Comparative Study of Electroless Platinum Deposition Using Multivalent Metal Ions or Hydrazine As Reducing Agents

Abstract

Two new type electroless plating processes for deposition of continuous platinum layer are proposed and compared with known process of electroless platinum daeposition using hydrazine as reducing agent. In this study investigation of the kinetics of electroless Pt deposition, using reducing agents such as Co(II)/Co(III) and Ti(III)/Ti(IV) redox systems, is presented. The Pt layers were deposited on the copper or nickel surfaces. The morphology of Pt layers deposited using different reducing agents was investigated by means of Field Emission Scanning Electron Microscopy (FESEM). Kinetics of deposition rate of Pt was investigated by means of the Electrochemical Quartz Crystal Microgravimetry (EQCM). It was found that the deaeration of the electroless Pt plating solutions with argon, using Co(II)/Co(III) or Ti(III)/Ti(IV) redox systems as reducing agents, results in higher deposition rates of Pt. When using Co(II)/Co(III) redox system as a reducing agent, the rate of electroless deposition of Pt is ca. 0.3 µg cm-2 min-1 when using Ar-deaerated plating solution, whereas the one in non-deaerated plating solution is significantly lower, e.g. 0.02 µg cm-2 min-1. When, using the Ti(III)/Ti(IV) redox system as reducing agent, the Pt deposition rate in Ar-deaerated plating solution is higher compared with that using CoII)/Co(III) redox couple. It should be noted that the obtained Pt layers deposited on the surface of Cu using Co(II)/Co(III) or Ti(III)/Ti(IV) redox pairs as reducing agents are continuous and compact. The kinetic data of the mentioned reactions is discussed and compared with that obtained using hydrazine as reducing agent. Acknowledgment This research was funded by a Grant (No. TEC-06/2015) from the Research Council of Lithuania.