The surfactant addition effect in the elaboration of electrodepositated NiP-SiC composite coatings

In this work, NiP-SiC composite coatings were prepared by electrodeposition from a plating bath containing NiSO4·6H2O; NiCl2·6H2O; H3PO3; H3PO4; Na2SO4 and SiC particles (average diameter of 600 nm) in suspension. Anionic surfactant (SDS — sodium dodecyl sulfate, CH3(CH2)11SO4Na) or cationic surfactant (CTAHS — cetyltrimethylammonium hidrogensulfate, C19H43NO4S) were also added to this suspension. The number of incorporated particles by area unit (αnp/A) was evaluated by image analysis of micrographs obtained by scanning electron microscopy (SEM). It was observed that organic additive addition influences the incorporated SiC particles rate on the metallic matrix. Addition of organic additives such as SDS or CTAHS modifies the characteristic of suspensions. Depending on particle size organic additive addition can change the number of incorporated particles in deposits during growth of the matrix. Decrease of the incorporated particle amount with the increase of particle size was verified. The selective incorporation process is associated to the presence of organic additive and it was not dependent on surfactant charge.