New Features in Electroless Deposition of Ternary Coatings on the Base of Ni-P and Co-P

The new features in the electroless (autocatalytic) deposition, structure and properties of Ni-Cu-P, Ni-Sn-P, Ni-Zn-P, Ni-W-P, Co-W-P, and Co-Re-P as well as the quaternary coatings Ni-Sn-Cu-P, Ni-W-Re-P, and Co-Re-Ni-P established in the Institute of Physical Chemistry of the Bulgarian Academy of Sciences (IPC BAS) are reviewed. The role of disproportionation reactions of Cu(I), Sn(II) and Re(VI) during electroless deposition of Ni-Cu-P, Ni-Sn-P and Co-Re-P is considered. The data about the localization and chemical state of Zn, W and Re are presented. The influence of Cu and Sn added to high P (> 10 wt. %) Ni-P coatings on the thermal stability of their amorphous state is illustrated. A comparison of the corrosion resistance of Ni-Cu-P and Ni-Sn-P with that of Ni-P with the same quantity of phosphorus is given. The application of Ni-Cu-P in a hybrid multilayer with TiN is demonstrated.