Study of the behavior of Moroccan coin 1/2 DH in a simulated sweat solution and 3% NACL

The copper-nickel alloy is known for its good corrosion resistance in different environments. it also has good mechanical properties. this alloy has been used for the manufacture of coins for the first time in the united kingdom in 1947. in this work,we studied the behavior of one of the most used pieces of moroccan currency (the coin of 1/2 dh type 2002) in different medium: acidic or neutral (artificial sweat,3% nacl and 3% nacl at ph = 2). this coin is composed of 75% copper and 25% nickel. the results showed by atomic absorption spectrophotometer and electrochemical measurements that the coin 1/2 dh resists in a neutral medium (artificial sweat and 3% nacl). the amounts of ni2+ and cu2+ released after seven days of the two media is: [cu2+] (sueur artificial) = 37.8 mg/l [ni2+] (sueur artificial) = 11.9 mg/l,[cu2+] (3% nacl) = 59.1 mg/l and [ni2+] (3% nacl) = 16.1 mg/l. therefore,its manipulation is not very dangerous. against,in the solution of 3% nacl at ph = 2,the quantity ni2+ and cu 2+ released is significant,[cu2+] (3% nacl) = 59.1 mg/l and [ni2+] (3% nacl) = 16.1 mg/l. furthermore,we found that the coin releases more copper than nickel in the three medium. this confirms the trend to substitute cupronickel alloy by nickel or steel nickel coated.