Good morning/evening excuse me I want to ask about potential open circuit (OCP) corrosion. Prior to OCP testing, the specimens were sandblasted at different angles and distances (45⁰ angle 50 cm distance and 75⁰ 50 cm distance), then the specimens were painted and had different paint thicknesses, where the 75⁰ angle 50° distance had the highest paint thickness. Materials and time used:
1. Low carbon steel ss400
2. Corrosion medium HCL 0.5 m
3. Before testing the OCP, the specimen is immersed in HCL for 3 hours
4. OCP testing time is 600 seconds
5. International ship paint
What to ask:
1. How to read the OCP chart?
2. Why does the corrosion potential result at an angle of 45⁰ a distance of 50 cm immediately increase?
3. If the result is negative, what does it show? If positive what?
4. Can it go from negative to positive and vice versa
5. what is meant by a straight line in the figure?
thanks for the information Dr. Chaitanya Kumar Kanukula
1. for 45 and 75 I have marked
I want to ask again:
2. If the result is negative (-), what happens to the potential? and vice versa if (+) what happens?
3. Can the initial potential (-) then increase (+) and decrease again (-), what is the cause of this reaction?
note: before testing the coated OCP steel I soaked it in 0.5M HCL for 3 hours
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