Chemical Solution Deposition of Nickel and Cobalt Contacts on Catalytically Active Surfaces of Thermoelectric Materials

Abstract

The structure of contacts was determined, and a method was developed for applying them to nanostructured thermoelectric materials. Contacts were formed by the chemical solution deposition (CSD) of nickel or cobalt on catalytically active surfaces from alkali solutions using hypophosphite ions as reducing agents. The nickel and cobalt CSD films 5 to 8 µm thick form continuous uniform coatings that contain at least 82 wt % metals and 7.4 to 9.1 wt % phosphorus. The phosphorus enhances the barrier properties of the contacts. The resistivity of cobalt and nickel films was 10 × 10^–8 and 12×10^–8 Ω m, respectively. The contacts had a high adhesive strength (up to 20 MPa) and low contact resistivity (at a level of 10^–9 Ω m²) and were thermally stable up to 600 K.