A REVIEW WITH RESPECT TO ELECTROLESS Ni-P (ENP) COATINGS: FUNDAMENTALS AND PROPERTIES. PART I

Metal deposition by the electroless method (electroless) is successful to obtain coatings from aqueous solutions, it needs no current for deposition of metal ions in solution, but these are precipitated after reacting with an electron donor agent. The electroless process begins with the immersion of the substrate in the electroless bath in operating conditions (pH, T and bath formulation) properly fixed. By this method can be deposited copper (Cu), nickel (Ni), nickel-boron (Ni-B), nickel-phosphorus (Ni-P) and many compound coatings. This article, fundamental for beginners in the area is a compilation of basic principles and abundant information from reports regarding the main characteristics of the electroless Ni-P (ENP) coatings and of the compound coatings with this binary matrix. This first part contains aspects such as the kinetic of coating formation, the coating bath formulation, the applications and the surface morphology. The second part shall comprise the preparation of the surface to be covered, the anti-wear performance and the corrosion protection that offer the electroless coating.