
The responding variable was the change in mass of the plated object.
To measure the responding variable I used a triple beam balance.
| QUANTITY | ITEM DESCRIPTION |
| 1 | Triple beam balance |
| 9 |
Copper strips |
| 9 |
Zinc strips |
| 200 ml. | Copper nitrate solution |
| 1 | Stopwatch |
| 1 | Beaker |
| 2 | Alligator clips |
| 2 | Wires |
| 1 | DC power source |
| 1 | Digital multi-meter w/ wires, alligator clips |
| 2 | Circuit connectors |
| 1 | Fine Grain sandpaper (220 grit) |
| 1 | Pegboard assembly |
| 2 | Clamps |
| 3 |
Paper towels |
1.) Sand both sides of the 3 copper strips and the 3 zinc strips with the fine grain sandpaper on a paper towel.
2.) Find the mass of the 3 copper and zinc strips by using the triple beam balance.
3.) Record the mass of each copper and zinc strip.
4.) Lay the metal strips on a paper towel and label them 1, 2, and 3 according to which one you measured first, second, and third.
5.) Attach the two clamps onto the pegboard assembly so they will hold the electrodes at the right height and width.
6.) Fill the beaker with 200 ml. of copper nitrate solution.
7.) Connect the plug on the red wire to the red slot of the power source in the 0-5 volt range.
8.) Connect the plug on the black wire to the black slot of the multi-meter in the 0-5 volt range.
9.) Put one copper strip into one clamp and tighten the clamp by turning the wing nut until it holds the copper strip.
10.) Repeat step 9 for a zinc strip except place it in the other clamp.
11.) Connect the alligator clip on the red wire from the power source to the copper strip.
12.) Connect the alligator clip on the black wire from the power source to the zinc strip.
13.) Attach the alligator clip on the red wire from the digital multi-meter to the copper strip.
14.) Attach the alligator clip on the black wire from the digital multi- meter to the zinc strip.
15.) Set the digital multi-meter to volts DC.
16.) Set the stopwatch to 25 minutes.
17.) Turn on the power source.
18.) Turn the knob on the power source until the digital multi-meter reads 4.8 volts.
19.) Start the stopwatch so that the watch counts down from 25 minutes.
20.) Every 5 minutes check the digital multi-meter to make sure the volts are holding steady at 4.8 volts. If not, then adjust the power.
21.) After 25 minutes turn off the power source.
22.) Take the alligator clips off the metal strips.
23.) Loosen the clamp holding the copper strip and set the copper strip on a piece of paper towel.
24.) Repeat step 23 for the zinc strip.
25.) Once the metal strips have dried, measure the mass of the copper strip, then measure the mass of the zinc strip and record the measurements.
26.) Repeat steps 9-25 for the next two trials at 4.8 volts.
27.) Repeat steps 9-26 for the three trials at 2.4 volts and 1.2 volts.
The original purpose of this experiment was to determine the amount of voltage that would be the most suitable for copper electroplating.
The results of the experiment were that at 1.2 volts the increase in mass of the zinc strip was an average of 0.28 grams. At 2.4 volts the increase in mass of the zinc strip averaged 0.68 grams, and at 4.8 volts the increase of mass was an average of 1.3 grams.
See my table and graph
My hypothesis was that 4.8 volts would be the most suitable for copper electroplating.
The results indicate that this hypothesis should be rejected because I predicted that 4.8 volts would be the most suitable for electroplating, but it plated so much onto the zinc that bits and parts of the coating were falling off. The lower voltages plated better than 4.8 volts did.
Because of the results of this experiment, I wonder if the thickness of the copper or zinc electrodes would affect the mass of the copper plated on the zinc. I also wonder if the amount of copper nitrate solution used as an electrolyte during testing would affect the copper’s plating ability. Finally I wonder if a different electrolyte like copper sulfate solution would affect how much the copper plated onto the zinc
If I were to conduct this project again I would do more trials, or repeat my experiment again to see if my results were similar. I would use more voltage intervals like 1 volt, 2 volts, 3 volts, etc. Finally I would use a better power source that supplied more than 5 volts.
My findings should benefit manufacturers everywhere because now they know the amount of voltage that is proper for copper electroplating.
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Introduction: Electroplating is important in manufacturing today. It’s an electrochemical process. It can purify metals like the silverware that one uses everyday at their home. It also helps prevent corrosion on metals. Electroplating: Electroplating is an electrochemical process that distributes a layer of metal coating from one metal onto another metal. It requires an electric circuit. There are many uses for electroplating today. One use for electroplating is to improve the look of a metal such as silverware. It is also used to protect metals against corrosion and produce a metal from molt. Electroplating isn’t a complicated process. The coating of the metal needs to be from .03-.05 of a millimeter, and it requires a low amount of voltage between 1 and 6 volts. First one needs to clean the metals that will be used. Then put each metal in a bath of electrolyte solution. Next hook the metals up in a circuit by connecting the article that is depositing its metal to the anode and the metal going to be plated to the cathode. Once the electricity starts flowing through the circuit it acts on the metallic ions of the metal connected to the anode. The metallic ions then are attracted to the metal connected to the cathode therefore depositing a metal coating. Once the cathode has enough metal coating plated on it then you can stop the electric current. There are many solutions that can be used for the electroplating process but it all depends on the metals being used. If gold, silver, zinc, or cadmium are used then their needs to be some kind of cyanide solution depending on which metal is connected to the anode. If copper is the metal connected to the anode then you can use copper cyanide solution, copper sulfate solution, or copper nitrate solution. If chromium is the metal used then the solution needs to be chromic sulfate solution. When nickel is used you need a nickel sulfate solution. These are all solutions and metals you can use for the electroplating process. Metal: “Today metal forms a large part of the world.” (“Metal” World Book Encyclopedia 1998). Eighty percent of the elements used in today’s society are metal. Metal is important for manufacturing. Industries that use metal usually build machinery with it. Metal has many assets that make it a unique material. Metal can reflect light and have a shiny look because of it. Metal is a very good conductor of heat and electricity. Most metals though are hammered, rolled into thin sheets, or are drawn into wires for electricity. When a metal has a chemical reaction with a non-metal, the metal atoms give up electrons to the non-metal. There are properties of a pure metal that make it different from a compound metal. Metal has a lot of history behind it. Ancient people knew about metal and used it to make materials. Around 3500 B.C. gold was being used to make utensils, plates, and ornaments. Silver was first used around 2400 B.C. The ancient people believed that silver was more valuable than gold at the time because it was harder to find. Copper was also found at an early time and was used to make supplies. Since 1000 B.C. iron, and steel have been the metals used for construction purposes. Today iron is being used for steel making and is being used at a rapid rate. Copper, zinc, and lead are also being used rapidly. Aluminum and magnesium have become important metals recently. Copper: “Copper has been one of the most useful metals over the past 7,000 years.” (“Copper” World Book Encyclopedia 1996). Copper is a reddish-orangish colored metal. Copper is used for house gutters to electronic systems. Copper is the best low-cost conductor of electricity. Sixty percent of the copper produced today is copper wire and is mostly used for electronic equipment. Copper has many properties that make it valuable. Copper is probably best known for its conductivity of heat and electricity. This property of copper makes it useful for cooking utensils and radiators. Copper is highly malleable. Copper doesn’t crack when it is hammered, stamped, or put into unusual shapes. Copper can be rolled into sheets less than .05 millimeter. Copper also can be drawn into thin wires without breaking so it has ductility. A copper rod 1 centimeter in diameter can be drawn into a wire thinner than human hair. Finally copper has great tensile strength because it won’t break even when there is 50,000-70,000 pounds per square inch. Copper keeps its strength up to 400 degrees Fahrenheit. Copper has been used since the ancient times. It was the first metal known to man, and was used to make tools, weapons, and ornaments. Copper was discovered in 8000 B.C. Copper was later found and used by the American Indians and Chinese. In 3500 B.C. people found out how to melt copper and arsenic to make bronze. Ancient people later found out how to mix copper and zinc and make brass. In the 1800’s ways to make copper and use it changed slightly. In the late 1800’s there became a great demand for copper for telephones and electric lighting. There are many sources in the world that supply copper. There are about 9 million short tons of copper mined each year throughout the world. Every continent supplies copper. Most of the copper in the world is found between Alaska and the tip of South America. The way that is mostly used to supply copper is mining. “The US mines 1/5 of the world’s copper. Arizona supplies 2/3 of the copper in the US.” (“Copper” World Book Encyclopedia 1996). Chile is the world’s leading copper producer. Copper is being recycled at will, from wires to motors. Electricity: Electricity is the energy source that makes up everything in the world. Whenever people hear the word electricity they think of the electronic devices that are used everyday in society. The electrical force is also accountable for holding the atoms and molecules together to keep each piece of matter together. In this way electricity determines the structure of the object. An atom is made up of protons (positive charges), neutrons (no charge), and electrons (negative charges). In the atom the positive charges form a core called the nucleus. The nucleus is positive charged because it has only protons and no electrons, although it attracts electrons because opposite charges attract. These electrons rotate around the nucleus just like planets orbit the sun. Each type of atom has a different number of protons in its nucleus. For example a hydrogen atom has 1 proton in its nucleus, oxygen has 8 protons, iron has 26 protons, and uranium has 92 protons. Usually atoms have the same number of protons and electrons. The result is that the atom is neutral. Electric energy is an important property of electricity. Electric energy began in the 1800’s when people learned how to use electricity. This new source of energy changed the way people lived. Later inventors and scientists found ways to generate electricity in great amounts. They also learned ways to use energy to produce light, heat, and motion. In the late 1800’s they made electronics device that let people communicate from great distances. In the 1900’s the demand for electric energy steadily grew. Electric energy has a great effect on today’s society. Many things in this world rely on electricity. Developed nations in the world use many electric devices everyday. One of the most important electronic devices made was the computer. The computer changed the way people work at their house, at school, and at their job. Houses run on electricity. Electricity has also changed the way we communicate to people. The telephone runs on electricity and that lets us communicate with people who are great distances away. Transportation has also been changed by electricity because now we have trolleys and subways that run on electricity. In the health area doctors use electricity to treat their patients. Electric Current: “Electric current is the movement or flow of electric charges.” (“Electric Current” World Book Encyclopedia 1996). There are different electric charges that flow through an electric current. These charges are either positive or negative. A proton is a positive charge and an electron is a negative charge. An electric current can have one of these or both of these flowing through the current. Electric charges flow through an electric current from negative to positive. Scientist Ben Franklin first got the idea of which way electricity flowed. He thought that electricity flowed from positive to negative but other scientists later proved that this theory was wrong. He also failed to figure out that there is at least one electron in the atoms of a metal wire that flow freely, while the others are held together to the nucleus. An electric current flows the easiest through conductors. The number of free electrons determines how much electricity the metal conducts. Good conductors are copper, gold, silver, and aluminum. Lead and tin are poor conductors. Copper, gold, silver, and aluminum are good conductors because they have at least one free electron per atom. Lead and tin are poorer conductors because they have less than one free electron per atom. Materials with no free electrons don’t conduct electricity most of the time. These materials are called insulators. A couple of insulators are glass and rubber. There are some materials like germanium and silicon that are neither good conductors nor insulators, so they are semiconductors. Depending on the source, an electric current is either an alternating current or a direct current. A direct current flows the same direction while an alternating current reverses its direction rapidly. Things that use direct current are batteries, trains, and electrical system in a car. Things that run on alternating currents are buildings, and most electrical devices. A big advantage for alternating currents is that it is easier to transmit and it is more efficient than direct currents. A measurement for electric current is volts. Voltage: A volt is an electrical measurement that is used in the metric system. The symbol of a volt is “V”. Volts was named after the inventor of the battery, Alessandro Volta. “Volt is defined as the difference in electric potential energy between two points on a wire carrying one ampere of current and producing one watt.” (“Volt” World Book Encyclopedia 1998). Voltage is the difference in potential. Voltage is related to electrical forces that push the electric charges through a conductor. One volt of potential difference across the resistance of one ohm produces one ampere. Most batteries or other electromotive items are usually labeled by the amount of voltage that they have. Most flashlights use two 1.5-volt batteries. The main device that measures the amount of volts of something is the voltmeter. The voltmeter measures the voltage between two points of an electric current. Most commercial voltmeters are connected in a series circuit and have a high resistance. The voltmeter has a scale that read volts. A regular DC voltmeter has a magnet shaped horseshoe. On each end of the magnet there is a soft piece of iron and one small iron cylinder connected. The soft iron pieces directs where the magnetic field is coming from. Since the soft iron is magnetized the cylinder moves to wherever the magnetic field is. Around the cylinder is a coil of copper wire wound around a small rectangular frame. The copper coil is moveable so it carries the electric current to the scale. Summary: Electroplating is important in manufacturing. It is an electrochemical process that uses electricity and different types of metals. Metals that can be used for the process are copper, zinc, gold, silver, brass, and cadmium. The voltage used in electroplating affects the finished item. |
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“A Short History of Electroplating”.
http://www.artisanplating.com/articles/platinghistory.htm, November 5,
2004. Alley, Phillip. “Electric Current”. World Book Encyclopedia. 1996. Volume 6. Bellis, Mary. “Electroplating”. http://inventors.about.com/library/inventors/blelectroplating.htm. October 29, 2004. Bernstein, Melvin. “Electroplating”. World Book Encyclopedia. 1998. Volume 6. “Electroplating”. Microsoft Encarta Encyclopedia. 2001. George, David. “Copper”. World Book Encyclopedia. 1996. Volume 4. Prigo, Robert. “Volt”. World Book Encyclopedia. 1998. Volume 20. Shriver, Duward. “Metal”. World Book Encyclopedia. 1998. Volume 13. Wolfson, Richard. “Electricity”. World Book Encyclopedia. 1996. Volume 6. |
I would like to thank the following people for helping make my project possible:
• My parents for giving me encouragement throughout my project.
• Mr. Newkirk for correcting my rough drafts of my report, and for setting up times that we could meet so I could work on my experiment.
• Mrs. Helms for helping me with my mind map.
• Mrs. Gustin for providing me the materials I needed to complete my experiment.
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