Metal Protection Crossion

DBT 303 METALS security department ASSIGNMENT 1 1) 2) 3) What is meant by oxidation and reduction processes? What is meant by anode and cathode? salvage both half chemical reaction equations and total equations in an electrochemical electric cell that consists of Pb and Zn in their respective 1M ion solutions. 4) Write both half reaction from the total equilibrium electrochemical cell below? set what happen for each half reaction? Calculate the voltage that is generated Zn + 2HCL->ZnCl2 + H2 5) What is meant by wearing Penetration Rate, CPR? (i) (ii) gear up CPR. Give its unit. ) 7) 8) separate three (3) wearing away medium? State the difference between emf series and galvanic series that you know? What is meant by? (i) (ii) Corrosion? Corrosion rate? 9) One half of an electrochemical cell consists of a unmingled Nickel electrode in a solution of Ni2+. The other is a cadmium electrode immersed in a Cd2+ solution. (i) If the cell is a standard one, write the offhanded ov erall reaction and calculate the voltage that is generated. (ii) Compute the cell authority at 25? C if the Cd2+ and Ni2+ concentrations are 0. 5 and 10-3 M, respectively.Is the spontaneous reaction direction still the same as for the standard cell? 10) 11) Define passivity. Give an example of passivity. Briefly explain how passivity behaviour protects the admixture surface from further corrosion. 12) 13) 14) 15) State two (2) examples of metals that displays passivity behaviour. Define corroding corrosion and how does it happen? What is sally corrosion? Give an example of crevice corrosion. Where are intergranular corrosion always occur? How to prevent intergranular corrosion? 16) A piece of corroded steel plate was found in underwater ocean vessel.It was estimated that the original area of the plate was 15 in. 2 and around 2. 8 kg had corroded away during the submersion. Assuming a corrosion penetration rate of 180 mpy for this alloy in seawater, estimate the epoch of subme rsion in unit of years. The density of the steel is 7. 9 g/cm3. 17) 18) 19) 20) How does Activation Polarization occur? Explain about sacrificial anode and in what environment can be used? Explain about impress current and how does it operated? Give four (4) common methods to apply metallic finish?