Introduction Corrosion is a big field with metals that can be corrode or resisting the corrode . This report about metals and how we can represent a data about the metals and from the data we can know everything about the metal . in the beginning representing definition about what we use in the laboratory. After that we jump to the sample of the experiment and what should we do before starting the experiments and what is the type of the metal and little information about it. Then showing how to connect the wires with each other and showing some pictures . After that showing the result of our calculation and represented on a figure. The data is presented in four experiments . each experiments has two figure with data, One from our calculation and the other from different group and find the reason behind the different in data with the other group , The data going to show which metal is rusting and which is not or the two can be rusting .

Definitions ocp: ocp is short for Open circuit potential which is one of the electorchimal methods that tend to measure the corrosion performance of organic coating. [1] Active: Metals that has law resistance to corrosion and oxidationNoble:Metals that has resistance to corrosion and oxidation such as (platinum). Passive : The materials are in the lower area of the oxidizing power.

Trans passive:The materials are in the high concentration of oxidizers .

Reference electrode:is used in measuring the working electrode potential of an electrochemical cell.[2] Counter electrode:is used for receiving the current that come from the work electrode and given it to the device which is the potential state.Work electrode: Is used for giving the current to the counter electrode.Potential state: Is An electronic hardware that measures and controls the voltage difference between a Working Electrode and a Reference Electrode. It measures the current flow between the Working and Counter Electrodes. The device as shown in pic(2).[3]

Sample of experiment Sample of experiment is about the metals which we are going to use is stainless steel 316 , stainless steel 202 and Ag/AgCl (silver silver chloride).

The connection of the experiment Before doing anything first, we Clean the tap water by sand paper and clean it by acetone to move oxide part . After that we begin our connection. Frist we brought the tap water and put the silver silver chloride in it , After that we brought the holder to hold the sample so it cant be move. Then we connect counter electrode and reference electrode in the silver silver chloride , Then we connected to the potential state device and in the computer . after we finish the connection we run the program which is (nova 1.6) on the computer, Then it will stop at steady state and shows all the result. Picture (1) &(2) shows whole connection. . Pic(1): the connection of the experiment

Pic(2): the potential state

Result Experiment 1 (tab water + ss202) :Experiment one is about tab water (1000 ml) + stain steel 202 . This experiment had done to show that the metal can be passive, Active, Noble or trans passive . the connection as explained before and the graph of this experiment is:

Fig(1): tab water + ss202Dissection:As shown in the graph :1- The metal is active .2- The graph stopped at steady state at (-0.0983 volt- 120 second).3- The passive region (-0.1001 to -0.099). 4- Trans passive start at -0.0995- 0cp (-0.098223) Fig(2): tab water + ss202Dissection : This is another result for the same metal and conditions. As you can see there is difference between the two graph . as shown in graph :1- The metal is active .2- The graph stopped at steady state at (-0.0987 volt- 32second).3- Trans passive start at (-0.09869 volt )4- 0cp (-0.0986938).

Experiment 2 (tab water + ss202+sea water):Experiment two is about tab water (1000 ml) + stain steel 202+ sea water (20 ml) . This experiment had done to show that the metal can be passive,active,noble or trans passive . the connection as explained before and the graph of this experiment is :

Fig(3): tab water + ss202+seawaterDissection: As shown in the graph :1- The metal is active .2- Ocp (-1.09468 volt).

Fig(4): tab water + ss202+seawater

Dissection:This another result for the same metal and conditions. As you can see there is difference between the two graph . As shown in the graph :1- The metal is active .2- The graph stopped at steady state at (-0.0859 volt- 121 second).3- The passive region (-0.0885 to -0.0863). 4- Trans passive start at -0-.0863.5- 0cp (-0.0858154 volt).

Experiment 3 (tab water + ss316):Experiment 3 is about tab water (1000ml)+ stain steel 316 . This experiment had done to show that the material can be passive,active,noble or trans passive . the connection as explained before and the graph of this experiment is:

Fig(5): tab water + ss316

Dissection:As shown in the graph :1- The metal is active .2- The graph stopped at steady state at (-1.1 volt- 120 second).3- 0cp (-0.012153 volt ) .

Fig(6): tab water + ss316Dissection: This another result for the same material and conditions. As you can see there is difference between the two graph . As shown in the graph :1- The metal is active .2- The graph stopped at steady state at (-0.0352997 volt- 114 second).3- The passive region (-0.0345 to -0.0352). 4- Trans passive start at -0.03525- 0cp (-0.0352971 volt).

Experiment 4 (tab water + ss316+ sea water):Experiment 4 is about tab water (1000 ml) + stain steel 316+sea water(20 ml) . This experiment had done to show that the material can be passive, active, noble or trans passive . the connection as explained before and the graph of this experiment is:

Fig(7): tab water + ss316+seawaterDissection : As shown in the graph:1- The metal is noble.2- No passivity.3- 0cp (0.0178837 volt) .

Fig(8): tab water + ss316+seawaterDissection : This another result for the same material and conditions. As you can see there is difference between the two graph . As shown in the graph:1- The meal is active.2- Passivity region (-0.021295)3- Trans passive region (-0.021301)4- 0cp (-0.0213008 volt) . Conclusion After taking this laboratory I know now what is ocp , Potentiostat and how it connected with the wires . Now Based on my calculation I found that stainless steel + tab water is active , stainless steel +tab water seawater is active, stainless steel +tab water is active and final experiment stainless steel+ tab water +seawater is noble . based on the other group calculation I found That stainless steel + tab water is active , stainless steel +tab water seawater is active, stainless steel +tab water is active and final experiment stainless steel+ tab water +seawater is active. I have several reasons behind that there are different calculation between the two groups . First The wires maybe not connected wright , the Potentiostat is did not run wright maybe we should tested first on metal we know there value to know that everything is wright , Or the material Ag/Agcl expired to air for a long time.

Reference [1]http://www.scientiairanica.com/PDF/Articles/00000501/mohamad%20atar.pdf [2]http://events.nace.org/library/corrosion/References/Introduction.asp[3] http://en.wikipedia.org/wiki/Potentiostat.

Dr. mohmmed abdulsalam