Лаборатория иши №5

Determination of corrosion resistance of metals in acidic environments.

The following should be considered in determining the corrosion resistance of metals under stationary conditions.

1. 
   Metal plates should have a precise size, they should be 15-20 cm2. When measuring small-sized plates, the errors increase and the accuracy of the results decreases.
   
2. 
   For plates of the specified size, 150 ml of acid will be required. When the amount of acid is low, especially if its concentration is not large, a decrease is observed due to the interaction of the metal with the acid.
   
3. 
   In acid, the metal has a mass of 0.1000 -0.3000 gis reduced to. When the mass losses are less, the accuracy of the experimental results is reduced.
   

Required equipment and materials:

1. 
   Steel plates
   
2. 
   Laboratory glasses with a capacity of 150-200 ml, glass hanging sticks.
   
3. 
   Chloride or sulfuric acid.
   

Procedure.
Six steel plates are cleaned on sand paper, degreased and weighed on an analytical balance and hung on rods and immersed in hydrochloric or sulfuric acid solutions with concentrations of 1, 3, 5.7 n. After a few hours (2 - 4) the plates are removed from the acid and then washed in water, dilute soda solution. The water is then washed in alcohol and ethers. After drying, the plates are weighed and the corrosion rate is determined according to the following formula.

In this case m1 and m2 are the masses of the plates; S is the surface area of ​​the plate (m2);

t- time; r- corrosion rate (g / m2. h)

Sample mass (g)