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					                                                                                Matt Brinda

           Electroplating Plastic And the Affects of F, B, and H Type Graphite

Introduction

          The purpose of our research project was to determine what effect different types

of pencil graphite had on the ability to electroplate copper. We used three different types

of graphite, each having their own purpose (one for points, one for blackness, and one for

hardness). We electroplated each type five times keeping all of our variables the same

except for what type of graphite we used. We calculated theoretical yield of copper

plated using plating duration and amps. We also drew conclusions from the visual aspect

of the plating based on how much surface area was copper plated. We compared our

experimental yield of copper with our theoretical and drew conclusions from that.

Background Chemistry

          In our project we electroplated copper onto plastic where positive copper ions,

Cu+2, were platted onto a cathode, which was negatively charged. In our project two

solid copper anodes oxidized into copper ions that were reduced and then platted onto the

cathode (1). The solid copper anodes oxidized as follows: Cu° (s)  Cu+2 (aq) + 2e-. The

copper anode loses mass during the plating process because it oxidized to copper ions

replenish the copper ions lost in the sulfate solution (1).

          The solution that we used to plate our cathode was mainly made up of copper (II)

sulfate (Cu+2SO4-2). The copper ions within the solution were reduced from a copper

Cu+2 ion to Cu0 on the cathode. The reduction reaction for this is Cu+2 (aq) + 2e- 

Cu0(s).
       Sulfuric acid, H2SO4, was also put into the bath solution to increase conductivity

and to prevent precipitation of copper (II) sulfate. Brighteners were used during the

plating process and had to be replenished. The brightener gives the copper being plated

onto the cathode a smooth lustrous deposit (2).

       There was a current running through this whole system where electrons were

flowing from the anode to the cathode as seen in Figure 1 (3). The ions then travel

through the solution to complete the circuit (3). This is shown in Figure 1.

       The flow of current was measured in amperes where 1 amp equals the passage of

1 coulomb which is 6.24x1018 per second (3). Our current was equal to 0.8A which

equals 0.8 coul/sec. We plated for 10 minutes at 0.8 amps. So the equation for calculating

theoretical yield of copper platted is:

 0.8 coul/sec x 600 sec x 1F/96500coul x 1 mole e- /1F x 1 molCu/2mole e- x 63.6g Cu/1

mole Cu

       The quantity of copper platted was proportional to the amount of coulombs passed

through the wire during the plating process (3).

       In our project we used different types of graphite as a plating surface. We used F,

B, H, type pencil graphite. The composition of the graphite is measured by F which is

used to measure how fine a point can be used, and B which determines the blackness of

the pencil graphite, and H which is the hardness of the graphite in the pencil. In our

project we compared how well each different type of graphite plated. Manufacturers mix

different amounts of powdered clay into the graphite to achieve different hardness of

pencils. Carbon black is also used to create pencils with different darkness (6).
(1)


Question: How will using different types of graphite: H, B, and F affect how well copper
plates onto the graphite design on the plastic.

Procedure:

       We began by buffing up a small 7 x 7 cm plastic sheet with a piece of coarse

sandpaper keeping the buffing technique constant. Matt buffed the plastic using ten

strokes in each direction with equal pressure using 100-c sandpaper. We then weighed

the plastic and recorded the initial weight. Using a soft-graphite pencil, we drew a design

on the plastic card (a 5 x 5 cm design) making sure the design was bold and connected in

all places. We then attached a copper wire electrode to the plastic. We placed the plastic

on a paper towel in the fume hood and brushed silver conducting paint (Electrode #415)

on the plastic in order to connect the copper wire electrode joint to the graphite drawing.
We then re-weighed the plastic and recorded the final mass. After that we hooked up the

plating bath as shown in the picture below and added 5 mL of brightener to the solution:

Copper sulfate, 6 M sulfuric acid, 0.1 M hydrochloric acid. We attached the wire on the

plastic to the alligator clip. We started the aquarium bubbler and set the current to 0.80

amperes. We then plated for 10 minutes maintaining a constant current. When the

plating was complete we washed the plastic to remove the excess solution and weighed

the final product. We then calculated the theoretical yield and compared our

experimental yield to that. From observing the different varieties of graphite we

electroplated we analyzed the difference of different types of graphite on the

electroplating.

Results


              Figure 2 Comparison of Mass of Copper Plated to
                           Total Mass before plating

       1.2

          1

      0.8
 Mass (g)                                                            Mass before plating
       0.6                                                           Mass Cu

       0.4

       0.2

          0
                  F     B      H   F     B H      F B H          F     B   H      F     B H
                                       Test 2     Test 3                              Test 5
                      Test 1                                         Test 4

                                            Type of graphite


       This graph compares the mass differences between copper plated and total mass

before plating. The total mass before plating includes the mass of the plastic, graphite,
silver paint, and copper wire. We subtracted the mass before plating from the final mass

that we recorded to get the mass of the copper. This graph helps determine whether or

not the mass of our cathode being plated has to do with how much copper is plated onto

it. In this graph all of the masses before plating were relatively the same and the copper

plated onto them had no direct relation to their similarities in mass. In test 3 however the

mass of the copper plated onto the cathode was almost two times the amount of any of

the other tests.


                     Figure 3 Comparison of Theoretical Yield to
                               Experimental Yield of Copper

        0.35
          0.3
        0.25
 Mass (g)                                                                   Theoretical Yield of
          0.2                                                               Cu
        0.15                                                                Mass Cu

          0.1
        0.05
             0
                   F B H      FBH        FBH        FBH        F B H
                               Test 2     Test 3
                   Test 1                            Test 4     Test 5
                              Type of Graphite



        Figure 3 compares the theoretical yield of copper platted onto the plastic surface

to the experimental yield that we recorded. In tests 1 and 2 and 4 the experimental yield

was relatively close to the theoretical yield that was calculated. The calculated yield was

0.158g of copper. Another thing that all of these tests had in common was that every

single test was lower than the theoretical yield except for the H pencil used in test 2
which was only a little above the theoretical yield. Test 4 stands out the most with the

experimental yield being drastically different than the theoretical. The B pencil alone

was more than double the weight of the theoretical yield. In test 2 our B pencil graphite

was plated with 0.131g of copper, while in test 3 was plated with 0.333g of copper.

Before we did test 5 we added 5 mL of brightened which could have effected the amount

of copper plated onto the graphite which gave us a recording of experimental yield of a

higher mass than the theoretical yield with every kind of pencil graphite.

         Figure 4 Electroplated Plastic

                  Graphite F         Graphite B     Graphite H



Test 1



Test 2




Test 3



Test 4




Test 5
       Figure 4 is shows plated pieces of plastic arranged by which test they were done

during, and which type of graphite we used. The first column is all of the F graphite

tests, the second is the B, and the third is the H. The first row shows all three of each

different pencil graphite in Test 1. The second row shows all three of each different

pencil graphite in Test 2 and so on down to Test 5. The one type of pencil graphite that

always plated very well was the B pencil in the second column which always plated at

least half of the graphite surface, while the other graphite types in columns one and three

most often plated more than a tenth of the surface. Test 1 of H also plated the graphite

area almost completely. Test 1 of F also plated most of the surface, but the rest of the

tests barely plated any surface onto the plastic.

Discussion

The purpose of our research project was to determine whether or not the different types

of pencil graphite: F, B, and H, had an effect on how each different type plated copper.

As shown in Figure 3, the results were not conclusive, but further testing could be done to

achieve a more accurate result. We determined through five different electroplating tests

that F, B, and H graphite pencils plated about the same amount of copper. Figure 3

clearly shows experimental yield of copper plated was very close to theoretical yield.

However, Test 3 for all three types of graphite did not follow the theoretical trend. Test 3

showed copper masses of almost double all of the other tests in every case. The data in

Test 3 seem so off that conclusions couldn’t be drawn from the data collected. However,

the only variable that could have made a difference is that I was not there on that testing

day, so my partner may have done something different than we did together. On the
visual aspect of our plating, the B graphite pencil always plated more surface area than

any of the other pencils during that particular test. Throughout all of the tests the B

graphite pencil plated at least half of the graphite design while the others did not even

though the time and amps were kept the same for all. Although the mass of copper plated

onto each piece of plastic was relatively similar, the B graphite consistently plated more

surface area than any of the other types of graphite. The B graphite was more conductive

than the F and the H and clearly is a different kind of graphite. Further electroplating

tests could be done with copies pencils or maybe all H type pencils which have different

harnesses H, H2, H4, H6 as well as comparing real graphite which Mrs. Fruen has to that

which is put into pencils.

Annotated Bibliography

(1) Weil, Rolf, "Electroplating of Metals,” (2001) http://www.accessscience.com
Available from Access Science Date Accessed 21 April 2005.

       This article discusses the process of electroplating and some of the uses.

       Essentially a circuit is sent through a power-source, in our case an amp meter, a

       cathode, anode, and some sort of electric conducting solution. The thing being

       plated is hooked up so that negative charges can flow through it, while the anode

       is positive. The solution in which all of this is placed has to contain ions of the

       metal that need to be deposited onto the cathode. Some instances where

       electroplating is used in circuit boards, jewelry and plating in general because of

       its wear resistance and hard coating, and conductive abilities.


(2) J. Hill, Chemistry For Changing Times. MacMillian Publishing Company, New
York, (1992), : 210-211. Date Accessed 21 April 2005.
       These pages discuss electrochemical cells and describe how oxidation occurs.

       The electrode where oxidation occurs is called the anode, and reduction occurs in

       the cathode. In the example in the book there is a zinc anode which is oxidizing

       and a copper cathode which is reducing with copper ions. This example shows

       how the solution of copper sulfate conducts the current through which the power

       source is sent through, and therefore has the ability to run a light bulb.


(3) Allen J. Bard, "Electrolysis,” (2001) http://www.accessscience.com Available from
Access Science Date Accessed 21 April 2005.

       This article discusses how current travels through reactions at electrodes with an

       electrolyte. The power supply is connected to the electrolysis cells, in our case

       it’s the two copper anodes, which is immersed in a liquid that can conduct

       electricity through ion movement. This article also discusses the oxidation-

       reduction reaction occurring in the electroplating process. Reduction reactions

       occur where substances add electrons, the cathode, and oxidation reactions where

       species lose electrons, the anode. Some applications of this process are: industrial

       synthesis of chemicals, electroplating of metal, metallurgical extraction, refining

       of metals, and metal finishing. This article discusses further about the current

       which is measured in amperes which flow through the electrolysis cell, and that

       the quantity of a substance produced or consumed in an electrode reaction is

       proportional to the quantity of electricity.




(4) Chin, Barry, “Barrier and Seed Layers for Damascene Copper Metallization,” Solid
State Technology (1998)
http://search.epnet.com/login.aspx?direct=true&db=aph&an=848929 Available from
EBSCO Date Accessed 21 April 2005.

       This article discusses the benefits of electroplating over copper etching and other

       processes. The process of electroplating is used for many different purposes but

       such purposes as computer circuit boards is particularly efficient because circuit

       can be produced directly instead of etching. It discusses that copper has low

       resistivity and high electromigration resistance which are beneficial for its uses.

       Copper filling however is a much harder process in which variables must be

       controlled more carefully and technique must be flawless because of build up

       possibilities and possible gap formations to disconnect a circuit.


(5) Alvin J. Salkind, "Wet cell,” (2000) http://www.accessscience.com Available from
Access Science Date Accessed 21 April 2005.

       This article discusses the uses of wet cells in which cells such as copper would be

       places in a copper sulfate solution, and an outer cell of zinc would be placed out

       side of the copper electrode. The outer zinc shell would dilute the copper solution

       to a more suitable copper sulfate distribution. In Lalande-Chaperon cell there is a

       zinc anode and a cupric oxide cathode placed in an aqueous solution of sodium

       hydroxide as the electrolyte. The same reaction occurs in this process as does in

       our electroplating, but instead the cupric oxide cathode is converted into metallic

       copper within the sodium hydroxide, and the zinc anode reduce the hydrogen

       evolution to control the aqueous solution that the cupric oxide is reacting with.


(6) Chemical and Engineering News, “Pencils and Pencil Lead,” (2001), p.1-4,
http://pubs.acs.org/cen/whatstuff/stuff/7942sci4.html.
This article discusses what the different types of pencil graphite mean.

Specifically this article discusses what F, B, and H pencils are used for. F pencil

graphite is used for fine points. B pencil graphite is used for different blackness

of the graphite. And the H pencil graphite determines how hard the pencil

graphite is. Manufactures can change these qualities with different amounts of

clay and carbon.

				
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