Contacts to Thermoelectric Materials Obtained by Chemical and Electrochemical Deposition of Ni and Co

Chemical and electrochemical methods of obtaining thick-film nickel and cobalt contacts to thermoelectric (TE) materials based on bismuth and antimony chalcogenides have been proposed. Chemical deposition of Ni and Co films was carried out on a sublayer of these metals formed by magnetron sputtering. Electrochemical deposition was carried out on the sublayer and directly on the TE material. In both cases, a uniform homogeneous coating with a thickness from 8 to 12 µm was obtained. In the films formed by chemical deposition, the content of Ni and Co was at least 62 at%, with the phosphorus content of up to 21 at%. The electrochemically deposited films contained at least 91 at% Ni and Co. The specific resistances of the Ni and Co films obtained by electrochemical deposition were 6.78 × 10 −8 Ohm m and 7.48 × 10 −8 Ohm m, respectively. For the chemically deposited Ni and Co films, the specific resistances were 12.48 × 10 −8 Ohm m and 9.65 × 10 −8 Ohm m, respectively. For the electrochemically deposited metals, the specific contact resistance for the Ni and Co films did not exceed 2.03 × 10 −9 Ohm m 2 , while, for the chemically deposited films, this parameter was 4.76 × 10 −9 Ohm m 2 . The adhesion strength for the films on the TE materials of n - and p -types did not differ significantly. For films formed by electrochemical deposition, the adhesion strength was higher in the case of using sublayers and was at least 12 MPa, which was 12–20% higher than for the films formed by chemical deposition. The investigation results can be successfully used in the technology of efficient thermoelements.