Question

In tin plating of a continuous steel pipe of outer diameter (OD) 8 cm, it is required to deposit the coating only on the outer surface. Plating is carried out from an electrolyte (valence charge = 2) contained in a 10 m long tank. The speed of the pipe through the tank is 200 m/min., and the current efficiency is 100%. Find the thickness of the coating deposited if a current density of 3,500 A.m-2 is used (density of tin = 7.31 g/cc, atomic weight of tin = 118.7).

Answer 1

0.0198 mm/sec

Step-by-step explanation:

Given:

d = 8 cm

L = 10 m = 1000 cm

v = 200 m/min

E = 100%

density = 3500 A.m^-2

Using Faraday's law of electrolysis, we have:

Q = n(e) * F

Where,

Q = electric charge

F = Faraday's constant=96500Cmol

n(e) = electron charge = 2

Therefore

Q= 96500 * 2 = 193000

Let's find the area of pipe, A = πr²(L)

But radius, r =
`(d)/(2) = (4)/(2) = 4cm`

Therefore,

A = 3.142 * 4² * 1000

A = 50272

To find the thickness of the coating deposited, we have :

`= (193000 * 7.31 * 118.7 * 200)/(96500 * 50272 * 3500) = 1.98 * 10^-^3`

= 0.0198 mm/sec