Electrochemical behavior of Aluminum coated with different alloys by electroless deposition

Abstract

The present study investigates the electroless deposition of binary Ni-P and ternary Ni-Sn-P on aluminum substrate in alkaline bath, as well as, studying the chemical, mechanical and electrochemical properties of the binary and ternary alloys. The experimental results obtained and their interpretation is included in chapter III. Chapter III deals with electroless nickel plating from alkaline bath containing sodium hypophosphite as a reducing agent and sodium citrate as a complexing agent. Also, the optimum compositions and operating conditions for deposition of Ni-P and Ni-Sn-P deposited alloys at 85oC are shown in the following table. Chemical Name Chemical formula Concentration Nickel sulphate NiSO4.7H2O 20g/l ● Sodium hypophosphite NaH2PO2.H2O 15g/l ● Sodium citrate Na3C6H5O7.H2O 35g/l ● Lactic acid CH3CH(OH)COOH 3.7ml/l ● Ammonium sulphate (NH4)2SO4 25g/l ● Tin chloride SnCl2 0.005 to1g/l ▲ Ammonium hydroxide NH4OH pH adjust (8, 8.5 and 9) Temperature 0C 850C